Homograft mitral valve replacement: five years' results.

Abstract

Results of mitral valve replacement with a mitral homograft were evaluated at 5 years to assess the suitability of the procedure. Thirty-seven patients (25 male subjects) aged 10 to 49 years (mean, 32 +/- 10 years) with rheumatic mitral valve disease underwent total (n = 35) or partial (n = 2) mitral valve replacement with a fresh antibiotic-preserved (n = 23) or cryopreserved (n = 14) mitral homograft. The predominant lesion was mitral stenosis (n = 30). There were 5 early deaths. Operative survivors were followed up for 1 to 60 months (mean, 26.6 +/- 12 months). Among these, 21 patients had severe mitral regurgitation during the follow-up period; 3 died and 8 underwent reoperation. The homograft failure rate was not affected by preoperative physiologic lesion (stenosis vs regurgitation, P =.4), type of homograft (antibiotic-preserved vs cryopreserved homograft, P =.9), papillary muscle pretreatment (yes vs no, P =.9), or addition of posterior collar annuloplasty (yes vs no, P =.2). Among the remaining patients, 5 had moderate mitral regurgitation, 4 had either trivial or mild mitral regurgitation, and 2 were lost to follow-up. Study of the explanted mitral homografts (n = 8) revealed that disruption of one of the donor papillary muscles was responsible for early failures (n = 2), whereas cuspal and chordal degeneration was responsible for late failures (n = 6). Microscopically, the explanted valve lacked any viable cellular elements, and there was no evidence of immunologic injury to the homografts. The mitral homograft did not fulfill our expectations as a suitable substitute for the diseased mitral valve.