Comparison of coronary thermodilution and Doppler velocity for assessing coronary flow reserve.
BACKGROUND
Thermodilution coronary flow reserve (CFRthermo) is a new technique for invasively measuring coronary flow reserve (CFR) with a coronary pressure wire and is based on the ability of the pressure transducer to also measure temperature changes. Whether CFRthermo correlates well enough with absolute flow-derived CFR (CFRflow) to replace Doppler wire-derived CFR (CFRDoppler) remains unclear.


RESULTS
In an open-chest pig model, CFRthermo was measured in the left anterior descending (LAD) artery and compared with CFRDoppler and CFRflow, measured with an external flow probe placed around the LAD. In 9 pigs, CFR was measured simultaneously by all 3 means in the normal LAD and after creation of an epicardial LAD stenosis. To determine the added effect of microvascular disease, measurements of flow reserve were also performed after disruption of the coronary microcirculation with embolized microspheres. Intracoronary papaverine (20 mg) was used to induce hyperemia. In a total of 61 paired measurements, CFRthermo correlated strongly with the reference standard CFRflow (r=0.85, P<0.001). CFRDoppler correlated less well with CFRflow (r=0.72, P<0.001). Bland-Altman analysis showed a closer agreement between CFRthermo and CFRflow.


CONCLUSIONS
CFRthermo correlates better with CFRflow than does CFRDoppler.
Division of Cardiovascular Medicine, Stanford University Medical Center, H3554, 300 Pasteur Dr, Stanford, Calif 94305, USA. wfearon@stanford.edu
William F
WF
Fearon
H M Omar
HM
Farouque
Leora B
LB
Balsam
Anthony D
AD
Caffarelli
David T
DT
Cooke
Robert C
RC
Robbins
Peter J
PJ
Fitzgerald
Alan C
AC
Yeung
Paul G
PG
Yock
D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D003326:Coronary Circulation; D023921:Coronary Stenosis / Q000175:diagnosis* / Q000503:physiopathology; D004195:Disease Models, Animal; D006940:Hyperemia / Q000139:chemically induced / Q000175:diagnosis / Q000503:physiopathology; D016014:Linear Models; D008863:Microspheres; D010208:Papaverine; D011237:Predictive Value of Tests; D013552:Swine; D013815:Thermodilution; D018608:Ultrasonography, Doppler
D010208:Papaverine