SIMULTANEOUS MEASUREMENT OF CORONARY FLOW RESERVE BY LEFT ANTERIOR DESCENDING CORONARY-ARTERY DOPPLER AND GREAT CARDIAC VEIN THERMODILUTION METHODS

Objectives. The objective of this study was to compare left anterior descending coronary artery Doppler Wood flow velocity and great cardiac vein thermodilution blood flow measurements coronary flow reserve and submaximal coronary vasodilation in humans. Background. Reported maximal coronary flow reserve values obtained with the coronary venous thermodilution method are lower than those obtained with other measurement methods. Methods. Thermodilution measurements of great cardiac vein flow in 11 subjects were compared with simultaneous Doppler measurements of changes in left anterior descending coronary flow velocity after intracoronary administration of papaverine, nitroglycerin, iohexol and intravenous administration of dipyridamole. Results. Coronary flow reserve (papaverine peak/rest flow ratio) was 3.7 +/- 1.7 (mean +/- SD) by the Doppler method and 2.0 +/- 0.7 by the thermodilution technique (p < 0.001). Thermodilution flow changes were also smaller than Doppler-measured changes during submaximal vasodilation and during prolonged coronary dilation after dipyridamole administration. Conclusions. Coronary flow reserve and submaximal flow increases measured with the thermodilution method were consistently and substantially smaller than Doppler-derived measurements. This discrepancy has important implications for the comparison of coronary flow reserve measurements performed with the use of different techniques.