Postconditioning (PC) has been suggested to reduce myocardial damage during primary percutaneous coronary intervention (PPCI), nevertheless clinical experience is limited. We aimed to explore the cardioprotective effect of PC using cardiac magnetic resonance (CMR) in ST-elevation myocardial infarction (STEMI) patients treated by PPCI.

A total of 78 patients with first STEMI (aged 59±12years) referred for PPCI, were stratified for STEMI location and randomly assigned to conventional PPCI or PPCI with PC. All patients, with occluded infarct related artery and no collateral circulation, received abciximab intravenously before PPCI. After reperfusion by effective direct stenting, control subjects underwent no further intervention, while in treated patients PC was performed within 1min of reflow by 4 cycles of 1-minute inflation and 1-minute deflation of the angioplasty balloon. Primary end-point was infarct size (IS) reduction, expressed as percentage of left ventricle mass assessed by delayed enhancement on CMR at 30±10days after index PPCI.

All baseline characteristics but diabetes (p=0.06) were balanced between groups. Postconditioning patients trended toward a larger IS compared to those treated by standard PPCI (20±12% vs 14±10%, p=0.054). After exclusion of diabetics, PC group still showed a trend to larger IS (p=0.116). Major adverse events seem to be more frequent in PC group irrespective to diabetic status (p=0.053 and p=0.080, respectively).

This prospective, randomized trial suggests that PC did not have the expected cardioprotective effect and on the contrary it might harm STEMI patients treated by PPCI plus abciximab. (Clinical Trial Registration-unique identifier: NCT01004289).