Aortic Regurgitation: Causes, Symptoms, Diagnosis, Management and Prevention

Aortic Regurgitation: Causes, Symptoms, Diagnosis and Management

~Introduction

Aortic regurgitation (AR), also known as aortic insufficiency, is a valvular heart disorder characterized by the backward flow of blood from the aorta into the left ventricle during diastole due to improper closure of the aortic valve. This results in volume overload of the left ventricle, compensatory dilation, and eventually heart failure if left untreated.

Aortic regurgitation can develop acutely—posing an immediate life threat—or chronically, allowing the heart to adapt over years. The condition affects both men and women and can arise from various causes including congenital malformations, degenerative changes, infection, or aortic root disease.

Timely diagnosis and appropriate management are crucial in preventing irreversible myocardial damage and improving patient outcomes.

~Anatomy and Physiology of the Aortic Valve

The aortic valve lies between the left ventricle and the aorta, ensuring unidirectional blood flow during the cardiac cycle. It normally consists of three cusps—the right coronary, left coronary, and non-coronary cusps—attached to the fibrous annulus of the aortic root.

During systole, the valve opens to allow blood to flow into the aorta. During diastole, it closes tightly to prevent retrograde flow. In aortic regurgitation, this closure mechanism fails, allowing blood to leak back into the ventricle.

The severity of regurgitation depends on:

• The size of the regurgitant orifice

• The pressure gradient between the aorta and the left ventricle

• The duration of diastole

Over time, this backflow leads to volume overload, ventricular dilation, and eccentric hypertrophy.

~Etiology and Causes of Aortic Regurgitation

Aortic regurgitation can result from disease of the aortic valve leaflets, the aortic root, or both. Causes are categorized as acute or chronic depending on the onset and progression.

1. Acute Aortic Regurgitation

Acute AR develops suddenly and is a medical emergency. The left ventricle has no time to adapt to the sudden volume overload, leading to rapid pulmonary edema and cardiogenic shock.

Causes include:

• Infective endocarditis: Bacterial infection damaging valve leaflets

• Aortic dissection: Tear in the aortic wall causing separation of the valve commissures

• Trauma: Blunt chest injury causing valve rupture

• Prosthetic valve failure or iatrogenic injury during cardiac procedures

2. Chronic Aortic Regurgitation

Chronic AR develops gradually, allowing compensatory mechanisms to maintain cardiac output for years before symptoms appear.

Valvular Causes:

• Congenital bicuspid aortic valve

• Rheumatic heart disease

• Degenerative (calcific) disease

• Infective endocarditis (healed stage)

• Ankylosing spondylitis or Reiter’s syndrome

Aortic Root Causes:

• Marfan syndrome or Ehlers-Danlos syndrome (connective tissue disorders)

• Aortic aneurysm or dilation

• Hypertension

• Syphilitic aortitis

• Chronic aortic dissection

~Pathophysiology of Aortic Regurgitation

In AR, blood leaks from the aorta into the left ventricle during diastole. This leads to:

1. Volume overload of the left ventricle

2. Eccentric hypertrophy—the ventricular wall enlarges and dilates to accommodate extra blood

3. Increased stroke volume to maintain forward output

4. Over time, compensatory mechanisms fail, leading to left ventricular dysfunction and heart failure

In acute AR, the ventricle cannot compensate quickly, leading to a rapid rise in diastolic pressure, pulmonary congestion, and hypotension.

In chronic AR, compensatory mechanisms delay symptoms for years until ventricular decompensation occurs.

~Clinical Presentation

1. Acute Aortic Regurgitation

Symptoms appear suddenly and may include:

• Severe dyspnea and orthopnea

• Chest pain

• Hypotension or shock

• Pulmonary edema

It is a medical emergency requiring urgent intervention.

2. Chronic Aortic Regurgitation

Symptoms develop gradually and include:

• Exertional dyspnea (shortness of breath on exertion)

• Palpitations (due to increased stroke volume)

• Fatigue and weakness

• Angina pectoris, especially at night

• Awareness of heartbeat, particularly when lying on the left side

As the disease progresses:

• Paroxysmal nocturnal dyspnea

• Orthopnea

• Heart failure symptoms may occur

~Physical Examination Findings

1. Pulse and Blood Pressure

• Bounding or “water hammer” pulse (Corrigan’s pulse)

• Wide pulse pressure: High systolic and low diastolic pressures

• De Musset’s sign: Head bobbing with each heartbeat

• Quincke’s sign: Capillary pulsations in the nail bed

• Duroziez’s sign: To-and-fro murmur over the femoral artery

2. Cardiac Auscultation

• Early diastolic decrescendo murmur: High-pitched blowing sound best heard at the left sternal border (3rd–4th intercostal space) with the patient leaning forward in full expiration.

• Austin Flint murmur: Low-pitched mid-diastolic rumble at the apex due to regurgitant jet impinging on the mitral valve.

• Systolic flow murmur may also be present due to increased stroke volume.

3. Palpation

• Displaced and hyperdynamic apex beat

• Left ventricular heave due to hypertrophy

~Diagnostic Evaluation

1. Echocardiography

The gold standard for diagnosis and quantification of AR. It assesses:

• Valve morphology and motion

• Regurgitant volume and fraction

• Left ventricular size and function

• Aortic root dimensions

Severity Classification:

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

2. Chest X-Ray

• Cardiomegaly due to LV enlargement

• Aortic root dilation

• Pulmonary congestion in advanced cases

3. Electrocardiogram (ECG)

• Left ventricular hypertrophy with or without strain pattern

• Possible left axis deviation

4. Cardiac MRI

• Precise quantification of regurgitant volume

• Assessment of ventricular size and function

5. Cardiac Catheterization

Used for:

• Hemodynamic assessment

• Coronary artery evaluation before valve surgery

~Natural History and Disease Progression

Chronic aortic regurgitation typically has a long asymptomatic phase. However, once symptoms or LV dysfunction develop, the prognosis worsens rapidly.

Average survival without treatment:

• After onset of angina: 5 years

• After onset of heart failure: 2 years

Therefore, early detection and timely valve replacement before irreversible LV dysfunction occurs are essential.

~Management of Aortic Regurgitation

Management strategies depend on the severity of regurgitation, symptoms, and left ventricular function.

1. Medical Management

Medical therapy aims to reduce afterload, improve forward flow, and control symptoms.

a. Vasodilators

• ACE inhibitors, ARBs, or nifedipine reduce afterload and regurgitant volume.

• Indicated in:

  • Patients with hypertension

  • Those with mild-to-moderate AR and preserved LV function

  • As a bridge to surgery in symptomatic patients not immediately operable

b. Diuretics

Used to relieve pulmonary congestion and heart failure symptoms.

c. Beta-blockers

Used cautiously—can prolong diastole, potentially worsening regurgitation.

d. Lifestyle and Activity

• Avoid strenuous exercise in severe AR

• Maintain blood pressure control

• Regular follow-up with echocardiography every 6–12 months for moderate-to-severe disease

2. Surgical Management

Aortic Valve Replacement (AVR) is the definitive treatment for severe, symptomatic AR or asymptomatic patients with evidence of LV dysfunction.

Indications for Surgery:

• Symptomatic severe AR regardless of LV function

• Asymptomatic severe AR with:

  • LVEF <50%

  • LV end-systolic dimension >50 mm

  • LV end-diastolic dimension >65–70 mm

• AR secondary to aortic root aneurysm requiring repair

Types of Surgery:

• Surgical Aortic Valve Replacement (SAVR):

  • Mechanical valve (durable, requires anticoagulation)

  • Bioprosthetic valve (less durable, no anticoagulation)

• Aortic Root Replacement (Bentall Procedure):

  • For combined valve and root disease

• Valve Repair or Valve-Sparing Aortic Root Surgery:

  • For younger patients or connective tissue disorders

Transcatheter Aortic Valve Replacement (TAVR):

• Limited role in pure AR, but emerging as an option for inoperable high-risk patients.

~Postoperative and Long-Term Management

• Anticoagulation: Required lifelong for mechanical prosthetic valves (target INR 2.0–3.0).

• Endocarditis prophylaxis: Recommended for high-risk patients.

• Echocardiographic follow-up: At 6 months post-surgery, then annually.

• Control of hypertension and aortic dilation with medical therapy.

~Complications of Aortic Regurgitation

If untreated or inadequately managed, AR can lead to:

• Left ventricular failure

• Arrhythmias (atrial fibrillation, ventricular tachycardia)

• Infective endocarditis

• Sudden cardiac death

• Aortic aneurysm or rupture

• Thromboembolism (in prosthetic valve patients)

~Prognosis

The prognosis of aortic regurgitation depends largely on:

• The stage of disease at diagnosis

• Timeliness of surgical intervention

• Left ventricular function

After successful valve replacement, most patients experience dramatic symptomatic improvement and excellent long-term survival.

Without treatment, severe AR leads to progressive heart failure and death within a few years after symptom onset.

~Prevention and Lifestyle Modifications

While congenital and degenerative causes are not preventable, certain measures can reduce risk and slow progression:

• Prompt treatment of streptococcal infections to prevent rheumatic fever

• Regular blood pressure monitoring and control

• Avoid smoking and alcohol abuse

• Routine cardiac evaluations for individuals with bicuspid valves or connective tissue disorders

• Antibiotic prophylaxis in patients with prosthetic valves or previous endocarditis

~Aortic Regurgitation in Special Populations

1. In Athletes

Athletes with mild-to-moderate AR and preserved LV function can often continue sports under close supervision. Severe cases require restriction from competitive activities.

2. In Pregnancy

Chronic AR is usually tolerated well due to reduced systemic vascular resistance in pregnancy, but acute severe AR requires urgent management.

3. In Elderly Patients

Degenerative AR is common; TAVR may offer a minimally invasive alternative to open surgery in high-risk individuals.

~Conclusion

Aortic regurgitation is a significant valvular heart disease with varied causes and presentations. Early detection through echocardiography and clinical vigilance is crucial for optimal outcomes.

While medical therapy can provide symptomatic relief and delay progression, surgical intervention remains the cornerstone of treatment for severe AR. Advances in valve replacement and repair techniques have greatly improved prognosis and quality of life for affected individuals.

With proper management, patients with aortic regurgitation can lead productive, active lives and achieve near-normal survival rates following successful treatment.