Variations of Atrioventricular Septal Defects Predisposing to Regurgitation and Stenosis

Background. An additional malformation of the atrioventricular valve is occasionally encountered in patients with complete atrioventricular septal defect, and this may compromise accurate correction. Methods. We reviewed 138 patients undergoing complete repair with two-patch technique between 1992 and 2008. The mean age was 7.1 +/- 8.3 months, and the mean body weight was 5.1 +/- 2.1 kg. Preceding pulmonary arterial banding was performed in 23 patients. Results. The operative record delineated additional malformations of the atrioventricular valve that posed difficulty in positioning the ventricular septal patch and in accurately approximating the cleft in 45 patients. Of them, four types (n = 40) were associated with increased incidence of postoperative left valvular problems (moderate or worse regurgitation or stenosis). These included abnormalities of the papillary muscles that accompanied hypoplastic mural leaflet or incomplete opening of one commissure in (n = 15; p = 0.0054), dense insertion of the chords of the superior leaflet that obscured the right side of the ventricle septal crest in (n = 13; p = 0.0004), double orifice valve (n = 7; p = 0.0225), and severe length disparities of the cleft that resulted from either disproportional size of superior against inferior leaflets or redundant chord supporting the left extremity of one of these leaflets (n = 5; p < 0.0001). Neither greater age at operation (more than 6 months) nor preceding pulmonary arterial band reduced the incidence of left valvular problems in the malformation group. Conclusions. An individualized technique is required to maintain coaptation of the atrioventricular valve, but in many cases, they are not completely correctable. Deferring complete repair by placing a pulmonary arterial band did not reduce left valvular problems. (Ann Thorac Surg 2010; 90: 614-21) (C) 2010 by The Society of Thoracic Surgeons