Abstract 1747: Post-Conditioning Reduces Infarct Size and Improves LV function During Acute Myocardial Infarction
The modification of reperfusion by Post-Conditioning (PC) following coronary occlusion in animals significantly reduces myocardial necrosis and improves left-ventricular function (LVEF). To see if this occurs in humans we randomized 43 patients (35 Male, 8 Female ) who presented with their first acute myocardial infarction to PC versus standard therapy (Control) during primary PTCA/stenting. All patients had 100 percent occlusion of a major epicardial vessel ( LAD -14, CX - 6, RCA - 23 ) with TIMI 0 flow and no evidence of collateral blood flow. PC was performed immediately upon passing the guidewire through the obstruction and consisted of 4 cycles of 30 sec occlusion followed by 30 sec of reperfusion. All patients underwent successful placement of a drug-eluting stent and LV function was assessed by cardiac MRI or echocardiography 1–2 days later. Both groups had identical times from the onset of chest pain to reperfusion and patients with pre-infarction angina (pre-conditioning) were excluded. Despite identical ischemic times, the PC group had smaller infarcts by peak CK and CKMB and better LV function. Both TIMI Flow and TMP was higher in the PC group suggesting that PC may reduce endothelial I/R injury in the heart as recently demonstrated in the peripheral vasculature and contribute to improved myocardial salvage during acute MI.