Myocardial blood flow in coronary artery disease: Studies at rest and during stress with inert gas washout techniques

Abstract

HIS article will review techniques using inert gases that have been utilized to measure average left ventricular and regional myocardial blood flow in man. The development of these techniques has been spurred primarily by the desire to evaluate clinically the disturbances of myocardial blood flow that occur in patients with coronary artery disease. Coronary atherosclerosis is a focal process that affects primarily large epicardial coronary arteries and their major branches and to a lesser extent the smaller intramyocardial vessels.‘,’ Discrete coronary lesions produce alterations in myocardial blood flow both in different regions of the heart (i.e., spatial heterogeneity of blood flow) and also in different layers of the ventricular wall (i.e., transmural heterogeneity of blood flow). In turn, these blood flow alterations in the myocardium may impair cardiac performance. Both global and segmental abnormalities of ventricular contraction are associated with coronary artery disease.” When the blood flow to a region of the myocardium is insufficient to meet the metabolic requirements of the working heart muscle for oxygen, &hernia develops and may produce angina pectoris, myocardial infarction, and/or local abnormalities of cardiac metabolism and function. Coronary arteriography is commonly used to visualize the extent and distribution of coronary artery obstructions. It is a necessary prerequisite to consideration of surgical therapy for angina, infarction, or ventricular failure.+ However, coronary arteriography does not reveal to what degree myocardial blood flow has been compromised by the obstructing lesion. It cannot reveal the presence of small vessel disease (i.e., abnormal vessels < 200~ in diameter) nor the extent