Echocardiographic predictors of the need for infundibular wedge resection in infants with aortic arch obstruction, ventricular septal defect and subaortic stenosis.

I nfants with aortic arch obstruction and outlet ventricular septal defect can have posterior displacement of the infundibular septum into the left ventricular outflow tract causing varying degrees of subaortic stenosis.1-3 Because of the large ventricular septal defect, left ventricular outflow tract velocities are frequently normal. For this reason, Doppler peak gradients are often not helpful for assessing the severity of the outflow tract narrowing preoperatively. Preoperative evaluation of the degree of subaortic obstruction and, thus, the need for surgical intervention is usually based on qualitative assessment of the anatomic 2-dimensional echocardiographic image.2-6 This study defines 2-dimensional echocardiographic predictors of the need for subaortic resection in infants with aortic arch obstruction, outlet ventricular septal defect and posterior deviation of the infundibular septum. From November I987 to November 1991,12 consecutive infants with this combination of cardiac defects were evaluated with 2-dimensional and Doppler echocardiography. Ten of the 12 patients had no previous cardiac evaluation, whereas 2 patients had undergone prior surgery at a referring institution 1 for repair of an interrupted aortic arch and patch closure of the ventricular septal defect and the other for repair of an interrupted aortic arch alone. The patients ranged in age from 2 days to 9 months (mean 42 days) and in weight from 1.3 to 7.1 kg (mean 3.5). The initial diagnosis was interrupted aortic arch in 6 infants and coarctation of the aorta in 6 infants. Associated defects included an atria1 septal defect in 10 patients, patent ductus arteriosus in 6, bicuspid aortic valve in 5, mild mitral regurgitation in 3, and anomalous right subclavian artery in 1. Of the 12 patients, 11 underwent patch closure of the ventricular septal defect by a transtricuspid approach, 10 had primary aortic arch repair, 9 had wedge resection of the infundibular septum (8 through the tricuspid valve and ventricular septal defect and 1 through a transaortic approach), and 1 had revision of a previous aortic arch repair. The patients’ echocardiographic measurements were compared with those of a control group of age and weight-matched infants with normal hearts by 2-dimensional and Doppler echocardiography. The control group consisted of 15 infants whose ages ranged from 1 day to 2 months (mean 13 days) and whose weights ranged from 2 to 4 kg (mean 3.1). In these infants, echocardiographic evaluation was performed because of noncardiac congenital anomalies in 9, murmur in 5, and arrhythmia in 1. The following measurements were obtainedfrom the 2-dimensional and Doppler echocardiograms. From the