Late results after extracardiac conduit repair for congenital cardiac defects.

Analysis of the late results in 352 patients surviving insertion of an extracardiac conduit before mid 1977 has provided a mean follow-up interval of 65 months. Three fourths of the patients remain in improved condition after operation. Serial measurements of transconduit gradient are available in 90. The median change was +7 mm Hg and the mean +21 mm Hg. Reoperation was required in 16 percent of patients (mortality rate 9 percent), most commonly (77 percent) because of progressive conduit stenosis, more commonly for transposition of the great arteries than for other types of anomalies, and more commonly after use of a homograft aortic conduit than a Hancock conduit. The side of the aorta on which the conduit was placed exerted no significant influence. The postrepair transconduit gradient did not affect the need for reoperation. Late survival was 95 percent at 1 year, 85 percent at 5 years, and 73 percent at 10 years and was significantly better (probability [p] less than 0.006) for patients with pulmonary atresia than for the others. The hospital mortality rate was highest, and the late mortality rate lowest, for children less than 5 years of age; the overall survival rate in this age group was lower. The postrepair right ventricular to left ventricular pressure ratio, together with age, was a principal prognostic indicator of late survival, being less good when more than 0.73. THe most frequent causes of late death were progressive congestive heart failure and sudden death.