Physiological Insight Into the Discordance Between Non-Hyperemic Pressure Ratio-Guided and Fractional Flow...

Area of Science:

• Cardiovascular physiology
• Interventional cardiology
• Medical device technology

Background:

• Previous trials showed higher mortality with instantaneous wave-free ratio (iFR)-guided revascularization versus fractional flow reserve (FFR)-guided revascularization.
• This discrepancy may stem from differing revascularization decisions in discordant lesions.
• Microvascular function assessment is crucial for understanding these outcomes.

Purpose of the Study:

• To compare microvascular function between resting full-cycle ratio (RFR)-guided and FFR-guided strategies in discordant lesions.
• To investigate the impact of microvascular resistance reserve (MRR) on outcomes.

Main Methods:

• Retrospective analysis of 837 intermediate lesions in 620 patients.
• Virtual randomization of discordant lesions into RFR- and FFR-guided groups.
• Assessment of microvascular function using MRR, independent of epicardial stenosis.

Main Results:

• Discordant lesions showed significant differences in age, sex, and MRR.
• RFR-guided revascularized lesions in discordant cases had lower MRR, higher age, and were more often female compared to FFR-guided.
• MRR significantly predicted all-cause death in the total and revascularized cohorts.

Conclusions:

• RFR-guided revascularization in discordant lesions is linked to impaired microvascular function (low MRR).
• This impaired microvascular function may contribute to the increased mortality seen with iFR-guided revascularization.