Significant ischaemic mitral regurgitation at discharge following a second myocardial infarction was an independent predictor of major adverse cardiac events (HR 2.46; 95% CI 1.01-5.96; p=0.04).
Cohort (n=99)
Does significant ischaemic mitral regurgitation at discharge worsen prognosis in patients with recurrent myocardial infarction treated with primary PCI?
In patients with recurrent myocardial infarction, residual significant ischaemic mitral regurgitation at discharge is an independent predictor of major adverse cardiac events over 5 years.
Effect estimate: HR 2.46 (95% CI 1.01 to 5.96)
p-value: p=0.04
Abstract Background Recurrent myocardial infarction (MI) is well known to have a worse prognosis than an initial MI. However, the dynamics of ischaemic mitral regurgitation (IMR) and its prognostic impact in patients with recurrent MI have rarely been investigated. It remains unclear whether this can be explained by myocardial damage alone or by pre-existing conditions such as diabetes mellitus. While previous studies have demonstrated the negative prognostic impact of IMR following an initial MI, they have been limited by the inability to assess patients’ baseline cardiac condition prior to infarction. Purpose This study aimed to assess the changes in IMR before and after a second MI and its clinical impact on prognosis in patients with recurrent MI treated with primary percutaneous coronary intervention (PCI). Methods A total of 3,439 consecutive patients who underwent successful primary PCI for acute coronary syndrome between May 2008 to July 2022 were retrospectively analysed. Among them, 99 patients with a second MI were selected for serial standard echocardiographic evaluation. Echocardiographic assessments were performed at three time points: (1) in the chronic phase after the first MI, specifically at the last assessment before the onset of the second MI; (2) upon hospital arrival with the second MI, prior to revascularisation, in the emergency department; and (3) at hospital discharge. The severity of MR was determined by the average vena contracta width. Major adverse cardiac events (MACE), including all-cause mortality, a third MI, and hospitalisation for heart failure, were assessed during a 5-year follow-up period. Results Among the 99 patients studied, 88 were evaluated at discharge (4 died in hospital, and 7 were excluded due to inadequate assessment). The proportion of patients with significant IMR (≥mild) at the onset of the second MI was significantly higher than before the onset (p0.01). Although revascularisation and medical therapy reduced the prevalence of significant IMR at discharge, it remained significantly higher than before the onset (p=0.01) (Figure 1A). A significant correlation was observed between left ventricular ejection fraction (LVEF) and the severity of IMR at discharge (r=-0.53; 95% CI, -0.64 to -0.36; p0.01). Prognosis was significantly worse in patients with more severe IMR at discharge (p0.01) (Figure 1B). Cox proportional hazards analysis identified significant IMR and LVEF at discharge as independent risk factors for poor prognosis (HR, 2.46; 95% CI, 1.01 to 5.96; p=0.04) (HR, 2.87; 95% CI, 1.16 to 7.12; p=0.02) (Figure 2). Conclusions This is the first study to assess the clinical significance of IMR in recurrent MI. IMR worsened after a second MI and was correlated with LVEF, both being independent prognostic factors. While medical therapy may improve IMR, residual significant IMR at discharge remains associated with a worse prognosis and requires closer attention.
Nishino et al. (Sat,) conducted a cohort in Recurrent myocardial infarction (n=99). Significant ischaemic mitral regurgitation (IMR) at discharge vs. No or non-significant IMR was evaluated on Major adverse cardiac events (MACE), including all-cause mortality, a third MI, and hospitalisation for heart failure (HR 2.46, 95% CI 1.01 to 5.96, p=0.04). Significant ischaemic mitral regurgitation at discharge following a second myocardial infarction was an independent predictor of major adverse cardiac events (HR 2.46; 95% CI 1.01-5.96; p=0.04).