Log in to MyACC
Discordance Between iFR and FFR
Study Questions:
What are the physiologic characteristics of discordant lesions between instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) and the prognosis at 5 years?
Methods:
The investigators classified a total of 840 vessels from 596 patients according to iFR and FFR; high iFR–high FFR (n = 580), low iFR–high FFR (n = 40), high iFR–low FFR (n = 69), and low iFR–low FFR (n = 128) groups, which were compared with a control group (n = 23). The differences in coronary circulatory indices including the coronary flow reserve (CFR), index of microcirculatory resistance (IMR), and resistance reserve ratio (RRR) (resting distal arterial pressure [Pd] x mean transit time [Tmn] / hyperemic Pd x hyperemic Tmn), which reflect the vasodilatory capacity of coronary microcirculation, were compared. Patient-oriented composite outcomes (POCO) at 5 years including all-cause deaths, any myocardial infarctions, and any revascularizations were compared among patients with deferred lesions. Event rates were calculated based on Kaplan-Meier censoring estimates and presented with cumulative incidences at the 5-year follow-up, and the log-rank test or the Breslow test was used to compare survival curves between the groups.
Results:
In the low iFR–high FFR group, CFR, RRR, and IMR measurements were similar to the low iFR–low FFR group: CFR 2.71 vs. 2.43 (p = 0.144); RRR 3.36 vs. 3.68 (p = 0.241); and IMR 18.51 vs. 17.38 (p = 0.476), respectively. In the high iFR–low FFR group, the CFR, RRR, and IMR measurements were similar to the control group: CFR 2.95 vs. 3.29 (p = 0.160); RRR 4.28 vs. 4.00 (p = 0.414); and IMR 17.44 vs. 17.06 (p = 0.818), respectively. Among the four groups, classified by iFR and FFR, CFR and RRR were all significantly different, but not for the IMR. However, there were no significant differences in the rates of the POCO, regardless of discordance between the iFR and FFR. Only the low iFR–low FFR group had a higher POCO rate compared with the high iFR–high FFR group (adjusted hazard ratio, 2.46; 95% confidence interval, 1.17-5.16; p = 0.018).
Conclusions:
The authors concluded that differences in coronary circulatory function were found, especially in the vasodilatory capacity between the low iFR–high FFR and high iFR–low FFR groups.
Perspective:
This study reports that there were substantial differences in coronary circulatory indices, especially in the vasodilatory capacities between the low iFR–high FFR and high iFR–low FFR groups. While the CFR, RRR, and IMR of the low iFR–high FFR group were similar to those of the low iFR–low FFR group, those of the high iFR–low FFR group were similar to those of the high iFR–high FFR and control groups. However, among patients with deferred lesions, discordance between iFR and FFR was not associated with an increased risk of CV events, compared with the high iFR–high FFR group at 5 years. The risk of adverse events was increased only in deferred patients with low iFR–low FFR, compared with the high iFR–high FFR group. These data underscore the importance of comprehensive physiologic evaluations to guide treatment decision making. Additional studies are needed to clarify the optimal treatment strategies and the role of revascularization for lesions with discordant iFR and FFR results.
Clinical Topics: Cardiac Surgery, Cardiovascular Care Team, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Prevention, Vascular Medicine, Atherosclerotic Disease (CAD/PAD), Cardiac Surgery and Arrhythmias, Cardiac Surgery and Heart Failure, Interventions and Coronary Artery Disease, Interventions and Vascular Medicine
Keywords: Arterial Pressure, Coronary Artery Disease, Fractional Flow Reserve, Myocardial, Hyperemia, Microcirculation, Myocardial Infarction, Myocardial Ischemia, Myocardial Revascularization, Secondary Prevention, TCT19, Transcatheter Cardiovascular Therapeutics
< Back to Listings
