Update of Coronary Doppler Flow Measurements

Abstract

As percutaneous coronary revascularization was performed on an increasing number of patients, the indications of many procedures were considered inappropriate because of the lack of objective evidence of significant coronary stenosis. This problem is the result of the limitations of noninvasive tests in assessing the physiological significance of a lesion and poor correlation between anatomy shown by quantitative coronary angiography and physiology of the stenosis. Even with intracoronary ultrasound study, the correlation between morphology and physiological significance has been poor, especially with lesions of intermediate severity. With recent technical improvements, measurement of coronary flow reserve (CFR) by Doppler catheters was advocated as the “gold‐standard” in assessing the physiological significance of epicardial coronary artery stenosis. Advantages and limitations of various Doppler indices commonly used in the catheterization laboratory were discussed. Because of its simple applicability, ease of validation using a clearly cut‐off value, virtual freedom from confounding factors, and usefulness even in the presence of triple vessel disease, fractional flow reserve (FFR) was found to be a better index for physiological assessment than absolute CFR or relative CFR.