A Longitudinal Study of Mitral Regurgitation Detected after Acute Myocardial Infarction

Mitral regurgitation (MR) is common following myocardial infarction (MI). However, the subsequent trajectory of MR, and its impact on long-term outcomes are not well understood. This study aimed to examine the change in MR severity and associated clinical outcomes following MI.

Records of patients admitted to a single centre between 2016 and 2017 with acute MI treated by percutaneous coronary intervention (PCI) were retrospectively examined.

294/1000 consecutive patients had MR on baseline (pre-discharge) transthoracic echocardiography (TTE), of whom 126 (mean age: 70.9 ± 11.4 years) had at least one follow-up TTE. At baseline, most patients had mild MR (n = 94; 75%), with n = 30 (24%) moderate and n = 2 (2%) severe MR. Significant improvement in MR was observed at the first follow-up TTE (median 9 months from baseline; interquartile range: 3-23), with 36% having reduced severity, compared to 10% having increased MR severity (p < 0.001). Predictors of worsening MR included older age (mean: 75.2 vs. 66.7 years; p = 0.003) and lower creatinine clearance (mean: 60 vs. 81 mL/min, p = 0.015). Change in MR severity was significantly associated with prognosis: 16% with improving MR reached the composite endpoint of death or heart failure hospitalisation at 5 years, versus 44% (p = 0.004) with no change, and 59% (p < 0.001) with worsening MR.

Of patients with follow-up TTE after MI, MR severity improved from baseline in approximately one-third, was stable in around half, with the remainder having worsening MR. Patients with persistent or worsening MR had worse clinical outcomes than those with improving MR.