Effects of ischemic preconditioning on myocardial protective on cardiac surgery: possibility of ischemic preconditioning and adenosine administration.

SUBJECT We evaluated the efficacy for concomitant use of ischemic preconditioning (IPC) and cardioplegic arrest with adenosine premedication on myocardial protection. METHODS Twenty-one pigs were divided into three groups: 1) control group, 2) IPC group which had IPC, 3) IPC+adenosine triphosphate (ATP) group which had an administration of 140 gamma of ATP (Adetphos, Kowa, Tokyo, Japan) during IPC. IPC was employed by 3 minutes of aortic cross clamping and 5 minutes of reperfusion. After cardioplegic arrest, the hemodynamical state was observed during 60 minutes of reperfusion. Serum adenosine, troponin-T, E-max, and Tau (the time constant of early diastolic left ventricular pressure decay) were compared. RESULTS Serum adenosine levels and at the end of IPC and 60 minutes reperfusion were significantly higher in the IPC and IPC+ATP groups than the control group. Comparison of the myocardial contractile force indicator E-max showed that the IPC and IPC+ATP groups showed significantly higher recovery rates of myocardial contractile force than the control group. Tau was the lowest in the IPC+ATP group than the other groups. In the histopathological study, the control group showed widely distributed hypercontraction bands and waving degeneration of myofibrils. On the other hand, the structure of myofibrils was well preserved in the IPC and IPC+ATP groups. CONCLUSIONS The concomitant use of IPC enhanced the effect of a myocardial protective solution. However, the administration of adenosine during IPC did not show any further advantage than IPC along. (Ann Thorac Cardiovasc Surg 2003; 9: 307-13)