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Background: Exenatide has been demonstrated to be cardioprotective as an adjunct to primary percutaneous coronary intervention in patients with ST-segment-elevation myocardial infarction (STEMI). The aim of the post hoc analysis study was to evaluate the effect of exenatide in relation to system delay, defined as time from first medical contact to first balloon., Methods and Results: Patients with STEMI and Thrombolysis In Myocardial Infarction flow 0/1 were randomly assigned to intravenous exenatide or placebo continuous infusion. Study treatment was commenced 15 minutes before intervention and maintained for 6 hours after the procedure. The patients were stratified according to median system delay (132 minutes). Final infarct size and myocardial area at risk were measured by cardiovascular magnetic resonance. Among patients with a system delay ≤132 minutes (n=74), treatment with exenatide resulted in a smaller infarct size (9 grams [interquartile range (IQR), 4-13] versus 13 grams [IQR, 8-24], P=0.008, corresponding to 8% [IQR, 4-12] versus 11% [IQR, 7-17] of the left ventricle, P=0.015). In a regression analysis adjusting for myocardial area at risk the data points of the exenatide group lay significantly lower than for the placebo group (P=0.006). In the patients with system delay >132 minutes (n=74) no difference was observed in infarct size expressed as grams (P=0.49) or percentage (P=0.46). There was significant interaction between system delay (less than or equal to median versus greater than median) and treatment allocation in terms of infarct size (P=0.018)., Conclusions: In this post hoc analysis, exenatide treatment was associated with a 30% decrease in final infarct size in patients with short system delay, whereas no cardioprotective effect in patients with long system delay was seen. However, this finding must be confirmed in larger studies., Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00835848.

Background: Postconditioning has been suggested to reduce myocardial damage during primary percutaneous coronary intervention (PPCI) in patients with ST-segment-elevation myocardial infarction. However, because clinical experience is limited, we examined the cardioprotective effects of postconditioning, using cardiac MRI in patients treated with PPCI., Methods and Results: One hundred eighteen patients with ST-segment-elevation myocardial infarction referred for PPCI were randomly assigned to have either conventional PPCI or PPCI with postconditioning. Postconditioning was performed immediately after obtained reperfusion with 4 balloon occlusions, each lasting 30 seconds, followed by 30 seconds of reperfusion. The primary end point was myocardial salvage after 3 months as judged by delayed enhancement cardiac MRI. We found a 19% relative reduction of infarct size in the postconditioning group (51+/-16% of total area at risk versus 63+/-17%, P<0.01), corresponding to a 31% increase in salvage ratio. The number of patients developing heart failure was significantly fewer in the postconditioning group (27% versus 46%, P=0.048). No significant evidence of interaction between the impact of postconditioning and the location of the culprit lesion or size of the myocardium at risk was detected (P=0.21 and P=0.71)., Conclusions: Mechanical postconditioning reduces infarct size in patients with ST-segment-elevation myocardial infarction treated with PPCI. The impact of mechanical postconditioning seems to be independent of the size of myocardium at risk., Clinical Trial Registration- Url: http://www.clinicaltrials.gov. Unique Identifier: NCT00507156.

Background: Implantation of drug-eluting stents (DES) limits the rate of coronary restenosis in most patients with coronary artery disease, but data are scarce with regard to their use in patients with ST-segment-elevation myocardial infarction and in connection with distal protection of the microvascular perfusion during primary percutaneous coronary intervention., Methods and Results: We randomly assigned 626 patients referred within 12 hours from symptom onset of an ST-elevation myocardial infarction to have a DES or a bare metal stent implanted in the infarct-related lesion with or without distal protection during primary percutaneous coronary intervention. Quantitative coronary angiography was performed during the index treatment and 8 months later. The primary end point was loss of the lumen diameter in the infarct-related lesion induced by neointimal proliferation. Patients were comparable with regard to baseline demographic and angiographic characteristics. The mean late lumen loss was significantly lower in patients treated with a DES (0.06 mm; SD, 0.66 mm) than in patients who had a bare metal stent implanted (0.47 mm; SD, 0.69 mm; P<0.001). The rate of the composite end point of cardiac death, recurrent myocardial infarction, and target lesion revascularization was 8.6% in the DES group versus 14.4% in the bare metal stent group (P=0.03). Cardiac death occurred in 4.2% and 1.6% of the patients (P=0.09) and stent thrombosis occurred in 2.0% and 2.6% (P=0.72), respectively., Conclusions: Implantation of DES improves the angiographic outcome and need for repeat revascularization without increasing the short-term risk of stent thrombosis but has a tendency to increase cardiac death in patients with ST-segment-elevation myocardial infarction.

Background: Granulocyte-colony stimulating factor (G-CSF) after myocardial infarction does not affect systolic function when compared with placebo. In contrast, intracoronary infusion of bone marrow cells appears to improve ejection fraction. We aimed to evaluate the G-CSF mobilization of subsets of stem cells., Methods and Results: We included 78 patients (62 men; 56+/-8 years) with ST-elevation myocardial infarction treated with primary percutaneous intervention <12 hours after symptom onset. Patients were randomized to double-blind G-CSF (10 microg/kg/d) or placebo. Over 7 days, the myocardium was exposed to 25x10(9) G-CSF mobilized CD34+ cells, compared with 3x10(9) cells in placebo patients (P<0.001); and to 4.9x10(11) mesenchymal stem cells, compared with 2.0x10(11) in the placebo group (P<0.001). The fraction of CD34+ cells/leukocyte increased during G-CSF treatment (from 0.3+/-0.2 to 1.1+/-0.9 x10(-3), P<0.001 when compared with placebo), whereas the fraction of putative mesenchymal stem cells/leukocyte decreased (from 22+/-17 to 14+/-11 x10(-3), P=0.01 when compared with placebo). An inverse association between number of circulating mesenchymal stem cells and change in ejection fraction was found (regression coefficient -6.8, P=0.004), however none of the mesenchymal cell subtypes analyzed, were independent predictors of systolic recovery., Conclusions: The dissociated pattern for circulating CD34+ and mesenchymal stem cells could be attributable to reduced mesenchymal stem cell mobilization from the bone marrow by G-CSF, or increased homing of mesenchymal stem cells to the infarcted myocardium. The inverse association between circulating mesenchymal stem cells and systolic recovery may be of clinical importance and should be explored further.

Background: Phase 1 clinical trials of granulocyte-colony stimulating factor (G-CSF) treatment after myocardial infarction have indicated that G-CSF treatment is safe and may improve left ventricular function. This randomized, double-blind, placebo-controlled trial aimed to assess the efficacy of subcutaneous G-CSF injections on left ventricular function in patients with ST-elevation myocardial infarction., Methods and Results: Seventy-eight patients (62 men; average age, 56 years) with ST-elevation myocardial infarction were included after successful primary percutaneous coronary stent intervention <12 hours after symptom onset. Patients were randomized to double-blind treatment with G-CSF (10 microg/kg of body weight) or placebo for 6 days. The primary end point was change in systolic wall thickening from baseline to 6 months determined by cardiac magnetic resonance imaging (MRI). An independent core laboratory analyzed all MRI examinations. Systolic wall thickening improved 17% in the infarct area in the G-CSF group and 17% in the placebo group (P=1.0). Comparable results were found in infarct border and noninfarcted myocardium. Left ventricular ejection fraction improved similarly in the 2 groups measured by both MRI (8.5 versus 8.0; P=0.9) and echocardiography (5.7 versus 3.7; P=0.7). The risk of severe clinical adverse events was not increased by G-CSF. In addition, in-stent late lumen loss and target vessel revascularization rate in the follow-up period were similar in the 2 groups., Conclusions: Bone marrow stem cell mobilization with subcutaneous G-CSF is safe but did not lead to further improvement in ventricular function after acute myocardial infarction compared with the recovery observed in the placebo group.

BACKGROUND: The impact of disease severity on the outcome after complete revascularization in patients with ST-segment--elevation myocardial infarction and multivessel disease is uncertain. The objective of this post hoc study was to evaluate the impact of number of diseased vessel, lesion location, and severity of the noninfarct-related stenosis on the effect of fractional flow reserve--guided complete revascularization. METHODS AND RESULTS: In the DANAMI-3-PRIMULTI study (Primary PCI in Patients With ST-Elevation Myocardial Infarction and Multivessel Disease: Treatment of Culprit Lesion Only or Complete Revascularization), we randomized 627 ST-segment--elevation myocardial infarction patients to fractional flow reserve--guided complete revascularization or infarct-related percutaneous coronary intervention only. In patients with 3-vessel disease, fractional flow reserve--guided complete revascularization reduced the primary end point (all-cause mortality, reinfarction, and ischemia-driven revascularization; hazard ratio [HR], 0.33; 95% confidence interval [CI], 0.17--0.64; P=0.001), with no significant effect in patients with 2-vessel disease (HR, 0.77; 95% CI, 0.47--1.26; P=0.29; P for interaction =0.046). A similar effect was observed in patients with diameter stenosis ≥90% of noninfarct-related arteries (HR, 0.32; 95% CI, 0.18-- 0.62; P=0.001), but not in patients with less severe lesions (HR, 0.72; 95% CI, 0.44--1.19; P=0.21; P for interaction =0.06). The effect was most pronounced in patients with 3-vessel disease and noninfarct-related stenoses ≥90%, and in this subgroup, there was a nonsignificant reduction in the end point of mortality and reinfarction (HR, 0.32; 95% CI, 0.08--1.32; P=0.09). Proximal versus distal location did not influence the benefit from complete revascularization. CONCLUSIONS: The benefit from fractional flow reserve--guided complete revascularization in ST-segment--elevation myocardial infarction patients with multivessel disease was dependent on the presence of 3-vessel disease and noninfarct diameter stenosis ≥90% and was particularly pronounced in patients with both of these angiographic characteristics. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01960933. [ABSTRACT FROM AUTHOR]