Impact of Major Residual Lesions on Outcomes After Surgery for Congenital Heart Disease

Background: Many factors affect outcomes after congenital cardiac surgery. Objective: The Residual Lesion Score (RLS) Study explored the impact of severity of residual lesions on postoperative outcomes across operations of varying complexity. Methods: In a prospective, multicenter, observational study, 17 sites enrolled 1149 infants undergoing five common operations: tetralogy of Fallot repair (TOF, n=250), complete atrioventricular septal defect repair (CAVSD, n=249), arterial switch operation (ASO, n=251), coarctation/interrupted arch with ventricular septal defect repair (Arch/VSD, n=150), and Norwood operation (n=249). RLS was assigned based on postoperative echocardiography and clinical events: RLS 1, trivial/none; RLS 2, minor; or RLS 3, reintervention for or major residual lesions before discharge. The primary outcome was days alive and out of hospital within 30 postoperative days (60 for Norwood). Secondary outcomes assessed postoperative course, including major medical events and days in hospital. Results: RLS 3 (vs. RLS 1) was an independent risk factor for fewer days alive and out of hospital (p≤0.008) and longer postoperative hospital stay (p≤0.02) for all 5 operations, and for all secondary outcomes after Arch/VSD and Norwood (p≤0.03). Outcomes for RLS 1 vs. 2 did not differ consistently. RLS alone explained 5% (TOF) to 20% (Norwood) of variation in the primary outcome. Conclusions: Adjusting for preoperative factors, residual lesions after congenital cardiac surgery impacted in-hospital outcomes across operative complexity with greatest impact following complex operations. Minor residual lesions had minimal impact. These findings may provide guidance for surgeons when considering short-term risks and benefits of returning to bypass to repair residual lesions.