Clinical Research
Cardiac Imaging
VERIFY (VERification of Instantaneous Wave-Free Ratio and Fractional Flow Reserve for the Assessment of Coronary Artery Stenosis Severity in EverydaY Practice): A Multicenter Study in Consecutive Patients

https://doi.org/10.1016/j.jacc.2012.09.065Get rights and content
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Objectives

This study sought to compare fractional flow reserve (FFR) with the instantaneous wave-free ratio (iFR) in patients with coronary artery disease and also to determine whether the iFR is independent of hyperemia.

Background

FFR is a validated index of coronary stenosis severity. FFR-guided percutaneous coronary intervention (PCI) improves clinical outcomes compared to angiographic guidance alone. iFR has been proposed as a new index of stenosis severity that can be measured without adenosine.

Methods

We conducted a prospective, multicenter, international study of 206 consecutive patients referred for PCI and a retrospective analysis of 500 archived pressure recordings. Aortic and distal coronary pressures were measured in duplicate in patients under resting conditions and during intravenous adenosine infusion at 140 μg/kg/min.

Results

Compared to the FFR cut-off value of ≤0.80, the diagnostic accuracy of the iFR value of ≤0.80 was 60% (95% confidence interval [CI]: 53% to 67%) for all vessels studied and 51% (95% CI: 43% to 59%) for those patients with FFR in the range of 0.60 to 0.90. iFR was significantly influenced by the induction of hyperemia: mean ± SD iFR at rest was 0.82 ± 0.16 versus 0.64 ± 0.18 with hyperemia (p < 0.001). Receiver operating characteristics confirmed that the diagnostic accuracy of iFR was similar to resting Pd/Pa and trans-stenotic pressure gradient and significantly inferior to hyperemic iFR. Analysis of our retrospectively acquired dataset showed similar results.

Conclusions

iFR correlates weakly with FFR and is not independent of hyperemia. iFR cannot be recommended for clinical decision making in patients with coronary artery disease. (Comparison of Fractional Flow Reserve Versus Instant Wave-Free Ratio for Assessment of Coronary Artery Stenosis Severity in Routine Practice; NCT01559493)

Key Words

adenosine
angina
FFR
hyperemia
iFR

Abbreviations and Acronyms

ACC
American College of Cardiology
ESC
European Society of Cardiology
FFR
fractional flow reserve
iFR
instantaneous wave-free ratio
Pa
aortic pressure
Pd
distal coronary pressure
PCI
percutaneous coronary intervention

Cited by (0)

St. Jude Medical provided the coronary pressure wires as an unrestricted research grant. Dr. Berry has received research grant support from St. Jude Medical. Dr. Witt has received speakers' fees and honoraria from St. Jude Medical. Dr. Fearon has received research support from St. Jude Medical. Dr. Tonino has received research grant support from St. Jude Medical. Dr. De Bruyne has received speakers fees and research grant support from St. Jude Medical. Dr. Pijls is a consultant to St. Medical; and has received research grants from Abbott, Maquet, and St. Jude Medical. Dr. Oldroyd has received speakers' fees from St. Jude Medical and Volcano. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.