Comparison of Doppler Flow Velocity and Thermodilution Derived Indexes of Coronary Physiology

Time Course of Microvascular Stunning in ST-Segment–Elevation Myocardial Infarction

“…[1][2][3] A recent study that compared these measures demonstrated a modest correlation between thermodilution-derived vs Doppler-derived CFR, although CFR calculated by thermodilution overestimated Doppler-derived CFR; therefore, authors concluded the optimal CFR threshold should be 2.5. 8 Patients with acute coronary symptoms had lower CFR (2.07±1.26 with thermodilution and 1.67±0.71 by Doppler) than patients with stable coronary disease (3.12±1.61 versus 2.37±0.90). There was only a weak correlation between IMR and HMR even when patients with an FFR <0.8 were excluded.…”

“…In fact, 44% of patients had discordant IMR and HMR values and there was also suboptimal correlation between either HMR or IMR and CFR. 8 Therefore, it is not surprising there are differences in post-STEMI IMR and CFR.…”

Coronary Physiology: Modern Concepts for the Guidance of Percutaneous Coronary Interventions and Medical Therapy

“…Nevertheless, a variability in the normality of CFR has been reported, with a range between approximately 2.5 and 6; therefore, a value >2.0 can be abnormal for a particular patient in a specific vessel. For example, Demir et al recently documented an overestimation of thermodilution-derived CFR as compared to Doppler-derived CFR, with a poor diagnostic accuracy of the common threshold of <2.0 and a weak correlation between hyperemic microvascular resistance and the index of microvascular resistance [ 51 ]…”

Invasive Assessments For Coronary Vasomotor Disorders: Current State of the Art Methods Collection

“…However, it should be mentioned that obtaining a good Doppler signal can sometimes be challenging. There are also substantial differences in the microvascular resistance indices assessed by the Doppler technique, which provides HMR values based on the coronary blood flow velocity, and the thermodilution technique, which provides IMR values based on the coronary bolus transit time 9 . While IMR and HMR automatically have different thresholds due to their different units, recent data suggest the use of different thresholds for CFR Doppler and CFR Thermo too 9 .…”

“…There are also substantial differences in the microvascular resistance indices assessed by the Doppler technique, which provides HMR values based on the coronary blood flow velocity, and the thermodilution technique, which provides IMR values based on the coronary bolus transit time 9 . While IMR and HMR automatically have different thresholds due to their different units, recent data suggest the use of different thresholds for CFR Doppler and CFR Thermo too 9 . Accordingly, a CFR range of <2.0 may be considered abnormal using CFR Doppler , whereas a <2.5 cutoff may be considered abnormal, with a grey zone of 2.0-2.5, using CFR Thermo .…”