RESUMO
The current status of valve replacement was reviewed by analyzing six groups of 100 consecutive patients, each receiving the standard Carpentier-Edwards bioprosthesis, the Starr-Edwards valve or the Björk-Shiley valve in the mitral or aortic position and operated on by the same surgeons in the same institution during an identical time frame. Data were evaluated for valve failure, reoperation, thromboembolism and valve-related deaths. Long-term results up to 9 years showed the superiority of bioprostheses over mechanical valves in terms of valve-related deaths and thromboembolic and anticoagulant complications for a similar rate of valve failure. Persistent drawbacks associated with valvular bioprostheses, namely, transvalvular gradients, limited durability and tissue calcification in young patients, led to continual improvements in valve design and preservation techniques and the development of the third generation Carpentier-Edwards bioprosthesis: the supraanular porcine valve and pericardial valve. The supraanular porcine valve was designed with the aim of decreasing the transvalvular gradient, decreasing turbulence, increasing longevity and decreasing calcification. The pericardial valve was designed with the aim of improving hemodynamics in small-sized orifices, improving mounting techniques to avoid fixation sutures at the commissures, achieving a flexible stent and improving preservation. Between July 1980 and October 1984, there were 391 supraanular porcine and 61 pericardial valves implanted. The supraanular valves were used for three purposes: isolated aortic, isolated mitral and mitral valve replacement associated with tricuspid anuloplasty. The pericardial valves were used for isolated aortic valve replacement. Short-term results (1 to 4 years) are presented concerning the clinical use of these third generation bioprostheses.