Introduction and objectives: Interventricular fibromuscular septal defects of the outlet tract are subarterial infundibular ventricular septal defects (VSDs). This anatomical situation predisposes to aortic cusp prolapse (AoP) and/or regurgitation (AoR).
Methods: In order to determinate the frequency of VSDs and the presence or development of aortic valve alterations detected by two-dimensional echocardiography, we studied 35 patients with VSDs. The defect area and presence, severity, and evolution of AoP and/or AoR were evaluated. Ten anatomic specimens were studied to verify the echocardiographic correlation.
Results: Subarterial infundibular defect was present in 6.9% of all ventricular septal defects. The average age at time of diagnosis was 5,8 years. VSDs diameter and gradient did not change during follow-up. At time of diagnosis, 30 patients (87%) did not have AoR, but during an average follow-up of 8 years, 11 (32%) developed it. By the end of the study, 46% had AoR. When the time to progression of AoR was compared in the group that developed it versus the group that did not, the median values were similar in both groups. There was a greater tendency to development and/or progression of regurgitation in small VSDs. The echo-anatomic correlation was precise.
Conclusions: Aortic valve damage was a frequent finding in VSD. Most cases did not progress to more severe AoR. Small VSDs developed more severe regurgitation in less time. Surgery must be considered when AoR is detected. Regular evaluation by echocardiography is important in follow-up.