Clinical characteristics and long-term outcome of patients with bioprosthetic mitral valve- Experience from a South Asian country.

Objectives: Due to rheumatic heart disease, young people are more likely to develop valvular heart disease in developing countries. In countries like Pakistan, surgeons implant more bioprosthetic mitral valves (MVs) in younger patients. However, bioprosthetic valves degenerate rapidly in younger people, leading to bioprosthetic MV dysfunction (BMVD). This study aims to evaluate the clinical characteristics and long-term outcomes of patients with bioprosthetic MV replacement (MVR) at a tertiary care hospital in a South Asian country.

Material and methods: This is a retrospective observational study, conducted at a tertiary care hospital. We included a total of 502 patients who underwent bioprosthetic MVR from the year 2006 to 2020. Clinical and surgical characteristics along with transthoracic echocardiographic findings (pre-surgery and recent most follow-up studies) were noted. Follow-up data were also collected.

Results: Out of 502 patients, 322 (64%) were female, mean age at the time of surgery was 49.42 ± 14.56 years. Mitral regurgitation was more common, found in 279 (55.6%) patients followed by mitral stenosis in 188 (37.5%) patients. MVR was done as an elective procedure due to the New York Heart Association (NYHA) II to IV symptoms at the time of surgery in 446 (88.8%) patients. In the mean follow-up of 6.59 ± 2.99 years, BMVD was observed in 183 (36.5%) patients. However, re-do MV surgery was done in only 49 (9.8%) patients. Patients were divided into two groups based on normal functioning bioprosthetic MV and BMVD. Comparing the two groups, individuals with normal functioning bioprosthetic MV had a mean age of 51.6 ± 14.27 years, while those with BMVD had a mean age of 45.639 ± 14.33 years at the time of index surgery (P = 0.000). There were more long-term complications including heart failure (n = 16, 8.74%), atrial fibrillation (n = 11, 6.01%), and death (n = 6, 3.28%) in the BMVD group which were statistically significant.

Conclusion: This study is distinct because it demonstrates the outcomes of bioprosthetic valve replacement in a relatively younger South Asian population. Due to rapid degeneration of bioprosthetic valve in younger patients, significant number of patients developed BMVD along with poor long-term clinical outcomes, even at a short follow-up period of <10 years. These findings are similar to international data and signify that mechanical MVR may be a more reasonable alternative in younger patients.