Long-term Outcomes of Mitral Valve Repair for Atrial Functional Mitral Regurgitation.

Background: Atrial functional mitral regurgitation (AFMR), defined by normal left ventricular function, enlarged left atrium, and a dilated mitral valve annulus, has been a concept discussed for >10 years. However, there are still no established guidelines for its treatment in the American College of Cardiology/American Heart Association recommendations. This study aimed to determine the long-term outcomes of mitral annuloplasty as a treatment for AFMR.

Methods: We analyzed 1435 patients who underwent mitral valve repair at our institution between 2005 and 2020, with 162 classified as having AFMR. Exclusion criteria for AFMR were established based on preoperative echocardiography and operative notes. The primary outcome was overall mortality, and the secondary outcome was MR recurrence, which was defined as moderate or greater mitral regurgitation observed on echocardiography during the follow-up period, analyzed using our hospital's medical records and data from the National Statistical Office.

Results: The median follow-up duration for the entire patient cohort was 6.1 years (interquartile range, 3.2-11.2 years). Patients had a 5-year survival rate of 86% and a 10-year survival rate of 73%, with freedom from MR recurrence rates of 89% and 80% at 5 and 10 years, respectively. Although all 162 patients had moderate or greater MR before surgery, most experienced trivial or mild MR after mitral valve repair throughout the follow-up period.

Conclusions: In summary, mitral valve repair effectively treats patients with AFMR, addressing survival and mitigating MR recurrence.