Experience with the extracardiac conduit.

A review is made of all Mayo Clinic cases wherein 468 patients have received 516 extracardiac conduits in the repair of congenital heart defects. All patients had complex defects, which are classified in 10 basic diagnostic categories. The early mortality rate (which ranged from 4% to 49%, according to diagnostic group) averaged 25%, improving with experience. The postoperative complication rate was 70%. In 1% of operations, compression of the conduit was encountered at chest closure. The conduits placed in 333 patients contained a porcine valve. The conduit diameter averaged 22 mm. At completion of the operation, the mean gradient across the conduit was 22.8 mm Hg. At late study this mean gradient remained at 26 mm Hg in patients who had received the currently employed porcine-valved conduit. The average ratio of intraoperative postrepair ventricular (RV/LV) systolic pressures was 0.68. It was lower among the group who were to survive but was not ov prognostic value in individual cases. Among patients who survived the postoperative period, the late mortality rate (based on a mean of 3.6 years' follow-up) averaged 3.5% per year. Of the long-term survivors, 18% have required reoperation, primarily for replacement of calcified aortic homograft conduits used in the earlier part of the experience. Only 0.8% of porcine-valved conduits have required reoperation. Unrestricted life-styles were possible for 90% of survivors.