Application of AMR in evaluating microvascular dysfunction after ST-elevation myocardial infarction

Area of Science:

• Cardiology
• Interventional Cardiology
• Vascular Physiology

Background:

• Coronary microvascular dysfunction (CMD) assessment is crucial in ST-elevation myocardial infarction (STEMI).
• Quantitative flow ratio (QFR)-derived angiography-derived microcirculatory resistance (AMR) shows diagnostic accuracy for CMD.
• Limited research exists on AMR's specific application in STEMI patients.

Purpose of the Study:

• To evaluate the utility of the AMR index in assessing CMD in STEMI patients.
• To determine if AMR can predict adverse cardiac events in STEMI patients after percutaneous coronary intervention (PCI).

Main Methods:

• Retrospective study including STEMI patients undergoing PCI (June 2020 - Sept 2021).
• Patients categorized into CMD (n=215) and non-CMD (n=291) groups, matched to 382 total patients.
• One-year follow-up for major adverse cardiac events (MACEs).

Main Results:

• The primary endpoint (MACEs) occurred in 10.7% of patients, with significantly higher rates in the CMD group (14.1% vs. 7.3%, p=0.042).
• Heart failure readmission was higher in the CMD group (7.9% vs. 1.6%, p=0.010).
• Post-PCI AMR ≥250 was an independent predictor of MACEs (HR 2.265, p=0.020).

Conclusions:

• Retrospective AMR assessment (cutoff ≥250) post-PCI predicts significantly different 1-year MACE rates in STEMI patients.
• AMR serves as a valuable tool for identifying STEMI patients at higher risk for adverse cardiac events.