Coronary Perfusion Pressure-Induced Changes in Coronary Vascular Volume in the Canine Right Ventricle

Yu, Ying, Coronary Perfusion Pressure-induced Changes in Coronary Vascular Volume in the Canine Right Ventricle. Master of Science (Biomedical Sciences), December 1997; 33 pp; 4 tables; 5 figures; bibliography, 24 titles. Changes in coronary perfusion pressure cause changes in myocardial contractile function and oxygen consumption (MVO2), particularly in the right ventricle (RV). This study determined the effects of right coronary (RC) perfusion pressure (RCP) on RC vascular volume (RCB) and its relationship to MVO2 of in situ, working canine hearts, and also investigated whether changes in MVO2 are due primarily to altered RCP or RC blood flow (RCF). In 15 open chest, anesthetized dogs, the RC artery was cannulated and perfused with arterial blood diverted from a femoral artery. To blunt RCP-induced changes in RCF, vasopressin was infused into the RC perfusion line in seven dogs. RCV was measured by an indicator dilution method as RCP was varied without vasopressin (RCP=60, 100, 140, and 180 mmHg) and with vasopressin (RCP=60 and 100 mmHg). Without vasopressin, changes in RCP induced changes in MVO2 which were associated with changes in RCV and RCF. With vasopressin, increasing RCP from 60 mmHg to 100 mmHg produced no changes in RCF, RCV, or MVO2. These results indicate that RCP-induced changes in RV MVO2 are mediated by RCV and/or RCF, but not by RCP per se.