1982 年 46 巻 12 号 p. 1345-1352
Aspartate aminotransferase (EC 2.6.1.1.:AST) is known to have two isoenzymes, one associated with the cytoplasm (c-AST) and the other with the mitochondria (m-AST). We studied the relationships of m-AST activity in the coronary sinus blood to left ventricular function, coronary blood flow, water content and high-energy phosphate stores of the left ventricle following hypothermic ischemic cardiac arrest. Under cardiopulmonary bypass with hypothermia of 20°C of myocardial temperature, 120 min of aortic occlusion was employed in 15 mongrel dogs. Left ventricular function (peak left ventricular pressure, left ventricular enddiastolic pressure, max dp/dt, cardiac index, left ventricular stroke work index), coronary blood flow, myocardial oxygen consumption, myocardial enzyme activity (m-AST, CK-MB), myocardial water content and high-energy phosphate stores (adenosine triphosphate, creatine phosphate) of the subendocardium of the left ventricle were measured. Data was obtained in the control state, and after 0, 30 and 60 min of reperfusion. Significant negative correlations were obtained between m-AST activity and peak left ventricular pressure (r = -0.81, p<0.001), max dp/dt (r = -0.83, p<0.001), cardiac product (r= -0.73, p<0.01), coronary blood flow (r = -0.59, p<0.05), adenosine triphosphate level (r = -0.72, p<0.01) and creatine phosphate level (r = -0.72, p<0.02) after 60 min of reperfusion. Significant positive correlations were obtained between m-AST activity and left ventricular end-diastolic pressure (r = 0.75, p<0.01) and water content (r = 0.78, p<0.0 1 ) after 60 min of reperfusion. These results led to the assumption that serum m-AST activity in the coronary venous blood is a useful index to evaluate the degree of myocardial injury.
