Abstract 9841: Outcomes Following Biventricular Repair of Atrioventricular Septal Defect With a Single Left Ventricular Papillary Muscle

Abstract

Introduction: In patients with atrioventricular septal defect (AVSD) with single papillary muscle attachments in the left ventricle (LV), the left AV valve (LAVV) is at risk for suboptimal repair. This study aimed to evaluate outcomes following repair of AVSD with single LV papillary muscle attachments and to identify preoperative predictors of postoperative LAVV outcomes. Methods: All patients with AVSD and anatomically or functionally single LV papillary muscle who underwent biventricular repair at our institution from 07/01/2000 - 07/01/2020 were retrospectively reviewed. Univariate analysis was used to identify associations between patient demographics, preoperative echocardiographic measures, and surgical characteristics with the degree of LAVV stenosis or regurgitation postoperatively and the need for reintervention on the LAVV. Results: Of 38 patients included, nearly all (97%) were repaired with no or partial closure of the LAVV cleft. Freedom from LAVV reintervention was 91% and 84% at 1 and 3 years. Five patients (13%) required reintervention on the LAVV with a median time to reintervention of 3.3 months post-AVSD repair; indication was LAVV regurgitation for four of the five patients. Preoperative LAVV regurgitation > mild was associated with an increased risk for LAVV reintervention (p= 0.02). At discharge, 63% of patients had > mild LAVV regurgitation and 5% had > mild LAVV stenosis. At most recent follow-up, 32% had > mild LAVV regurgitation and 12% had > mild LAVV stenosis. Patients with younger age at repair and preoperative AV valve index <0.67 had significantly increased risk of > mild LAVV regurgitation at discharge (p=0.01 and p=0.04, respectively), however this did not persist at most recent follow-up. More pronounced unbalance of the AVSD was not associated with postoperative LAVV stenosis. Conclusions: Despite concern for repair in patients with AVSD and single papillary muscle attachments, surgical outcomes are favorable with low risk for reintervention. Risk of LAVV stenosis is low when repair of LAVV cleft is modified. Preoperative LAVV regurgitation, younger age at repair, and more pronounced unbalance of the AVSD predicted early postoperative LAVV regurgitation, with improvement over time.