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Aortic regurgitation (AR) is incompetency of the aortic valve causing flow from the aorta into the left ventricle during diastole. Causes include idiopathic valvular degeneration, rheumatic fever, endocarditis, myxomatous degeneration, congenital bicuspid aortic valve, aortic root dilatation or dissection, and connective tissue or rheumatologic disorders. Symptoms include exertional dyspnea, orthopnea, paroxysmal nocturnal dyspnea, palpitations, and chest pain. Signs include widened pulse pressure and an early diastolic murmur. Diagnosis is by physical examination and echocardiography. Treatment is surgical aortic valve replacement or repair. Percutaneous valve replacement is being evaluated.
Etiology
AR may be acute or chronic.
The primary causes of acute AR are
Chronic AR in adults is most often caused by
In children, the most common cause is a ventricular septal defect with aortic valve prolapse.
Rarely, AR is caused by seronegative spondyloarthropathies (ankylosing spondylitis, reactive arthritis, psoriatic arthritis), RA, SLE, arthritis associated with ulcerative colitis, luetic (syphilitic) aortitis, osteogenesis imperfecta, thoracic aortic aneurysm, aortic dissection, supravalvular aortic stenosis, Takayasu arteritis, rupture of a sinus of Valsalva, acromegaly, and temporal (giant cell) arteritis. AR due to myxomatous degeneration may develop in patients with Marfan syndrome or Ehlers-Danlos syndrome.
Pathophysiology
In chronic AR, left ventricular (LV) volume and stroke volume gradually increase because the LV receives aortic blood regurgitated in diastole in addition to blood from the pulmonary veins and left atrium. LV hypertrophy compensates for the increase in LV volume over years, but decompensation eventually develops. These changes may ultimately cause arrhythmias, LV impairment, and heart failure (HF).
Symptoms and Signs
Acute AR causes symptoms of HF and cardiogenic shock. Chronic AR is typically asymptomatic for years; progressive exertional dyspnea, orthopnea, paroxysmal nocturnal dyspnea, and palpitations develop insidiously.
Symptoms of HF correlate poorly with objective measures of LV function. Chest pain (angina pectoris) affects only about 5% of patients who do not have coexisting coronary artery disease (CAD) and, when it occurs, is especially common at night. Patients may present with endocarditis (eg, fever, anemia, weight loss, embolic phenomena) because the abnormal aortic valve is predisposed to bacterial seeding.
Signs vary by severity and acuity. In acute AR, the physical signs are less than might be expected from its severe hemodynamic consequences. As chronic disease progresses, systolic BP increases while diastolic BP decreases, creating a widened pulse pressure. With time, the LV impulse may become enlarged, sustained, increased in amplitude, and displaced downward and laterally, with systolic depression of the entire left parasternal area, giving a rocking motion to the left chest.
A systolic apical or carotid thrill may become palpable in later stages of AR; it is caused by large forward stroke volumes and low aortic diastolic pressure.
Auscultatory findings include a normal 1st heart sound (S1) and a nonsplit, loud, sharp or slapping 2nd heart sound (S2) caused by increased elastic aortic recoil. The murmur of AR is often unimpressive. The murmur is blowing, high-pitched, diastolic, and decrescendo, beginning soon after the aortic component of S2 (A2); it is loudest at the 3rd or 4th left parasternal intercostal space. The murmur is heard best with the diaphragm of the stethoscope when the patient is leaning forward, with breath held at end-expiration. It increases in volume in response to maneuvers that increase afterload (eg, squatting, isometric handgrip). If AR is slight, the murmur may occur only in early diastole. If LV diastolic pressure is very high, the murmur is short because aortic and LV diastolic pressures equalize earlier in diastole.
Other abnormal sounds include a forward ejection and backward regurgitant flow (to-and-fro) murmur, an ejection click soon after the S1, and an aortic ejection flow murmur. A diastolic murmur heard near the axilla or mid left thorax (Cole-Cecil murmur) is caused by fusion of the aortic murmur with the 3rd heart sound (S3), which is due to simultaneous filling of LV from the left atrium and AR. A mid-to-late diastolic rumble heard at the apex (Austin Flint murmur) may result from rapid regurgitant flow into the LV, causing mitral valve leaflet vibration at the peak of atrial flow; this murmur mimics the diastolic murmur of mitral stenosis.
Other signs are unusual; sensitivity and specificity are low or unknown. Visible signs include head bobbing (Musset sign) and pulsation of the fingernail capillaries (Quincke sign, best seen with slight pressure) or uvula (Müller sign). Palpable signs include a large-volume pulse with rapid rise and fall (slapping, water-hammer, or collapsing pulse) and pulsation of the carotid arteries (Corrigan sign), retinal arteries (Becker sign), liver (Rosenbach sign), or spleen (Gerhard sign). BP findings may include popliteal systolic pressure ≥ 60 mm Hg higher than brachial pressure (Hill sign) and a fall in diastolic BP of > 15 mm Hg with arm elevation (Mayne sign). Auscultatory signs include a sharp sound heard over the femoral pulse (pistol-shot sound, or Traube sign) and a femoral systolic bruit distal and a diastolic bruit proximal to arterial compression (Duroziez murmur).
Diagnosis
Diagnosis is suspected based on history and physical examination and confirmed by echocardiography. Doppler echocardiography is the test of choice to detect and quantify the magnitude of regurgitant blood flow and grade overall severity of the AR. Two-dimensional echocardiography can quantify aortic root size and anatomy and LV function. An end-systolic LV volume > 60 mL/m2, end-systolic LV diameter > 50 mm, and LV ejection fraction (LVEF) < 50% suggest decompensation. Echocardiography can also assess severity of pulmonary hypertension secondary to LV failure, detect vegetations or pericardial effusions (eg, in aortic dissection), and provide information about prognosis. Transesophageal echocardiography provides additional delineation of aortic dilatation and valve anatomy, which is especially useful when surgical repair is being considered. If the aorta is enlarged, CT or MRI is recommended to evaluate the entire thoracic aorta. MRI also can help assess LV function and degree of AR when echocardiographic images are suboptimal.
Radionuclide imaging may be used to determine LVEF if echocardiographic results are borderline abnormal or if echocardiography is technically difficult.
ECG and chest x-ray should be done. ECG may show repolarization abnormalities with or without QRS voltage criteria of LV hypertrophy, left atrial enlargement, and T-wave inversion with ST-segment depression in precordial leads. Chest x-ray may show cardiomegaly and a prominent aortic root in patients with chronic progressive AR. If AR is severe, signs of pulmonary edema and HF may also be present. Exercise testing may help assess functional capacity and symptoms in patients with documented AR and equivocal symptoms.
Coronary angiography should be done before surgery, even if no angina is present, because about 20% of patients with severe AR have significant CAD, which may need concomitant coronary artery bypass graft surgery.
Prognosis
With treatment, the 10-yr survival for patients with mild to moderate AR is 80 to 95%. With appropriately timed valve replacement (ie, before HF and using criteria below), long-term prognosis for patients with moderate to severe AR is good. However, the prognosis for those with severe AR and HF is considerably poorer.
Treatment
Treatment of acute AR is aortic valve replacement or repair. Valve repair or replacement in chronic AR is indicated when symptoms develop or when certain echocardiographic criteria are met. Criteria include LVEF < 50%, LV end-systolic dimension > 50 to 55 mm, or LV end-diastolic dimension > 70 to 75 mm. Sometimes dilatation of the ascending aorta > 55 mm is the determinant for surgery (> 50 mm in Marfan syndrome and bicuspid aortic valve). If such patients are not candidates for surgery, palliation may be achieved with vasodilators (eg, ACE inhibitors or angiotensin II receptor blockers). Also, diuretics or nitrates to reduce preload may be beneficial for severe AR.
Patients with severe AR who do not meet these criteria for intervention should be reevaluated by physical examination and echocardiography every 6 to 12 mo.
Antibiotic prophylaxis against endocarditis is no longer recommended for AR except for patients who have had valve replacement (see Table 4: Endocarditis: Recommended Endocarditis Prophylaxis During Oral-Dental or Respiratory Tract Procedures* ).
Key Points
Last full review/revision November 2012 by Guy P. Armstrong
Content last modified December 2012
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