The impact of surgical repair on left ventricular outflow tract in atrioventricular septal defect with common atrioventricular valve orifice

OBJECTIVE: Although a narrow left ventricular outflow tract in atrioventricular septal defect is related to its intrinsic morphology, the contribution from the repair technique remains to be quantified. METHODS: A total of 108 patients with an atrioventricular septal defect with a common atrioventricular valve orifice were divided into 2 groups: 2-patch (N = 67) and modified 1-patch (N = 41) repair. The left ventricular outflow tract morphometric was analyzed by quantifying the degree of disproportion between subaortic and aortic annular dimensions (disproportionate morphometrics ratio was defined as ≤ 0.9). Z-scores (median, interquartile range) were further analyzed in a subset of 80 patients with immediate preoperative and postoperative echocardiography. A total of 44 subjects with ventricular septal defects served as controls. RESULTS: Before repair, 13 patients (12%) with an atrioventricular septal defect had disproportionate morphometrics (vs 6 [14%] ventricular septal defect P = .79), but the subaortic Z-score (−0.53, −1.07 to 0.06) was lower than the ventricular septal defect (0.07, −0.57 to 1.17; P < .001). After repair, both 2-patch (8 [12%] preoperatively vs 25 [37%] postoperatively; P = .001) and modified 1-patch (5 [12%] vs 21 [51%], P < .001) procedures showed a greater degree of disproportionate morphometrics. Both 2-patch (postoperatively −0.73, −1.56 to 0.08 vs preoperatively −0.43, −0.98 to 0.28; P = .011) and modified 1-patch (−1.42, −2.63 to –0.78 vs −0.70, −1.18 to −0.25; P = .001) procedures also demonstrated lower subaortic Z-scores postrepair. The postrepair subaortic Z-scores were lower in the modified 1-patch group (–1.42 [−2.63 to −0.78]) compared with the 2-patch group (–0.73 [−1.56 to 0.08]; P = .004). Low postrepair subaortic Z-scores (<−2) were observed in 12 patients (41%) in the modified 1-patch group and 6 patients (12%) in the 2-patch group (P = .004). CONCLUSIONS: Surgical correction resulted in greater disproportionate morphometrics seen immediately postrepair. The impact on the left ventricular outflow tract was observed in all repair techniques, with a greater burden seen after modified 1-patch repair. VIDEO ABSTRACT: This morphometric study in AVSD with common atrio-ventricular valve orifice confirmed further derangements of LV outflow tract morphometrics immediately after surgical repair.