Original Article Effects of Ischemic Preconditioning on Myocardial Protective on Cardiac Surgery: Possibility of Ischemic

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 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 histopatho-logical study, the control group showed widely distributed hypercontraction bands and wav-ing degeneration of myofibrils. On the other hand, the structure of myofibrils was well pre-served 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) Key words: ischemic preconditioning, cardioplegic arrest, adenosine administratio