Dynamic Changes and Prognostic Impact of Ischemic Mitral Regurgitation in Recurrent Myocardial Infarction

The prognostic impact of ischemic mitral regurgitation (IMR) in recurrent myocardial infarction (MI) remains poorly defined. This study evaluated dynamic changes in IMR during recurrent MI and determined prognostic implications.

We retrospectively reviewed 4,091 patients who underwent primary percutaneous coronary intervention for acute MI between May 2008 and July 2022. Of these patients, 88 experienced a second MI and underwent transthoracic echocardiography at 3 time points: before recurrent MI, at onset, and at discharge. IMR severity was assessed using mean vena contracta width. Logistic regression was used to determine predictors of persistent IMR, and Cox analysis was used to evaluate 5-year adverse outcomes (a composite of all-cause death, heart failure hospitalization, and third MI). IMR worsened at the onset of recurrent MI and remained elevated at discharge (P<0.001). Older age, lower left ventricular ejection fraction (LVEF), and greater IMR severity at onset independently predicted persistent IMR. In multivariable Cox analysis, residual IMR (per 1-mm increase: hazard ratio [HR] 1.22; 95% confidence interval [CI] 1.08-1.38) and reduced LVEF (per 1% decrease: HR 0.95; 95% CI 0.92-0.98) were independently associated with a higher risk of 5-year adverse events.

IMR changes dynamically during recurrent MI and often persists despite acute treatment. Residual IMR and reduced LVEF predicted long-term adverse outcomes, highlighting the importance of residual IMR assessment for risk stratification.