The Medtronic Intact porcine bioprosthesis: clinical performance to eight years

The Medtronic Intact porcine bioprosthesis was implanted in 274 patients, in 278 operations, between 1984 and 1992 inclusive. Of the total patient population, 171 patients had 175 aortic valve replacements (AVR), 75 had mitral valve replacement (MVR), two had tricuspid valve replacement and 26 had multiple valve replacement (MR). Concomitant procedures, primarily coronary artery bypass, was performed in 97 (34.9%). The follow up was 98.2% complete; total follow up was 758 patient-years, mean 2.8 years. The early mortality was 6.5% (18 patients) and the late mortality 4.0% per patient-year (30 patients). Of the late deaths, 10 were valve-related-thromboembolism (n = 2), anticoagulant-related hemorrhage (n = 1), prosthetic valve endocarditis (n = 4), non-structural dysfunction (n = 2), and structural valve deterioration (n = 1). Only one death occurred as a consequence of reoperation. The freedom from thromboembolism at six and eight years was-overall 86 +/- 4%; major 96 +/- 1%; fatal 99 +/- 1%. The overall linearized rate of thromboembolism was 3.0% per patient-year. The freedom from anticoagulant-related hemorrhage was 93 +/- 3%; non-structural dysfunction 87 +/- 9%; and structural valve deterioration 97 +/- 2% (AVR 97 +/- 2% at six and eight years, MVR 100% at six years). The freedom from SVD by age groups was- < or = 35 years 100%; 36-50 years 94 +/- 6%; 51-65 years 98 +/- 2%; and > or = 65 years 97 +/- 2% (p = NS). The freedom from valve-related mortality at six and eight years was 86 +/- 8%; residual morbidity 96 +/- 1%; and reoperation 91 +/- 3%. The Medtronic Intact, zero-pressure glutaraldehyde fixed prosthesis requires continued long term assessment to determine if the low incidence of structural valve deterioration is maintained.