CONCORDANCE OF NUTRITIVE MYOCARDIAL PERFUSION RESERVE AND FLOW VELOCITY RESERVE IN CONDUCTANCE VESSELS IN PATIENTS WITH CHEST PAIN WITH ANGIOGRAPHICALLY NORMAL CORONARY-ARTERIES

We have previously shown that myocardial perfusion can be quantified b y positron emission tomography (PET) with O-15-labeled water ((H2O)-O- 15), as experimentally validated with radiolabeled microspheres in ani mal hearts. The purpose of our study was to determine whether myocardi al nutritive perfusion reserve assessed with PET in human subjects was parallel to flow velocity reserve assessed in conductance vessels mea sured with intracoronary Doppler probes. We studied nine patients with chest pain and angiographically normal coronary arteries with intraco ronary Doppler flow velocity assessments before and after administrati on of 16 mug of intracoronary adenosine. We also assessed myocardial n utritive perfusion with PET (H2O)-O-15 before and after intravenous ad ministration of dipyridamole (0.56 mg/kg). Perfusion reserve (the rati o of absolute values of myocardial perfusion after dipyridamole admini stration to perfusion at rest) estimated with PET (3.5 +/- 0.9 s.d.) c orrelated closely with flow velocity reserve (the ratio of hyperemic i ntracoronary flow velocity to flow velocity at rest) (3.5 +/- 1.2, r = 0.80, p < 0.01). Absolute values of perfusion assessed tomographicall y averaged 1.22 +/- 0.19 ml/g/min in patients at rest and 4.16 +/- 0.9 3 after dipyridamole administration. Our data indicate that noninvasiv e assessment of myocardial perfusion with PET provides results that pa rallel intracoronary Doppler flow velocity measurements. Because PET d elineates nutritive perfusion throughout the heart in absolute terms, its use may facilitate detection of impaired coronary arterial functio n and enhance delineation of the efficacy of potentially therapeutic i nterventions in patients with chest pain and angiographically normal c oronary arteries.