Corrected transposition and ventricular septal defect. Surgical experience.

The entire 21-year experience at our institution with intracardiac repair of corrected transposition of the great arteries (CTGA) associated with ventricular septal defect (VSD) is reviewed. There were 53 such operations. The hospital mortality rate fell from 50% before 1972 to 18% since then (p < 0.02), and was 19% when a systemic ventriculotomy was not used compared to 60% when it was used (p < 0.01). A technique is described for correction of CTGA with VSD and pulmonary outflow tract obstruction (POTO) designed to minimize risk of heart block and to increase the degree of relief of POTO: the VSD patch is placed to the right side of the conduction tissue and the pulmonary outflow tract, and POTO is bypassed with an extracardiac conduit. This technique reduced the incidence of complete heart block from 67% by direct relief of POTO to 28% (p < 0.05) and decreased the frequency of inadequate relief of POTO from 50% to 8% (p < 0.01). However, experience with these two approaches was not concurrent. Successful intraoperative mapping of the conduction bundle was associated with operatively induced heart block in 37%, whereas prior to the availability of mapping the incidence of heart block was 57% (difference not significant). Twelve patients required atrioventricular (AV) valve repair or replacement, and in them the operative mortality was 50%, compared to 20% in the remainder (p < 0.05). For the 21 patients with VSD and POTO who achieved good relief of POTO, the operative mortality was only 5%. These findings suggest that good progress has been made in the surgical repair of CTGA with VSD, though further improvement in results is required.