ANEURYSM OF THE MEMBRANOUS SEPTUM IN ADULT PATIENTS WITH PERIMEMBRANOUS VENTRICULAR SEPTAL-DEFECT

Objective: The aneurysm of the membranous septum (AMS) has often been considered as benign in the minds of many previous investigators. We h ave analyzed the complications associated with AMS in adult patients. Methods: Fifty-one cases (20%) of AMS in 254 adult patients with perim embranous ventricular septal defect (VSD) are described. The diagnosis of AMS was based on angiographic criteria. Thirty-nine (76.5%) of the 51 patients with AMS were aged between 20 and 29 years. All patients but one with AMS had a pulmonary-to-systemic flow (Q(p)/Q(s)) of less than 2.3 (range 1-2.1, mean 1.4). In a patient who had a ruptured aneu rysm, the Q(p)/Q(s) was 2.7. There were six main complications affecte d by AMS and/or VSD; aortic valve prolapse in 24 patients (47%), aorti c regurgitation in 15 (29.4%), tricuspid insufficiency in nine (17.6%) , right ventricular outflow tract obstruction in two (4%), and rupture of the aneurysm in one patient (2%). Seven patients (13.7%) had prior bacterial endocarditis. All patients underwent surgery. Aneurysm and VSD were closed by direct suture in nine and with a patch in 42 patien ts. Aortic valve repair was performed in 13 patients in whom regurgita tion was mild to moderate, and replacement was required in two patient s with severe aortic regurgitation. Results: There were no early or la te deaths. Residual communication and recurrence of the aneurysm was n oted three and seven years postoperatively in two patients where VSD h ad been closed by direct suture. Conclusions: According to present dat a, aneurysm formation functionally reduces the VSD size, but it has th e potential consequence of promoting tricuspid insufficiency, aortic v alve prolapse, right ventricular outflow tract obstruction, rupture an d bacterial endocarditis. Therefore, we recommend that AMS should be r esected completely and the defect produced closed with a patch in orde r to prevent further enlargement and consequent complications even if there are no cardiac symptoms. (C) 1997 Elsevier Science B.V.