Isolated aortic stenosis in the neonate. Natural history and hemodynamic considerations.

Abstract

We have reviewed the clinical and catheterization data and pathologic findings in ten infants under one month of age with isolated severe aortic valve stenosis. All presented with evidence of progressive cardiac failure and diminished cardiac output. A hyperdynamic right ventricular impulse was present in nine infants who were subsequently shown to have a left-to-right atrial shunt, through a stretched patent foramen ovale. Calculated aortic valve area ranged from 0.12 cm 2 /m 2 to 0.29 cm 2 /m 2 . Three patients died prior to surgical intervention because of low cardiac output and refractory metabolic acidosis. Aortic valvotomy was attempted in the remaining seven. Five died intraoperatively or in the immediate postoperative period and one other died six months after surgery. Necropsy was obtained in all nine patients who died. We believe that, in this group, the clinical course reflects fetal and postnatal hemodynamics. We have discussed the probable hemodynamic factors which occur and have related them to the morphological development of aortic stenosis in these infants. The poor prognosis of these patients probably results from a combination of factors which include left ventricular outflow obstruction, often associated with a small aortic annulus, a markedly thickened left ventricle, and left ventricular malfunction secondary to subendocardial ischemia and/or endocardial fibroelastosis.