Left Ventricular Systolic Dysfunction Following Repair of Ventricular Septal Defects in Infants

Background: Left ventricular systolic dysfunction (LVSD) is frequently observed following surgical closure of a ventricular septal defect (VSD), although little is known about its incidence, time course, or risk factors. Among infants undergoing VSD repair, for postoperative LVSD, we sought to determine (1) incidence, (2) predictors, and (3) time to resolution.

Methods: We retrospectively queried our institution’s surgical database for infants with isolated moderate or large VSDs who underwent repair from November 2001 through January 2019. Pre- and postoperative echocardiograms were reviewed. The primary outcome was postoperative LVSD, which was defined as a shortening fraction of <26% by M-mode. Postoperative echocardiograms were independently reviewed by two pediatric cardiologists (JAD and EHB) and measurements were made using standard methods. Receiver operating characteristic analysis was generated to determine the preoperative left ventricular internal dimension (LVIDd) z-score most predictive of LVSD. Multivariable analysis was conducted to determine associations with LVSD; covariates in the model were weight percentile, genetic syndrome, preoperative diuretic, VSD type, and preoperative LVIDd z-score. Kaplan-Meier curves for freedom from LVSD were constructed among children who experienced postoperative LVSD.

Results: Of the 164 patients who met inclusion criteria, all had normal preoperative left ventricular systolic function, and 62 (38%) had postoperative LVSD. Follow-up echocardiograms were available in 60/62 patients (97%) with LVSD, 58 (94%) of whom had resolution of LVSD within 9 months of surgery. Preoperative LVIDd z-score of >3.1 (sensitivity 0.63, specificity 0.83) was associated with both an increased incidence of postoperative LVSD and prolonged time to resolution. In univariate analysis, LVSD was less common in patients with a genetic syndrome compared to patients without a genetic syndrome (19% vs 48.1%, p = 0.002). However, multivariable logistic regression analysis showed only preoperative LVIDd z-score was independently associated with postoperative LVSD.

Conclusion: LVSD following VSD closure in infants is common, but nearly all cases resolve by 9 months postoperatively. High LVIDd prior to surgery is associated with postoperative LVSD. These data suggest VSD closure should be considered prior to the development of significant left ventricular dilation.