Postoperative Physiological Instability, Not Operative Duration, Drives Mortality After Surgical Ventricular Septal Defect Closure in Infancy: A Prospective Study from a Public Tertiary Centre in India

Background: Surgical closure of ventricular septal defect (VSD) in infancy carries low mortality in experienced centres, yet perioperative morbidity remains significant. Identifying predictors of adverse outcomes is critical for risk stratification and perioperative planning, particularly in resource-limited settings. Methods: A prospective observational study was conducted at ABVIMS & Dr. RML Hospital, New Delhi. Sixty infants (aged ≤12 months) undergoing elective surgical VSD closure under cardiopulmonary bypass (CPB) were enrolled (2023–2026). Demographic, clinical, intraoperative, and postoperative data were collected using a standardised proforma. Primary outcome was in-hospital mortality; secondary outcomes included prolonged mechanical ventilation (>24 h), postoperative infection, renal failure, reoperation, and delayed sternal closure. Mann–Whitney U test, Fisher's exact test, and univariable logistic regression were used for statistical analysis. Results: Median age was 8 months (IQR 6–12) and median weight 5.0 kg (IQR 4.2–7.1). The cohort was 71.7% male (n = 43). Perimembranous VSD was the most common type (53.3%; n = 32). Severe PAH was present in 33.3% (n = 20). In-hospital mortality was 13.3% (8/60). Non-survivors required significantly longer mechanical ventilation (median 30 h vs. 12 h; p = 0.029). Prolonged ventilation (>24 h) was significantly associated with mortality (p = 0.002). Postoperative infection (p = 0.027) and renal failure (p = 0.006) were both significantly associated with mortality. CPB time and aortic cross-clamp (ACC) time did not differ significantly between survivors and non-survivors. Conclusion: Prolonged postoperative ventilation, postoperative infection, and renal failure are the strongest predictors of in-hospital mortality following surgical VSD closure in infancy. Severe PAH, younger age, and lower body weight represent important clinical risk markers. Intraoperative variables (CPB and ACC time) were not independently associated with mortality.