Prevalence and Predictive Factors of Early Degeneration of Bioprosthetic Mitral Valves: A Single-Center Cohort Study

Background. Bioprosthetic mitral valves (MV) have limited durability. Dysfunction and degeneration of these valves can lead to reoperation and progressive heart failure. We investigated the frequency and predictors of MV bioprosthesis early degeneration within three years following MV replacement surgery. Methods. In this retrospective cohort study, we retrieved the data of consecutive patients who underwent bioprosthetic MV replacement through midsternotomy at Tehran Heart Center between 2013 and 2019. Based on the reviewed parameters of the bioprosthetic MV in the follow-up echocardiography, the patients were divided into two groups to compare the variables respecting early degeneration. Finally, the predictors of early degeneration were recognized using the Cox regression hazards model. Results. We reviewed and analyzed data of 177 patients from our hospital database. The mean age of the patients was 63.9 ± 11.7 years and 100 (56.5%) were women. 39 (22.0%) patients had experienced early degeneration and two (1.1% of the total) had died during the follow-up period. Patients in the degeneration group tended to have a history of stroke and renal failure, although not statistically significant. The sole independent predictor of early degeneration of bioprosthetic MV was a high MV mean gradient in the first postoperative echocardiography study (HR = 11.01, 95% CI: 4.80–25.24; P < 0.001 ). Conclusion. About 22.0% of our patients had echocardiographic criteria for early degeneration, and according to our results, increased MV gradients (without considering the reason) in the first postoperative echocardiography were the sole independent predictor for it. Careful valve selection can be essential in reducing early degeneration.