Differentiation of supravalvar aortic stenosis from valvular and subvalvular variety
Murmur of subvalvular aortic stenosis is unlikely to radiate to the carotids. Murmur of supravalvar aortic stenosis may radiate more to the right carotid. Murmur of valvular aortic stenosis radiates to both carotids.
Ejection click is in favour valvular aortic stenosis.
Associated aortic regurgitation
Supravalvar aortic stenosis is unlikely to be associated with aortic regurgitation, while it can occur in valvular and subvalvular variety. In fact aortic regurgitation may be seen in almost half of those with subvalvular membranous aortic stenosis. It may be noted that discrete subvalvular membranous aortic stenosis is different from dynamic subaortic obstruction seen in hypertrophic obstructive cardiomyopathy.
Pulse asymmetry or anisosphygmia
Anisosphygmia with right brachial pulse more prominent than left, may occur in supravalvar aortic stenosis, due to the direction of the jet towards the right brachiocephalic artery. There may be a corresponding difference of blood pressure more than 10 mm Hg between the two upper limbs. Anisosphygmia is not a feature of subvalvular or valvular aortic stenosis.