Valva mitral heteróloga sem suporte: resultados clínicos a médio prazo

Abstract

The concept of replacing diseased mitral valve with porcine mitral stentless valve allowed to address the idiosyncrasy of the left ventricular flow and contractility. From March 92 to December 95, 108 patients had their mitral valves replaced by stentless mitral valves. Their age varied from 11 to 65 years (mean 35.22 ± 14.98). There were 67 (62%) females and 41 (38%) males. The predominant ethiology was rheumatic heart disease 94 (87%) cases, followed by a prosthetic dysfunction 6 (5.6%) cases, myxomatous disease 5 (4.6%) cases, infective endocarditis 2 (1.9%) cases and ischemic lesion 1 (0.9%) case, 26 (24.1%) patients had mitral stenosis, 24 (22.2%) mitral regurgitation and the remaining 58 (53.7%) mixed lesions; 21.3% of the patients had previous open heart operations. The great majority of the operated patients (97.2%) were in functional class III and IV (NYHA). Associated procedures were performed in 9.3% (10) of the cases. RESULTS: Hospital mortality occurred in 7 (6.5%) patients non valved related with exception of one whom developed early endocarditis. Of the 101 remaining 3 required reoperations, in two due to valved size mismatch and 1 due to papillary muscle tear. Of the 98 remaining patients, 2 were lost to follow-up, 96 patients have been followed for 3.2 to 45 months. During the late follow-up there were six (6.25%) deaths, of the 3 patients with late prosthetic endocarditis, 2 had their valves replaced with standard bioprosthesis, with one death. The third patient expired before reoperation. The late death patient (mitral insufficiency) died early after reoperation. The other 3 patients expired: 1 due to myocardial infarction, 1 due to stroke and 1 with pancreatitis. LATE REOPERATIONS: There were 12 patients reoperated, in 8 due to mitral regurgitation with one death, in 2 due to decrease of the mitral valve area, and 2 late endocarditis with one death. CURRENT CLINICAL FOLLOW-UP: 80 patients are being currently followed. The ecodopplercardiographic studies have shown 63 patients with normal functioning mitral stentless valves, 15 with mild but stable mitral regurgitation and two with reduction on the mitral valve area by the pressure half time. In all but two, serial echocardiographic studies have shown improvement in the left ventricular function, with decreased end systolic and end diastolic volumes. CONCLUSION: Porcine mitral stentless valves have shown better performance, are hemodynamicaly superior with greater possibility of maintaining normal ventricular size and function. Although this study showed a distinct learning curve related to the new product and technique, these can be overcome by training and following current described operative technique.