Isolated mitral valve replacement with the Hancock porcine bioprosthesis in rheumatic heart disease: analysis of 213 operative survivors followed up 4.5 to 8.5 years.

An analysis is presented of 236 patients aged greater than or equal to 20 years who underwent isolated mitral valve replacement for rheumatic heart disease with a glutaraldehyde Hancock bioprosthesis from June 1974 through June 1978. Of 213 patients discharged from the hospital, 3 were lost to follow-up study and are excluded from the analysis. The range of follow-up of the surviving patients was 54 to 102 months. There were 17 late deaths, an incidence of 1.3% per patient-year. The actuarial probability of survival of all patients at 102 months, excluding hospital mortality, is 88 +/- 6%. There were 24 thromboembolic events in 22 patients (1.8% per patient-year); none was fatal, and 3 patients were receiving coagulant therapy at the time. The probability of freedom from thromboembolism at 8.5 years is 84 +/- 9%. Primary tissue failure occurred in 17 patients (1.3% per patient-year). Average duration of the explanted valves was 70 months (range 55 to 90). Reoperation was undertaken in the 17 patients 2 days to 63 months (mean 9 months) after the appearance of a new murmur and 2 days to 23 months (average 4 months) after the onset of worsening symptoms. The probability of being free from primary tissue valve failure at 8.5 years of follow-up is 87 +/- 7%. Currently, 14 patients have valve dysfunction on the basis of the appearance of a new murmur 20 to 89 months after operation (average 5.2 years).(ABSTRACT TRUNCATED AT 250 WORDS)