Outcomes of Left Atrioventricular Valve Operation following Atrioventricular Septal Defect Repair.

Objectives: Left atrioventricular valve (LAVV) operation following repair of atrioventricular septal defects (AVSD) can be challenging. We sought to describe characteristics and outcomes of patients requiring LAVV operation.

Methods: Retrospective review of AVSDs requiring LAVV operation between 2000-2020. Patients who experienced adverse events (AEs; defined as the need for a LAVV reoperation (repair or replacement) or death) were compared to patients without AEs. Freedom from adverse events was displayed using the Kaplan-Meier method. Reoperation and death were characterized in terms of cumulative incidence function, estimated using competing risk models.

Results: Of 843 patients with AVSD repaired, 59 (7.3%) required a LAVV operation and 7 (9%) valve replacement. A simple repair (cleft closure and/or annuloplasty) occurred in 26 (48.1%) and complex repair using multiple techniques in 28 (51.8%) cases. Eleven patients (20%) required further LAVV reoperation; 3 replacement of mechanical valve, 6 new valve replacement (2 Melody, 4 Mechanical) and 2 re-repair. The cumulative incidence of freedom from AE was 84.1% (75.0%, 94.2%), 78.3% (68.2%, 90.0%), 73.4% (62.2%, 86.7%), 69.7% (57.5%, 84.7%) at 1, 5, 10 and 15 years respectively. Cox univariable regression showed smaller weight (p=0.027) and early need for LAVV operation (p=0.02) were associated with AEs while cleft closure (p = 0.003) was protective against AEs. The estimated cumulative incidence of reoperation was higher in complex repairs (17.3% (7.8%, 38.7%) vs 0.5% (NA, NA) at 1 year. Greys p = 0.02). In a comparison of eras (2000-2009, 2010- 2020) there was no difference in AE (Greys p = 0.96).

Conclusions: Adverse outcomes following LAVV reoperation remain common. Smaller infants, those requiring earlier reoperation and complex type repairs are at highest risk. Future studies should focus on which high risk LAVVs are more suited to early LAVV replacement.