Midterm evaluation of the Tissuemed (Aspire) porcine bioprosthesis: 493 patients, 506 bioprostheses

Background. Valve durability has been a major concern with bioprostheses, and the Tissuemed (Aspire) porcine bioprosthesis was designed to provide a solution to structural valve failure. Because bioprostheses tend to fail by 8 years, the aim of our study was to determine its midterm durability and performance. Methods. We reviewed 506 prostheses that were implanted in 493 patients (287 men; mean age 73 ± 6 years) between 1991 and 1999. Preoperatively 316 (68%) patients were in New York Heart Association class III or IV. There were 417 (85%) aortic, 61 (12%) mitral, 13 (2.6%) aortic and mitral, and two (0.4%) tricuspid procedures. Concomitant procedures were performed in 163 (33%) patients. Follow-up was complete in 488 (98.9%) patients with a total cumulative follow-up of 1,402 patient-years. Results. The 30-day mortality in this elderly population was 10% (95% confidence interval, 8 to 13), with no early valve-related deaths. Patients’ survival at 8 years was 46% ± 7%. This was influenced by the following factors: (1) the patient’s age, being worse for those 70 years or older (p = 0.005); (2) those in New York Heart Association functional class III and IV (p = 0.004); (3) those in atrial fibrillation before the operation (p = 0.006); (4) those with poor left ventricular function (p = 0.009); and (5) those who had a previous cardiac operation (p = 0.003). Valve-related complications (expressed as percent per patient-year) were thromboembolism at 0.9%/patient-year; major hemorrhage at 1.4%/patient-year; bacterial endocarditis at 0.4%/patient-year; nonstructural dysfunction at 0.2%/patient-year, and reoperation at 0.2%/patient-year. At 8 years, freedom from thromboembolism was 93% ± 7%, major hemorrhage, 90% ± 4%, nonstructural dysfunction, 99% ± 1%, structural valve failure, 100%, and reoperation, 99% ± 1%. At follow-up, 98% of survivors were in New York Heart Association class I or II. Conclusions. Our study suggests that at 8 years, the Tissuemed (Aspire) porcine bioprosthesis is durable and has satisfactory performance with low complication rates.