Abstract 3795: Permanent Reduction in Myocardial Infarct Size by Postconditioning in Patients after Primary Coronary Angioplasty
Background: Postconditioning, defined as an intermittent interruption of blood flow at the onset of reperfusion, has been previously shown to reduce acute myocardial infarct size (<72 h) in animal and human hearts. However, it is unknown whether the infarct size reduction with postconditioning is a long-term effect. The present study tested the hypothesis that postconditioning during percutaneous transluminal coronary angioplasty (PTCA) reduces infarct size in patients after a prolonged reperfusion.
Methods and results: Forty-one patients undergoing PTCA with stenting in a major epicardial coronary artery were randomly assigned to a control (n=18) or postconditioning (n=23) group within 90 min after admission. In the control patients, no intervention was given at the onset of reperfusion, while in the postconditioning group, three cycles of 30 s angioplasty balloon inflation and 30 s deflation were repetitively applied at the onset of reperfusion. Collateral blood flow determined by coronary angiograms was comparable between the two groups. ST segment resolution, TIMI flow and blush grade between the two groups were compatible. There was a trend toward increased ejection fraction detected by echocardiography in the postconditioning group compared to that in the Control group (52.1 ±12.9% vs. 44.5±16.7%, p>0.05). Infarct size represented by area under the curve of serum creatine kinase release during the first 72 h of reperfusion was significantly reduced less by 27% in the postconditioning group than that in the control group (58002±5273 vs. 79787±7253, p=0.04). At 7 days after reperfusion, infarct size detected by nuclear imaging was 30% smaller in the postconditioning group than that in the control group (31.3±8.6% vs. 22.8±6.7% of left ventricle, p<0.05).
Conclusion: This study demonstrates that postconditioning during PTCA significantly protects the heart against reperfusion-induced myocardial injury. More importantly, our study indicates that protection with postconditioning is still preserved after an extended reperfusion, suggesting a permanent protection.