Comprehensive Angiography-Derived Functional Assessment of Epicardial and Microvascular Coronary Disease. Correlation...

Area of Science:

• Cardiology
• Interventional Cardiology
• Physiology

Background:

• Coronary angiography (CA) shows poor correlation with non-invasive myocardial stress imaging (NSI).
• Myocardial ischemia is frequently observed in patients with unobstructed coronary arteries, suggesting limitations in current diagnostic methods.
• The diagnostic utility of combined epicardial and microcirculatory assessment using angiography remains unclear.

Purpose of the Study:

• To evaluate the diagnostic performance of combined quantitative flow ratio (QFR) and angiography-derived index of microcirculatory resistance (IMR_angio).
• To assess the correlation of combined QFR/IMR_angio with NSI findings.
• To determine the predominant mechanism of myocardial ischemia in patients with suspected coronary artery disease.

Main Methods:

• Retrospective analysis of 917 coronary vessels in 319 patients who underwent both CA and NSI.
• Quantitative flow ratio (QFR) for epicardial function and angiography-derived index of microcirculatory resistance (IMR_angio) for microcirculatory function were calculated.
• Diagnostic accuracy was assessed using receiver operating characteristic (ROC) curves.

Main Results:

• NSI indicated myocardial ischemia in 76% of cases.
• IMR_angio was significantly higher and QFR was significantly lower in vessels subtending ischemic territories.
• Combined QFR/IMR_angio assessment demonstrated incremental diagnostic performance over isolated assessments and identified the predominant ischemia mechanism in 77% of patients with positive NSI.

Conclusions:

• Combined angiography-derived assessment of epicardial and microvascular function is valuable for defining myocardial ischemia mechanisms.
• This integrated approach enhances diagnostic accuracy in patients with suspected coronary artery disease.
• The study highlights the importance of evaluating both epicardial and microcirculatory function for comprehensive ischemia assessment.