Is the diagnostic performance of FFRangio affected by coronary microvascular dysfunction?

Area of Science:

• Cardiology
• Medical Imaging
• Diagnostic Tools

Background:

• FFRangio, derived from coronary angiography, demonstrates high diagnostic concordance with invasive fractional flow reserve (FFR).
• Its diagnostic utility in the presence of coronary microvascular dysfunction (CMD) has not been previously evaluated.
• This study investigates FFRangio's performance in patients with CMD.

Purpose of the Study:

• To assess the diagnostic performance of FFRangio in patients with coronary microvascular dysfunction (CMD).
• To evaluate the impact of CMD, categorized by the index of microcirculatory resistance (IMR), on FFRangio's accuracy.

Main Methods:

• 111 coronary vessels (94 patients) underwent FFRangio, invasive FFR, and IMR measurements.
• Patients were stratified into low IMR (IMR < 25) and high IMR (IMR ≥ 25) groups.
• Invasive FFR served as the reference standard to evaluate FFRangio's diagnostic performance.

Main Results:

• FFRangio showed high overall diagnostic performance (AUC: 0.92).
• Diagnostic performance was significantly lower in the high-IMR group (AUC: 0.83) compared to the low-IMR group (AUC: 0.98; p=0.04).
• Correlation and agreement between FFRangio and invasive FFR were reduced in the high-IMR group.

Conclusions:

• Coronary microvascular dysfunction (CMD) may decrease the diagnostic concordance between FFRangio and invasive FFR.
• The reliability of FFRangio may be compromised in the presence of significant microvascular impairment.