Evaluation of perioperative myocardial tissue damage in ischemically preconditioned human heart during aorto coronary bypass surgery

Background. Preconditioning myocardium with short periods of ischaemic stre ss interspersed with reperfusion increases its resistance to infarction. Is chaemic preconditioning protection occurred in human beings during unstable angina preceding myocardial infarction, during percutaneous transluminal c oronary angioplasty and during aorto coronary bypass surgery. The purpose o f this study was to test (utilised cardiac troponin T measurement) whether ischaemic preconditioning was able to protect myocardial tissue during the perioperative period and how long that protection lasted. Methods. Patients were recruited to the preconditioned group (n=29), receiv ed 4-min of aortic crossclamping and 6 min reperfusion prior to CABG perfor med with intermittent ischaemic arrest and the control group (n=27) receive d only an ischaemic insult of operating procedure. TnT measurements were de termined from blood samples taken before surgery (A), 1 hour after onset of CPB (B), 4 hours (C), 8 hours (D), 12 hours (E), 24 hours (F), 48 hours (G ) and 72 hours after CPB (H). Results. Results were expressed as the median, range and standard deviation (SD) of TnT concentration (mu g/l). Ischaemic preconditioning decreased Tn T concentration with statistical significance 1 hour after onset of CPB (pr econditioned B: median 0.12+/-0.25 vs control B: median 0.32+/-0.43, p=0.03 ). There were notable differences in TnT concentration in C, D, E, F, G, H blood samples between the control and the preconditioned group but with p v alue of no statistical significance. Conclusions. These data illustrate that ischaemic preconditioning Limits my ocardial damage during operative procedure and it may probably afford prote ction during a postoperative period.