The intact porcine bioprosthesis: early world-wide clinical experience and analysis of a single institution's experience

The Intact porcine bioprosthesis is a new-generation valve fixed under stress-free conditions and subjected to a mineralization-inhibiting treatment. The valve is undergoing multi-centre prospective clinical evaluation sponsored by Medtronic, Inc., with 19 centres participating world wide. Since April 1986, 1465 valves have been implanted in the aortic position (AVR, n = 965), mitral position (MVR, n = 438), or both (n = 62), and followed up to 5 years. The data recorded at our participating centre, with 115 valves implanted (AVR n = 93, MVR n = 22) closely match the overall event and death rates in the prospective study. Early mortality in the overall study is 5.6% in AVR and 6.6% in MVR; 3-year actuarial survival rates are 88.5% in AVR and 85.6% in MVR; structural valve-failure-free rates at 3 years are 99.8% in AVR and 98.5% in MVR; 3-year freedom from valve-related reoperation is 97.3% in AVR and 95.8% in MVR. The preferential use of bioprosthetic valves in patients aged 70 years and older with no other indication for anticoagulant treatment entails the not infrequent occurrence of patient/prosthesis mismatch in AVR. Hence, when implanting bioprostheses in old patients, the acceptance of some mismatch has to be weighed against the freedom from anticoagulation treatment and the expected long-term freedom from structural valve failure. Further long-term follow-up will be required to demonstrate the greater durability expected from the stress-free fixation and the anti-mineralization treatment.