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Background: The pericardial bovine prosthesis Pericarbon should offer some advantages in comparison with the former generations, because its development is focused on solving previous problems and resulted in the variation of the pericardial fixation method, of valve structure and of stent coating. This hypothesis was evaluated through a retrospective follow-up., Methods: Between 1985 and 1989, 78 Pericarbon prostheses O 29 were implanted in mitral position by the same surgeon. All patients received warfarin for the first three months to maintain an International Normalized Ratio between 2.5 and 3.5; after which they received antiaggregant therapy indefinitely. With an average follow-up period of 7.34 years for a total of 573 patient-years, we evaluated perioperative and late mortality, late morbidity (thromboembolic and haemorrhagic events, reoperations, primary tissue failures, endocarditic events) and patient clinical conditions., Results: Perioperative mortality was 1.28% (1/78), late mortality was 11.6% (9/77) with 5 valve-related deaths. 5-year survival was 93% and 10-year survival 97%. Fifteen patients required reoperation for prosthetic replacement, fourteen for primary tissue failure. There were ten minor thromboembolic events, one major event, one haemorrhage and one prosthetic endocarditis (the last two with patient exitus). After 10 years (75% of patients were in New York Heart Association class I-II., Conclusions: Besides the known better haemodynamic performance, Pericarbon bioprosthesis seems to present a survival and redofreedom curve comparable to the best porcine prosthesis, with less incidence of endocarditis, thromboembolic events and prosthesis leakage.

Background: Stent deformation seems to be effective in the long term performances of bioprostheses., Methods: The Inward Banding Angle (IBA) of three different models of bioprostheses explanted during the period 1991-1992 at our Division of Cardiac Surgery in 45 different patients (26 males; 9 females; mean age 59.71 +/- 10.74, range 26-75) has been measured. Explanted valves were as follow: Hancock, (H = 13); Carpentier-Edwards (C = 14) e Xenomedica (X = 18). Primary tissue failure was the most common cause of re-operation (n = 30; 66.7%) but also endocarditis (n = 6; 13.3%) and paraprothetic leak (n = 10; 22.2%). A semi-quantitative score (0-4) was used to assess calcifications (1.51 +/- 1.56); tears (0.41 +/- 0.98); vegetation's (0.51 +/- 0.99) and fibrosis (2.7 +/- 1.27). The mean follow-up was 7.77 +/- 3.79 years (range 1.5 +/- 16 years). The mean IBA evaluated after explantation was 3.34 +/- 2.29 degrees., Results: Statistical analysis showed a significance in term of IBA in the Hancock group vs Carpentier (P < 0.02); a less duration in the Xenomedica group vs H and C (p < 0.001) and an increased susceptibility to vegetation's and fibrosis in the Xvs C (p < 0.01) and H (p < 0.05) respectively. A suggestive correlation between IBA and time and between IBA and diameter was found but no statistical significance was observed., Conclusions: In conclusions, it is suggested that all materials tends to deform during time and a possible explanation of stent deformation can be the different material used in the stent fabrication. Moreover, mechanical stress and compression around the ring can be another mechanism of creep.