Porcine xenograft valve failure in children: an immunologic response.

Thirty-six children underwent placement of either an intracardiac porcine xenograft valve (n = 17) or an extracardiac porcine xenograft-valve conduit (n = 20). Eleven of 17 patients with intracardiac porcine valves and only one of patients with 20 extracardiac porcine valved conduits had severe hemodynamic valvular changes (p less than 0.01). Twelve of 17 of the intracardiac xenograft patients had symptoms: eight had congestive heart failure, one had angina and three had exercise intolerance. The only extracardiac conduit patient with hemodynamic changes had congestive heart failure. Calcification was noted in 11 of 18 intracardiac porcine valves and in none of the extracardiac valved conduits. Pathologic valve material was available in nine of 18 intracardiac porcine valve patients and disclosed extensive ingrowth of host tissue in eight valves, histiocytic infiltrates in all nine valves, plasma cell infiltrates in three valves and positive immunofluorescence for immunoglobulin in all three valves. Three of 17 patients with intracardiac porcine xenograft valves had increased plasma immunoglobulins and one patient had bone marrow plasmocytosis. Our data suggest that children have a high incidence of early xenograft dysfunction only when intracardiac porcine valve replacement is performed. The infiltration of plasma cells and histiocytes and the immunoglobulin response in children with intracardiac glutaraldehyde-preserved porcine valves suggest the xenograft dysfunction may in part be due to an immunologic reaction.