Aortic Regurgitation: Symptoms, Types, Causes and Treatment

Aortic regurgitation (AR) is a complex valvular heart disease that poses unique diagnostic and therapeutic challenges. Characterized by the backflow of blood from the aorta into the left ventricle during diastole, AR can remain silent and clinically compensated for years or present suddenly with catastrophic symptoms. Understanding its symptoms, types, causes, and treatment options is crucial for patients, clinicians, and researchers alike.

Symptoms of Aortic Regurgitation

The clinical presentation of aortic regurgitation is remarkably variable, depending on whether the disease is acute or chronic, and on the severity of the regurgitation. Many individuals with chronic AR remain asymptomatic for years, even in the presence of significant hemodynamic changes and left ventricular enlargement. This long asymptomatic phase is especially common among younger individuals and can persist for decades, with symptoms typically emerging in the fourth or fifth decade of life as cardiac reserve diminishes 1 2 5.

Common Symptoms

When symptoms do appear, they often reflect the heart’s reduced ability to compensate for the regurgitant volume. The most frequently reported symptoms include:

• Dyspnea (shortness of breath): Often initially present during exertion and later at rest as heart failure develops.
• Fatigue: Due to diminished cardiac output and reduced perfusion of the body’s tissues.
• Palpitations: Patients may experience awareness of their heartbeat, which can be irregular or forceful.
• Chest pain (angina): While less common, some individuals may experience chest discomfort, although true ischemic pain is rare in AR 1.
• Orthopnea and paroxysmal nocturnal dyspnea: These symptoms, associated with advanced heart failure, may occur as the disease progresses.

It is important to note that the severity of symptoms does not always correlate with the degree of regurgitation or left ventricular hypertrophy. Some patients with severe AR and marked ventricular changes may continue to feel well, whereas others develop symptoms earlier 1 2.

Symptoms of Acute Aortic Regurgitation

In contrast to the often indolent course of chronic AR, acute AR is a medical emergency. Symptoms develop rapidly and may include:

• Sudden severe dyspnea
• Pulmonary edema
• Severe hypotension
• Signs of cardiogenic shock

Acute AR can be difficult to diagnose clinically because its presentation may mimic other acute illnesses such as sepsis or pneumonia. If untreated, it can quickly lead to advanced heart failure and early death 2 5.

Physical Findings

Characteristic peripheral signs are often present in chronic AR due to the widened pulse pressure and high stroke volume:

• Bounding pulses (Corrigan pulse)
• “Water hammer” pulse
• De Musset’s sign (head bobbing with each heartbeat)
• Quincke’s pulse (capillary pulsations in the nail beds)

These signs reflect the distinctive hemodynamic state produced by AR, with high systolic and low diastolic pressures 2.

Types of Aortic Regurgitation

Aortic regurgitation is broadly classified into two types, each with distinct pathophysiological and clinical features: chronic and acute AR.

Chronic Aortic Regurgitation

Chronic AR develops gradually, allowing the left ventricle time to adapt to the increased volume load through chamber dilation and hypertrophy. This adaptation delays the onset of symptoms, and many patients remain asymptomatic for years. Over time, however, persistent volume overload leads to progressive ventricular dilation, declining systolic function, and eventually heart failure 1 2 5.

• Hemodynamic Features: Chronic AR causes both volume and pressure overload of the left ventricle, leading to systolic hypertension and a widened pulse pressure 2.
• Clinical Course: The disease course is often protracted. Hemodynamic abnormalities generally precede symptom onset, and patients may have significant ventricular dysfunction before symptoms develop 1.

Acute Aortic Regurgitation

Acute AR is characterized by a sudden onset of regurgitation, often overwhelming the left ventricle, which has not had time to adapt.

• Causes: Acute AR most frequently results from infective endocarditis, aortic dissection, or trauma 5 6.
• Clinical Presentation: Unlike chronic AR, acute AR presents with rapid hemodynamic deterioration, including pulmonary edema, hypotension, and signs of cardiogenic shock 2 5.
• Urgency: Acute severe AR is a surgical emergency. Without prompt intervention, mortality is high 5 6.

Severity Grading

Aortic regurgitation is further graded by severity—ranging from mild to severe—usually via echocardiography. Even mild regurgitation, especially after procedures like transcatheter aortic valve replacement (TAVR), is associated with increased long-term mortality, underscoring the importance of precise grading and follow-up 3.

Mechanistic and Anatomic Subtypes

AR can also be classified based on the underlying valve anatomy (tricuspid, bicuspid, unicuspid, or quadricuspid valves) and the pathophysiological mechanism (cusp prolapse, restriction, root dilation, perforation, or mixed mechanisms) 4. This detailed classification is particularly relevant for surgical planning.

Causes of Aortic Regurgitation

The causes of AR are diverse, encompassing congenital and acquired conditions affecting either the aortic valve itself or the surrounding aortic root and ascending aorta. The relative frequency of these causes can vary by age, region, and over time.

Valve Abnormalities

1. Congenital Malformations:

   • Bicuspid aortic valve is a common congenital cause, predisposing to incomplete valve closure and later AR 4 7 9.
   • Quadricuspid and unicuspid valves are rare but recognized causes 4 7.

2. Idiopathic (Degenerative) Valve Disease:

   • Idiopathic degeneration, characterized by altered collagen and elastic fibers, is a frequent cause of isolated AR, particularly in older adults 4 7 11.
   • Redundant, thickened, or retracted valves with no identifiable etiology often fall into this category 11.

3. Postinflammatory Disease:

   • Historically, rheumatic fever was a leading cause of AR, producing scarring and retraction of the valve cusps. Its incidence has declined in Western countries 7 9.

4. Infective Endocarditis:

   • Infection of the aortic valve can result in perforation, cusp destruction, and acute or chronic AR 5 7 9.

Aortic Root and Ascending Aorta Abnormalities

1. Aortic Root Dilatation:

   • Dilatation of the aortic root (including the sinuses of Valsalva and the sinotubular junction) is now a leading cause of severe AR, especially in older adults 7 8 9 10.
   • Root dilation may be idiopathic or associated with connective tissue disorders (e.g., Marfan syndrome) 8 9.
   • Generalized dilation is linked to more severe left ventricular dysfunction and a greater likelihood of requiring surgery 8.
   • Dilatation of the sinotubular junction can specifically cause AR by preventing proper valve coaptation 10.

2. Aortic Dissection:

   • Acute type A aortic dissection can disrupt the aortic annulus or the valve itself, resulting in acute severe AR 5 6 9.

3. Aortitis:

   • Inflammatory diseases such as Takayasu arteritis or other forms of aortitis may damage the aortic root or valve, leading to AR 9 12.

Other and Unclear Causes

• Ventricular septal defects and other congenital heart diseases can occasionally result in AR 7 9.
• In a significant proportion of patients, particularly older adults with hypertension and minor valve calcification, the cause remains unclear even after thorough evaluation 9.

Changing Epidemiology

The relative importance of these causes has shifted over time, with aortic root dilatation becoming increasingly recognized as the most common cause of pure AR in surgical populations, as the incidence of rheumatic heart disease declines 7 8 9.

Treatment of Aortic Regurgitation

The management of AR depends on the type (acute or chronic), severity, symptoms, and underlying cause. Treatment strategies range from careful monitoring and medical therapy to advanced surgical and transcatheter interventions.

Medical Therapy

Chronic Aortic Regurgitation

• Asymptomatic Patients with Normal Left Ventricular Function:

  • These patients may remain stable for years. Regular follow-up with echocardiography is essential to monitor for the onset of symptoms or left ventricular dilation/dysfunction 1 2.
  • Vasodilator therapy (e.g., ACE inhibitors, nifedipine) can be used to reduce systolic blood pressure and afterload, potentially delaying surgery in patients with hypertension or high afterload 2.
  • Beta-blockers (such as carvedilol) have shown promise in animal models, reducing left ventricular hypertrophy and improving function, but their role in humans remains under study 15.

• Symptomatic Patients or Those with Left Ventricular Dysfunction:

  • Medical therapy is primarily a bridge to surgery or an option for those unable to undergo surgery 2 15.

Acute Aortic Regurgitation

• Urgent medical stabilization is required, often involving intravenous vasodilators and inotropic support, but definitive therapy is surgical 2 5.

Surgical Therapy

Aortic Valve Replacement (AVR):

• The gold standard for severe symptomatic AR or patients with evidence of left ventricular dysfunction (ejection fraction <55% or end-diastolic dimension ≥55 mm) 2.
• Timing of surgery is critical; irreversible myocardial damage may occur before symptoms become severe, creating a therapeutic dilemma 1 2.

Valve-Sparing and Repair Techniques:

• In selected patients, particularly those with aortic root aneurysm or suitable valve anatomy, valve-sparing root replacement (reimplantation technique) offers excellent long-term survival and durability, with low rates of valve-related complications 4 16.
• The choice between repair and replacement is influenced by valve anatomy (bicuspid vs tricuspid), mechanism of AR (prolapse, restriction, root dilation), and surgical expertise 4 16.

Transcatheter Aortic Valve Replacement (TAVR)

• TAVR has traditionally been used for aortic stenosis, but experience is growing in high-risk patients with native AR who are not candidates for surgery 13 14.
• Device success and clinical outcomes have improved with newer generation transcatheter heart valves, though challenges remain, particularly in non-calcific, pure AR 14.
• TAVR is associated with acceptable early mortality and can be considered for patients at prohibitive surgical risk 13 14.
• However, even mild residual AR after TAVR is associated with increased long-term mortality, emphasizing the need for careful patient selection and device choice 3.

Special Considerations

• Aortic Dissection and Infective Endocarditis:
  • Acute AR due to these causes requires emergent surgical intervention, often involving complex aortic and valve repair or replacement 5 6.
• Aortitis (e.g., Takayasu arteritis):
  • Surgical management must account for the underlying inflammatory process and the potential for recurrence or progression 12.

Monitoring and Long-Term Care

• Echocardiography remains the cornerstone of diagnosis, severity assessment, and surveillance 2 4.
• Patients with repaired or replaced valves require ongoing follow-up for the detection of complications such as prosthetic valve dysfunction, endocarditis, or progressive aortic disease.

Conclusion

Aortic regurgitation is a multifaceted disease with a wide spectrum of clinical presentations, underlying mechanisms, and management strategies. While many patients with chronic AR remain asymptomatic for years, the risk of sudden decompensation and irreversible cardiac damage underscores the need for vigilant monitoring and timely intervention. Advances in surgical and transcatheter techniques have expanded treatment options, particularly for high-risk and anatomically complex cases. Ongoing research into medical therapies and molecular mechanisms holds promise for further improving outcomes in this challenging condition. By integrating careful clinical assessment, individualized therapy, and the latest technological innovations, clinicians can offer patients with AR a promising outlook for the future.