Brazilian Journal of Cardiovascular Surgery (Dec 1996)
Estudo comparativo in vitro entre biopróteses de pericárdio bovino e porcinas In vitro comparative study between bovine pericardial and porcine bioprosthesis
Abstract
A maioria dos implantes valvulares cardíacos realizados no Brasil é representada pelas válvulas de pericárdio bovino, seguidas por próteses porcinas. Na avaliação de válvulas biológicas, deve-se considerar: desempenho hidrodinámico, resistência à fadiga e processo de calcificação. No presente estudo, foi avaliado o desempenho hidrodinámico de biopróteses de pericárdio bovino (Biopro-PB-Braile Biomédica) comparativamente às válvulas porcinas (Biopro-PP-Braile Biomédica) através do gradiente médio transvalvular. Os testes hidrodinámicos foram realizados em próteses de diâmetros variando de 19 a 35 mm, submetidas ao Sistema Duplicador de Pulsos Shelhigh (Shelhigh Inc.). O volume de ejeção foi mantido constante em 90 ml, com freqüência de pulso de 60, 70,80, 90 e 100 ciclos por minuto, possibilitando fluxos entre 5 e 9 litros por minuto, equivalentes a fluxos contínuos aproximados de 8 a 18 litros por minuto. Houve tendência à diminuição dos gradientes pressóricos à medida em que aumenta o diâmetro externo das próteses. O gradiente pressórico médio encontrado em próteses de pericárdio bovino foi significativamente menor que o de próteses porcinas (pMost of the cardiac valve implantations in Brazil are represented by bovine pericardial valves, followed by the porcine prostheses. In the evaluation of biological valves, the following should be taken into consideration: hydrodynamic performance resistance to fatigue and calcification process. In this study, the hydrodynamic performance of bovine pericardial bioprostheses (Biopro-BP-Braile Biomedica) was evaluated comparatively to porcine valves (Biopro-PP-Braile Biomedica), through the transvalvular medium gradient. The hydrodynamic tests were made on prostheses varying from 19 to 35 mm in diameter, which underwent the pulse duplicator system Shelhigh (Shelligh Inc.). The ejection volume was constantly kept at 90 ml. The pulse frequencies varied between 60 and 100 cycles per minute, allowing flows between 5 and 9 liters per minute, equivalent to approximate continuos flows of 8 to 18 liters per minute. There was tendency to decrease the gradients, in proportion to increase of the bioprostheses external diameters. The medium pressure gradient found in the bovine pericardial prostheses was significantly smaller than that in the porcine prostheses (p<0.01), for all diameters studied. Respecting the large variability of protocols of tests in the literature for hydrodynamic evaluation of valve prostheses, the necessity of standard tests becomes stronger, seeking adequate comparison among the several valves.
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