ObjectiveTo evaluate the short- and long-term outcomes of cardiac repair versus nonoperative management in patients with trisomy 13 and trisomy 18 with congenital heart disease. MethodsAn institutional review board-approved, retrospective review was undertaken to identify all patients admitted with trisomy 13/18 and congenital heart disease. Patients were divided into 2 cohorts (operated vs nonoperated) and compared. ResultsBetween 1985 and 2023, 62 patients (34 operated and 28 nonoperated) with trisomy 13 (n = 9) and trisomy 18 (n = 53) were identified. The operated cohort was 74% girls, underwent mainly The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery mortality category 1 procedures (n = 24 [71%]) at a median age of 2.5 months (interquartile range [IQR], 1.3-4.5 months). This compares with the nonoperative cohort where 64% (n = 18) would have undergone The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery mortality category 1 procedures if surgery would have been elected. The most common diagnosis was ventricular septal defect. Postoperative median intensive care unit stay was 6.5 days (IQR, 3.7-15 days) with a total hospital length of stay of 15 days (IQR, 11-49 days). Thirty-day postoperative survival was 94%. There were 5 in-hospital deaths in the operated and 7 in the nonoperated cohort. Median follow-up was 15.4 months (IQR, 4.3-48.7 months) for the operated and 11.2 months (IQR, 1.2-48.3 months) for the nonoperated cohorts. One-year survival was 79% operated versus 51.5% nonoperated (P < .003). Nonoperative treatment had an increased risk of mortality (hazard ratio, 3.28; 95% CI, 1.46-7.4; P = .004). ConclusionsControversy exists regarding the role of primary cardiac repair in patients with trisomy 13/18 and congenital heart disease. Cardiac repair can be performed safely with low early mortality and operated patients had higher long-term survival compared with nonoperated in our cohort.