Author + information
- Received September 26, 2011
- Revision received November 3, 2011
- Accepted November 3, 2011
- Published online April 10, 2012.
- Sayan Sen, MBBS⁎,⁎ (, )
- Javier Escaned, MD, PhD†,
- Iqbal S. Malik, MBBS, PhD‡,
- Ghada W. Mikhail, MBBS, MD‡,
- Rodney A. Foale, MD⁎,
- Rafael Mila, MD†,
- Jason Tarkin, MBBS⁎,
- Ricardo Petraco, MD⁎,
- Christopher Broyd, MBBS⁎,
- Richard Jabbour, MBBS⁎,
- Amarjit Sethi, MBBS, PhD‡,†,
- Christopher S. Baker, MBBS, PhD‡,
- Micheal Bellamy, MBBS, MD‡,
- Mahmud Al-Bustami, MD‡,
- David Hackett, MD‡,
- Masood Khan, MB, BChir, MA‡,
- David Lefroy, MB, BChir, MA‡,
- Kim H. Parker, PhD§,
- Alun D. Hughes, MBBS, PhD⁎,
- Darrel P. Francis, MB, BChir, MA, MD⁎,
- Carlo Di Mario, MD, PhD∥,
- Jamil Mayet, MBChB, MD, MBA⁎ and
- Justin E. Davies, MBBS, PhD⁎
- ↵⁎Reprint requests and correspondence:
Dr. Sayan Sen, International Centre of Circulatory Health, National Heart and Lung Institute, 59-61 North Wharf Road, London W2 1LA, United Kingdom
Objectives The purpose of this study was to develop an adenosine-independent, pressure-derived index of coronary stenosis severity.
Background Assessment of stenosis severity with fractional flow reserve (FFR) requires that coronary resistance is stable and minimized. This is usually achieved by administration of pharmacological agents such as adenosine. In this 2-part study, we determine whether there is a time when resistance is naturally minimized at rest and assess the diagnostic efficiency, compared with FFR, of a new pressure-derived adenosine-free index of stenosis severity over that time.
Methods A total of 157 stenoses were assessed. In part 1 (39 stenoses), intracoronary pressure and flow velocity were measured distal to the stenosis; in part 2 (118 stenoses), intracoronary pressure alone was measured. Measurements were made at baseline and under pharmacologic vasodilation with adenosine.
Results Wave-intensity analysis identified a wave-free period in which intracoronary resistance at rest is similar in variability and magnitude (coefficient of variation: 0.08 ± 0.06 and 284 ± 147 mm Hg s/m) to those during FFR (coefficient of variation: 0.08 ± 0.06 and 302 ± 315 mm Hg s/m; p = NS for both). The resting distal-to-proximal pressure ratio during this period, the instantaneous wave-free ratio (iFR), correlated closely with FFR (r = 0.9, p < 0.001) with excellent diagnostic efficiency (receiver-operating characteristic area under the curve of 93%, at FFR <0.8), specificity, sensitivity, negative and positive predictive values of 91%, 85%, 85%, and 91%, respectively.
Conclusions Intracoronary resistance is naturally constant and minimized during the wave-free period. The instantaneous wave-free ratio calculated over this period produces a drug-free index of stenosis severity comparable to FFR. (Vasodilator Free Measure of Fractional Flow Reserve [ADVISE]; NCT01118481)
This study was supported by the Volcano Corporation. This study was funded by the NIHR Biomedical Research Centre and the Coronary Flow Trust. Dr. Sen is a Medical Research Council fellow (G1000357). Dr. Davies (FS/05/006), Dr. Francis (FS 04/079), and Dr. Petraco (FS/11/46/28861) are British Heart Foundation fellows. Dr. Mikhail is on the Steering Committee for a trial conducted by Abbott Vascular. Drs. Davies and Mayet hold patents pertaining to this technology. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received September 26, 2011.
- Revision received November 3, 2011.
- Accepted November 3, 2011.
- American College of Cardiology Foundation