History
Symptoms caused by supravalvar aortic stenosis (SVAS) usually develop in childhood. Rarely, symptoms may develop in infancy; in some cases, symptoms develop in the second or third decade of life.
Most pediatric patients present because of a heart murmur or the features of Williams syndrome. Patients with Williams syndrome may also develop systemic hypertension and involvement of joints, peripheral pulmonary artery stenosis, coarctation of aorta, and mitral insufficiency. [14]
Dyspnea on exertion, angina, and syncope develop in the course of the disease if SVAS is untreated. These symptoms indicate at least a moderate degree of left ventricular outflow tract (LVOT) obstruction. Because of the coronary artery involvement, angina may arise early and more often than in other obstructive LVOT lesions. Because of the risk of sudden death in SVAS, the development of angina and syncope should prompt immediate investigation.
Physical Examination
The physical examination focuses on upper extremity pulses, the precordium, heart sounds, and heart murmurs.
Asymmetrical upper extremities pulses
Discrepancies between carotid pulsations and upper extremity pulses and blood pressure are the characteristic clinical findings in supravalvar aortic stenosis (SVAS) . The discrepancies occur because the jet of blood flow from SVAS has a preferential trajectory into the brachiocephalic (innominate) artery (ie, Coanda effect).
Precordium
The precordium is usually hyperdynamic, and the apex of the heart is displaced laterally and inferiorly because of ventricular hypertrophy. A thrill in the suprasternal notch is usually felt because of the trajectory of the blood flow jet from SVAS.
Heart sounds
The first heart sound is generally normal. A narrowly split, single, or paradoxically split second heart sound and a fourth heart sound are present in severe SVAS.
Heart murmurs
The characteristic systolic murmur of SVAS is crescendo-decrescendo in shape, low pitched, and best heard at the base of the heart, sited higher than in valvular aortic stenosis. It mainly radiates to the right carotid artery and tends to peak during the last two thirds of ventricular systole if the obstruction is severe.
A high-pitched, short, early diastolic aortic regurgitation murmur is uncommon in SVAS unless the aortic valve has become damaged due to the supravalvar obstruction and has become regurgitant. An ejection click is absent.
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Two-dimensional suprasternal echocardiographic image of supravalvar aortic stenosis.
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Aortogram of a patient with supravalvar aortic stenosis and dilated sinus of Valsalva.
