Aortic regurgitation is the backflow of blood from the aorta into the left ventricle during diastole due to incompetent closure of the aortic valve, leading to left ventricular volume overload.

Exam domain	One-glance essentials
Definition / diagnosis	Diastolic backflow from the aorta into the LV due to cusp incompetence or aortic-root/ascending-aortic disease ^[1]^[3] Acute AR is a pressure catastrophe in a non-compliant LV; chronic AR permits compensatory LV dilatation and high stroke volume ^[1]
Epidemiology / risks	Valve lesions: bicuspid valve, infective endocarditis, rheumatic disease, trauma, or degeneration ^[1]^[2] Root disease: hypertension, Marfan/other heritable aortopathy, aortic dissection, and inflammatory aortitis ^[1]^[3] Spondyloarthritis + dyspnoea + early diastolic murmur is a tested association ^[4]
Core mechanism	Chronic regurgitant volume → eccentric LV hypertrophy/dilatation → increased total stroke volume and wide pulse pressure → eventual fibrosis and LV failure ^[1] Acute large regurgitant volume enters a small, non-compliant LV → abrupt LVEDP rise → premature mitral closure, pulmonary oedema, and shock ^[1]
Clinical picture	Chronic: exertional dyspnoea, awareness of forceful heartbeat, displaced hyperdynamic apex, wide pulse pressure, and collapsing pulse ^[1]^[2] High-pitched early diastolic decrescendo murmur at the left sternal edge, louder sitting forward in expiration ^[1]^[2] Severe AR may produce an apical Austin Flint mid-diastolic murmur without organic MS ^[1]
Investigations	TTE is first line: integrate valve morphology, colour/CW Doppler, regurgitant severity, LV dimensions/LVEF, and aortic-root size ^[1]^[3] Use CMR when echo severity or LV volumes are uncertain; use CT to define root/ascending-aortic anatomy and plan intervention ^[3] In acute severe AR, urgently look for endocarditis and aortic dissection with TOE/CT as clinically appropriate—without delaying surgery in an unstable patient ^[2]^[3]
Management	Acute severe AR → emergency surgical assessment; vasodilator/inotrope support is only a bridge, and IABP is contraindicated because diastolic balloon inflation worsens regurgitation ^[1] Chronic severe AR: intervene for symptoms or asymptomatic LV dysfunction/dilatation—LVEF ≤50%, LVESD >50 mm, or LVESDi >25 mm/m² ^[3] Treat hypertension and the underlying cause; conventional TAVI is not routine for pure AR, though selected inoperable/high-risk patients may be considered at expert centres ^[1]^[3]
Complications	Progressive LV dilatation → systolic HF, pulmonary hypertension, AF/ventricular arrhythmia, and sudden death ^[1]^[2] Acute AR → flash pulmonary oedema, cardiogenic shock, myocardial ischaemia, or death ^[1] Root disease may progress to aneurysm/dissection; endocarditis may cause abscess or embolisation ^[2]^[3]
Prevention / follow-up	Tight blood-pressure control and serial echo prevent silent progression beyond the LV intervention window ^[3] Measure the aortic root/ascending aorta; inherited aortopathy and bicuspid disease need phenotype-guided surveillance and family assessment ^[3] Good dental hygiene matters, but antibiotic endocarditis prophylaxis is reserved for high-risk cardiac groups, not native AR alone ^[2]^[3]
Exam traps	Acute severe AR may have a short, soft diastolic murmur and no wide pulse pressure because aortic and LV pressures equalise rapidly ^[1] Austin Flint murmur ≠ mitral stenosis: severe AR functionally impedes anterior mitral leaflet opening ^[1] Spondyloarthritis with an early diastolic murmur points to AR, not apical pulmonary fibrosis or MS ^[4]

References

^[1] Senior notes: Ryan Ho Cardiology.pdf (pp. 160–161, aortic regurgitation); Ryan Ho Fundamentals.pdf (pp. 35–36, diastolic murmurs) ^[2] Senior notes: Maksim Medicine Notes.pdf (pp. 15, 35, 37, aortic dissection, valvular disease, and endocarditis) ^[3] Guideline: 2025 ESC/EACTS Guidelines for the management of valvular heart disease (section 7, aortic regurgitation) ^[4] Past paper: 2022 Fourth Summative MCQ.pdf (Question 51, spondyloarthritis with an early diastolic murmur)

Aortic Regurgitation (AR)

Aortic regurgitation (AR) — also called aortic incompetence or aortic insufficiency — is the retrograde flow of blood from the aorta back into the left ventricle (LV) during diastole due to failure of the aortic valve to coapt properly. Breaking down the name: "aortic" = pertaining to the aorta; "regurgitation" = backward flow (Latin re- = back, gurgitare = to flood).

The fundamental problem is a volume overload on the LV. Unlike aortic stenosis (pressure overload), AR dumps extra blood back into the ventricle with every heartbeat, forcing it to handle both the normal venous return plus the regurgitant volume.

Prevalence: Trace-to-mild AR is extremely common — detectable echocardiographically in up to 10% of the general adult population. Moderate-to-severe AR is far less common (~0.5–1%).
Sex: More common in males (approximately 3:1 M:F for significant AR), partly because bicuspid aortic valve is more common in males ^[1].
Age distribution: Depends on aetiology:
- Young adults: Rheumatic heart disease (still the most common cause in Hong Kong and Asia), congenital bicuspid aortic valve.
- Middle-aged to elderly: Degenerative (calcific) disease, aortic root dilatation from hypertension, connective tissue disorders.
In Hong Kong, rheumatic heart disease remains a significant cause of AR, though degenerative and bicuspid aetiologies are increasingly common as the population ages and rheumatic fever incidence declines ^[1]^[2].

Anatomy and Function of the Aortic Valve

The aortic valve sits at the junction of the left ventricular outflow tract (LVOT) and the ascending aorta, within the aortic root. Understanding its structure is essential because AR can arise from disease of the valve cusps or the root.

Three semilunar cusps (right coronary, left coronary, and non-coronary cusps) — named for the coronary ostia that arise from the corresponding sinuses of Valsalva above them.
Annulus: The fibrous ring to which the cusps attach; dilation of this ring → cusps cannot coapt → AR.
Sinuses of Valsalva: Three outpouchings of the aortic root behind each cusp; they create space for cusp opening and house the coronary ostia.
Sinotubular junction (STJ): The transition from the sinuses to the tubular ascending aorta; dilation here also prevents cusp coaptation.
Commissures: Where adjacent cusps meet; they are suspended at the level of the STJ.

During systole: LV pressure exceeds aortic pressure → cusps open → blood ejected into aorta.
During diastole: Aortic pressure exceeds LV pressure → cusps fall back and coapt, sealing the outflow tract → no backward leak. The coronary arteries fill primarily in diastole because the cusps are closed and diastolic aortic pressure drives blood into the coronary ostia.

Why does diastolic coronary perfusion matter in AR? In AR, diastolic aortic pressure drops (blood leaks back into the LV instead of staying in the aorta), reducing the driving pressure for coronary filling. This is a key mechanism of angina in AR.

Aetiology

AR can be broadly divided into two categories based on the mechanism: cusp (valvular) disease and aortic root/ascending aorta dilation ^[1]^[2].

Aetiology	Mechanism / Notes
Degenerative (most common overall)	Calcification and fibrosis of cusps → retraction and poor coaptation. Increasingly dominant in ageing populations ^[1].
Rheumatic heart disease (RHD)	Chronic rheumatic inflammation → fibrosis, thickening, and retraction of cusps ± commissural fusion. Often coexists with mitral valve disease. Still an important cause in Hong Kong and Asia ^[1]^[2].
Congenital bicuspid aortic valve	Present in 1–2% of the population (M > F). Two cusps instead of three → unequal mechanical stress → premature degeneration, prolapse, or associated aortopathy → AR (and/or AS). Most common congenital cause ^[1]^[2].
Infective endocarditis (IE)	Vegetation destruction, perforation, or rupture of cusps → acute or acute-on-chronic AR. Can be dramatic and rapidly progressive ^[1]^[2].
Myxomatous degeneration	Prolapse of one or more cusps (uncommon compared with mitral valve prolapse).
Ruptured sinus of Valsalva aneurysm	Congenital weakness of the sinus wall → rupture into LV or RV → sudden AR ± L-to-R shunt ^[2].
Trauma	Deceleration injury, blunt chest trauma → cusp avulsion or tear → acute AR ^[2].

When the aortic root dilates, the annulus and STJ stretch apart → the cusps can no longer meet in the middle during diastole → central regurgitant jet.

Aetiology	Mechanism / Notes
Hypertension	Chronic afterload → progressive aortic root dilation ^[1].
Connective tissue disease: Marfan syndrome, Ehlers-Danlos syndrome (EDS)	Defective fibrillin-1 (Marfan) or collagen (EDS) → cystic medial degeneration → aortic root aneurysm and AR. Marfan classically causes annuloaortic ectasia ^[1]^[2].
Aortic dissection (Type A)	Dissection flap disrupts aortic root geometry or detaches a commissure → acute severe AR — a surgical emergency ^[1]^[2].
Syphilitic aortitis	Tertiary syphilis → vasa vasorum obliterative endarteritis → medial necrosis → ascending aortic dilation → AR. Now rare but historically important ^[1]^[2].
Inflammatory aortitis: Ankylosing spondylitis (AS), Takayasu arteritis, Giant Cell Arteritis (GCA)	Chronic aortitis → fibrosis and dilation of aortic root ^[1]^[2]^[3].
Osteogenesis imperfecta	Defective type I collagen → aortic root fragility and dilation.
Idiopathic aortic root dilation	Age-related dilation of the ascending aorta, particularly in hypertensive elderly patients.

Acute vs. Chronic AR — Know the Causes

Students commonly forget to distinguish acute from chronic causes:

Acute AR: Aortic dissection (Type A), infective endocarditis, trauma, ruptured sinus of Valsalva. These are emergencies!
Chronic AR: Degenerative, RHD, bicuspid AV, Marfan, HTN, syphilis. The clinical picture is dramatically different because in acute AR the LV has no time to dilate and compensate.

Pathophysiology

This is the crux of understanding AR. Every clinical feature flows from the pathophysiology.

Volume overload: During diastole, blood leaks back from the aorta into the LV. The LV must now handle normal venous return (preload) PLUS the regurgitant volume.
Eccentric LV hypertrophy (dilation): To accommodate the increased end-diastolic volume (EDV), the LV dilates. New sarcomeres are laid down in series (lengthening myocytes) → eccentric hypertrophy. This is in contrast to aortic stenosis, where concentric hypertrophy occurs (sarcomeres in parallel).
Increased stroke volume (SV): By the Frank-Starling mechanism, the dilated LV ejects a much larger total SV (up to 2–3× normal ^[2]) to maintain forward cardiac output despite the regurgitant fraction being "wasted."
LV EDV is increased but LV EDP (end-diastolic pressure) remains relatively normal initially — the LV is compliant because it has had time to remodel ^[2].
Widened pulse pressure: The large total SV raises systolic BP, while the regurgitant leak lowers diastolic BP → characteristic wide pulse pressure → all the eponymous peripheral signs (Corrigan's, de Musset's, Quincke's, etc.) ^[1]^[2].
The "largest heart in cardiology": Chronic severe AR produces the most dilated LV of any valvular lesion (the so-called cor bovinum — "ox heart").

Why is the patient asymptomatic for so long? Because the dilated, compliant LV maintains a normal forward cardiac output and normal filling pressures for years — even decades. Asymptomatic patients with severe AR develop symptoms or LV dysfunction at only ~5% per year ^[2].

Failing compliance: Eventually, the LV can no longer dilate without raising filling pressures. LV EDP rises → transmitted backward → pulmonary congestion → dyspnoea.
Reduced forward cardiac output: The LV begins to fail → ↓CO → fatigue, exercise intolerance.
Further decline is rapid: Once symptomatic or once LVEF falls, the mortality rate is 10–20% per year without intervention ^[2].

AR causes angina through two simultaneous mechanisms ^[1]^[2]:

Mechanism	Explanation
↓ Coronary perfusion pressure	Diastolic BP is low (blood leaks back into LV rather than staying in aorta to perfuse coronaries). Coronary perfusion pressure ≈ diastolic aortic pressure − LV end-diastolic pressure; both are working against you in AR.
↑ Myocardial oxygen demand	The dilated, hypertrophied LV has a greater muscle mass and increased wall stress (LaPlace's law: wall stress ∝ pressure × radius / wall thickness), so it needs more O₂.

Angina in AR is characteristically worse at night ^[1]. Why? During sleep, heart rate drops → longer diastole → more time for regurgitation per beat → more volume overload, lower diastolic BP, and worse coronary perfusion.

In acute AR (e.g., aortic dissection, IE, trauma), the LV is of normal size and compliance. A sudden large regurgitant volume floods a non-dilated, non-compliant LV → dramatic rise in LV end-diastolic pressure → immediately transmitted to the pulmonary veins → acute pulmonary oedema.

Key differences from chronic AR:

Feature	Chronic AR	Acute AR
LV size	Massively dilated	Normal
LV compliance	Increased (compensated)	Normal (non-compliant)
LVEDP	Normal → late ↑	Acutely very high
SV	↑↑	Not increased (cannot dilate)
Pulse pressure	Wide (bounding pulse)	May be near normal or only mildly wide
Clinical picture	Asymptomatic → gradual HF	Acute pulmonary oedema — surgical emergency ^[2]
Peripheral AR signs	Present	Absent or minimal ("classical signs may be absent" ^[2])
Mitral valve	Normal opening	Early (premature) MV closure — LVEDP exceeds LA pressure before atrial systole even starts ^[2]

Acute AR is a Surgical Emergency

If a patient presents with acute pulmonary oedema and a new early diastolic murmur — think acute AR (dissection, IE, trauma). The classic peripheral signs of chronic AR (bounding pulse, wide pulse pressure) will be absent because the LV has not had time to dilate. This is one of the most commonly missed diagnoses. Urgent echocardiography and likely urgent surgery are needed.

Classification

Acute AR: Sudden onset, non-dilated LV, presents as acute pulmonary oedema / cardiogenic shock.
Chronic AR: Gradual onset, compensatory LV dilation, long asymptomatic phase before decompensation.

Type 1 — Normal cusp motion, but defective coaptation due to root/annular dilation: e.g., Marfan, HTN, aortitis.
Type 2 — Cusp prolapse (excessive motion): e.g., bicuspid AV with prolapsing raphe, myxomatous degeneration, IE with flail cusp.
Type 3 — Cusp restriction (reduced motion): e.g., rheumatic fibrosis/retraction, calcific degeneration.

Parameter	Mild	Moderate	Severe
Jet width / LVOT width	< 25%	25–64%	≥ 65%
Vena contracta (mm)	< 3	3–6	> 6
Regurgitant volume (mL/beat)	< 30	30–59	≥ 60
Regurgitant fraction (%)	< 30	30–49	≥ 50
ERO (cm²)	< 0.10	0.10–0.29	≥ 0.30
Pressure half-time (ms)	> 500	200–500	< 200 (rapid equalization)
LV size	Normal	Normal or dilated	Usually dilated

ERO = effective regurgitant orifice

Clinical Features

Symptoms

Every symptom links back to the pathophysiology outlined above.

Symptom	Pathophysiological Basis
Awareness of heartbeat / palpitations	↑SV → hyperdynamic circulation → patient feels forceful, bounding heartbeats, especially when lying on the left side (LV closer to chest wall) ^[2].
Generally asymptomatic	Compensatory LV dilation maintains forward CO and normal filling pressures for years.

Symptom	Pathophysiological Basis
Exertional dyspnoea (SOB) ^[1]	↑LVEDP → pulmonary venous congestion → interstitial/alveolar oedema → ↓gas exchange → breathlessness.
Fatigue ^[1]	↓ forward CO → inadequate tissue perfusion → fatigue and exercise intolerance.
Orthopnoea, PND	Progressive LV failure → pulmonary congestion worsened by recumbency (↑venous return).
Chest pain (angina) ^[1]	Dual mechanism: (1) ↓diastolic BP → ↓coronary perfusion pressure; (2) LVH + dilation → ↑myocardial O₂ demand. Worse at night due to ↓HR → longer diastole → more regurgitation ^[1].
Syncope	↓ forward CO (decompensated) → inadequate cerebral perfusion, especially on exertion. Less common than in AS ^[2].

Symptom	Pathophysiological Basis
Acute severe dyspnoea / respiratory distress	Non-dilated LV → sudden ↑LVEDP → acute pulmonary oedema ^[2].
Chest pain	May be from the underlying cause (e.g., aortic dissection — tearing, radiating to back) or from acute myocardial ischaemia (sudden drop in diastolic perfusion).
Collapse / cardiogenic shock	Sudden ↓forward CO + acute LV failure → hypotension, tachycardia, altered consciousness.

Signs

The famous eponymous signs of AR are all consequences of the wide pulse pressure (high SV raises systolic BP, regurgitant leak drops diastolic BP). They are present in chronic AR but may be absent in acute AR ^[2].

Sign	Description	Mechanism
Wide pulse pressure	> 50 mmHg; SBP elevated, DBP low (sometimes < 50 mmHg)	↑SV → ↑SBP; diastolic leak → ↓DBP ^[1]^[2].
Collapsing (water-hammer) pulse	Rapidly rising, bounding pulse that collapses quickly; best felt by lifting the patient's arm above the heart	Rapid run-off of blood back into LV in diastole → abrupt drop in arterial pressure after systole ^[2].
Corrigan's sign	Visible carotid pulsation	Exaggerated SV → forceful systolic distension of carotid arteries ^[1].
De Musset's sign	Head bobbing with each heartbeat	↑SV → transfer of momentum to head/neck ^[2].
Quincke's pulse (sign)	Capillary pulsation in fingertips or nail beds (alternate flushing and blanching)	Wide pulse pressure transmitted to capillary bed ^[2].
Traube's sign	"Pistol-shot" systolic and diastolic sounds heard over large arteries (e.g., femoral)	Rapid systolic distension and diastolic collapse of large arteries ^[2].
Duroziez sign	To-and-fro murmur over the femoral artery when gentle pressure applied with stethoscope	Forward systolic flow + backward diastolic flow in femoral artery due to regurgitant leak ^[2].
Pulsus bisferiens	A double-peaked pulse in the carotid	Observed in mixed aortic valve lesions (combined AS + AR) — the percussion wave and tidal wave become palpable ^[1].
Lighthouse sign (Landolfi sign)	Alternating constriction and dilation of the pupil with each heartbeat	Wide pulse pressure transmitted to iris vasculature (rare, exam trivia).
Mueller's sign	Visible pulsation of the uvula	Wide pulse pressure transmitted to palatal vessels.
Hill's sign	Popliteal SBP exceeds brachial SBP by > 20 mmHg (normally ≤ 10 mmHg difference)	Augmented pulse pressure in lower limbs. A difference > 60 mmHg suggests severe AR.

Eponymous Signs — Why So Many?

AR was recognised clinically long before echocardiography existed, so clinicians devised many bedside manoeuvres to assess severity. You don't need to memorise every one, but know the mechanism: all are manifestations of widened pulse pressure from a high SV and low diastolic pressure. For exams, the key ones are Corrigan's sign, collapsing pulse, de Musset's, Quincke's, Traube's, and Duroziez's.

Sign	Description	Mechanism
Displaced, thrusting (volume-loaded) apex beat	Apex displaced downward and laterally, often to the anterior axillary line in severe cases	LV dilation (eccentric hypertrophy) — the LV enlarges to accommodate the increased EDV ^[2].
Hyperdynamic precordium	Vigorous cardiac impulse	↑SV

Finding	Description	Mechanism
Early diastolic murmur (EDM)	High-pitched, decrescendo, blowing murmur beginning immediately after A₂ (S2)	Blood regurgitates from aorta → LV during diastole; loudest at the start (when aortic-LV pressure gradient is maximal) and fades as pressures equalize ^[2]^[4].
Best heard at the left sternal border (tricuspid area) ^[2]	Patient sitting up, leaning forward, in full expiration	Brings the aortic root closer to the chest wall; expiration reduces lung volume between stethoscope and heart ^[4].
Ejection systolic murmur (ESM)	Often present, can be loud	↑SV causes relative functional aortic stenosis even without structural stenosis (flow murmur) ^[2]. This can be confused with true AS in mixed lesions.
Austin-Flint murmur	Mid-diastolic, low-pitched, rumbling murmur at the apex, WITHOUT pre-systolic accentuation	The AR regurgitant jet impinges on the anterior leaflet of the mitral valve → partially closes it → creates functional mitral stenosis ^[1]^[2]^[4]. Distinguishing from true MS: no opening snap, no pre-systolic accentuation (the jet holds the leaflet partially closed throughout diastole).
S₃ (third heart sound)	Low-pitched sound in early diastole	Rapid LV filling into a volume-overloaded, dilated LV — indicates decompensation in chronic AR ^[1].
Soft or absent A₂	Diminished aortic closure sound	If cusps are destroyed/calcified, they cannot produce a crisp closure sound.

These are high-yield for exams — they tell you the AR is haemodynamically significant:

Sign of Severity	Explanation
Wide pulse pressure	The wider the pulse pressure, the more regurgitant volume ^[1].
Long duration of diastolic murmur (may be holodiastolic)	In mild AR, the murmur is short (early diastolic). In severe AR, the pressure gradient persists throughout diastole → the murmur occupies more of diastole ^[1]. Paradoxically, in very severe acute AR, the murmur may become shorter and softer (rapid pressure equalization).
S₃	Indicates volume overload and LV decompensation ^[1].
Austin-Flint murmur	Indicates a large regurgitant jet impacting the mitral valve → severe AR ^[1].
Pulmonary hypertension	Elevated LVEDP → pulmonary venous hypertension → pulmonary arterial hypertension ^[1].
Pulmonary congestion (CXR findings)	Reflects elevated filling pressures ^[1].
Displaced apex	Greater LV dilation = more severe volume overload.
Short pressure half-time on echo (< 200 ms)	Rapid equalization of aortic and LV diastolic pressures → severe AR.
Diastolic flow reversal in the descending aorta	Holodiastolic flow reversal on Doppler indicates severe AR.

The Paradox of Acute Severe AR Murmur

In acute severe AR, the early diastolic murmur may actually be soft and short — not loud and long. Why? Because LVEDP rises so quickly in the non-compliant LV that the aortic-LV pressure gradient equalizes rapidly → the murmur is cut short. Don't be falsely reassured by a quiet murmur in an acutely unwell patient with pulmonary oedema!

Finding	Suggests
Fever + new murmur + splinter haemorrhages / Janeway lesions / Osler nodes	Infective endocarditis
Marfanoid habitus (tall, arachnodactyly, pectus excavatum, lens subluxation)	Marfan syndrome
BP asymmetry, tearing chest/back pain, radial-radial delay	Aortic dissection
Ankylosing spondylitis features (bamboo spine, ↓spinal mobility, question-mark posture)	Spondyloarthropathy-related aortitis
Argyll-Robertson pupils (accommodation but not to light)	Tertiary syphilis

High Yield Summary

Definition: Retrograde diastolic flow from aorta → LV due to aortic valve incompetence.

Key Aetiologies (Think: Valve vs. Root):

Valve: Degenerative (MC overall), RHD (MC in young/HK), bicuspid AV, IE, trauma, ruptured sinus of Valsalva.
Root dilation: HTN, Marfan/EDS, aortic dissection, syphilitic aortitis, spondyloarthropathy.
Acute AR: Dissection (Type A), IE, trauma — surgical emergencies!

Pathophysiology — Chronic:

Volume overload → eccentric LV dilation → ↑SV (2–3×) → wide pulse pressure → all peripheral signs.
LVEDP initially normal (compensated) → eventually rises → pulmonary congestion → LV failure.
Angina: ↓DBP (↓coronary perfusion) + ↑O₂ demand (LVH), worse at night (↓HR → longer diastole).

Pathophysiology — Acute:

Non-dilated LV → sudden ↑LVEDP → acute pulmonary oedema. No wide pulse pressure. No peripheral signs. Emergency!

Signs of Severity: Wide PP, long EDM (holodiastolic), S₃, Austin-Flint murmur, pulmonary HTN, pulmonary congestion, displaced apex.

Eponymous Signs: All due to wide pulse pressure — Corrigan's (visible carotid pulsation), de Musset's (head bobbing), Quincke's (nail-bed capillary pulsation), Traube's (pistol shots over arteries), Duroziez's (to-and-fro femoral murmur).

Austin-Flint murmur: AR jet impinges on anterior mitral leaflet → functional MS → mid-diastolic rumble at apex WITHOUT pre-systolic accentuation.

Pulsus bisferiens: Double-peaked pulse — mixed aortic valve disease (AS + AR).

Active Recall - Aortic Regurgitation (Definition to Clinical Features)

^[1] Senior notes: Maksim Medicine Notes.pdf (p35, p37, p15 — Valvular heart disease, Infective endocarditis, Aortic dissection sections) ^[2] Senior notes: Ryan Ho Cardiology.pdf (p155–160, p221–222 — Aortic Valve Diseases, Aortic Regurgitation, Aortic Dissection and Aneurysms sections) ^[3] Senior notes: Ryan Ho Rheumatology.pdf (p95–96 — Giant Cell Arteritis, Takayasu Arteritis sections) ^[4] Senior notes: Ryan Ho Fundamentals.pdf (p36 — Diastolic Murmurs section)

Differential Diagnosis of Aortic Regurgitation

When you encounter a patient with features suggestive of AR — an early diastolic murmur, a collapsing pulse, wide pulse pressure, or signs of left ventricular volume overload — you need to think systematically. The differential diagnosis operates on two levels:

What else could mimic the clinical presentation of AR? (i.e., the DDx of the early diastolic murmur and the DDx of the wide pulse pressure / bounding pulse)
What is the underlying cause of the AR itself? (i.e., the aetiological DDx — already covered in detail in the prior section, but important to revisit here as a clinical reasoning exercise)

Let me walk you through both levels from first principles.

The early diastolic murmur (EDM) is the cardinal auscultatory sign of AR. But it is not pathognomonic — other conditions can produce a similar-sounding murmur ^[4].

Condition	Murmur Characteristics	How to Differentiate from AR
Pulmonary regurgitation (PR) — Graham-Steell murmur	High-pitched, early diastolic, decrescendo murmur at the left upper sternal border (pulmonic area)	Increases with inspiration (right-sided murmur → increased venous return during inspiration augments it). AR is accentuated by leaning forward with exhalation ^[4]. PR is typically associated with loud P₂ (indicating pulmonary hypertension) and is most commonly secondary to severe pulmonary HTN from mitral stenosis or other causes. No wide pulse pressure or peripheral AR signs.
Combined AS/AR	Both an ejection systolic murmur (ESM) and an early diastolic murmur; murmur interrupted by S₂	Pulsus bisferiens (double-peaked carotid pulse) ^[1]. The pulse character depends on the dominant lesion — if AR dominant → collapsing; if AS dominant → slow-rising. Mixed features on echo ^[4].

Why does the Graham-Steell murmur increase with inspiration? Inspiration increases negative intrathoracic pressure → increases venous return to the right heart → increases the volume of blood regurgitating through the incompetent pulmonary valve. This is the same principle that makes all right-sided murmurs louder on inspiration.

Why does the AR murmur increase when leaning forward in expiration? Leaning forward brings the aortic root closer to the chest wall. Expiration reduces the air-filled lung tissue between the heart and stethoscope, improving sound transmission. Additionally, expiration slightly increases intrathoracic pressure, increasing aortic-LV gradient in early diastole ^[4].

The wide pulse pressure and bounding/collapsing pulse of chronic AR are distinctive, but other conditions can produce a similar haemodynamic picture. The key concept: any condition that either (a) markedly increases stroke volume, or (b) causes rapid diastolic arterial run-off, can mimic the peripheral signs of AR.

Condition	Mechanism of Wide Pulse Pressure	Key Distinguishing Features
Patent ductus arteriosus (PDA)	Continuous L→R shunt from aorta to pulmonary artery → aortic run-off in both systole and diastole → low diastolic BP + high SV	Continuous "machinery" murmur (crescendo-decrescendo through S₂, not interrupted by S₂) ^[4]. Left parasternal heave (RV volume overload from pulmonary overcirculation). Collapsing pulse present. Usually in paediatric patients or young adults with unrepaired CHD.
High-output states	↑↑ cardiac output → ↑SV → ↑systolic BP with relatively lower diastolic BP due to ↓SVR	No early diastolic murmur. Look for the underlying cause: anaemia (pallor, tachycardia), thyrotoxicosis (tremor, weight loss, heat intolerance, goitre, lid lag) ^[5], Paget's disease (bone pain, skull enlargement, ↑ALP), pregnancy, arteriovenous fistula (thrill/bruit over fistula), beriberi (wet — thiamine deficiency), severe liver disease (spider naevi, palmar erythema).
Aortic dissection (Type A) with acute AR	Dissection flap disrupts aortic root → acute AR. But also: tearing chest/back pain, asymmetric BP/pulses, widened mediastinum on CXR	Sudden onset, tearing pain radiating to back ^[1]^[6]. May have signs of malperfusion (stroke, limb ischaemia, mesenteric ischaemia). Acute AR signs — pulmonary oedema dominant, peripheral AR signs often absent. CT aortogram diagnostic.
Significant arteriovenous fistula	Continuous shunt from arterial to venous system → rapid arterial run-off → low diastolic BP, high SV	Palpable thrill / continuous bruit at fistula site (e.g., dialysis AV fistula, traumatic AV fistula). Branham's sign: compression of the fistula → reflex bradycardia (as peripheral resistance and BP are restored).

This is a classic exam question. The Austin-Flint murmur of AR can closely mimic the mid-diastolic rumble of mitral stenosis (MS) ^[1]^[2]^[4].

Feature	Austin-Flint Murmur (Functional MS from AR)	True Mitral Stenosis
Mechanism	AR jet impinges on anterior mitral leaflet → partial closure → functional obstruction to LA outflow → turbulent flow ^[1]^[2]^[4]	Organic fibrosis/calcification of mitral valve → fixed obstruction to LA emptying
Opening snap	Absent	Present (snap of rigid mitral leaflets opening)
Pre-systolic accentuation	Absent (the AR jet holds the leaflet partially closed throughout diastole, preventing the normal atrial kick from augmenting flow) ^[2]^[4]	Present in sinus rhythm (atrial contraction forces blood through stenosed valve → crescendo before S₁)
S₁	Soft (MV closing early due to elevated LVEDP)	Loud (rigid MV leaflets slam shut from a widely open position)
Peripheral signs	Wide pulse pressure, bounding pulse, peripheral AR signs	No wide pulse pressure; may have malar flush, AF
Associated murmur	Early diastolic murmur of AR	No EDM (unless coexistent AR)
Echo	Structurally normal MV; may see MV fluttering from the AR jet	Thickened, calcified, restricted MV leaflets; ↑transmitral gradient

Austin-Flint vs. True MS — The Two Absent Features

If you hear a mid-diastolic rumble at the apex in a patient with AR, think Austin-Flint. The two features that are absent compared with true MS are: (1) no opening snap and (2) no pre-systolic accentuation. Also look for an early diastolic murmur — if present, the rumble is likely Austin-Flint secondary to AR rather than primary MS.

Patients with AR can present with angina, and you need to consider whether the chest pain is from the AR itself or from a coexistent or alternative pathology ^[1]^[2]^[5].

Diagnosis	Key Features / Mechanism
Angina from AR	↓ diastolic BP → ↓ coronary perfusion; LVH → ↑ O₂ demand. Characteristically worse at night (↓HR → longer diastole → more regurgitation) ^[1]. May occur without epicardial coronary disease.
Coronary artery disease (CAD)	Coexistent atherosclerotic CAD is common, especially in older patients with degenerative AR. Classical effort-related angina, risk factors for atherosclerosis. Coronary angiography may be needed pre-operatively ^[1].
Aortic dissection	Type A dissection can cause acute AR + chest/back pain. Tearing, sudden onset, radiating to back. Asymmetric BP/pulses ^[1]^[6]. This is the critical "must-not-miss" diagnosis.
Infective endocarditis	AR valve is predisposed to IE. Fever, new/changing murmur, constitutional symptoms, peripheral stigmata (Janeway lesions, Osler nodes, splinter haemorrhages). Can cause acute worsening of AR via cusp destruction ^[1]^[2].
Pericarditis	Sharp, pleuritic, positional chest pain (better sitting forward). Pericardial rub. Can coexist with aortic root pathology in connective tissue diseases.

When a patient with AR presents with breathlessness, consider whether it is from progressive AR decompensation or an alternative/co-existing cause ^[1]^[6].

Diagnosis	Distinguishing Features
Decompensated AR (LV failure)	Progressive exertional dyspnoea, orthopnoea, PND. Echo shows severe AR with ↑LVEDP, ↓LVEF, LV dilation.
Mitral valve disease (coexistent)	RHD often affects both aortic and mitral valves. Look for mid-diastolic rumble (MS) or pansystolic murmur (MR). Echo confirms.
Pulmonary disease (COPD/asthma)	Wheeze, productive cough, smoking history, obstructive pattern on spirometry.
Pulmonary embolism	Sudden onset dyspnoea, pleuritic pain, tachycardia, risk factors (immobility, DVT).
Anaemia	Can exacerbate symptoms of AR (↑demand state). Pallor, fatigue, ↑HR. Check CBC.

When you have confirmed AR (by echo), you then need to determine the cause. This is critical because management differs (e.g., urgent surgery for dissection vs. medical management for mild degenerative AR).

Clinical clues to the aetiology:

Clue	Points Towards
Young patient, HK, with mitral valve disease	Rheumatic heart disease ^[1]^[2]
Male, systolic murmur also present, dilated ascending aorta	Bicuspid aortic valve
Marfanoid habitus (tall, arachnodactyly, lens subluxation)	Marfan syndrome ^[2]
Bamboo spine, reduced spinal mobility, enthesitis, HLA-B27+	Ankylosing spondylitis (SpA) — remember the "4 As": Apical fibrosis, Anterior uveitis, Aortic regurgitation, Achilles tendinitis ^[7]
Fever, new murmur, embolic phenomena	Infective endocarditis ^[1]
Sudden onset, tearing chest pain, asymmetric pulses	Aortic dissection ^[1]^[6]
Argyll-Robertson pupil, ascending aortic calcification	Syphilitic aortitis (tertiary syphilis)
Elderly, hypertension, atherosclerotic risk factors	Degenerative + hypertensive root dilation
Constitutional symptoms, ↓pulses, bruits, Asian female of reproductive age	Takayasu arteritis ^[3]
Elderly woman, temporal headache, jaw claudication, very high ESR	Giant cell arteritis (with aortitis) ^[3]

The 4 As of Ankylosing Spondylitis

A favourite exam mnemonic: Apical fibrosis, Anterior uveitis, Aortic regurgitation, Achilles tendinitis ^[7]. If you see a young male with chronic back pain and an early diastolic murmur — think ankylosing spondylitis with associated aortitis.

High Yield Summary

DDx of Early Diastolic Murmur: AR vs. PR (Graham-Steell murmur). AR louder leaning forward in expiration; PR louder in inspiration with loud P₂.

DDx of Wide Pulse Pressure/Bounding Pulse: AR, PDA (continuous machinery murmur), high-output states (anaemia, thyrotoxicosis, Paget's, AV fistula, pregnancy), aortic dissection with AR.

Austin-Flint vs. True MS: Austin-Flint has NO opening snap and NO pre-systolic accentuation. Always look for the EDM of AR.

DDx of Chest Pain in AR: AR-related angina (worse at night), coexistent CAD, aortic dissection (must-not-miss), IE, pericarditis.

Aetiological DDx clues: RHD (young, HK, mitral involvement), bicuspid AV (male, ESM also), Marfan (habitus), AS/SpA (4 As), IE (fever, embolic), dissection (tearing pain, asymmetric pulses), syphilis (Argyll-Robertson pupil).

Always ask: Is this acute or chronic AR? Acute AR = no wide PP, APO, emergency. Think dissection, IE, trauma.

Active Recall - DDx of Aortic Regurgitation

References

^[1] Senior notes: Maksim Medicine Notes.pdf (p5, p15, p18, p35 — Clinical approach, Aortic dissection, Heart failure, Valvular heart disease sections) ^[2] Senior notes: Ryan Ho Cardiology.pdf (p54, p155, p158, p160 — Chest Pain, MR, AS, AR sections) ^[3] Senior notes: Ryan Ho Rheumatology.pdf (p95–96 — Giant Cell Arteritis, Takayasu Arteritis sections) ^[4] Senior notes: Ryan Ho Fundamentals.pdf (p36 — Diastolic Murmurs section) ^[5] Senior notes: Ryan Ho Endocrine.pdf (p111 — Acromegaly section, re: high-output states) ^[6] Senior notes: Maksim Medicine Notes.pdf (p15 — Aortic dissection section) ^[7] Senior notes: Ryan Ho Rheumatology.pdf (p57, p60 — Spondyloarthritis, Ankylosing spondylitis sections)

Diagnostic Criteria, Algorithm and Investigations for Aortic Regurgitation

Unlike conditions such as infective endocarditis (Duke criteria) or rheumatic fever (Jones criteria), AR does not have a formal set of diagnostic criteria with sensitivity/specificity scores. Instead, the diagnosis rests on:

Clinical suspicion — history, examination (early diastolic murmur, wide pulse pressure, peripheral signs).
Echocardiographic confirmation — this is the gold standard. Echo tells you: (a) AR is present, (b) its severity (mild/moderate/severe), (c) the mechanism (cusp vs. root), (d) the impact on the LV (size, function), and (e) the aetiology.
Additional investigations — to determine the cause, assess the aorta, plan for surgery, and evaluate complications.

The key clinical question is not just "is there AR?" but "is the AR severe enough to warrant intervention, and what is the cause?"

Echocardiographic Grading of AR Severity

This is the closest thing to "diagnostic criteria" for AR — the echocardiographic parameters used to grade severity per the 2020/2021 ACC/AHA and ESC 2021 guidelines.

Parameter	Mild	Moderate	Severe
Colour Doppler jet width / LVOT diameter	< 25%	25–64%	≥ 65%
Vena contracta width (narrowest portion of the jet, mm)	< 3	3–6	> 6
Diastolic flow reversal in descending aorta	Brief, early diastolic	Intermediate	Holodiastolic (pan-diastolic reversal indicates severe AR — blood flowing backward throughout all of diastole)
Pressure half-time (ms)	> 500	200–500	< 200 (rapid equalization of aortic and LV pressures → severe leak)

Why does pressure half-time shorten in severe AR? Pressure half-time (PHT) measures how quickly the aortic-LV diastolic pressure gradient decays. In severe AR, there is a large regurgitant orifice → blood pours back into the LV rapidly → LV pressure rises quickly → the gradient between aorta and LV disappears fast → short PHT (< 200 ms). In mild AR, only a trickle leaks back → the gradient is maintained for longer → long PHT (> 500 ms).

Parameter	Mild	Moderate	Severe
Regurgitant volume (mL/beat)	< 30	30–59	≥ 60
Regurgitant fraction (%)	< 30	30–49	≥ 50
Effective regurgitant orifice area (ERO, cm²)	< 0.10	0.10–0.29	≥ 0.30

What is ERO? The effective regurgitant orifice area is the cross-sectional area of the "hole" through which blood regurgitates. It is calculated using the PISA (proximal isovelocity surface area) method on Doppler echocardiography. A larger ERO = a bigger leak = more severe AR.

Parameter	Implication
LV end-diastolic diameter (LVEDD)	> 75 mm suggests chronic severe volume overload ^[1]
LV end-systolic diameter (LVESD)	> 55 mm → LV failing to compensate (indication for surgery even if asymptomatic) ^[1]
LVEF	< 50% indicates LV systolic dysfunction — another surgical trigger ^[1]

Integrated Approach to Severity Grading

No single echo parameter is sufficient. You must integrate multiple parameters — jet width, vena contracta, PHT, regurgitant volume/fraction, ERO, flow reversal, and LV dimensions. If parameters are discordant, err on the side of more detailed quantitative assessment (volumetric/PISA methods) and consider CMR.

The diagnostic approach to AR proceeds in a structured manner: clinical suspicion → echocardiographic confirmation and grading → aetiological workup → assessment for surgical triggers.

Investigation Modalities: Detailed Breakdown

ECG: LVH ± strain ^[1]^[2]

Finding	Explanation (From First Principles)
LV hypertrophy (LVH) voltage criteria	Chronic volume overload → eccentric LV dilation + hypertrophy → greater LV muscle mass generates higher voltages. Sokolow-Lyon criteria: S in V1 + R in V5/V6 ≥ 35 mm. Cornell criteria: R in aVL + S in V3 > 28 mm (M) or > 20 mm (F).
LV strain pattern	ST depression + T-wave inversion in lateral leads (I, aVL, V5, V6). Reflects subendocardial ischaemia from increased wall stress and oxygen demand in the hypertrophied LV.
Left axis deviation	LV enlargement shifts the mean electrical axis leftward.
Conduction abnormalities	In advanced cases, LBBB may develop if the hypertrophied septum impinges on the left bundle branch, or if the aortic root pathology (e.g., calcification in bicuspid AV) extends into the conduction system.
Initially normal	In early/compensated AR, the ECG may be entirely normal ^[2]. Do not be falsely reassured by a normal ECG in a patient with clinical AR.

The ECG is not diagnostic for AR — it shows the consequences of AR on the LV. It is a baseline investigation that provides supporting evidence and helps exclude other pathology (e.g., AF, ischaemia).

CXR: cardiomegaly ^[1], dilated aortic arch ^[2]

Finding	Explanation
Cardiomegaly	LV dilation → enlarged cardiac silhouette with cardiothoracic ratio > 0.5. The apex is displaced downward and to the left, giving the classic "boot-shaped" heart (LV configuration). ^[1]
Dilated ascending aorta / aortic arch	If the AR is due to aortic root dilation (Marfan, HTN, etc.), the ascending aorta will be widened. Even in cusp disease, the chronically elevated SV can progressively dilate the ascending aorta. ^[2]
Pulmonary congestion	In decompensated AR: upper lobe pulmonary venous distension ("cephalization"), Kerley B lines (interstitial oedema), perihilar haziness (alveolar oedema), pleural effusions. Reflects elevated LVEDP transmitted backward. ^[1]
Aortic valve calcification	May be visible on a well-penetrated lateral CXR in degenerative or bicuspid AV disease.

The mid-portion of the ascending aorta is difficult to visualise by echocardiography ^[1] — this is why CXR (and more importantly CT) is essential for assessing aortic root and ascending aortic dimensions when root dilation is the mechanism of AR.

3. Echocardiography (The Gold Standard)

ECHO ^[1] — Transthoracic echocardiography (TTE) is the cornerstone investigation for AR. It answers three fundamental questions: (1) Is there AR, and how severe is it? (2) What is the mechanism? (3) What is the impact on the LV?

Modality	What It Shows	Key Findings
2D Echo	Valve morphology, cusp number, cusp motion, vegetations, flail leaflet, root dimensions	Bicuspid valve (two cusps with raphe), thickened/retracted cusps (RHD), vegetations (IE), aortic root dilation
Colour-flow Doppler	Regurgitant jet visualization	Jet width relative to LVOT — severe if ≥ 65% of LVOT width. Central jet (root dilation) vs. eccentric jet (cusp prolapse/perforation).
Continuous-wave Doppler	Pressure half-time, signal density	PHT < 200 ms = severe (rapid equalization). Dense CW Doppler signal = severe.
Pulsed-wave Doppler	Diastolic flow reversal in descending aorta	Holodiastolic reversal in the descending aorta = severe AR. This is very specific and one of the most reliable parameters.
PISA method	ERO, regurgitant volume, regurgitant fraction	Quantitative: severe if ERO ≥ 0.30 cm², RVol ≥ 60 mL, RF ≥ 50%.

Parameter	Significance	Why It Matters
LVEDD (end-diastolic diameter)	> 65 mm = significant dilation; > 75 mm = very dilated ^[1]	Reflects chronic volume overload. Part of surgical decision-making in asymptomatic patients.
LVESD (end-systolic diameter)	> 50 mm or > 25 mm/m² BSA = at risk; > 55 mm = surgical trigger ^[1]	LVESD is a better predictor of irreversible LV dysfunction than LVEDD because it reflects contractile reserve — a ventricle that remains large at end-systole is failing to empty adequately.
LVEF	< 50% = LV systolic dysfunction = surgical trigger even if asymptomatic ^[1]	EF may be "preserved" (> 50%) for a long time in AR because the dilated LV ejects a large total SV. An EF drop below 50% in severe AR is a late and ominous sign — the LV is decompensating.
LV mass index	Increased in LVH	Reflects the degree of eccentric remodelling.

Measurement	Normal	Significance
Aortic annulus diameter	~23 mm (varies with BSA)	Dilation → central AR
Sinuses of Valsalva diameter	~34 mm	Dilation in Marfan (annuloaortic ectasia)
Sinotubular junction diameter	~30 mm	Dilation pulls cusps apart
Ascending aorta diameter	< 40 mm	> 50 mm → indication for surgery even in mild AR (to prevent dissection/rupture) ^[1]

The mid-portion of the ascending aorta is difficult to visualise by ECHO ^[1] — hence the importance of CT thorax for complete aortic assessment when root pathology is suspected.

TEE is more sensitive than TTE for specific indications ^[1]^[8]:

Indication for TEE	Reason
Suspected infective endocarditis	Better sensitivity for detecting vegetations, perivalvular abscesses, cusp perforations. TTE sensitivity ~60-70% vs. TEE ~95%. ^[8]
Aortic dissection	Visualises intimal flap, true/false lumen, proximal extent of dissection. However, CT aortogram is usually preferred for initial diagnosis ^[6].
Prosthetic valve AR	TTE produces acoustic shadowing from the prosthesis → poor visualisation of regurgitant jets. TEE looks from behind (oesophagus) → avoids the prosthesis shadow. ^[8]
Inadequate TTE windows	Obesity, COPD, chest wall deformity → poor acoustic windows on TTE.
Intraoperative guidance	During valve repair/replacement to assess result.

CT thorax ^[1] — Essential when echocardiography cannot fully visualise the aorta.

Indication	What It Shows
Mid-ascending aorta assessment	ECHO blind spot — CT fills the gap ^[1]. Precise measurement of aortic dimensions at annulus, sinuses, STJ, and ascending aorta.
Aortic root aneurysm / dilation measurement	Accurate sizing for surgical planning. Critical for Marfan, bicuspid aortopathy, and any patient where root dimensions trigger surgery (> 50 mm, or > 45 mm in Marfan).
Aortic dissection	CT aortogram is the investigation of choice: true lumen traceable from normal aorta, compressed by false lumen ^[6].
Pre-operative planning	3D reconstruction for graft sizing, coronary anatomy relative to the annulus.
Follow-up of known aortic dilation	Serial measurements to track growth rate (> 5 mm/year = rapid expansion, consider surgery).

CT vs. MRI for aortic assessment: Both are excellent. CT is faster, more widely available, and preferred in acute settings (dissection). MRI avoids radiation and iodinated contrast, making it preferred for serial follow-up of young patients (e.g., Marfan). Both are superior to echo for the mid-ascending aorta.

CMR is increasingly used when echo findings are equivocal or discordant:

Role	Details
Quantification of AR severity	Measures regurgitant volume and fraction directly by comparing LV and RV stroke volumes (by volumetric analysis) or by phase-contrast flow mapping in the aorta. This is the most accurate non-invasive quantification method.
LV volume and function	CMR is the gold standard for LV volumes and EF — more accurate and reproducible than echo. Important for surgical decision-making in borderline cases.
Aortic morphology	Excellent for aortic root and ascending aorta dimensions. Preferred for serial follow-up in young patients (no radiation).
Tissue characterisation	Late gadolinium enhancement (LGE) can detect myocardial fibrosis — a marker of irreversible LV damage. Emerging evidence suggests LGE may help identify patients who have already developed irreversible LV injury despite preserved EF.

Coronary angiogram ^[1]

Indication	Reason
Pre-operative assessment	Before aortic valve surgery, coronary angiography is performed to detect coexistent CAD ^[1]. If significant coronary stenosis is found → simultaneous CABG + valve surgery.
Age > 40 or with CAD risk factors	Even in younger patients, if multiple risk factors are present, coronary assessment is warranted.
Assessment of AR during catheterisation	Aortography (injection of contrast into the aortic root) can demonstrate the AR jet visually and semi-quantitatively grade its severity (Sellers grade I-IV). However, this is now largely superseded by echocardiography.

Why is coronary angiography needed before valve surgery? Patients with severe AR, especially those with risk factors for atherosclerosis, frequently have coexistent CAD. If you replace the valve but leave a 90% LAD stenosis untreated, the patient may have a perioperative MI. Therefore, coronary angiography (or CT coronary angiography in lower-risk patients) is a routine part of the pre-operative workup ^[1].

Blood: VDRL, blood culture (IE) ^[2]

Test	Indication / Interpretation
VDRL / RPR + FTA-ABS	Screen for syphilis as a cause of aortitis ^[2]. VDRL/RPR are non-treponemal screening tests (cheap, sensitive but not specific); FTA-ABS is a confirmatory treponemal test.
Blood cultures (≥ 3 sets)	If IE is suspected (fever + new murmur + embolic phenomena) ^[2]. At least 3 sets from different sites to demonstrate persistent bacteraemia.
BNP / NT-proBNP	Elevated in heart failure from decompensated AR. Helps distinguish cardiac from non-cardiac dyspnoea. Not specific for AR.
CBC	Anaemia (may exacerbate AR symptoms), leucocytosis (infection/IE), normocytic normochromic anaemia of chronic disease (IE, SLE).
ESR / CRP	Elevated in IE, aortitis (GCA, Takayasu, spondyloarthropathy), SLE.
RFT	Baseline renal function (pre-operative, contrast nephropathy risk, cardiorenal syndrome).
LFT	Hepatic congestion in right heart failure (advanced decompensated AR → biventricular failure).
HLA-B27	If spondyloarthropathy-associated aortitis is suspected (young male, back pain, enthesitis).
ANA, dsDNA, complement	If SLE-related Libman-Sacks endocarditis is a consideration.

Role	Details
Assess exercise capacity in "asymptomatic" patients	Some patients with severe AR unknowingly limit their activity. Exercise testing can unmask symptoms (dyspnoea, ↓BP response) and an abnormal LVEF response to exercise.
Not routinely required	If the patient is clearly symptomatic, exercise testing is unnecessary and potentially dangerous (as with AS) ^[1].
Prognostic value	Failure to augment LVEF with exercise, or drop in BP, suggests impending decompensation.

The Essential Investigations for AR — Think in Layers

Layer 1 — Confirm and grade: TTE (gold standard). If equivocal → CMR.

Layer 2 — Assess the aorta: CT aortography or MRA (especially when root dilation suspected; echo cannot visualise mid-ascending aorta well).

Layer 3 — Determine cause: VDRL (syphilis), blood cultures (IE), HLA-B27 (SpA), connective tissue disease workup (Marfan/EDS genetics), inflammatory markers (aortitis).

Layer 4 — Pre-operative: Coronary angiogram (coexistent CAD?), full bloods, pulmonary function, frailty assessment.

Layer 5 — Baseline/monitor: ECG (LVH, strain), CXR (cardiomegaly, pulmonary congestion), BNP.

Common Mistakes in AR Diagnosis

Missing acute AR: The murmur is short and soft, peripheral signs are absent, the echo may show a normal-sized LV. The clue is acute pulmonary oedema with a new diastolic murmur → urgent echo.
Over-relying on LVEF: LVEF can remain "normal" (> 50%) for years in severe AR because the large total SV masks early contractile decline. By the time LVEF drops below 50%, significant irreversible myocardial damage may have occurred. This is why LV dimensions (LVESD > 50 mm) and trends are equally important.
Forgetting to image the aorta: If you confirm AR on echo but don't measure the ascending aorta, you may miss a 55 mm aneurysm that independently requires surgery. Always request CT or MRA if the aortic root/ascending aorta is dilated or not well visualised on TTE.
Not doing blood cultures when fever + AR: AR predisposes to IE. A "known" AR patient with fever must have blood cultures drawn before antibiotics.

Investigation	Key Findings in AR	Why It's Done
ECG	LVH ± strain pattern ^[1]^[2]	Baseline, assess LV remodelling consequences
CXR	Cardiomegaly, dilated aortic arch ^[1]^[2], pulmonary congestion	Baseline, assess aortic silhouette, pulmonary status
TTE	AR jet, severity grading, LV size/function, aortic root dimensions, valve morphology	Gold standard for diagnosis and severity
TEE	Vegetations, abscess, dissection flap, prosthetic valve assessment	When IE/dissection suspected or TTE inadequate
CT aortography	Aortic dimensions, dissection, aneurysm, calcification	Mid-ascending aorta (ECHO blind spot) ^[1], surgical planning
CMR	Regurgitant volume/fraction, LV volumes/EF, myocardial fibrosis	When echo findings equivocal, most accurate quantification
Coronary angiogram	Coronary artery disease assessment	Pre-operative workup ^[1]
Bloods (VDRL, cultures)	Syphilis, IE	Aetiological workup ^[2]

High Yield Summary

There are no formal "diagnostic criteria" for AR — diagnosis is clinical + echocardiographic.

Echo is the gold standard. Key severe AR parameters: jet/LVOT ≥ 65%, vena contracta > 6 mm, PHT < 200 ms, holodiastolic flow reversal in descending aorta, RVol ≥ 60 mL, RF ≥ 50%, ERO ≥ 0.30 cm².

LV parameters that trigger surgery even in asymptomatic patients: LVEF < 50%, LVESD > 50 mm (or > 25 mm/m²), LVEDD > 65 mm.

Ascending aorta > 50 mm (or > 45 mm in Marfan/bicuspid with risk factors) = indication for aortic surgery regardless of AR severity.

CT aortography fills the echo blind spot (mid-ascending aorta) and is essential when root pathology is suspected.

Pre-operative coronary angiogram is routine before valve surgery to detect coexistent CAD.

Bloods for aetiology: VDRL (syphilis), blood cultures ×3 sets (IE), HLA-B27 (SpA), inflammatory markers (aortitis).

ECG: LVH ± strain (may be normal early). CXR: cardiomegaly, dilated aortic knuckle, pulmonary congestion.

Active Recall - Diagnosis and Investigations for AR

References

^[1] Senior notes: Maksim Medicine Notes.pdf (p6, p35, p37 — Investigations, Valvular heart disease, Terminologies and indications for surgery sections) ^[2] Senior notes: Ryan Ho Cardiology.pdf (p160 — Aortic Regurgitation section) ^[4] Senior notes: Ryan Ho Fundamentals.pdf (p35–36, p39 — Murmurs sections) ^[6] Senior notes: Maksim Medicine Notes.pdf (p15 — Aortic dissection section) ^[8] Senior notes: Maksim Medicine Notes.pdf (p6 — Echocardiography section)

Management of Aortic Regurgitation

Before diving into specific treatments, understand the three core principles that drive all management decisions in AR:

Timing is everything: The natural history of chronic severe AR is a long compensated phase (years to decades) followed by a relatively rapid decompensation. The goal is to intervene surgically before irreversible LV damage occurs — but not so early that you expose a well-compensated patient to unnecessary surgical risk.
Medical therapy cannot fix the valve: Unlike heart failure from cardiomyopathy where drugs are the mainstay, in AR the fundamental problem is a mechanical valve defect. Medical therapy is supportive (managing symptoms, controlling blood pressure) but cannot reverse the regurgitation or prevent progression. Definitive treatment is surgical ^[1]^[2].
Acute AR ≠ Chronic AR: Acute severe AR is a surgical emergency. There is essentially no role for prolonged medical optimisation — the patient needs the valve fixed or replaced urgently ^[2].

A. Medical Management

Medical therapy in AR is supportive, not curative. Its role is to: (1) manage blood pressure, (2) reduce symptoms of heart failure, and (3) bridge patients to surgery if needed.

Vasodilators for HT: ACEI/ARB/CCB ^[1]

Drug Class	Mechanism in AR	When to Use	Notes
ACEI (e.g., ramipril, perindopril)	Inhibits angiotensin-converting enzyme → ↓angiotensin II → ↓afterload (arteriolar dilation) + ↓aldosterone → ↓preload. In AR: ↓afterload reduces the diastolic aortic-LV pressure gradient → reduces regurgitant volume → reduces volume overload on LV	Hypertension (SBP > 140 mmHg) in chronic AR ^[2]. Also for symptomatic HF or LV dysfunction if surgery is not contemplated ^[2]	First-line for HT in AR. Also provide neurohormonal blockade (RAAS inhibition) beneficial in LV remodelling.
ARB (e.g., losartan, valsartan)	Same pathway but blocks AT1 receptor directly	Alternative to ACEI if ACEI-intolerant (e.g., cough).	Equivalent efficacy to ACEI in afterload reduction.
DHP CCB (e.g., nifedipine, amlodipine)	Dihydropyridine calcium channel blockers → arterial vasodilation → ↓afterload	Hypertension in AR ^[1]^[2]. Historically, nifedipine was studied specifically in AR.	DHP CCBs (dihydropyridine) are the appropriate subclass — they are predominantly vasodilatory. Non-DHP CCBs (verapamil, diltiazem) are rate-limiting and should generally be avoided (see below).

Why does afterload reduction help in AR? Think of it from first principles: in AR, blood can either go forward into the systemic circulation or backward through the leaky valve into the LV. This is a competition between two pathways. If you reduce systemic vascular resistance (afterload), you make it "easier" for blood to go forward → proportionally less blood regurgitates backward → ↓regurgitant fraction → ↓LV volume overload.

Vasodilators Are NOT Indicated in Asymptomatic Normotensive Patients

A common misconception: "all patients with AR should be on vasodilators." Wrong. Current guidelines (ESC 2021, ACC/AHA 2020) recommend vasodilators only if the patient has hypertension (SBP > 140 mmHg) or symptomatic HF when surgery is not feasible. There is no proven benefit of vasodilators in asymptomatic, normotensive patients with severe AR — they do not delay the need for surgery ^[2].

Diuretics ^[1]

Drug	Mechanism	When to Use
Loop diuretics (furosemide/frusemide)	Inhibit Na-K-2Cl cotransporter in thick ascending limb of loop of Henle → ↓Na and water reabsorption → ↓intravascular volume → ↓preload → ↓pulmonary congestion	Symptomatic HF with pulmonary congestion (dyspnoea, orthopnoea, PND, peripheral oedema) ^[1].
Thiazides (hydrochlorothiazide, indapamide)	Inhibit Na-Cl cotransporter in distal convoluted tubule → milder diuresis + vasodilation	Add-on for refractory fluid overload, or for blood pressure control.
Aldosterone antagonists (spironolactone, eplerenone)	Block aldosterone in collecting duct → K-sparing diuresis; also inhibit myocardial fibrosis	Symptomatic HF with reduced EF. Proven mortality benefit in HFrEF (RALES trial).

Diuretics provide symptomatic relief by reducing pulmonary and systemic congestion, but they do not alter the natural history of AR. They are a bridge — if the patient needs diuretics for AR-related HF, they likely need surgery.

ACEI/ARB + BB for symptomatic or LV dysfunction if surgery is not contemplated ^[2]

Consideration	Explanation
Potential benefit	In decompensated AR with LV systolic dysfunction (reduced EF), beta-blockers provide the same neurohormonal benefits as in any HFrEF (↓HR → ↓myocardial O₂ demand, ↓sympathetic activation, ↓remodelling).
Potential harm	BB can worsen regurgitant fraction due to prolonged diastolic time ^[2]. Slower HR → longer diastole → more time for blood to regurgitate back into the LV per cardiac cycle → ↑regurgitant volume per beat.
Net effect	In compensated AR, the negative effect (↑regurgitation from slower HR) may outweigh the benefit. In decompensated AR with significant HFrEF and tachycardia, the benefit of rate control and neurohormonal blockade generally outweighs the risk — but use cautiously and monitor.
Practical approach	Use beta-blockers in AR only when: (1) there is clear HFrEF and surgery is not planned/possible, (2) there is a coexistent indication (e.g., AF rate control, post-MI), (3) Marfan syndrome (to slow aortic root dilation — but this is for the aortopathy, not the AR per se).

BB in AR vs. AS — Different Logic

In aortic stenosis, beta-blockers are generally avoided because they ↓contractility in a pressure-overloaded LV and can precipitate decompensation. In aortic regurgitation, the concern is different: BB prolongs diastole → more regurgitant time → worse volume overload ^[2]. Different valve lesion, different mechanism of harm, but both warrant caution.

Drug	Why Avoid
Intra-aortic balloon pump (IABP)	Absolutely contraindicated in AR. The IABP inflates in diastole to augment coronary perfusion and deflates in systole to reduce afterload. In AR, diastolic inflation increases aortic diastolic pressure → drives MORE blood back through the incompetent valve → catastrophic worsening of AR.
Non-DHP CCB (verapamil, diltiazem)	Negative chronotropic and inotropic effects → ↓HR (→ more regurgitation time) and ↓contractility (→ worse forward output). Use DHP CCBs instead.
Excessive preload reduction	While diuretics help with congestion, over-diuresis can ↓preload excessively → in AR the LV depends on a high EDV (Frank-Starling) to maintain forward CO → excessive preload reduction → ↓CO → cardiogenic shock.

IABP is CONTRAINDICATED in AR

This is a classic exam question. The IABP augments diastolic aortic pressure — which is exactly what you do NOT want in AR because it drives more blood backward through the leaky valve. In acute severe AR with cardiogenic shock, use IV vasodilators (nitroprusside) + inotropes instead.

B. Surgical Management — Aortic Valve Replacement (AVR)

Valvular replacement ^[1] — Surgical AVR: majority of AV cannot be repaired (cf MR) ^[2]

Unlike the mitral valve (where repair is often preferred and technically feasible), the aortic valve is a much more demanding structure to repair. The three cusps must coapt perfectly under high diastolic pressures, and any imperfection → residual AR. However, in select centres with expertise, aortic valve repair is increasingly performed for:

Bicuspid aortic valve with cusp prolapse
Root dilation with normal cusps (valve-sparing root replacement — David or Yacoob procedures)
Cusp perforation from IE (pericardial patch repair)

For the majority of patients, aortic valve replacement remains the standard surgical treatment ^[2].

Indications for Surgery

These are critical for exams. The indications follow a logical framework: symptoms, LV dysfunction, LV dilation, aortic root disease, and acute severe AR ^[1]^[2].

Indication	Rationale
Symptomatic severe AR (HF, angina, syncope) ^[1]	Once symptoms develop, prognosis deteriorates rapidly (10–20%/year mortality without surgery ^[2]). Surgery relieves symptoms and improves survival.
Asymptomatic severe AR with LVEF < 50% ^[1]	LV systolic dysfunction indicates myocardial damage has already begun. Operating before LVEF drops further improves post-operative outcomes and the chance of LV recovery.
Asymptomatic severe AR with severe LV dilation: LVESD > 50 mm (or > 25 mm/m² BSA) ^[1]	LVESD reflects contractile reserve. An LVESD > 50 mm predicts future LV dysfunction and symptoms. The older cutoff of > 55 mm used in some notes ^[1] has been revised downward to > 50 mm in current 2021 ESC guidelines.
Severe AR undergoing concomitant cardiac surgery (e.g., CABG, other valve surgery)	If you're already opening the chest, fix the leaky valve at the same time. The added risk is minimal compared with the benefit.
Acute severe AR (e.g., IE, dissection) ^[1]	Surgical emergency — the LV cannot compensate → acute pulmonary oedema / cardiogenic shock.

Indication	Rationale
Asymptomatic severe AR with LVEDD > 65 mm (or > 50 mm in senior notes: LVEDD > 75 mm) ^[1]	Extreme LV dilation predicts future decompensation. Note: the ACC/AHA 2020 uses LVEDD > 65 mm as a Class IIa trigger; senior notes cite > 75 mm which is an older, more conservative threshold ^[1].
Asymptomatic severe AR with progressive decline in LVEF to low-normal range (50–55%) on serial imaging	Falling EF trajectory even if still > 50% suggests early decompensation.
Rapidly increasing LV dimensions on serial echo	Rate of change matters — a ventricle enlarging quickly is more concerning than one that is stable.

Indication	Rationale
Ascending aorta > 50 mm (regardless of AR severity) ^[1]	Risk of dissection/rupture. Combined aortic root + valve surgery.
Ascending aorta > 45 mm in Marfan syndrome	Marfan patients have defective fibrillin → higher risk of dissection at smaller diameters.
Ascending aorta > 45 mm in bicuspid AV with additional risk factors (family history of dissection, aortic growth > 3 mm/year, coarctation, systemic HTN)	Bicuspid aortopathy carries intermediate risk — lower threshold for surgery when risk factors present.

Why the different thresholds for aortic size? The risk of aortic catastrophe (dissection/rupture) increases exponentially with diameter. Normal ascending aorta is ~30 mm. At 50 mm, the annual risk of dissection/rupture is ~5%. At 60 mm, it is ~7–10%. For Marfan, the tissue is inherently weaker, so the same risk occurs at a smaller diameter (hence 45 mm threshold).

Approach: mid-sternotomy (traditional), hemisternotomy, thoracotomy (smaller incisions) ^[2]

Approach	Description	When Used
Median sternotomy	Traditional full sternal split → excellent access to the aortic valve, ascending aorta, and coronary arteries	Standard approach for most AVR, especially when concomitant CABG or aortic surgery is needed
Minimally invasive (hemisternotomy, right anterior thoracotomy)	Partial sternotomy or intercostal approach → smaller incision, less tissue disruption	Isolated AVR without need for aortic root surgery or CABG. Faster recovery, less pain, better cosmesis

Technique: homograft (from external), PV autotransplant ± root replacement and CABG ^[2]

The choice of valve prosthesis is one of the most important shared decisions in valve surgery:

Prosthesis Type	Durability	Anticoagulation	Best For
Mechanical valve (e.g., bileaflet St. Jude, Medtronic)	Lifelong (virtually no structural deterioration)	Lifelong warfarin required (INR 2.5–3.5 for aortic position). Cannot use DOACs — the RE-ALIGN trial showed excess thromboembolic and bleeding events with dabigatran in mechanical valves	Younger patients (< 50–60 y) who can comply with lifelong anticoagulation and INR monitoring. Avoids reoperation.
Bioprosthetic valve (e.g., porcine or bovine pericardial)	10–20 years (structural valve degeneration accelerated in younger patients, slower in elderly)	No long-term anticoagulation needed (only aspirin ± short-term warfarin for first 3–6 months)	Older patients (> 65 y), patients with contraindications to anticoagulation (bleeding risk, falls), women planning pregnancy (warfarin is teratogenic — category X).
Homograft (allograft)	15–20 years	No anticoagulation	IE (resistant to re-infection), young patients who want to avoid anticoagulation. Limited availability.
Ross procedure (pulmonary autograft)	Excellent long-term (autograft grows with patient)	No anticoagulation	Selected young patients, especially children/adolescents. The patient's own pulmonary valve is transplanted to the aortic position, and a homograft replaces the pulmonary valve. Complex surgery requiring expertise.

The Ross procedure in detail: "Ross" = pulmonary valve autotransplant. The patient's pulmonary valve (which is under lower pressure and less prone to degeneration) is moved to the aortic position. A homograft then replaces the pulmonary valve. Advantages: living tissue that can grow (ideal for children), no anticoagulation, excellent haemodynamics. Disadvantages: technically demanding, two valves at risk instead of one, potential for autograft dilation in the aortic position.

When the aortic root is dilated (Marfan, bicuspid aortopathy, etc.), replacing the valve alone is insufficient — you must also replace the diseased aorta.

Procedure	Description	When Used
Bentall procedure	Composite replacement of the aortic valve + aortic root + ascending aorta with a mechanical or biological valved conduit. Coronary arteries reimplanted (buttons) into the graft.	Dilated ascending aorta > 50 mm (or > 45 mm in Marfan) with diseased cusps requiring replacement ^[2].
Valve-sparing root replacement (David procedure)	The ascending aorta and root are replaced, but the patient's own aortic valve cusps are preserved and resuspended inside the graft	Aortic root aneurysm with structurally normal cusps (e.g., Marfan with normal leaflets). Avoids need for anticoagulation or bioprosthetic degeneration.
Yacoob (remodelling) procedure	Root replaced with sinuses recreated; valve preserved	Similar to David but less secure fixation of the annulus; higher risk of late AR recurrence.

Transcatheter AVR CANNOT be done (relies on stenotic AV to hold prosthetic valve in place) ^[2]

This is a very important point. TAVI/TAVR works by deploying a stent-mounted valve inside the calcified native aortic valve. The calcified, stenotic valve acts as an anchor — the new valve is wedged into it. In pure AR without significant stenosis/calcification, there is nothing to anchor the transcatheter valve against → it will migrate or embolise. Therefore, TAVI is contraindicated in isolated AR.

Emerging evidence (2023–2025) from newer-generation devices (e.g., JenaValve, J-Valve) shows promise for TAVI in pure AR using clipping mechanisms that grasp the native leaflets, but this is not yet standard practice and remains investigational or limited to selected centres.

TAVI Cannot Be Used for Pure AR

TAVI relies on the calcified stenotic valve as an anchor. In pure AR without calcification/stenosis, there is nothing to hold the transcatheter valve in place. Surgical AVR remains the standard. This is a frequently tested concept.

Outcome and Cx: mortality 1–5%, complications ~5% ^[2]

Outcome	Details
Operative mortality	1–3% for isolated AVR in good-risk patients; up to 5% in higher-risk patients or combined procedures (AVR + CABG + root replacement) ^[2]
10-year survival	~80% post-AVR for severe AR (significantly better than medical management alone in symptomatic patients)
LV recovery	LVEF usually improves post-operatively, but recovery is less complete if surgery is delayed until LVEF is very low (< 35%) or LVESD is very large — hence the emphasis on timely intervention

General: CVA, bleeding, infection, multiorgan failure. Specific: heart block, heart failure, MI ^[2]

Complication	Mechanism
CVA (stroke)	Thromboembolism from cardiopulmonary bypass, air embolism, manipulation of calcified aorta
Bleeding	Surgical, anticoagulation-related
Infection	Wound infection, prosthetic valve endocarditis (PVE) — most feared complication. Early PVE (< 60 days): staph; Late PVE (> 60 days): strep, enterococci
Heart block	The aortic valve annulus is adjacent to the conduction system (AV node, bundle of His). Surgical manipulation, sutures, or oedema can damage these structures → complete heart block requiring permanent pacemaker (2–5% risk)
Paravalvular leak	Sutures not perfectly seating the prosthesis → residual AR around the sewing ring
Structural valve degeneration	Bioprosthetic: leaflet calcification, tearing over 10–20 years → need for reoperation (or valve-in-valve TAVI)
Thromboembolism	Especially with mechanical valves if INR subtherapeutic
Haemolysis	Shear stress from mechanical valve leaflets → chronic subclinical haemolysis (↑LDH, ↑reticulocytes, ↓haptoglobin). Usually mild.

This is a medical and surgical emergency. The patient presents with acute pulmonary oedema ± cardiogenic shock.

Step	Action	Rationale
1. Stabilise	IV vasodilators (sodium nitroprusside) ± inotropes (dobutamine)	Nitroprusside → ↓afterload → promotes forward flow, ↓regurgitation. Dobutamine → ↑contractility → ↑forward CO.
2. Diuretics	IV furosemide	↓pulmonary congestion
3. Avoid IABP	IABP is absolutely contraindicated	Diastolic balloon inflation ↑ aortic diastolic pressure → ↑ regurgitant volume → catastrophic worsening
4. Treat the cause	IE → high-dose IV antibiotics (empirical: vancomycin + ampicillin + gentamicin). Dissection → anti-impulse therapy (labetalol/esmolol + nitroprusside)	Control infection / stabilise dissection before operating
5. Urgent surgery	Emergency surgical AVR	Definitive treatment. Do not delay for prolonged medical optimisation — the LV cannot cope. In dissection: aortic root repair ± AVR (often Bentall procedure)

AR Severity	Follow-Up Protocol	Rationale
Mild AR, normal LV	Clinical review + echo every 2–3 years	Very slow progression; mainly surveillance for change
Moderate AR	Clinical review + echo every 1–2 years	Intermediate risk of progression
Severe AR, asymptomatic, normal LV function	Clinical review + echo every 6–12 months	Close monitoring to detect early LV dysfunction/dilation before symptoms develop (the "window" for optimal surgery)
Post-operative (AVR)	TTE at 6 weeks post-op (baseline), then annually	Detect paravalvular leak, prosthetic valve dysfunction, LV recovery. Mechanical valves: INR monitoring.

Lifestyle and Activity Advice

Recommendation	Rationale
Avoid competitive / strenuous isometric exercise in severe AR	Intense isometric exercise (weightlifting) → acute ↑afterload → ↑regurgitant volume → risk of acute decompensation or arrhythmia
Moderate aerobic exercise is generally safe and encouraged	Aerobic exercise → peripheral vasodilation → ↓afterload → actually favourable in AR
Endocarditis prophylaxis	Only for high-risk groups (prosthetic valve, previous IE, certain congenital HD) during dental procedures. Routine prophylaxis is NOT recommended for native valve AR ^[1]

Scenario	Management
Mild-moderate AR, asymptomatic	Serial echo monitoring. Treat HTN if present (ACEI/ARB/DHP CCB). No surgery.
Severe AR, asymptomatic, normal LV	Echo every 6–12 months. Vasodilators only if HTN. Surgery only if LV parameters deteriorate.
Severe AR, symptomatic (HF/angina) ^[1]	Surgical AVR + medical optimisation (diuretics, vasodilators as bridge).
Severe AR, asymptomatic, LVEF < 50% ^[1]	Surgical AVR (even without symptoms — LV dysfunction = decompensation has begun).
Severe AR, asymptomatic, LVESD > 50 mm ^[1]	Surgical AVR (LVESD reflects impaired contractile reserve).
Severe AR + ascending aorta > 50 mm ^[1]	AVR + ascending aortic replacement (Bentall or valve-sparing root).
Acute severe AR ^[1]	Emergency surgical AVR. Medical stabilisation with IV vasodilators + inotropes. No IABP.
IE-related AR ^[1]	High-dose IV antibiotics ×6 weeks. Surgery if haemodynamically unstable, persistent infection, or abscess.

High Yield Summary

Medical therapy: Supportive only. Vasodilators (ACEI/ARB/DHP CCB) for hypertension ^[1]. Diuretics for HF symptoms ^[1]. BB use cautiously (prolongs diastole → ↑regurgitation) ^[2]. Vasodilators NOT indicated in asymptomatic normotensive patients.

IABP is absolutely contraindicated in AR (↑diastolic aortic pressure → worsens regurgitation).

Surgical AVR is the definitive treatment. TAVI cannot be used for pure AR (no calcified valve anchor) ^[2].

Indications for surgery (exam must-know):

Symptomatic severe AR (HF, angina, syncope) ^[1]
Asymptomatic severe AR + LVEF < 50% ^[1]
Asymptomatic severe AR + LVESD > 50 mm (or > 55 mm in older guidelines) ^[1]
Asymptomatic severe AR + LVEDD > 65 mm ^[1]
Ascending aorta > 50 mm (> 45 mm in Marfan) ^[1]
Acute severe AR ^[1]
Concomitant cardiac surgery

Valve choice: Mechanical (lifelong, warfarin); Bioprosthetic (10–20 yr, no anticoagulation); Homograft (IE); Ross procedure (young patients).

Bentall procedure: Composite valve + aortic root + ascending aorta replacement with coronary reimplantation — for root disease.

Acute severe AR: Surgical emergency. IV vasodilators + inotropes → urgent AVR. NO IABP.

Active Recall - Management of Aortic Regurgitation

References

^[1] Senior notes: Maksim Medicine Notes.pdf (p35, p37 — Valvular heart disease, Terminologies and general indications for surgery) ^[2] Senior notes: Ryan Ho Cardiology.pdf (p160–161 — Aortic Regurgitation management section)

Complications of Aortic Regurgitation

Every complication of AR can be understood by tracing it back to the fundamental pathophysiology: chronic LV volume overload → eccentric dilation → eventual decompensation, combined with reduced diastolic aortic pressure → impaired coronary perfusion, and the predisposition of the abnormal valve to secondary pathology (infection, thromboembolism). Let's work through each systematically.

A. Complications of the Disease Itself (Untreated or Progressive AR)

This is the most important and most common complication of severe chronic AR. It is the final common pathway of the disease.

Pathophysiology from first principles:

Chronic volume overload → LV dilates (eccentric hypertrophy, sarcomeres added in series) → initially compensated (normal LVEDP, ↑SV via Frank-Starling) ^[2].
Over years, the myocardium exhausts its compensatory reserve → contractile dysfunction develops → LVEF falls below 50% ^[1].
As the LV fails: ↑LVEDP → transmitted backward to LA → pulmonary veins → pulmonary congestion (dyspnoea, orthopnoea, PND) → eventually pulmonary arterial hypertension → right heart failure ^[1]^[2].
Once symptomatic HF develops, mortality without surgery is 10–20% per year ^[2]. This is the point of no return if left untreated.

Clinical features of LV failure in AR:

SOB on exertion → orthopnoea → PND → resting dyspnoea ^[1]
Fatigue from ↓forward cardiac output ^[1]
Peripheral oedema, elevated JVP, hepatomegaly (when RV failure ensues)
S₃ gallop (reflecting rapid filling of a volume-overloaded, failing ventricle) ^[1]
Pulmonary congestion on CXR, pulmonary hypertension on echo ^[1]

Why does the LV eventually fail? There is a limit to how much the LV can dilate. According to LaPlace's law (wall stress = pressure × radius / 2 × wall thickness), as the radius increases, wall stress increases — the heart has to work harder with each beat. Eventually, the hypertrophy cannot keep up with the dilation, wall stress exceeds the compensatory capacity, and contractile function declines irreversibly.

Irreversible LV Damage — The Window of Opportunity

The critical concept in AR management is that there is a window between the onset of LV dysfunction (detectable by echo as ↓LVEF or ↑LVESD) and the development of irreversible myocardial fibrosis. If you operate within this window, the LV can recover. If you wait too long (LVEF < 30%, LVESD > 55 mm for a prolonged period), the fibrosis is permanent and LV function will not normalise even after successful AVR. This is why serial echo surveillance and timely surgical intervention are so important ^[1]^[2].

Chest pain (↓DBP, LVH) more at night (↓HR) ^[1]

AR causes angina through a double-hit mechanism — unique among valvular lesions:

Mechanism	Explanation
↓ Diastolic BP → ↓ coronary perfusion pressure	Regurgitant leak drops diastolic aortic pressure. Since coronaries fill primarily in diastole, the driving pressure for coronary perfusion falls ^[1]^[2].
LVH → ↑ myocardial O₂ demand	The dilated, hypertrophied LV has greater muscle mass and wall stress → needs more oxygen ^[1].
↑ LVEDP → external compression of subendocardium	As the LV decompensates, LVEDP rises → compresses the subendocardial coronary vessels from the outside → further reduces perfusion

Why worse at night? During sleep, heart rate drops → longer diastole → more time per beat for blood to regurgitate → lower diastolic BP, higher regurgitant volume, worse coronary perfusion. This is characteristic of AR angina and is a classic exam point ^[1].

This angina can occur even without epicardial coronary artery disease — it is a supply-demand mismatch caused by the haemodynamics of AR itself. However, coexistent CAD is common, especially in older patients with degenerative AR, and must always be considered.

Arrhythmia	Mechanism	Clinical Significance
Atrial fibrillation (AF)	Chronic LV dilation → ↑LVEDP → transmitted backward → LA dilation → atrial remodelling → AF. Also: new-onset AF is considered a complication and an indication for surgery ^[1]	AF causes loss of atrial kick (reduces LV filling by ~20%) → worsens forward CO in an already volume-overloaded heart. Also increases thromboembolic risk.
Ventricular arrhythmias (VT/VF)	LVH + myocardial fibrosis → re-entrant circuits → ventricular tachycardia. Subendocardial ischaemia also predisposes to arrhythmia.	Risk of sudden cardiac death, though less common in AR than in AS.
Conduction abnormalities	If the AR is caused by conditions affecting the aortic root/annulus (e.g., calcific degeneration, endocarditis with abscess), the nearby conduction system (AV node, bundle of His) can be damaged.	LBBB, first-degree heart block, or complete heart block.

Pulmonary HT ^[1]

Pathophysiology:

LV failure → ↑LVEDP → ↑LA pressure → ↑pulmonary venous pressure → passive (post-capillary) pulmonary hypertension
Chronic elevated pulmonary venous pressure → reactive pulmonary vasoconstriction + pulmonary vascular remodelling → the pulmonary hypertension becomes mixed (pre- and post-capillary) and eventually fixed
Once fixed pulmonary vascular disease develops → RV pressure overload → RV failure → biventricular failure

This cascade — LV failure → pulmonary HTN → RV failure — is the final common pathway of all left-sided valvular diseases. In AR, it typically occurs late because the LV compensates for so long.

Pathophysiology:

Severe LV dilation → the mitral annulus stretches (it sits at the base of the LV) → the mitral leaflets can no longer coapt → central MR develops
Additionally, LV dilation displaces the papillary muscles laterally → tethers the mitral leaflets → further prevents coaptation

This creates a vicious cycle: AR → LV dilation → functional MR → additional volume overload on the LV → more dilation → more MR. This is one of the reasons why surgery should not be delayed until the LV is massively dilated.

Infective endocarditis despite optimal medical therapy (an indication for surgery) ^[1]

Why is an AR valve susceptible to IE?

The regurgitant jet creates turbulent flow → damages the endothelial surface of the valve cusps → exposes subendothelial collagen and tissue factor → promotes platelet-fibrin deposition (non-bacterial thrombotic endocarditis, NBTE) → a nidus for bacterial seeding during transient bacteraemia
The aortic valve is the second most commonly affected valve in IE (after the mitral valve) ^[1]

Consequences of IE on an AR valve:

Cusp destruction/perforation → acute worsening of AR → acute pulmonary oedema
Vegetation formation → systemic embolisation (stroke, splenic infarct, renal infarct, mycotic aneurysm, Janeway lesions, Osler nodes)
Perivalvular abscess → conduction system damage (AV block, bundle branch block) → this is a strong indication for urgent surgery
Persistent infection despite antibiotics → indication for surgical debridement and valve replacement ^[1]

When AR is caused by aortic root dilation (Marfan, bicuspid aortopathy, HTN, aortitis), the root itself is a source of additional complications:

Complication	Mechanism
Aortic dissection	Weakened aortic wall (cystic medial degeneration in Marfan/bicuspid, inflammation in aortitis) → intimal tear → acute Type A dissection → can cause acute severe AR + cardiac tamponade ^[6]. This is the most feared acute complication.
Aortic rupture	Progressive dilation → wall tension increases exponentially (LaPlace) → eventual rupture (usually into pericardium → tamponade, or into left pleural space → haemothorax)
Compression of adjacent structures	Large ascending aortic aneurysm → compression of SVC (SVC syndrome), trachea/bronchus (dyspnoea, stridor), recurrent laryngeal nerve (hoarseness — Ortner's syndrome equivalent for thoracic aneurysm)

Uncommon in AR (more typical of AS), but can occur due to:
- Ventricular arrhythmias (VT/VF) triggered by myocardial fibrosis or ischaemia
- Acute aortic dissection with tamponade
- Acute IE with cusp rupture → acute severe AR → refractory pulmonary oedema/shock

B. Complications of Surgical Treatment (Post-AVR)

Outcome and Cx: mortality 1–5%, complications ~5% ^[2]

General: CVA, bleeding, infection, multiorgan failure. Specific: heart block, heart failure, MI ^[2]

Complication	Mechanism	Incidence / Notes
CVA (stroke)	Thromboembolism from cardiopulmonary bypass circuit, air embolism, atheromatous embolism from calcified aorta during surgical manipulation	1–3%. Higher risk with combined procedures (AVR + CABG) or heavily calcified aortas.
Bleeding	Surgical haemostasis issues, coagulopathy from cardiopulmonary bypass (platelet dysfunction, fibrinolysis), anticoagulation for mechanical valves	May require re-exploration (3–5%). Mediastinal drains monitored closely post-op.
Infection	Wound infection, sternal wound dehiscence/mediastinitis, pneumonia, line sepsis, early prosthetic valve endocarditis (PVE)	Early PVE (< 60 days): predominantly S. aureus, coagulase-negative staphylococci (skin flora introduced at surgery). Very high mortality (40–50%).
Heart block	The aortic valve annulus is anatomically adjacent to the conduction system (AV node, bundle of His, left bundle branch). Surgical manipulation, sutures placed through the annulus, or post-operative tissue oedema can damage these structures ^[2]	2–5% require permanent pacemaker. Risk higher with bicuspid AV (aberrant conduction anatomy) and with annular debridement for IE.
Myocardial infarction	Air embolism to coronary ostia, coronary button kinking/occlusion (in Bentall), inadequate myocardial protection during cardioplegia, or missed CAD	1–2%. Coronary angiography pre-op minimises the risk of missed CAD.
Heart failure	Post-operative myocardial stunning, inadequate myocardial protection, prosthesis-patient mismatch (too-small prosthesis relative to body size → residual obstruction), pre-existing irreversible LV dysfunction	May need temporary inotropic support. If LV function was severely reduced pre-op, full recovery may not occur.
Multiorgan failure	Prolonged cardiopulmonary bypass → systemic inflammatory response, low-output state post-operatively → renal failure, liver failure, coagulopathy	Rare with modern techniques. Higher risk in redo operations, emergency surgery, elderly/frail patients.
Cardiac tamponade	Post-operative bleeding into pericardium → compression of cardiac chambers → ↓CO	Surgical emergency requiring pericardial drainage/re-exploration.

Complication	Mechanism	Notes
Prosthetic valve endocarditis (late PVE)	Bacteraemia seeding prosthetic material. Late PVE (> 60 days): usually Streptococcus viridans, Enterococcus (similar organisms to native valve IE)	Incidence ~1–2%/year. Both mechanical and bioprosthetic valves have similar risk ^[9]. Requires prolonged antibiotics ± surgical re-replacement. All prosthetic valve patients require IE prophylaxis for high-risk dental procedures ^[1].
Structural valve degeneration (bioprosthetic)	Calcification, fibrosis, and leaflet tearing of bioprosthetic valves over time → progressive stenosis or regurgitation	~50% structural failure at 15 years ^[9]. Accelerated in younger patients (higher calcium turnover), renal failure (hypercalcaemia), hyperparathyroidism. May be treated with redo surgical AVR or valve-in-valve TAVI.
Thromboembolism	Thrombus formation on mechanical valve (especially if INR subtherapeutic) → systemic embolisation (stroke, limb ischaemia, visceral infarction)	Incidence ~1–2%/year even with well-controlled anticoagulation. Higher with older-generation mechanical valves. Emphasises importance of strict INR monitoring (target 2.5–3.5 for mechanical aortic valves).
Valve thrombosis / obstruction	Thrombus or pannus formation on mechanical valve → obstruction to flow → acute haemodynamic deterioration (mimics acute AS)	Presents with sudden HF, muffled prosthetic click, elevated transvalvular gradient on echo. Emergency: thrombolysis vs. redo surgery depending on clinical stability and thrombus size ^[9].
Paravalvular leak	Sutures not perfectly seating the prosthesis against the annulus → blood leaks around (not through) the valve → regurgitation	Mild paravalvular leak is very common and usually benign. Significant leak → haemolysis (shear stress on RBCs) + volume overload → may need reoperation or percutaneous closure.
Haemolytic anaemia	Mechanical shear stress from prosthetic valve leaflets (especially mechanical) → chronic subclinical haemolysis. Worsened by paravalvular leak (turbulent flow at leak site)	Labs: ↑LDH, ↑unconjugated bilirubin, ↑reticulocytes, ↓haptoglobin, schistocytes on blood film. Usually mild and compensated. Severe cases (usually with paravalvular leak) → iron deficiency anaemia from chronic haemoglobinuria.
Anticoagulation-related bleeding	Lifelong warfarin for mechanical valves → risk of haemorrhage (intracranial, GI, other)	Annual major bleeding risk ~1–2% with well-controlled INR. Patient education on INR monitoring, drug interactions (CYP2C9 inducers/inhibitors), dietary vitamin K consistency is essential.
Prosthesis-patient mismatch	Prosthetic valve effective orifice area is too small relative to the patient's body surface area → residual transvalvular gradient (functional stenosis)	More common in patients with small aortic roots. Leads to persistent LVH, incomplete symptom relief, and ↓long-term survival. Prevention: careful prosthesis sizing intraoperatively; consider root enlargement (Nicks, Manouguian, or Konno procedures) if needed.

Prosthetic Valve Endocarditis — High-Yield

PVE is one of the most feared late complications of valve surgery. Key points:

All prosthetic valve patients are in the "high-risk" group for IE prophylaxis ^[1].
Early PVE (< 60 days): staphylococcal (nosocomial); Late PVE (> 60 days): streptococcal/enterococcal (community-acquired).
PVE has higher mortality than native valve endocarditis and more often requires surgical re-replacement.
Prophylaxis: amoxicillin 2g PO single dose 30–60 min before dental procedures (clindamycin 600mg if penicillin-allergic) ^[1].

Category	Complications
Cardiac (from AR itself)	LV failure (HFrEF), angina/ischaemia, arrhythmias (AF, VT), pulmonary HTN, functional MR, sudden death
Valve-related	Infective endocarditis, progression of underlying disease (e.g., further cusp destruction, worsening root dilation)
Aortic (root disease)	Aortic dissection, aortic rupture, compression of adjacent structures
Post-operative early	CVA, bleeding, heart block, MI, infection/PVE, HF, tamponade, multiorgan failure
Post-operative late	PVE, structural valve degeneration, thromboembolism, valve thrombosis, paravalvular leak, haemolysis, anticoagulant bleeding, prosthesis-patient mismatch

High Yield Summary

Most important complication: LV failure — the end result of chronic volume overload. Once symptomatic, mortality is 10–20%/year without surgery. Key: operate before irreversible myocardial fibrosis develops.

Angina in AR: Dual mechanism — ↓DBP (↓coronary perfusion) + LVH (↑O₂ demand). Worse at night (↓HR → longer diastole → more regurgitation) ^[1].

Arrhythmias: AF (from LA dilation) is both a complication and an indication for surgery ^[1]. VT/VF from myocardial fibrosis → sudden death (uncommon).

IE: AR valve is susceptible (turbulent flow → endothelial damage → NBTE → bacterial seeding). Can cause acute worsening (cusp destruction), embolism, abscess. IE despite optimal therapy = indication for surgery ^[1].

Aortic root complications: Dissection (acute severe AR + tamponade), rupture. Particularly relevant in Marfan, bicuspid aortopathy.

Post-AVR complications: Heart block (2–5%, proximity to conduction system) ^[2], CVA, bleeding, PVE ^[2]. Late: structural valve degeneration (bioprosthetic ~50% failure at 15 years) ^[9], thromboembolism (mechanical — needs lifelong warfarin), haemolysis, paravalvular leak.

PVE: Early (< 60d) = staphylococcal; Late (> 60d) = streptococcal/enterococcal. All prosthetic valves = high-risk group for IE prophylaxis ^[1].

Active Recall - Complications of Aortic Regurgitation

References

^[1] Senior notes: Maksim Medicine Notes.pdf (p15, p35, p37 — Aortic dissection, Valvular heart disease, Terminologies and indications for surgery sections) ^[2] Senior notes: Ryan Ho Cardiology.pdf (p155, p158, p160–161, p220 — MR, AS, AR, Aortic dissection sections) ^[6] Senior notes: Maksim Medicine Notes.pdf (p15 — Aortic dissection section) ^[9] Senior notes: Ryan Ho Cardiology.pdf (p163 — Prosthetic heart valves section)

Aortic Regurgitation

Definition

Epidemiology

Anatomy and Function of the Aortic Valve

Normal Aortic Valve Anatomy

Normal Function

Aetiology

A. Valvular (Cusp) Disease

B. Aortic Root / Ascending Aorta Dilation (Supravalvular)

Pathophysiology

Chronic AR — The Compensated Phase

Chronic AR — The Decompensated Phase

Angina in AR — A Double Hit

Acute AR — No Time to Compensate

Classification

By Chronicity

By Mechanism (Carpentier-like for Aortic Valve)

By Severity (Echocardiographic — 2020/2021 ACC/AHA Guidelines)

Clinical Features

Symptoms

A. Chronic Compensated AR

B. Chronic Decompensating / Decompensated AR

C. Acute AR

Signs

General Inspection and Peripheral Signs

Precordial Examination

Auscultation

Signs of Severity of AR [1]

Signs Specific to the Underlying Cause

Summary of Pathophysiology → Clinical Features Linkage

Active Recall - Aortic Regurgitation (Definition to Clinical Features)

References

Level 1: Differential Diagnosis of the Early Diastolic Murmur

Level 2: Differential Diagnosis of the Wide Pulse Pressure / Hyperdynamic Circulation

Level 3: DDx of the Austin-Flint Murmur vs. True Mitral Stenosis

Level 4: DDx of Chest Pain in a Patient with Known AR

Level 5: DDx of Dyspnoea in a Patient with AR

Systematic Approach to the Aetiological Differential

Summary Flowchart: Clinical Approach to the DDx of AR Presentation

Active Recall - DDx of Aortic Regurgitation

Important Principle: AR is Not Diagnosed by "Criteria" — It is Diagnosed by Echocardiography

Echocardiographic Grading of AR Severity

Qualitative and Semi-Quantitative Parameters

Quantitative Parameters (PISA / Volumetric Method)

Supportive LV Parameters

Diagnostic Algorithm

Investigation Modalities: Detailed Breakdown

1. Electrocardiogram (ECG)

2. Chest X-ray (CXR)

3. Echocardiography (The Gold Standard)

A. Assessment of AR Severity

B. Assessment of LV Size and Function

C. Assessment of the Aortic Root and Ascending Aorta

D. Transesophageal Echocardiography (TEE)

4. CT Thoracic Aortography

5. Cardiac MRI (CMR)

6. Coronary Angiogram

7. Blood Tests

8. Exercise Testing

Key Diagnostic Pitfalls

Summary Table: Investigation Modalities at a Glance

Active Recall - Diagnosis and Investigations for AR

Guiding Principles

Management Algorithm

A. Medical Management

1. Vasodilators for Hypertension

2. Diuretics

3. Beta-Blockers — A Nuanced Agent in AR

4. Drugs to AVOID in Chronic AR

B. Surgical Management — Aortic Valve Replacement (AVR)

Why Repair is Rarely Possible for the Aortic Valve

Indications for Surgery

Class I Indications (Surgery Recommended — Strong Evidence)

Class IIa Indications (Surgery Should Be Considered)

Aortic Root / Ascending Aorta Indications

Surgical Approaches

Valve Prosthesis Options

Aortic Root Replacement Procedures

Transcatheter AVR (TAVR/TAVI) — NOT for AR

Surgical Outcomes