Outcome of membranous ventricular septal defects: Relationship with echocardiographic anatomy.

The aim of this study was to analyse the outcome of membranous ventricular septal defects (VSD) with respect to the echocardiographic data obtained du ring the first year of life. This retrospective series included patients bo rn between January Ist 1986 and December 31st 1995, in the Indre et Loire d epartment, with membranous ventricular septal defects alone or associated w ith minor abnormalities. The initial echocardiography, an echocardiography performed 2 to 6 months later, one a year later and the final echocardiogra phy were compared. Three groups of VSD were constituted according to their diameter : group I (less than or equal to 3 mm), group II (3-6 mm), and gro up III (> 6 mm). Depending on the outcome, the patients were classified as spontaneous closure (group A), surgical closure (group B) or persistent VSD (group C). The population comprised 84 children. There were 6 spontaneous deaths, thre e of which were unexplained, and 7 children were lost to follow-up. After t he initial echocardiography, the VSD were classified as group 1 (38%), grou p II (26.2%) and group III (35.7%). After the second echocardiogram, 24 VSD changed group (31.5%), by increase (N = 10) or decrease! (N = 14) in diame ter. Aneurysms of the membranous septum were observed during the first two echocardiographies in 31.2% and 79.3% of VSDs of group 1, 31.8% and 70% of VSDs of group II and 6.6% and 3.3% of VSDs of group III (p< 0.01). The aver age follow-up was 3.1 years (range 1 month-10 years). In group A (N = 22), the mean age of closure of the VSD was 26 months (3 months-7 years). In gro up B (N = 28), surgery was undertaken at an average age of 10 months (range 3 months-5 years). In group C (N = 21), the VSDs were classified as group I (N = 19) or group II (N = 2) at the last echocardiography. The frequency of aneurysms of the membranous septum in groups A, B and C were respectivel y 100%. 7.1% and 66.6% (p< 0.01). At the second echocardiographic examinati on, a significant relationship (p< 0.001) was observed between the diameter of the VSDs and their outcome. The VSDs of group A were associated with an eurysms of the membranous septum more often than those of group C (p< 0.005 ). The authors conclude that surgery is required in about one third of membran ous VSD. At medium term, the others either close spontaneously or become sm aller in comparable numbers. The outcome is directly related to the diamete r of the VSD and the development of an aneurysm of the membranous septum. D uring the first 6 months, the dimensions of membranous VSDs change in about 30% of cases with an increase in frequency of aneurysms of the membranous septum.