Clinical application of coronary flow reserve using an intracoronary Doppler guide wire.

Coronary flow reserve (CFR) is a critical measurement in the assessment of the coronary circulation. The development of this physiologic variable in animal and human studies is reviewed. Human studies documenting the limitations of coronary angiography, especially in the setting of severe diffuse coronary artery disease, are analyzed. Furthermore, the important variables that must be accounted for when CFR is measured are examined. With this background, the application of CFR in a variety of clinical settings and the development and use of the Doppler FloWire for its measurement are discussed.