ALTERATION IN REGULATION OF MYOCARDIAL BLOOD-FLOW IN ONE-VESSEL CORONARY-ARTERY DISEASE DETERMINED BY POSITRON EMISSION TOMOGRAPHY

The behavior of myocardial blood flow (MBF) regulation in territories supplied by angiographically normal vessels of patients with coronary artery disease (CAD) has been poorly investigated. Resting MBF and cor onary reserve were evaluated in 32 patients with stable angina, no pre vious myocardial infarction, and isolated left anterior descending or left circumflex coronary artery stenosis (greater-than-or-equal-to 50% diameter narrowing). MBF was measured, in the absence of any medical therapy, by means of dynamic positron emission tomography and N-13-amm onia. MBF measurements at baseline and after intravenous dipyridamole (0.56 mg/kg administered over 4 minutes), were obtained both in the st enosis-related regions and in contralateral territories. As a control group, 14 normal subjects were evaluated according to the same protoco l. At rest, the 32 patients with CAD had similar MBF values in the ste notic and remote regions (0.76 +/- 0.21 and 0.77 +/- 0.19 ml/min/g, re spectively, p = NS); both these values were significantly (p < 0.01) r educed with respect to mean MBF in normal subjects (1.03 +/- 0.25 ml/m in/g). The dipyridamole study was completed in 30 patients; these pati ents had lower values of maximal MBF in the stenotic than in the remot e regions (1.52 +/- 0.65 vs 1.76 +/- 0.68 ml/min/g, p < 0.05); however , both these values were significantly reduced (p < 0.01) with respect to mean dipyridamole MBF in normal subjects (3.66 +/- 0.92 ml/min/g). Thus, in patients with CAD, resting and maximal MBF can be reduced no t only in myocardial territories supplied by stenotic arteries, but al so in territories supplied by angiographically normal arteries.