Biopróteses aórticas porcinas, modelo convencional e sem suporte ("stentless"): estudo comparativo

objective: the purpose of this retrospective study is to compare clinical performance of 2 heart valve substitutes used in the aortic position. both groups were operated consecutively during the same period of time: group 1 (g1): patients with composite porcine aortic stentless valves; group 2 (g2): patients with composite porcine stented aortic bioprostheses. material and methods: the clinical data of 725 patients were reviewed and we found 752 operations for aortic valve replacement performed between january 1990 and december 1996. only patients with at least one year of follow-up were included. data collected included clinical characteristics, valve size implanted, cardiopulmonary bypass and aortic crossclamp time and in house and outpatient follow-up. echocardiographic data were also compared as far as the following parameters: effective orifice area, effective orifice area index, mean transvalvar gradient and severity of aortic insufficiency. results: we performed 169 operations in g1 and 583 operations in g2. clinical characteristics of the 2 groups were similar, except the data related to age (38.0 ± 17.5 vs 46.0 ± 19.0 years) (p < 0.05) and etiology of aortic valve disease, as there were more native and prosthetic endocardites in g1 (p < 0.02). perioperative data showed that more than 70% of patients of the 2 groups received bioprostheses no 25 or less, chosen in all cases based on the size of the aortic annulus. cardiopulmonary by-pass (99.9 ± 28.8 vs 86.3 ± 31.0 minutes) and aortic crossclamp time (80.9 ± 25.2 vs 65.0 ± 24.4 minutes) were longer in g1 (p < 0.0001). nevertheless, intensive care unit and hospital stay, morbidity and mortality of the 2 groups were similar. the echocardiographic studies disclosed effective orifice area (1.94 ± 0.31 vs 1.48 ± 0.33 cm2) and effective orifice area index (1.15 ± 0.23 vs 0.89 ± 0.06 cm2/m2) significantly larger in the stentless group (p < 0.000001), thus leading to lower mean transvalvar gradient (8.3 ± 4.9 vs 13.2