Right-Dominant Unbalanced Atrioventricular Septal Defects: Novel Echocardiographic Measurements and Surgical Outcomes

Background Decision making regarding biventricular (BiV) repair or single ventricle management pathway in patients with unbalanced atrioventricular septal defect (uAVSD) remains controversial. We describe the surgical outcomes for right-dominant uAVSD patients and novel echocardiographic measurements. Methods A retrospective (2004-2022) single-center study of patients receiving BiV repair or single ventricle palliation for right-dominant uAVSD was performed. Right-dominant uAVSD was defined as a modified atrioventricular valve index (mAVVI) less than 0.44. The primary endpoint was mortality and the secondary endpoint was BiV repair. Preoperative echocardiographic measurements were compared between repair types and receiver operating curves were generated to determine cut points. Results Forty-four patients with right-dominant uAVSD were included. Median age at first operation was 2.04 [IQR: 0.48-3.96] months. BiV repair was performed in 31/44 (70.5%) and single ventricle palliation in 13/44 (29.5%) patients, with 12/44 (27.3%) and 7/44 (15.9%) undergoing Glenn and Fontan, respectively. Preoperative median mAVVI, left atrioventricular valve (LAVV) inflow angle, left atrial/left ventricular (LA/LV) inflow angle, and LV pinching index were significantly different between single and BiV repair groups, and cutoff points for these measurements were determined. Patients who underwent single ventricle palliation had worse survival at 10 years; however, this difference was not statistically significant (75.2 [54.2%-100.0%] vs 96.0 [88.6%-100%], P = .18). Conclusions Patients with uAVSD who undergo BiV repair tend to have better survival than those who undergo single ventricle palliation. Preoperative measurements of the mAVVI, LAVV inflow angle, LA/LV inflow angle, and LV pinching index are associated with the type of repair. These echocardiographic measurements will require prospective validation.