Effect of Hyperoxia on Coronary Vascular Resistance under a Constant Myocardial Oxygen Consumption

概要

論文の詳細を見る
It is known that oxygen induces a constriction of coronary vessels and a reduction of myocardial oxygen consumption. The present study was performed to verify whether or not a constriction of coronary vessels by oxygen is secondary to a reduction in myocardial oxygen consumption. The regional myocardium was perfused with femoral arterial blood at a constant flow rate in 12 mongrel dogs. Coronary vascular resistance was compared between the following two conditions : 1) perfusion of the coronary artery with own femoral arterial blood (pO_2 : 95±14 mmHz) (Normoxia) and 2) perfusion with hyperoxic blood (pO_2 : 497±56 mmHg) (Hyperoxia). To maintain the myocardial oxygen consumption approximately the same between these two conditions, heart rate was changed by right atrial pacing. The coronary vascular resistance was increased by 13.7±16.2% (p<0.001) from 3.00±1.25 (Normoxia) to 3.36±1.28 mmHg/mL/min (Hyperoxia) even though the myocardial oxygen consumption was the same during normoxia and hyperoxia. This increase in coronary vascular resistance by oxygen was independent on the fluctuations of heart rate, coronary perfusion rate, and myocardial oxygen extraction rate. This suggests that the coronary vasoconstriction by oxygen is not secondary to a lesser demand to myocardial oxygen consumption, but it occurs even if the myocardium would be ischemic and need more oxygen.
近畿大学の論文
1977-12-28