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.