Microvascular dysfunction following ST-elevation myocardial infarction and its recovery over time

Area of Science:

• Cardiology
• Cardiovascular Research
• Interventional Cardiology

Background:

• Microvascular dysfunction is a complication of ST-elevation myocardial infarction (STEMI).
• The prognostic value of microvascular dysfunction and its recovery for long-term left ventricular function (LVF) remains unclear.

Purpose of the Study:

• To assess if microvascular dysfunction, measured by coronary flow reserve (CFR) in the infarct-related artery (IRA) within one week post-primary percutaneous coronary intervention (PPCI), predicts LVF at four months and two years.
• To determine if microvascular recovery is associated with LVF improvement.

Main Methods:

• Sixty-two patients with STEMI underwent assessment of CFR and hyperaemic microvascular resistance index (HMRI) in the IRA using intracoronary Doppler flow measurements.
• Cardiac magnetic resonance (CMR) was performed at baseline, four months, and two years to evaluate LVF, specifically left ventricular ejection fraction (LVEF).

Main Results:

• Baseline CFR in the IRA was significantly associated with LVEF at four months (p=0.03) and two years (p=0.02).
• Hyperaemic microvascular resistance index (HMRI) did not show an association with LVF.
• In patients with large infarcts, the improvement in CFR within the first four months was positively correlated with LVEF improvement (p=0.01).

Conclusions:

• Microvascular dysfunction, assessed by CFR in the subacute phase post-STEMI, serves as a significant predictor of LVEF at both four months and two years.
• These findings underscore the critical role of microvascular function in the long-term outcomes of patients following STEMI.