Early clinical experience with the Tissuemed porcine bioprosthesis

Tissuemed (Leeds, England) porcine bioprostheses are freshly mounted and dilated for correct functional sizing and commissural alignment, then fixed under low pressure. These valves closely approximate the natural leaflet geometry, reduce opening commissural bending stresses, and may provide a solution to structural valve failure from calcification and tears. To evaluate the performance of the bioprosthesis 207 Tissuemed bioprostheses were implanted in 203 patients, 114 men and 89 women (mean age 73 years; range 56 to 94 years), between 1991 and 1996. Preoperatively 66% of the patients were in New York Heart Association functional class III or IV. There were 175 aortic, 22 mitral, 2 tricuspid, and 4 multiple replacements. Concomitant procedures were performed in 26.1% (53 of 203) of patients. Follow-up was 99.5% (total cumulative follow-up 447.5 patient-years).

The 30 day mortality, influenced by age and valve position, was 11.8% with no early valve-related deaths. Patient survival at 5 years was 76% (standard error 3.3%). Valve-related complication rates (expressed as percent per patient-year and number of events) were thromboembolism 1.1% (5), hemorrhage 0.7% (3), bacterial endocarditis 0.2% (1), nonstructural valve failure 0.2% (1), and reoperation 0.5% (2). At 5 years freedom from valve-related events were as follows: thromboembolism 92.9% (standard error 2.7%), hemorrhage 96.1% (standard error 1.9%), endocarditis 98.1% (standard error 1.8%), nonstructural valve failure 99.2% (standard error 0.7%), structural valve dysfunction 100% (standard error 0.0%), and reoperation 98.1% (standard error 1.8%). At follow-up 73.8% of the patients were in New York Heart Association functional class I or II.

There were no early valve-related deaths, no episodes of structural valve failure, and valve-related complications compared favorably with other porcine series. There was overall clinical improvement in patient symptoms. Our experience suggests that the Tissuemed porcine bioprosthesis is a safe and reliable heart valve providing good clinical improvement in patient symptoms. Long-term clinical follow-up is, however, essential to complete the evaluation.