Average Coronary Blood Flow Per Unit Weight of Left Ventricle in Patients With and Without Coronary Artery Disease

Average left ventricular flow per unit mass (F/W) has been evaluated at rest in 20 normal individuals and 26 patients with arteriographically proven, advanced coronary artery disease, using inert gas techniques modified to take into account methodological problems presented by heterogeneous perfusion within the ventricle. Preliminary studies in a canine model in which corornary flow could be measured directly before and after coronary occlusion indicated (1) that inert gas techniques utilizing venous sampling are suitable for abnormal situations when appropriately long periods of saturation and desaturation, and careful resolution of prolonged venous-arterial differences, are employed; and (2) that traditional inert gas methods are not adequate when F/W is abnormally heterogeneous. Using helium as a tracer, coronary disease patients showed a systematic reduction, in comparison to normal individuals, in average left ventricular F/W at rest (54 ± 11 vs 70 ± 13 ml/min/100 g, P < 0.01). Simultaneous studies with traditional nitrous oxide and krypton techniques did not show this difference because of the methodological limitations of these techniques in the presence of abnormally heterogeneous F/W. We conclude: (1) that useful, accurate measurements of F/W can be obtained in coronary disease if appropriate methodological precautions are taken; and (2) that appreciable portions of the left ventricle have an abnormally low F/W, even at rest, in patients with advanced coronary disease.