Cardiac T1 mapping in non-ST-segment elevation myocardial infarction: temporal changes in myocardial fibrosis

Area of Science:

• Cardiology
• Medical Imaging
• Biomedical Engineering

Background:

• Non-ST-elevation myocardial infarction (NSTEMI) can lead to myocardial fibrosis, impacting cardiac function.
• Cardiac magnetic resonance (CMR) imaging techniques, including late gadolinium enhancement (LGE) and extracellular volume fraction (ECV), are used to quantify myocardial fibrosis.
• Understanding the temporal evolution of fibrosis after NSTEMI is crucial for patient management and risk stratification.

Purpose of the Study:

• To evaluate the changes in LGE and ECV in patients with NSTEMI over a 4-year follow-up period.
• To assess the impact of MI culprit coronary artery and remote myocardial regions on fibrosis progression.
• To investigate the association between multivessel coronary artery disease (CAD) and fibrosis changes.

Main Methods:

• Prospective, single-center study of 30 patients with type 1 NSTEMI.
• Comprehensive evaluation including coronary angiography, invasive coronary physiology, and biomarkers.
• CMR imaging at baseline and 4-year follow-up to assess left ventricular (LV) volume, function, and myocardial fibrosis (LGE and ECV).

Main Results:

• LV mass, volume, and contractility remained stable over 4 years.
• A significant decreasing trend in LGE was observed overall (p=0.051) and particularly in MI culprit artery regions (p=0.015).
• LGE volume regression occurred in 70% of patients; ECV measurements showed no significant changes. No significant changes in LGE or ECV were noted in remote myocardium, irrespective of multivessel CAD.

Conclusions:

• Following NSTEMI, myocardial fibrosis, as assessed by LGE, shows a regression trend in the infarct-related regions over 4 years.
• Diffuse myocardial fibrosis, indicated by ECV, remains stable post-NSTEMI.
• Multivessel CAD does not appear to influence the changes in myocardial fibrosis in remote regions.