INVITED COMMENTARY

Abstract

Aortic valve deformity becomes an overwhelming concern for those with an isolated subarterial ventricular septal defect who survive their early years without symptoms. Aortic valve prolapse may accompany peri-membranous defect with outlet extension when the aortic valve overrides the septum and makes the aortic cusp vulnerable to injury by the shunt flow. This study shows that the incidence of valve prolapse may be higher than what is generally believed, especially among Asians, and it warrants periodic aortic valve monitoring before surgery. The same management principle probably applies to all subtypes, although aortic deformity is relatively subtle with muscular outlet defects. This exception is partly due to the smaller size of the defect and possibly due to the fact that the midportion of the cusp is usually affected with a muscular outlet defect rather than the commissural portion in other subtypes. It is now generally believed that the cusp deformity does not progress once the ventricular septal defect is closed adequately. However, aortic regurgitation does progress in some patients after repair. We now know that significant aortic regurgitation develops in 20% to 30% of patients 10 to 20 years after repair of tetralogy with subarterial ventricular septal defect. This is caused either by placing the patch directly beneath the aortic valve and jeopardizing its integrity or simply by technical failure. It is important to delineate the precise mechanism of progressive aortic regurgitation after repair in this patient subset to determine the best closure method (ie, whether or not to use a patch to close subarterial defect) and the timing for surgery. In addition, subaortic ridge is sometimes associated with these defects. The ridge usually does not cause obstruction before operation; however, it can cause significant subaortic narrowing after repair. This is another anatomic feature that can jeopardize long-term outcome and also warrants further study.