[Interventricular defect with discrete aortic stenosis below the defect].

Abstract

"Discrete" (fixed) subaortic stenosis associated with ventricular septal defect (VSD) is a rare but important anomaly. Two types of left ventricular outflow tract obstruction should be distinguished on the basis of its relation with the VSD, depending on whether the stenosis is above or below the defect. The four cases presented here are all in the latter category. Usually the patients belonging in the former category are associated with severe anomalies of the aortic arch. The diagnosis was made by clinical examination and by means of non invasive techniques, ecg, chest x-rays and ecocardiograms in all but one patient (the case "3"), in whom a subpulmonary stenosis (SPS) was associated. The final diagnosis was established by catheterization, which demonstrated the pressure gradient on the withdrawal curve from the apical part of the left ventricle to the aorta, and by contrastography. Three of four patients underwent total correction and are in good condition from 6 to 18 months after surgery, one of these cases had also SPS. In the remaining case, we thought the operation was not indicated on the basis of small size of VSD, of mild pressure gradient, and mild aortic valvular insufficiency (case "4"). The surgical approach to resect the "fixed" obstruction and to closure the VSD was carried out through a right atriotomy in two patients, and through a right ventriculotomy in the patient with SPS. The trans-aortic approach has to be discarded because it affords limited exposure of both defects and could increase the risk of damage of conducting tissue. A careful evaluation of aortic and left ventricular pressure, in association with angled angiography is highly recommended in the study of VSD.