Reduction in myocardial infarct size by postconditioning in patients after percutaneous coronary intervention

Postconditioning has been shown to reduce infarct size during reperfusion (< 72 hours). However, it is unknown whether the infarct size reduction with postconditioning is a long-term effect after clinical percutaneous coronary intervention (PCI). The present study tested the hypothesis that postconditioning during primary PCI preserves global cardiac function and reduces infarct size in patients after prolonged reperfusion.

Fortyone patients undergoing PCI were randomly assigned to a control (n = 18) or postconditioning (n = 23) group within 90 minutes after admission. After predilatation, in the Control group, no intervention was applied in the first 3 minutes of reperfusion, while in the Postconditioning group, three cycles of 30-second angioplasty balloon deflation and 30-second inflation were repetitively applied.

There was a trend toward increased ejection fraction quantified by echocardiography in the Postconditioning group compared to that in the Control group (54 +/- 12.9% vs. 44 +/- 16.7%; p > 0.05). Infarct size represented by the area under the curve of creatine-kinase activity during the first 72 hours of reperfusion was significantly less by 27% in the Postconditioning group than that in the Control group (58,002 +/- 593 vs. 79,787 +/- 681; p = 0.04). After 7 days of reperfusion, infarct size quantified by single-photon emission computed tomography was 27% smaller in the Postconditioning group than that measured in the Control group (31.3 +/- 8.6% vs. 22.8 +/- 6.7% of left ventricle; p < 0.05).

This study demonstrates that postconditioning following PCI significantly protects the heart against ischemia/reperfusion-induced injury. More importantly, this study indicates that protection with postconditioning is still apparent 1 week following reperfusion, suggesting long-term protection.