Mitral valve repair for degenerative disease: a 20-year experience.

BACKGROUND

Recent advances in surgical technique allow repair of most mitral valves with degenerative disease. However, few long-term data exist to support the superiority of repair versus prosthetic valve replacement, and repair could be limited by late durability or other problems. This study was designed to compare survival characteristics of mitral valve repair versus prosthetic replacement for degenerative disorders during a 20-year period.

METHODS

From 1986 to 2006, 2,580 patients underwent isolated mitral valve procedures (with or without coronary artery bypass grafting), with 989 classified as having degenerative origin. Of these, 705 received valve repair, and 284 had prosthetic valve replacement. Differences in baseline characteristics between groups were assessed, and unadjusted survival estimates were generated using Kaplan-Meier methods. Survival curves were examined after adjustment for differences in baseline profiles using a Cox model, and average adjusted survival differences were quantified by area under the curve methodology. Survival differences during 15 years of follow-up also were assessed with propensity matching.

RESULTS

Baseline characteristics were similar, except for (variable: repair, replacement) age: 62 years, 68 years; concomitant coronary artery bypass grafting: 24%, 32%; ejection fraction: 0.51, 0.55; congestive heart failure: 68%, 43%; and preoperative arrhythmia: 11%, 7% (all p < 0.05). Long-term survival was significantly better in the repair group, both for unadjusted data (p < 0.001) and for risk-adjusted results (p = 0.040). Patient survival in the course of 15 years averaged 7.3% better with repair, and increased with time of follow-up: 0.7% better for 0 to 5 years, 4.9% better for 5 to 10 years, and 21.3% better for 10 to 15 years. Treatment interaction between repair or replacement and age was negative (p = 0.66). In the propensity analysis, survival advantages of repair versus replacement were similar in magnitude with a p value of 0.046.

CONCLUSIONS

As compared with prosthetic valve replacement, mitral repair is associated with better survival in patients with degenerative disease, especially after 10 to 15 years. This finding supports the current trend of increasing repair rates for degenerative disorders of the mitral valve.