Synonyms: aortic insufficiency, aortic incompetence
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).
- Rheumatic fever.
- Infective endocarditis.
- Collagen vascular diseases.
- Degenerative aortic valve disease.
- Rheumatic heart disease is the most common cause of AR 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.
- AR can occur in systemic lupus erythematosis. 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 AR is most often caused by infective endocarditis or aortic dissection.
- AR 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, 5]
- 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. 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:
- 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.
- Echocardiography is the key examination in the diagnosis and quantification of AR 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.
- In symptomatic acute severe AR, 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.
- Patients with mild-to-moderate AR 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.
- 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 AR 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.
- Indications for surgery:
- Symptomatic patients.
- Asymptomatic patients should also be operated on when left ventricular function begins to deteriorate, 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.
- 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.
- Aortic valve-sparing operations have been shown to have improved long-term survival and a reduced risk of aortic insufficiency and thromboembolic complications.
- Supra-coronary ascending aortic replacement can be performed with or without valve repair when root size is preserved. Replacement of the aortic valve with a pulmonary autograft is less frequently used and is mostly applied in young patients.
- Operative mortality is low (1-4%) in isolated aortic valve surgery, both for replacement and repair. Mortality increases with advanced age, impaired left ventricular function, and the need for concomitant coronary artery bypass grafting (CABG).
- Aortic root surgery with re-implantation of coronary arteries has a slightly higher mortality than isolated valve surgery.
- Patients with acute severe AR 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.
- 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).
Further reading and references
Nishimura RA, Otto CM, Bonow RO, et al; 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014 Jun 10129(23):2440-92. doi: 10.1161/CIR.0000000000000029. Epub 2014 Mar 3.
Siu SC, Silversides CK; Bicuspid aortic valve disease. J Am Coll Cardiol. 2010 Jun 2255(25):2789-800.
Guidelines on the management of valvular heart disease; European Society of Cardiology (2012)
Athappan G, Patvardhan E, Tuzcu EM, et al; Incidence, predictors, and outcomes of aortic regurgitation after transcatheter aortic valve replacement: meta-analysis and systematic review of literature. J Am Coll Cardiol. 2013 Apr 1661(15):1585-95. doi: 10.1016/j.jacc.2013.01.047.
Hamirani YS, Dietl CA, Voyles W, et al; Acute aortic regurgitation. Circulation. 2012 Aug 28126(9):1121-6. doi: 10.1161/CIRCULATIONAHA.112.113993.
Mokadam NA, Stout KK, Verrier ED; Management of acute regurgitation in left-sided cardiac valves. Tex Heart Inst J. 201138(1):9-19.
Maganti K, Rigolin VH, Sarano ME, et al; Valvular heart disease: diagnosis and management. Mayo Clin Proc. 2010 May85(5):483-500.
Tourmousoglou C, Lalos S, Dougenis D; Is aortic valve repair or replacement with a bioprosthetic valve the best option for a patient with severe aortic regurgitation? Interact Cardiovasc Thorac Surg. 2014 Feb18(2):211-8. doi: 10.1093/icvts/ivt453. Epub 2013 Nov 7.
Schmitto JD, Mokashi SA, Chen FY, et al; Aortic valve-sparing operations: state of the art. Curr Opin Cardiol. 2010 Mar25(2):102-6.
Lin A, Stewart R; Medical treatment of asymptomatic chronic aortic regurgitation. Expert Rev Cardiovasc Ther. 2011 Sep9(9):1249-54.