Comparison Between Non-Invasive Coronary Flow Reserve and Fractional Flow Reserve to Assess the Functional Significance of Left Anterior Descending Artery Stenosis of Intermediate Severity

The Physiologic Evaluation of Stenosis by Transthoracic Doppler: A Bit of Theory, a Lot of Practice

“…In the study by Meimoun et al 8 in this issue of JASE , transthoracic Doppler echocardiography was used to test the physiologic impact of intermediate severity stenosis in the LAD in patients referred for diagnostic angiography. The vast majority of these patients had one of the clinical scenarios described above where evaluation of the physiologic significance in the angiography suite may be helpful.…”

“…For FFR, lower hyperemic flow caused by hypotension would be expected to reduce the transstenotic gradient and, in theory, artificially raise the FFR. In the study by Meimoun, et al , 8 this issue is relevant because of the higher likelihood for hypotension with intravenous adenosine used during CFR rather than the intracoronary route of adenosine administration used for FFR. Blood pressures during hyperemia were not reported but would have been useful.…”

“…Despite the potential problems outlined above, Meimoun et al 8 found that the two techniques agreed reasonably well in their ability to differentiate normal from abnormal response according to thresholds defined a priori. There were only two patients in whom the tests were discordant because of an abnormal CFR but a normal FFR.…”

High precision invasive FFR, low‐cost invasive iFR, or non‐invasive CFR?: optimum assessment of coronary artery stenosis based on the patient‐specific computational models

“…It is defined as the ratio of the blood flow in coronary hyperemia to that under resting condition. CFR's relevant cut‐off value is 2 17,18 . Although one advantage of CFR over iFR and FFR is that it can be measured non‐invasively, some discordances between CFR and FFR results raise concerns about its usage 19,20 …”

Rationale and Pitfalls of Noninvasive Coronary Flow Reserve Estimation in Assessment of Microvascular Disease

“…Also with noninvasive assessment, it is not possible to rule out obstructive epicardial coronary artery disease, and we know that presence of obstructive stenoses in epicardial coronary arteries causes decrease in the CFR 13 . Moreover, in the presence of flow limiting epicardial coronary artery disease, there can be discordance between the measured CFR using Doppler echocardiography and invasive methods 14 . CFR could be diminished in the presence of left ventricular hypertrophy 15 .…”