The durability of porcine xenograft valves and conduits in children.

One hundred four patients younger than 20 years of age underwent intracardiac xenograft valve replacement (n = 41) or extracardiac conduit implantation (n = 63). Long-term follow-up averaged 4.5 and 4.3 years, respectively, and cumulative follow-up totaled 344 patient-years (pt-yr). Thirty patients were followed more than 5 years. Functional results and survival were satisfactory, but valve failure and conduit failure prompted 23 reoperations at linearized rates of 10.1 +/- 2.6% and 4.1 +/- 1.5%/pt-yr, respectively. The rate of valve failure due to leaflet fibrocalcification (primary tissue failure [PTF] was 8.1 +/- 2.4%/pt-yr. Among patients who underwent valve replacement, 52 +/- 13% were free of reoperation at 5 years (59 +/- 13% for PTF only), as were 80 +/- 9% of patients who received an extracardiac conduit. There were no deaths associated with the 22 late reoperations or with the 21 reoperations for PTF. Valve failure was due to PTF in 80% of cases; conversely, isolated valvular PTF was the cause of conduit failure in only one of eight patients. The most common cause of conduit failure was exuberant pseudointimal proliferation in the proximal conduit, which was seen in six of eight patients (75%) with or without other sites of obstruction and responsible for nine of the 15 obstructions (60%). These results underscore the palliative nature of these procedures, militate against indiscriminant use of conduits, prompt consideration of alternative nonconduit techniques where possible, and reemphasize the clinical need for superior valve substitutes and biomaterials for use in the pediatric age group.