Clinical Research
Coronary
Pre-Angioplasty Instantaneous Wave-Free Ratio Pullback Provides Virtual Intervention and Predicts Hemodynamic Outcome for Serial Lesions and Diffuse Coronary Artery Disease

https://doi.org/10.1016/j.jcin.2014.06.015Get rights and content
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Abstract

Objectives

The aim of this study was to perform hemodynamic mapping of the entire vessel using motorized pullback of a pressure guidewire with continuous instantaneous wave-free ratio (iFR) measurement.

Background

Serial stenoses or diffuse vessel narrowing hamper pressure wire–guided management of coronary stenoses. Characterization of functional relevance of individual stenoses or narrowed segments constitutes an unmet need in ischemia-driven percutaneous revascularization.

Methods

The study was performed in 32 coronary arteries with tandem and/or diffusely diseased vessels. An automated iFR physiological map, integrating pullback speed and physiological information, was built using dedicated software to calculate physiological stenosis severity, length, and intensity (ΔiFR/mm). This map was used to predict the best-case post–percutaneous coronary intervention (PCI) iFR (iFRexp) according to the stented location, and this was compared with the observed iFR post-PCI (iFRobs).

Results

After successful PCI, the mean difference between iFRexp and iFRobs was small (mean difference: 0.016 ± 0.004) with a strong relationship between ΔiFRexp and ΔiFRobs (r = 0.97, p < 0.001). By identifying differing iFR intensities, it was possible to identify functional stenosis length and quantify the contribution of each individual stenosis or narrowed segment to overall vessel stenotic burden. Physiological lesion length was shorter than anatomic length (12.6 ± 1.5 vs. 23.3 ± 1.3, p < 0.001), and targeting regions with the highest iFR intensity predicted significant improvement post-PCI (r = 0.86, p < 0.001).

Conclusions

iFR measurements during continuous resting pressure wire pullback provide a physiological map of the entire coronary vessel. Before a PCI, the iFR pullback can predict the hemodynamic consequences of stenting specific stenoses and thereby may facilitate the intervention and stenting strategy.

Key Words

coronary physiology
instantaneous wave-free ratio
percutaneous coronary intervention
pressure wire

Abbreviations and Acronyms

iFR
instantaneous wave-free ratio
PCI
percutaneous coronary intervention
QCA
quantitative coronary angiography

Cited by (0)

This research was supported by the NIHR Biomedical Research Centre based at Imperial College Healthcare National Health Service (NHS) Trust and Imperial College London. The views expressed are those of the author and not necessarily those of the NHS, the NIHR, or the Department of Health. S.S. Nijjer (G1100443) and S. Sen (G1000357) are Medical Research Council fellows. Dr. Petraco (FS/11/46/28861), Dr. Davies (FS/05/006), and Dr. Francis (FS 04/079) are British Heart Foundation fellows. Dr. Davies is a consultant for Volcano Corporation.; and co-inventor of iFR. Drs. Davies and Mayet have intellectual property interests in iFR Technology. Drs. Petraco, Sen, and Nijjer have received travel support from Volcano Corporation. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.