AORTIC REGURGITATION

✓ Medically ReviewedDISEASEID: MDBT0159🚨 TRIAGE: EMERGENCYICD-10: I35.1

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Definition

CLINICAL DEFINITION

Aortic regurgitation is a valvular heart disease characterised by the retrograde flow of blood from the aorta into the left ventricle during diastole due to incomplete closure or structural incompetence of the aortic valve leaflets or aortic root dilation. It results in left ventricular volume overload, leading to eccentric hypertrophy and eventual left ventricular systolic dysfunction if left untreated.

IN PLAIN ENGLISH

Aortic regurgitation occurs when the aortic valve does not close tightly, allowing blood to leak backward into the heart's main pumping chamber after each heartbeat. Over time, this extra volume forces the heart to work harder and can lead to heart failure if not monitored or treated.

COMMON MISCONCEPTION / WHAT IT DOES NOT MEAN

Aortic regurgitation is NOT aortic stenosis, which involves restricted forward blood flow due to valve narrowing rather than backward leakage. It is also distinct from mitral regurgitation, which involves backflow into the left atrium rather than the left ventricle.

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Word Breakdown

aort-

=aorta (from Greek 'aorte', meaning 'to hang' or 'lifted up', referring to the great artery suspended from the heart)

-regurgitation

=backward flow or surging back (from Latin 'regurgitare' — re- 'back' + gurgitare 'to engulf')

Literal Meaning: The backward flowing condition of the aorta

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Abbreviations

AR=Aortic Regurgitation — standard abbreviation in clinical notes and echocardiography reports

AI=Aortic Insufficiency — synonymous term frequently used interchangeably with AR

LV=Left Ventricle — primary cardiac chamber affected by volume overload in AR

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Synonyms & Variants

Aortic Insufficiency›Aortic Valve Regurgitation›

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Category-Specific Context

As a Disease, aortic regurgitation encompasses a spectrum from acute, life-threatening volume overload (e.g., aortic dissection or endocarditis) to chronic, compensated states where the left ventricle gradually dilates over years. It is classified by aetiology (primary valve disease vs. secondary aortic root disease) and severity (mild, moderate, severe) based on echocardiographic parameters.

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Clinical Context & Usage

CLINICAL SETTINGS

Cardiology ClinicEchocardiography LaboratoryEmergency DepartmentCardiothoracic Surgery WardIntensive Care Unit

USAGE & DOCUMENTATION NOTES

In clinical documentation, severity is typically graded using echocardiographic parameters such as vena contracta width, pressure half-time, and regurgitant volume. Notes often specify whether the AR is acute or chronic, and whether it is primary (valvular) or secondary (aortic root). The classic physical exam finding is documented as an early diastolic decrescendo murmur best heard at the left sternal border.

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Primary Causes & Pathophysiology

PATHOPHYSIOLOGY

In aortic regurgitation, incompetence of the aortic valve allows blood to flow retrograde from the high-pressure aorta into the left ventricle (LV) during diastole. This creates a state of LV volume overload, increasing LV end-diastolic pressure and wall stress. In chronic AR, the LV compensates through eccentric hypertrophy (adding sarcomeres in series) and progressive dilation, which maintains stroke volume and cardiac output for years. Eventually, compensatory mechanisms fail, leading to increased LV end-systolic volume, reduced ejection fraction, and clinical heart failure. In acute AR (e.g., infective endocarditis), the non-compliant LV cannot rapidly dilate, causing a sudden, severe rise in LV end-diastolic pressure that transmits to the pulmonary circulation, resulting in acute pulmonary oedema and cardiogenic shock.

PRIMARY CAUSES

Bicuspid Aortic Valve

Congenital malformation with two leaflets instead of three, leading to abnormal stress, premature calcification, and concurrent aortopathy causing root dilation.

Degenerative Calcific Valve Disease

Age-related wear and tear causing leaflet thickening, retraction, and poor coaptation during diastole.

Aortic Root Dilation (e.g., Marfan syndrome, hypertension)

Dilation of the aortic root and sinotubular junction pulls the valve commissures apart, preventing central leaflet coaptation despite normal leaflets.

Infective Endocarditis

Bacterial vegetation causes leaflet destruction, perforation, or prolapse, leading to acute, severe regurgitation.

Rheumatic Heart Disease

Immune-mediated inflammation causes leaflet thickening, retraction, and commissural fusion, often presenting with mixed stenosis and regurgitation.

Aortic Dissection (Type A)

Dissection flap extends into the aortic root, disrupting commissural support and causing acute, massive regurgitation.

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Drug-Induced Causes

💊 Fenfluramine and dexfenfluramine (withdrawn anorectics) ↗

Mechanism: Serotonergic metabolites stimulate 5-HT2B receptors on cardiac valves, promoting fibroblast proliferation and valvular interstitial thickening leading to retraction.

→ Discontinued globally; monitor exposed patients with echocardiography for progressive valvulopathy.

💊 Ergot-derived dopamine agonists (e.g., cabergoline, pergolide) ↗

Mechanism: Agonism of 5-HT2B receptors induces valvular fibroplasia and leaflet thickening, predominantly affecting left-sided valves.

→ Use lowest effective dose; perform baseline and periodic echocardiographic screening; switch to non-ergot alternatives if AR develops.

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Epidemiology

Prevalence:Mild AR is common in older adults, affecting up to 10% of the population over 65, while moderate-to-severe AR has an estimated prevalence of 0.5% to 1% in the general adult population. Bicuspid aortic valve, present in 1-2% of the population, is the most common cause of AR in developed nations under age 70.

Age Group:Acute AR can occur at any age depending on aetiology (e.g., endocarditis, dissection). Chronic AR typically presents in middle-aged to older adults (40–70 years) due to degenerative changes or bicuspid valve complications, while rheumatic AR presents earlier (20–40 years) in endemic regions.

Sex Predilection:Male

Geographic Distribution:Rheumatic AR remains highly prevalent in low- and middle-income countries (Sub-Saharan Africa, South Asia) due to untreated streptococcal infections. In high-income countries, degenerative disease, bicuspid aortic valve, and aortic root dilation predominate.

Red Flags & Triage ★

TRIAGE LEVEL

🚨 EMERGENCY

DO NOT MISS — LIFE-THREATENING PRESENTATIONS

Acute severe AR with pulmonary oedema — requires urgent surgical consultation for valve replacement, as medical management alone carries a very high mortality rate.
Aortic root dilation in bicuspid aortic valve or Marfan syndrome — the aorta must be measured, as concurrent aneurysm may require prophylactic root replacement even if AR is only moderate.

URGENT EVALUATION TRIGGERS

New-onset early diastolic murmur with signs of heart failure (e.g., dyspnoea, pulmonary oedema) — suggests acute severe AR.
Sudden tearing chest pain with a new diastolic murmur — highly suspicious for acute Type A aortic dissection involving the aortic root.
Fever, positive blood cultures, and a changing diastolic murmur — indicates infective endocarditis with potential leaflet destruction.

Contraindications & Precautions

CONTRAINDICATIONS

Vasodilators in acute severe AR — can cause profound hypotension by reducing diastolic blood pressure
which further compromises coronary perfusion and worsens the regurgitant fraction.
Intra-aortic balloon pump (IABP) — inflation during diastole exacerbates aortic regurgitation and is absolutely contraindicated.
Bradycardia-inducing agents (e.g.
high-dose beta-blockers
non-dihydropyridine CCBs) in severe AR — prolonged diastole increases the time available for regurgitant flow
worsening volume overload.

SPECIAL PRECAUTIONS

Strict blood pressure control — systemic hypertension increases afterload and worsens regurgitant volume; target systolic BP < 130 mmHg using ACE inhibitors or ARBs.
Endocarditis prophylaxis — no longer routinely recommended for native AR
but strict dental hygiene is essential; prophylaxis is required if a prosthetic valve is implanted.
Regular echocardiographic surveillance — asymptomatic patients with severe AR require imaging every 6–12 months to monitor LV dimensions and ejection fraction.

Complications

DOWNSTREAM CLINICAL COMPLICATIONS

Left Ventricular Systolic Dysfunction — progressive eccentric hypertrophy eventually leads to irreversible myocardial fibrosis and reduced ejection fraction.
Heart Failure — volume overload and elevated filling pressures lead to exertional dyspnoea
orthopnoea
and pulmonary oedema.
Infective Endocarditis — abnormal flow jets and damaged endothelium increase susceptibility to bacterial seeding on the valve.
Angina Pectoris — reduced diastolic aortic pressure decreases coronary perfusion pressure while LV hypertrophy increases myocardial oxygen demand.
Aortic Aneurysm and Dissection — particularly in patients with bicuspid aortic valve or connective tissue disorders where aortopathy coexists.

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Confused With (LASA & DDx) ★

LEXICAL (LASA) — SIMILAR NAMES

Aortic Stenosis

Both are aortic valve diseases, but aortic stenosis involves restricted forward flow (systolic murmur) rather than backward leakage (diastolic murmur).

Mitral Regurgitation

Both are regurgitant valvular lesions, but mitral regurgitation involves backflow into the left atrium during systole, producing a pansystolic murmur at the apex.

CLINICAL DIFFERENTIAL DIAGNOSES (DDx)

Pulmonary Regurgitation

Key Distinguishing Feature: Early diastolic murmur (Graham Steell murmur) heard at the left upper sternal border, associated with pulmonary hypertension rather than systemic volume overload.

Aortic Stenosis

Key Distinguishing Feature: Harsh crescendo-decrescendo systolic murmur radiating to the carotids, with a delayed and diminished carotid upstroke (pulsus parvus et tardus).

Mitral Stenosis

Key Distinguishing Feature: Low-pitched mid-diastolic rumble with an opening snap at the apex, causing left atrial enlargement rather than left ventricular dilation.

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Clinical Pearls

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The classic physical sign of chronic severe AR is a widened pulse pressure with bounding peripheral pulses (Corrigan's pulse or water-hammer pulse), resulting from a high systolic stroke volume and rapid diastolic run-off into the LV.

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In chronic AR, the apex beat is displaced laterally and inferiorly due to massive LV dilation, and a third heart sound (S3) may be present, indicating rapid ventricular filling and advanced volume overload.

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Medical therapy with vasodilators does not delay the need for surgery in asymptomatic patients with normal LV function; it is primarily indicated for symptom control in heart failure or for blood pressure management in patients with concurrent hypertension.

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The Austin Flint murmur, a mid-to-late diastolic rumble heard at the apex in severe AR, is caused by the regurgitant jet directing the anterior mitral leaflet into the LV inflow tract, functionally mimicking mitral stenosis without structural mitral valve disease.

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Example Usage & SOAP

CLINICAL SENTENCE

"Transthoracic echocardiogram reveals severe eccentric aortic regurgitation with a vena contracta of 8 mm, pressure half-time of 180 ms, and a dilated left ventricle with an end-diastolic dimension of 68 mm and preserved ejection fraction of 55%."

IN A SOAP NOTE

S: 54-year-old male with known bicuspid aortic valve presents with progressive exertional dyspnoea (NYHA class II-III) over the past 3 months. O: BP 145/50 mmHg, bounding radial pulses. Laterally displaced and hyperdynamic apex beat. Grade 3/6 early diastolic decrescendo murmur at the left lower sternal border. TTE: Severe AR, LV EDV 180 mL, LVEF 52%, aortic root 46 mm. A: Symptomatic severe primary aortic regurgitation with early LV systolic decline (EF < 55% in the context of severe AR is a trigger for surgery per ACC/AHA guidelines). P: Refer to cardiothoracic surgery for aortic valve replacement. Optimise afterload reduction with ramipril 5 mg daily. Repeat TTE in 4 weeks if surgery is delayed.

DIFFERENTIAL DIAGNOSIS CONTEXT

Differential for an early diastolic murmur: (1) Aortic regurgitation (best heard at left sternal border, widened pulse pressure, LV dilation); (2) Pulmonary regurgitation (Graham Steell murmur, associated with loud P2 and right ventricular heave due to pulmonary hypertension); (3) Aortic root dilation vs. primary leaflet disease (requires echocardiography to assess sinotubular junction and leaflet morphology).

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Classifications & Scoring

GRADING SYSTEM

ASE/EACVI Grading of Valvular Regurgitation

Classifies AR severity into mild, moderate, and severe based on structural and Doppler parameters. Severe AR is defined by a vena contracta width ≥ 6 mm, regurgitant volume ≥ 60 mL, regurgitant fraction ≥ 50%, and pressure half-time < 200 ms.

View Reference ↗

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Prognosis

SHORT-TERM OUTCOME

Asymptomatic patients with normal LV function have an excellent short-term prognosis with a rate of progression to symptoms or LV dysfunction of roughly 4% per year. Acute severe AR carries a high short-term mortality without urgent surgical intervention.

LONG-TERM PROGNOSIS

Once symptoms (dyspnoea, angina) or LV systolic dysfunction (LVEF < 50%) develop, the prognosis declines rapidly without surgery, with mortality exceeding 10-20% per year. Timely aortic valve replacement yields long-term survival rates comparable to the age-matched general population, though patients remain at risk for prosthetic valve complications or progressive aortopathy.

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References & Coding

ICD-10 DIAGNOSTIC CODE

I35.1

LITERATURE CITATIONS & GUIDELINES

[1]Otto CM et al. 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease. J Am Coll Cardiol. 2021;77(4):e25-e197.

[2]Vahanian A et al. 2021 ESC/EACTS Guidelines for the management of valvular heart disease. Eur Heart J. 2022;43(7):561-632.

[3]Zoghbi WA et al. Recommendations for Noninvasive Evaluation of Native Valvular Regurgitation: A Report from the American Society of Echocardiography. J Am Soc Echocardiogr. 2017;30(4):303-371.

MEDICAL DISCLAIMER — This content is intended for educational purposes and qualified healthcare professionals only. Always refer to current clinical diagnostic criteria, institutional protocols, and official guidelines. Medobo is not responsible for clinical decisions made based on this content.