Aortic Regurgitation Causes

Causes:

Acute Aortic Regurgitation

oInfective endocarditis may lead to destruction or perforation of the aortic valve leaflet. The vegetation can also interfere with proper coaptation of the valve leaflets and can sometimes lead to frank prolapse or flail of a leaflet.

oIn acute ascending aortic dissection (type A), the retrograde proximal dissection flap undermines the commissural suspensions of the aortic valve leaflets. Varying levels of aortic aortic malcoaptation ad prolapse occur.

oProsthetic valve malfunction can lead to AR.

oChest trauma may lead to a tear in the ascending aorta and discruption of the aortic valve support apparatus.

Chronic Aortic Regurgitation

oWhile a congenital bicuspid aortic valve often leads to progressive aortic stensosis., incomplete closure or prolapse can also lead to significant regurgitant flow across the valve. This common congenial lesion remains the most common cause of isolated AR requiring aortic valve surgery. Histologic abnormalities of the bicuspid root frequently lead to proximal aortic dilation and further exacerbation of AR.

oConnective tissue disorders syndrome, including Marfan syndrome, Ehlers-Danlos syndrome, floppy aortic valve, aortic valve prolapse, sinus of Valslva aneurysm, and aortic annular fistula can all lead to significant chronic AR. The use of diet drugs such as fenfluramine and dexfenfluramine (commonly referred to as Phenfen) may lead to chronic AR, although these data remain controversial at this time.

oRepresentative of connective tissue disorders, Marfan syndrome is a common cause of severe AR that requires intervention. This disorder is associated with dilated sinuses of Valsalva, progressing to aortic dilation and AR. These patients are also at very high risk for aortic dissection, depending on the size of the ascending aortic.

oRheumatic fever was a common cause of AR in the first half of the 20th century. The cusps become thickened with fibrous tissues and retract, which causes central valvular regurgitation. Most commonly, some fusion of the cusps occurs, resulting in some degree of aortic stenosis and regurgitation. Associated rheumatic mitral valve disease is also very common.

oSyphilltic aortitis leads to dilatation of the ascending aorta. The aortic annulus becomes dilated, and coaptation of the cusps is lost.

oTakayasu arteritis involves the aorta and its major branches. AR may complicate type 1 and type 3 of this disease.

oAnkylosing spondylitis leads to shortening and thickening of the aortic valve cusps and dilatation of the aortic root.

oReiter syndrome presents similarly to ankylosing spondylitis. Dilatation of the aortic root and associated AR occurs. Reiter syndrome may involve the coronary ostium rarely, producing angina.

oReiter syndrome presents similarly to ankylosing spondylitis. Dilatation of the aortic root and associated AR occurs. Reiter syndrome may involve the coronary ostium rarely, producing angina.

oRheumatoid arthritis can produce granulomata involving the valve leaflets and rings. The central portion of the leaflets is usually involved, with sparing of the peripheral portions.

oSystemic lupus erythematosus (SLE) is associated with Libman Sacks endocarditis, and these verrucous.

Electrocardiography findings can reveal of the following, although they are not an accurate predictor of the severity of AR.

oLV hypertrophy
oLeft axis deviation
oLeft atrial enlargement
oLV volume overload pattern (prominent Q waves in leads I, aVL, and V3 to V6 and relatively small R waves in V1
oLV conduction defect (late in disease process)