Supravalvar aortic stenosis
Aortic stenosis can be at the valvar, supravalvar or subvalvar levels. Supravalvar aortic stenosis (AS) is often part of the William’s syndrome with hypercalcemia, elfin facies and learning disability associated. The ejection systolic murmur of supravalvar AS is better heard to the right of the sternum in the aortic area and higher up. Due to the Coanda effect, the right radial and brachial pulses usually have a higher volume than the left, in supravalvar AS.
Echocardiography is useful in imaging the stenosis as well as documenting the pressure gradient, though it may at times overestimate the gradient. Sometimes exercise testing is used in asymptomatic individuals to assess the effort tolerance and blood pressure response. Effort related arrhythmias may also be brought out. Exercise testing may also be useful in timing of surgery. Cardiac magnetic resonance imaging (CMR) or computed tomography (CT) scanning is useful in the precise anatomical definition of the supravalvar stenosis as well as to identify any associated anomalies of pulmonary arteries or branches of aorta. Coronaries can be imaged well by computed tomography. Rare cases may need cardiac catheterisation and angiography.
Surgery is generally considered in supravalvar aortic stenosis if the mean Doppler gradient is 50 mm Hg or more and if they are symptomatic. Those with lower gradients may also be considered for surgery if there are obstructive symptoms like exertional dyspnea, angina or syncope. Left ventricular systolic dysfunction without other attributable causes, severe left ventricular hypertrophy and the need for concomitant surgery for coronary artery disease may also be reasons for operating on supravalvar aortic stenosis with mean gradients less than 50 mm Hg. Post operatively they need lifelong follow up including echocardiographic evaluation (+/- CMR/CT) to look for any late restenosis and for the development of aneurysms or progression of CAD.