Aortic regurgitation natural history, complications and prognosis
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Aortic Regurgitation Microchapters |
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Diagnosis |
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Treatment |
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Acute Aortic regurgitation |
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Chronic Aortic regurgitation |
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Special Scenarios |
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Case Studies |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-in-Chief: Varun Kumar, M.B.B.S.; Lakshmi Gopalakrishnan, M.B.B.S.
Overview
In acute aortic insufficiency symptoms of heart failure often develop acutely. Chronic aortic insufficiency is usually insidious and progressive and the patient may remain asymptomatic for years. Once left ventricular dilation and left ventricular failure occur, dyspnea on exertion and exercise intolerance begin to occur. Later symptoms such as angina, syncope, and other symptoms of heart failure are present.
Natural History
Acute Aortic Insufficiency
In acute aortic insufficiency symptoms of heart failure such as pulmonary edema often develop acutely. Acute aortic insufficiency is often secondary to either trauma or infective endocarditis. While the heart can accommodate the changes of chronic aortic insufficiency over time, the acute changes of acute aortic insufficiency are not well accommodated by the left ventricle.
The rapid rise in left ventricular pressure causes the mitral valve to close earlier during diastole. This early closure fortunately prevents backwards flow of blood into the pulmonary vascular bed. The very high left ventricular end diastolic pressure often keeps the aortic diastolic pressure from falling too low and thus there is often not a wide pulse pressure. Indeed absence of a wide pulse pressure in the patient with acute aortic insufficiency should alert the clinician to potential failure of the left ventricle.
Chronic Aortic Insufficiency
Chronic aortic insufficiency is usually insidious and progressive and the patient may remain asymptomatic for years. Once left ventricular dilation and left ventricular failure occur, dyspnea on exertion and exercise intolerance begin to occur. Later symptoms such as angina, syncope, and other symptoms of heart failure are present. The hemodynamic impact of aortic regurgitation causes progressive dilation and hypertrophy of the left ventricle. The mitral valve ring may also dilate which may lead in turn to mitral regurgitation. The left atrium may dilate as a result of the mitral regurgitation. It has been said that 'aortic regurgitation begets aortic regurgitation'. The high oscillatory shear associated with aortic regurgitation may lead to further dilation of the aorta, which in turn may lead to further aortic regurgitation.
Volume overload associated with aortic regurgitation leads to left ventricular hypertrophy. The sarcomeres replicate in series and there is elongation of the myocytes and myocardial fibrils. As a result of this hypertrophy the ratio of the ventricular wall thickness to cavity radius remains normal and therefore wall stress is normal. In aortic regurgitation there is eccentric hypertrophy where as in aortic stenosis there is concentric hypertrophy where there is replication of the sarcomeres in parallel. Once wall thickening fails to keep up with the hemodynamic load, end systolic wall stress rises and at this point the left ventricle fails. The dramatic enlargement of the heart that is seen with aortic regurgitation is called cor bovinum. Over time the left ventricle will decompensate and there will be increasing interstitial fibrosis and a stiffening or a reduction in the compliance of the left ventricular wall. At this point the patient will experience a rise in the end diastolic pressure and volume. The first decline is seen with exercise and then the patient begins to have a reduction in forward output at rest.
Patients with chronic aortic insufficiency may also develop myocardial ischemia. This is due to the fact that they have an increase in demand due to an increased thickness of the LV and also a reduction in the supply due to a lower perfusion pressure during diastole.
Complications
Acute Aortic Insufficiency
- Left ventricular volume overload in a non-compliant left ventricle with acute left ventricular failure
- Pulmonary edema
- Sudden cardiac death
Chronic Aortic Insufficiency
- Heart failure
- Arrhythmia
- Myocardial ischemia
- Aortic dissection in patients with bicuspid aortic valve
- Infective endocarditis
Prognosis
The prognosis and survival of patients with symptomatic aortic regurgitation has improved significantly over the last decade. The five year survival rate for symptomatic patients is now more than 80 percent.
Acute Aortic Insufficiency
The prognosis among patients with aortic insufficiency is poor with a high mortality and morbidity due to the acute onset of left ventricular failure, pulmonary edema, or myocardial ischemia due to the abrupt rise in LV wall stress and sudden cardiac death.[1] Early surgical intervention improves the prognosis in these patients.
Chronic Aortic Insufficiency
Asymptomatic Patients
- Mortality rate ≈ 2.8% per year
- Asymptomatic patients with normal ejection fraction:
- Rate of progression to symptoms or left ventricular dysfunction ≤ 6% per year
- Rate of progression to asymptomatic left ventricular dysfunction ≤ 3.5% per year
- Rate of sudden death ≤ 0.2% per year
- Asymptomatic patients with reduced ejection fraction:
- Rate of progression to symptoms ≥ 25% per year
Symptomatic Patients
- Mortality rate ≥ 10% per year
- NYHA class I - 3.0% per year
- NYHA class II - 6.3% per year
- NYHA class III-IV - 24.6% per year
Chronic Severe Aortic Insufficiency Managed Conservatively[2]
- Death from any cause - 4.7% per year
- Congestive heart failure - 6.2% per year
- Aortic valve surgery - 14.6% per year
References
- ↑ Bonow RO, Carabello BA, Chatterjee K, de Leon AC, Faxon DP, Freed MD, Gaasch WH, Lytle BW, Nishimura RA, O'Gara PT, O'Rourke RA, Otto CM, Shah PM, Shanewise JS (2008). "2008 Focused update incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons". Circulation. 118 (15): e523–661. doi:10.1161/CIRCULATIONAHA.108.190748. PMID 18820172. Retrieved 2011-04-19. Unknown parameter
|month=ignored (help) - ↑ Dujardin KS, Enriquez-Sarano M, Schaff HV, Bailey KR, Seward JB, Tajik AJ (1999). "Mortality and morbidity of aortic regurgitation in clinical practice. A long-term follow-up study". Circulation. 99 (14): 1851–7. PMID 10199882. Retrieved 2011-04-19. Unknown parameter
|month=ignored (help)