Aortic valve replacement with autologous pericardium: long-term follow-up of 15 patients and in vivo histopathological changes of autologous pericardium

OBJECTIVES: The study aimed to assess the long-term follow-up of patients with an autologous pericardial aortic valve (APAV) replacement and to analyse in vivo histopathological changes in implanted APAVs. METHODS: From 1996 to 1997, 15 patients (mean age, 34 years) underwent aortic valve replacement with the glutaraldehyde-treated autologous pericardium. All patients were followed up after discharge. The excised APAVs were processed for haematoxylin-eosin, Victoria blue-van Gieson and immunohistochemical staining. RESULTS: The mean clinical follow-up was 11.43 ± 4.50 years. APAV-related in-hospital and late mortalities were both 0%. Five (33%) patients required reoperation because of a prolapse of the right coronary cusp (n = 1), infective endocarditis (n = 1) or fibrocalcific degeneration (n = 3). Freedom from endocarditis, fibrocalcific degeneration and reoperation at the end of follow-up was 93, 80 and 67%, respectively. The remaining 10 patients were alive and well with a mean New York Heart Association class of 1.10 ± 0.32 and normally functioning aortic valves (peak pressure gradient: 7.70 ± 3.41 mmHg; mean pressure gradient: 1.79 ± 0.64 mmHg). Histopathology revealed that (i) a thin factor VIII-positive layer (endothelialization) was found on all non-endocarditis APAVs; (ii) pericardial cells in all APAVs were positive for α-smooth muscle actin (myofibroblast phenotype) and some cells in the fibrocalcific APAVs were positive for alkaline phosphatase (osteoblast phenotype) and (iii) an elastic band was found in 3 cases (in vivo >9 years). CONCLUSIONS: APAV replacement is a procedure with a low mortality. APAVs adapt to new environmental demands by producing an elastic band and by endothelialization, whereas myofibroblast/osteoblast transdifferentiation seems to be responsible for the fibrocalcification of APAVs.