Supravalvular

Supravalvular is an anatomical descriptor referring to structures located above a heart valve. In clinical use it most often refers to supravalvular aortic stenosis, a congenital narrowing of the ascending aorta just above the aortic valve, though the term can apply to similar constrictions above other valves.

The most common and well-described form is supravalvular aortic stenosis (SVAS). SVAS is rare and typically present at birth or in early childhood. It is strongly associated with Williams syndrome, a developmental disorder caused by deletion of the elastin gene, but can also occur as an isolated, non-syndromic anomaly. The underlying pathology usually involves localized thickening of the intima and media with abnormal elastin content, leading to a constricted segment that can impair blood flow to the coronary arteries.

Clinical features vary with severity. Mild cases may be asymptomatic, while more significant obstruction can cause exertional chest pain, dyspnea, syncope, or signs of heart failure in infancy. Blood pressure may be elevated in the arms relative to the legs in some patients, and a systolic murmur is often audible.

Diagnosis relies on imaging. Echocardiography is the initial modality to assess location and degree of narrowing and to evaluate the coronary ostia. Cardiac CT or MRI provides detailed anatomic mapping, and invasive angiography may be used for complex cases or preoperative planning.

Management ranges from observation in mild, asymptomatic individuals to surgical repair for obstructive SVAS. The standard surgical approach is patch aortoplasty to widen the supravalvular segment while protecting coronary blood flow. Catheter-based interventions have limited durability for SVAS. Long-term follow-up is required due to risk of restenosis and associated vascular anomalies, especially in Williams syndrome.