Background: Supravalvular aortic stenosis is a rare stenotic lesion of the left ventricular outflow tract (LVOT). We characterized the natural history of the disease and the effect of surgical intervention.
Methods: Ninety-five children diagnosed with supravalvular aortic stenosis between 1976 and 2006 were studied. Procedural and repeated echocardiography reports were analyzed.
Results: Stenosis morphology (localized, 82%; diffuse, 18%) was independent of Williams syndrome (n = 59, 62%). The risk of open operation (n = 47) was 46% +/- 6% at 10 years. Increased risk of operation was associated with higher baseline LVOT peak gradients (p < 0.001), smaller minimum LVOT z scores (p < 0.01; thresholds > 50 mm Hg and < -3, respectively), and the absence of Williams syndrome (p = 0.01). Patients who did not undergo operations had gradually reducing LVOT gradients and enlarging ascending aorta z scores over time. Persistently small minimum LVOT z scores and higher gradients were associated with children who required an operation. Operation resulted in persistent relief of LVOT obstruction and accelerated increases in ascending aorta dimensions. Overall survival was 94% +/- 3% and 85% +/- 7% at 10 and 15 years and was similar for surgical and nonsurgical groups. No independent risk factors for death were identified on univariate or multivariable analysis.
Conclusions: Many children-particularly those with Williams syndrome-show regression of stenosis without intervention. Children who undergo operation have high LVOT gradients and smaller LVOT z scores that do not improve over time. Surgical intervention alters the natural history: LVOT obstruction is relieved and does not recur, and ascending aortic dimensions progressively enlarge towards normal values.