Flowreserve

*Incorporating Anatomy and Physiology Into Clinical Practice*
	Although IVUS and physiologic lesion assessment are mature technologies, the general interventional community has not embraced their use.^[7] Three techniques may be used for physiologic lesion assessment: coronary flow reserve (CFR), relative coronary reserve (rCVR) (in which the CFR in the index vessel is compared to a reference vessel), and fractional flow reserve (FFR). The first 2 are measured using the Doppler FloWire; FFR is measured using 1 of several pressure wires.
	FFR assesses the contribution of the stenosis to decreased coronary flow independent of the existing hemodynamics and the status of the microcirculation. CFR is influenced by both the existing hemodynamics and the status of the microcirculation. The rCVR attempts to correct this latter shortcoming. Before intervention, a CFR >2.0 and an FFR >0.75 correlate with an IVUS minimum luminal area of >4.0 mm² and a negative exercise test result. Numerous studies show that interventions can be deferred safely in lesions with a CFR >2.0 or an FFR >0.75; the 1-year event rate in these lesions is <10%. After PTCA, a CFR of >2.5, an rCVR of >0.8, and an FFR of >0.9 indicate an optimal result. Despite the preponderance of stent-implantation procedures, these values can be used as end points in a provisional stent implantation strategy. After stent implantation, an FFR >0.94 is associated with an IVUS minimum stent area >90% of the reference (Multicentre Ultrasound Stent in Coronary Disease [MUSIC]) criteria).
References
	Mintz G. Intravasular ultrasound: insights into atherosclerosis and restenosis. Program and abstracts of the American College of Cardiology 49th Annual Scientific Session; March 12-16, 2000; Anaheim, Calif. Spotlight Session 74.
	Fitzgerald PJ. Intravasular ultrasound: a practical approach during coronary intervention. Program and abstracts of the American College of Cardiology 49th Annual Scientific Session; March 12-16, 2000; Anaheim, Calif. Spotlight Session 74.
	Karsch KR. IVUS guided balloon angioplasty. Program and abstracts of the American College of Cardiology 49th Annual Scientific Session; March 12-16, 2000; Anaheim, Calif. Spotlight Session 74.
	Yock PG. Three-dimensional vessel reconstruction: predicting the future. Program and abstracts of the American College of Cardiology 49th Annual Scientific Session; March 12-16, 2000; Anaheim, Calif. Spotlight Session 74.
	De Bruyne B. Fractional flow reserve: setting criteria and changing practice. Program and abstracts of the American College of Cardiology 49th Annual Scientific Session; March 12-16, 2000; Anaheim, Calif. Spotlight Session 74.
	Selwyn A. Assessment of endothelial function: relieving angina without pci. Program and abstracts of the American College of Cardiology 49th Annual Scientific Session; March 12-16, 2000; Anaheim, Calif. Spotlight Session 74.
	Kern MJ. Incorporating anatomy and physiology into clinical practice. Program and abstracts of the American College of Cardiology 49th Annual Scientific Session; March 12-16, 2000; Anaheim, Calif. Spotlight Session 74.