Development and Validation of a New Adenosine-Independent Index of Stenosis Severity From Coronary Wave–Intensity Analysis

• Published in: Journal of the American College of Cardiology Vol. 59; no. 15; pp. 1392 - 1402
• Main Authors: Sen, Sayan, MBBS, Escaned, Javier, MD, PhD, Malik, Iqbal S., MBBS, PhD, Mikhail, Ghada W., MBBS, MD, Foale, Rodney A., MD, Mila, Rafael, MD, Tarkin, Jason, MBBS, Petraco, Ricardo, MD, Broyd, Christopher, MBBS, Jabbour, Richard, MBBS, Sethi, Amarjit, MBBS, PhD, Baker, Christopher S., MBBS, PhD, Bellamy, Micheal, MBBS, MD, Al-Bustami, Mahmud, MD, Hackett, David, MD, Khan, Masood, MB, BChir, MA, Lefroy, David, MB, BChir, MA, Parker, Kim H., PhD, Hughes, Alun D., MBBS, PhD, Francis, Darrel P., MB, BChir, MA, MD, Di Mario, Carlo, MD, PhD, Mayet, Jamil, MBChB, MD, MBA, Davies, Justin E., MBBS, PhD
• Format: Journal Article
• Language: English
• Published: New York Elsevier Inc 10.04.2012; Elsevier Limited
• Subjects: adenosine; Biomedical research; Cardiology; Cardiovascular; Catheters; coronary stenosis; Coronary vessels; Diabetes; fractional flow reserve; Hypertension; Internal Medicine; Intubation; Medical imaging; revascularization; Software; Studies; Veins & arteries; adenosine; instantaneous wave-free ratio; revascularization; FFR; iFR; coronary stenosis; fractional flow reserve
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/j.jacc.2011.11.003

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 )