Pushing the Limits of Balance in Atrioventricular Septal Defect and Complex Techniques for Valve Re-repair in...

Repair of atrioventricular septal defect (AVSD) remains one of the most technically demanding procedures in congenital cardiac surgery. In patients with balanced anatomy, biventricular repair provides excellent long-term survival; however, borderline and unbalanced AVSD continue to pose major challenges, particularly in children with Down syndrome. Contemporary practice emphasizes that balance is not fixed but can be influenced by surgical planning, ventricular recruitment, and meticulous management of the left atrioventricular valve (LAVV). LAVV regurgitation remains the principal cause of early failure and late reoperation after AVSD repair, and its impact is especially pronounced in the setting of repeat operations, where annular dilation, leaflet deficiency, and prior surgical manipulation complicate repair. Institutional experience demonstrates that immediate moderate or greater LAVV regurgitation after repair strongly predicts both mortality and reoperation, highlighting the importance of rigorous intraoperative echocardiographic assessment and close collaboration between surgeons and cardiologists. Mild to moderate regurgitation represents a surgical "trap," as it frequently worsens during early follow-up. Longitudinal data show that nearly half of patients with postoperative moderate regurgitation deteriorate to severe, while almost one third improve spontaneously. Successful redo repair requires mechanism-driven strategies, including cleft closure or patch plasty, annuloplasty, papillary muscle splitting, and leaflet augmentation, tailored to residual pathology. Although advances in imaging, surgical techniques, and experience have improved outcomes, recurrent LAVV regurgitation continues to limit survival and freedom from reoperation. Early recognition and aggressive management remain essential, and the surgical threshold for reintervention should be low to optimize long-term results in this complex population.