Aortic regurgitation can occur due to damage to the aortic valve as well as due to dilatation of the aortic root so that aortic valve leaflets fail to coapt. The later condition occurs in annulo-aortic ectasia, often associated with Marfan syndrome. Aortic regurgitation due valvular damage can occur in rheumatic fever. A bicuspid aortic valve can also become regurgitant as age advances. In the yester years, tertiary syphilis was an important cause of aortic root dilatation and aortic regurgitation.
Aortic regurgitation is quantified in terms of regurgitant fraction,which is the fraction of left ventricular output that regurgitates back. It can be assessed by Doppler echocardiography as well as angiocardiography. Aortic regurgitation leads a high systolic pressure, low diastolic pressure and a wide pulse pressure. Most of the physical signs of aortic regurgitation are due to this wide pulse pressure. The pistol shot sounds over the femoral, collapsing or water hammer pulse, retinal arterial pulsations, locomotor brachii and dancing caortids are some of them.
Severe aortic regurgitation leads to dilatation of left ventricle and left ventricular failure. When the left ventricle fails, end diastolic pressure rises and leads to elevated left atrial pressure and pulmonary congestion. Symptomatic aortic regurgitation needs aortic valve replacement. Aortic valve replacement can be done using mechanical or bioprosthesis. Mechanical prosthesis requires life long anticoagulation while anticoagulation can be discontinued after an initial period in bioprosthesis. Another novel technique for aortic valve replacement, especially in children is pulmonary autograft. Homograft replacement of aortic valve can also be considered in places with homograft banks. Availability is often a problem in case of autografts.
Colour Doppler echocardiogram showing aortic regurgitation (multicoloured mosaic jet seen in left ventricle marked AR)