The Medtronic Intact xenograft: an analysis of 342 patients over a seven-year follow-up period.

Three hundred forty-two patients from December 1985 to January 1993 received 352 Medtronic Intact porcine xenograft valves (zero-pressure glutaraldehyde-fixed with toluidine blue anticalcification agent). The follow-up was 99.4% complete with a mean of 3.14 years (3 months to 7.9 years). The mean patient age was 64 years (range, 16 to 82 years) and the median age was 67 years. There were 14 aortic valve replacement patients (11.9%) and 62 mitral valve replacement patients (29.2%) who preoperatively were in New York Heart Association class IV to V. The hospital mortality was 8.4% +/- 2.9% (aortic valve replacement, 5.9%; mitral valve replacement, 9.4%; tricuspid valve replacement, 7.6%). Actuarial patient survival at 7 years was 65% +/- 5% (aortic valve replacement, 77% +/- 5%; mitral valve replacement, 63% +/- 5%). At 7 years, the freedom from thromboembolism was 74% +/- 4%, freedom from endocarditis 93% +/- 2%, and freedom from reoperation 90% +/- 3%. Reoperation was required for endocarditis (7 patients), periprosthetic leak (6), and 2 of 3 cases of structural deterioration. The actuarial freedom from structural deterioration at 5 years was 97% +/- 3%. The combined incidence of all important morbid valve-related events was analyzed with an actuarial freedom at 7 years of 63% +/- 3%. The durability of the Medtronic Intact is at least equal to that of other porcine bioprostheses. The relevant important time-frame of 7 to 12 years of follow-up has just begun, and possibly the reoperation rate for intrinsic value failure and the low incidence of calcification in the elderly patient may be showing improved characteristics of this valve. No stronger inferences are possible at this stage of the 7-year follow-up.