Surgical repair of multiple muscular ventricular septal defects: the role of re-endocardialization strategy.

OBJECTIVE: Surgical repair of multiple muscular ventricular septal defects (Swiss cheese septum) is associated with important morbidity and mortality. We sought to examine factors associated with permanent heart block, early mortality, and time-related survival. Additionally, we evaluated a new approach, transatrial re-endocardialization of interventricular septum, to mitigate risk.

METHODS: One hundred sixteen patients underwent surgery for multiple muscular ventricular septal defects (1982-2005), of whom 64 (55%) had associated cardiac anomalies. Twenty-seven consecutive patients (median age 0.54 years, range 15 days-7.2 years) underwent transatrial re-endocardialization (2002-2005). Forty-four percent had Swiss cheese septum (>4 defects). Multivariable regression analysis determined risk factors for pacemaker and survival.

RESULTS: Operative mortality for the entire cohort was 9%. Risk factors for death were double-outlet right ventricle (odds ratio 44.7, P = .003), ventriculotomy (odds ratio 6.4, P = .03), and fewer multiple muscular ventricular septal defects repaired (odds ratio 4.7/defect, P = .04). Era mortalities differed: 16% for 1982 through 1990, 13% for 1990 through 1998, and 0% for 1999 through 2005, P = .006). Fourteen patients (12%) required a pacemaker. Time-related survivals at 1 and 10 years were 90% +/- 3% and 82% +/- 5%. Risk factors for death were double-outlet right ventricle (hazard ratio 8.3, P = .02) and longer bypass (hazard ratio 1.02/min, P = .02). In 27 re-endocardialization patients, a combined closure strategy to close 184 defects were applied: transatrial re-endocardialization (median 5, range 2-21), patch (median 1, range 0-4), and device (range 0-1). Post-repair ventricular function was good in 25 of 27 patients. The median number of residual defects was 1.5 (range 0-3), and median residual jet width on color Doppler was 2.3 mm (range 0-4.2 mm). One child required a pacemaker. There were no early or late deaths.

CONCLUSIONS: Outcome of surgical repair of multiple muscular ventricular septal defects (Swiss cheese septum) has improved. Transatrial re-endocardialization strategy enables early complete or nearly complete obliteration of multiple muscular ventricular septal defects with minimal residual lesions (shunt, ventricular dysfunction). Long cardiopulmonary bypass duration is well tolerated. The incidence of permanent heart block has improved. Early echocardiographic and clinical outcomes are promising.