Subaortic obstruction in double outlet right ventricles. Surgical considerations for anatomic repair.

BACKGROUND: Subaortic obstruction is one of the risk factors for anatomic repair of double outlet right ventricles (DORV). A comprehensive approach to such lesions has been developed in our institution since 1981. This retrospective work analyzes the results of this approach.

METHODS AND RESULTS: Between January 1981 and September 1992, 30 patients aged 15 days to 15 years (mean, 44.8 months) underwent repair of a DORV associated with subaortic obstruction. Eighteen patients had a palliative procedure before complete repair. The ventricular septal defect (VSD) was subaortic in 15 patients, doubly committed in 1, noncommitted in 9, and subpulmonary in 5. The subaortic obstruction was a result of restrictive VSD in 29 patients and of double straddling of mitral and tricuspid valves once. The preoperative peak systolic pressure gradient between the left ventricle and the aorta (LV-Ao) was 68.7 +/- 23 mm Hg. Reconstruction of the left ventricular outflow tract comprised a ventral enlargement of the VSD in subaortic, doubly committed, and those subpulmonary VSDs scheduled for an arterial switch operation or a conal resection in noncommitted and other subpulmonary forms. Reconstruction of the right ventricular outflow tract included primary closure of the right ventricle in 12 patients, an infundibular patch in 9, a transannular patch in 4, and insertion of a right ventricular pulmonary valved conduit in 5. There were two early (6.6%) and two late (7.1%) deaths. Three patients required reoperation. A mean follow-up of 60.5 +/- 46.8 months was achieved in all the survivors. They were all in New York Heart Association class I or II, in sinus rhythm. At last follow-up, the mean LV-Ao gradient was 7.5 +/- 6.2 mm Hg, and LV function indices were within normal ranges. Actuarial survival and freedom from reoperation rates at 8 years were 86.6% and 87.0%, respectively.

CONCLUSIONS: Surgical relief of subaortic obstruction in DORV has to be adapted to VSD location and spatial arrangement of atrioventricular valves and great vessels.