Aortic regurgitation

Synonyms: aortic insufficiency, aortic incompetence

What causes aortic regurgitation?¹

Aortic regurgitation (AR) may be caused by either problems with the aortic valve or the aortic root. Valvular abnormalities causing AR include:

• Bicuspid aortic valve (the most common congenital cause). ²

• Rheumatic fever.

• Infective endocarditis.

• Collagen vascular diseases.

• Degenerative aortic valve disease.

How common is aortic regurgitation? (Epidemiology)¹

• Rheumatic heart disease is the most common cause of aortic regurgitation throughout the world.

• In developed countries, congenital and degenerative valve abnormalities are the most common cause and the peak age of presentation is 40-60 years.

• Estimates of the prevalence of AR of any severity range from 2-30% but only a minority of patients with AR have severe disease.

• Moderate or severe AR is common after transcatheter aortic valve replacement.³

Risk factors

• Aortic regurgitation can occur in systemic lupus erythematosus. It may also occur in Marfan's syndrome, Ehlers-Danlos syndrome type IV and Turner syndrome. AR as a result of advanced syphilis with aortic aneurysm is rarely seen nowadays.

• Aortic dilatation causing AR can also occur with ankylosing spondylitis and reactive arthritis, and after Takayasu's disease.

• It may also occur with Behçet's disease.

• Acute severe aortic regurgitation is most often caused by infective endocarditis or aortic dissection.

Aortic regurgitation symptoms (presentation)

See also the separate Heart Auscultation, Heart Murmurs in Children and Pulse Examination articles.

• Aortic regurgitation is diagnosed by the presence of a characteristic diastolic murmur, exaggerated arterial pulsations and low diastolic pressure.

• In acute AR, peripheral signs are attenuated. Cardiovascular collapse is the most obvious and common presentation of acute AR but findings may be subtle and the clinical presentation is often nonspecific.⁴
  

• In AR, the pulse pressure will be wide with a sudden collapse of the pulse at the end. The classical Corrigan or 'water hammer' pulse is rarely felt these days, as such marked disease is surgically corrected.⁵ For similar reasons, signs associated with very high pulse pressure, such as the head bobbing with each pulse and pulsus bisferiens, are largely of historical interest.

• Aortic regurgitation murmur:⁶

• • S1 is soft and there is an early diastolic murmur, best heard in the aortic area, with the patient sitting forward and in expiration. Both the murmur of regurgitation and the flow murmur from aortic dilatation are not well transmitted to the carotids. If significant regurgitation means that the stroke volume is very high, there will be an ejection flow murmur too.

  • In infective endocarditis, the only feature may be a change in nature of the murmur.

  • Rarely, the aortic valve may collapse and become completely incompetent, producing the sound of 'a cooing dove'. This requires urgent valve replacement.

Investigations⁷

• ECG.

• CXR.

• Echocardiography is the key examination in the diagnosis and quantification of aortic regurgitation severity, using colour Doppler and pulsed-wave Doppler.

• Cardiac magnetic resonance (CMR) or multi-slice computerised tomography (MSCT) scanning is recommended for evaluation of the aorta in patients with Marfan's syndrome, or if an enlarged aorta is detected by echocardiography, especially in patients with bicuspid aortic valves.

• Cardiac catheterisation is used to assess coronary anatomy before surgery in patients with the appropriate age and risk factor profile. Invasive assessment of left ventricular function and AR severity is reserved for selected patients in whom non-invasive imaging is inconclusive.⁸

Aortic regurgitation treatment and management⁷

• In symptomatic acute severe aortic regurgitation, urgent surgical intervention is indicated.

• In chronic severe AR, the goals of treatment are to prevent death, to diminish symptoms, to prevent the development of heart failure and to avoid aortic complications.

• Patients with Marfan's syndrome, or others with borderline aortic root diameters approaching the threshold for intervention, should be advised to avoid strenuous physical exercise and competitive, contact, and isometric sports.

• Given the family risk of thoracic aortic aneurysms, screening of first-degree relatives with appropriate imaging studies is indicated in Marfan's syndrome patients and should be considered in bicuspid patients with aortic root disease.

Monitoring

• Patients with mild-to-moderate aortic regurgitation can be reviewed on a yearly basis and echocardiography performed every two years.

• All patients with severe AR and normal left ventricular function should be seen for follow-up at six months after their initial examination.

• If left ventricular diameter and/or ejection fraction show significant changes, or become close to the threshold for intervention, follow-up should be continued at six-monthly intervals.

• Patients with stable parameters should be followed annually.

• In patients with a dilated aorta, especially in patients with Marfan's syndrome or with a bicuspid valve, echocardiography should be performed on a yearly basis.

• MSCT or CMR are recommended when the distal ascending aorta is not well visualised and/or when the surgical indication may be based on aortic enlargement, rather than left ventricular size or function.

Medical therapy

• Vasodilators and inotropic agents may be used for short-term therapy for patients with severe heart failure before proceeding with aortic valve surgery.

• In individuals with chronic severe aortic regurgitation and heart failure, angiotensin-converting enzyme (ACE) inhibitors or angiotensin-II receptor antagonists are useful in the presence of hypertension, when surgery is contra-indicated, or left ventricular dysfunction persists postoperatively.

• In patients with Marfan's syndrome, beta-blockers may slow aortic root dilatation and reduce the risk of aortic complications and should be considered before and after surgery.

Surgery

• Indications for surgery:⁹
  

  • Symptomatic patients.

  • Asymptomatic patients should also be operated on when left ventricular function begins to deteriorate (LVEF <55%) or when end systolic diameter is >50 mm or end systolic diameter index is >24 mm² on echocardiography, since the likelihood of developing irreversible myocardial dysfunction is high if intervention is delayed.

• Treatment of isolated AR has traditionally been by valve replacement. Valve replacement remains the most widely used technique but the proportion of valve repair procedures is increasing in experienced centres.¹⁰

• Surgery is recommended via median sternotomy or minimally invasive route, although transcatheter aortic valve insertion (TAVI) is not recommended for low or intermediate surgical risk.

• When there is an associated aneurysm of the aortic root, conventional surgical therapy has consisted of the combined replacement of the aorta and valve with re-implantation of the coronary arteries.

• Valve-sparing aortic replacement is increasingly employed in expert centres, especially in young patients, to treat combined aortic root dilatation and valve regurgitation:
  

  • Aortic valve-sparing operations which preserve the aortic cusps in aortic root dilation with aortic insufficiency can also be performed.¹¹

  • Aortic valve-sparing operations have been shown to have improved long-term survival and a reduced risk of aortic insufficiency and thromboembolic complications.¹¹

Prognosis⁷

• Patients with acute severe aortic regurgitation have a poor prognosis without intervention, due to their haemodynamic instability.

• Patients with chronic severe AR and symptoms also have a poor long-term prognosis. Chronic aortic regurgitation results in left ventricular dilation and increased left ventricular work, eventually leading to a decline in left ventricular function and to heart failure.¹²

• Once symptoms become apparent, mortality in patients without surgical treatment may be as high as 10-20% per year.

• The strongest predictors of death or aortic complications for patients with ascending aortic and root aneurysms are the root diameter and a family history of acute cardiovascular events (aortic dissection, sudden death).