Doubly committed subarterial ventricular septal defects: echocardiographic features and surgical implications

Doubly committed subarterial (supracristal, subpulmonary) ventricular septal defects are often complicated by aortic regurgitation resulting from aortic valve herniation into the defect. The clinical, echocardiographic and catheterization findings in 48 patients aged 0.3 to 46.4 years (median 9.5) with a doubly committed subarterial ventricular septal defect were reviewed. Aortic valve herniation was present in 38 (79%) and 55% of these had aortic regurgitation. The prevalence of both findings increased gradually with advancing age. The defect was closed surgically in 41 patients. Surgery during the first 2 years of life (median 0.4 year) was performed in 13 patients (group I), mainly because of a large shunt with a pulmonary to systemic flow ratio (Qp/Qs) 3.8 +/- 1.4 (mean +/- SD). Aortic regurgitation was present preoperatively in two patients (15%), persisted postoperatively in one patient and did not develop in any after repair (median duration of follow-up 2.3 years, range 0.1 to 7.4). In the other 28 patients (group II) surgery was performed between 4.8 and 46.4 years of age (median 11.5). These patients were generally less symptomatic and had a smaller shunt (Qp/Qs 1.5 +/- 0.5, p less than 0.001). Preoperative aortic regurgitation was present in 18 (64%). It persisted in 15 postoperatively, but in 13 of these it had diminished. Two-dimensional echocardiography in multiple views identified the site of the ventricular septal defect in all patients. Serial echocardiographic examinations demonstrated the progressive nature of aortic valve herniation, the partial occlusion of the defect by the herniated sinus and the development of aortic regurgitation. These findings suggest that timely surgical closure of these defects may prevent aortic regurgitation.