Correlation of Pharmacological 99 mTcwSestamibi Myocardial Perfusion Imaging With Poststenotic Coronary Flow Reserve in Patients With Angiographically Intermediate Coronary Artery

Backgrnd The physiological assessment of angiographically intermediate-severity stenoses remains problematic. Functional measurements of poststenotic intracoronary Doppler coronary flow reserve can be performed in humans but have not been correlated with hyperemic myocardial perfusion imaging or angiographic data in this patient population. Method and Resus Thirty-three patients undergoing diagnostic quantitative coronary angiography (QCA) for assessment of intermediate-severity coronary artery disease (mean QCA percent diameter stenosis, 56±14%) were studied. Proximal and distal poststenotic Doppler coronary flow velocities were measured (left anterior descending coronary artery, 16; right coronary artery, 10; left circumflex artery, 7 patients) before and during peak maximal hyperemia with intracoronary adenosine (8 to 12 gg). Intravenous pharmacological stress (adenosine, 20 patients; dipyridamole, 13 patients) 99ITcsestamibi tomographic perfusion imaging was performed within 1 week of coronary flow-velocity studies. K statistics were calculated to measure the strength of correlation among coronary flow velocities, perfusion imaging data, and QCA results. QCA stenosis severity (abnormal, >50% diameter stenosis) and poststenotic Doppler coronary flow reserve (ratio of abnormal distal hyperemic to basal flow, .2.0) were correctly correlated in 20 of 27 patients (74%; K=.48). QCA stenosis severity and 99Tc-sestamibi imaging (abnormal if one or more reversible myocardial segments were present in the poststenotic zone) were correlated in 28 of 33 patients (85%;