Atrioventricular Inflow and Subsequent Ventricular Growth After Staged Ventricular Recruitment for Unbalanced Atrioventricular Canal Defect

Abstract

Background: In patients with unbalanced atrioventricular canal (uAVC) defect, the hypoplastic ventricle grows variably after staged ventricular recruitment, which involves atrial septation without ventricular septal defect closure. We hypothesized that the atrioventricular inflow size into the hypoplastic ventricle after recruitment correlates with ventricular growth.

Methods: This single-institution retrospective review included 53 patients who underwent staged ventricular recruitment for uAVC between 2011 and 2024. Atrioventricular inflow jet width into the hypoplastic ventricle was assessed by intraoperative transesophageal echocardiography. End-diastolic volume index (EDVI) of the hypoplastic ventricle was measured by magnetic resonance imaging before and 1 year after recruitment. Changes were compared using the Wilcoxon matched-pairs signed-rank test.

Results: Forty-nine patients (92%) had right-dominant uAVC. Prerecruitment atrioventricular inflow width into the hypoplastic ventricle correlated with prerecruitment EDVI (r = 0.56, P < .001). Postrecruitment, there were increases in atrioventricular inflow jet width into the hypoplastic ventricle (median, 5.4 prerecruitment vs 7.5 mm postrecruitment, P < .001) and EDVI (median, 31 mL/m² prerecruitment vs 46 mL/m² postrecruitment; P < .001). Forty-four patients (83%) underwent biventricular conversion. Atrioventricular inflow jet width into the hypoplastic ventricle immediately after recruitment correlated with interval changes in EDVI (r = 0.62, P < .001). Patients who underwent biventricular conversion demonstrated greater interval changes in EDVI than those who did not (median, 17 mL/m² vs 5 mL/m², P = .045).

Conclusions: Staged ventricular recruitment promotes growth of the hypoplastic ventricle and subsequent biventricular conversion. Atrioventricular inflow jet width into the hypoplastic ventricle immediately after recruitment correlates with subsequent ventricular growth and informs intraoperative management in ancillary maneuvers to increase atrioventricular inflow. Further modifications and research are required.