Pulmonary vascular protective mechanisms in adult patients with an isolated large ventricular septal defect: a 21-year experience.

BACKGROUND: Ventricular septal defects (VSDs) are one of the most common congenital heart defects in adults. In adult patients with an anatomically large VSD and relatively preserved pulmonary vascular system, several pulmonary flow-limiting cardiac morphologic alterations (PFMA) are encountered.

PATIENTS: Ninety-eight male patients (mean age 22.5 +/- 2 years) operated for an anatomically large VSD in our institution were retrospectively reviewed. PFMA in patients with an anatomically large but functionally mild-to-moderate VSD (when ratio of pulmonary to systemic flow (Q(p)/Q(s)) < 2.2 and ratio of pulmonary to systemic vascular resistance (R(p)/R(s)) < 0.3) were recorded.

RESULTS: Thirty patients (31.2%) revealed a mild-to-moderate VSD in functional severity. Five PFMA were encountered in these patients: (1) ostium (os) infundibulum (n = 10, 33.3%), (2) aneurysm of the membranous septum (AMS) (n = 10, 33.3%), (3) systolic bulging of the conal septum toward the right ventricular outflow tract (n = 6, 20%), (4) prolapse of the aortic cusps (n = 2, 6.7%), and (5) attachment of the tricuspid septal leaflet to the septal crest (n = 2, 6.7%). Double-chambered right ventricle was encountered in four patients with os infundibulum and classic tetralogy-type septal malalignment in one patient with aortic cusp prolapse. Concurrent to VSD repair, resection of the os infundibulum and the AMS and aortic valve repair were performed.

CONCLUSION: Presence of a large VSD and relatively preserved pulmonary vascular system in adults is associated with several PFMA. Preoperative awareness and concurrent surgical treatment of these alterations seem to be crucial to improve the expected benefit of surgical repair of VSD in this subgroup of the patients.