QUANTITATION OF ECHOCARDIOGRAPHIC PREDICTORS OF OUTCOME IN INFANTS WITH ISOLATED VENTRICULAR SEPTAL-DEFECT

Clinical and morphometric features such as ventricular septal defect ( VSD) size and location may determine outcome in infants with an isolat ed VSD. However, no currently available data allow quantitative estima tion of the probability of spontaneous closure or surgery in individua l patients. To identify independent predictors of outcome and to quant itate the probability of spontaneous closure and surgery in patients w ith isolated VSD, we studied 156 consecutive infants who had a diagnos is of an isolated VSD between January 1, 1988, and December 31, 1990, and who were subsequently monitored for 28.5 +/- 15 months. Of the 149 patients with membranous (n = 100) and muscular (n = 49) defects who were studied, 46 (31%) patients had spontaneous closure, and an additi onal 37 (25%) patients underwent surgical repair. Univariate analysis identified defect cross-sectional area indexed to body surface area, l ocation in the muscular septum, presence of Down syndrome, and in memb ranous defects the presence of aneurysmal tissue as potential predicto rs of spontaneous closure or surgery. Multiple logistic regression ana lysis with these candidate variables identified indexed defect cross-s ectional area as an independent predictor of spontaneous closure and s urgery (p < 0.001). An inverse nonlinear relationship was seen between indexed VSD area and the probability of spontaneous closure (probabil ity = (1 + e[-1.74 + 4.57CSA])(-1) and a positive nonlinear relationsh ip between indexed VSD area and the probability of surgery (probabilit y = (1 + e[3.39 - 2.31CSA](-1)). Muscular defects were more likely to close spontaneously than membranous defects (odds ratio 2.6, 95% CL = 1.01 - 6.8, p = 0.04). Aneurysmal tissue formation and presence of Dow n syndrome did not predict outcome after controlling for defect size. Thus echocardiographic measurement of VSD cross-sectional area enables quantitation of probability of spontaneous closure and surgery in ind ividual infants with an isolated VSD.