Controlled reperfusion with intravenous bivalirudin and intracoronary abciximab combination therapy in the porcine myocardial infarction model.

INTRODUCTION: The reperfusion injury (RI) remains a significant limitation of primary PCI, therefore we evaluated the role of intracoronary abciximab and bivalirudin for anticoagulation on myocardial salvage and RI in the porcine model of ischemia/reperfusion. MATERIALS AND METHODS: Myocardial infarction was induced in 23 pigs by 60-minute over-the-wire (OTW) balloon occlusion of the LAD. Animals received intravenous bivalirudin and then five minutes prior to reperfusion, either a coronary downstream infusion of abciximab (n=11) or saline (n=12) through the central lumen of an OTW catheter. All animals were followed for 48 hours. RESULTS: Histological analysis showed that infarct area (IA) and area at risk (AAR) were comparable between groups (IA/AAR%: 57.6 ± 8% vs. 57.1 ± 7%, p=0.8). Confirming this trend, biochemical markers (troponin I, TNF-alpha, IL-6, hsCRP, adiponectin, and VCAM) and left ventricular ejection fraction were also similar at 48 hours. Adhesion markers like ICAM and P-selectin were significantly decreased in the study group, nevertheless histological evidence of leukocyte extravasation was similar. The enhancement of apoptosis by TUNEL was comparable in both groups. The number of hemorrhagic infarctions confirmed by micro and macroscopic evaluation tended to be higher in the study group (70% vs. 20%, p=0.07). CONCLUSIONS: Despite lowered concentrations of adhesion molecules, intracoronary abciximab with peripheral bivalirudin is not superior to bivalirudin unaided in terms of myocardial salvage caused by RI in the porcine ischemia/reperfusion model. This might be due to local hemorrhage caused by abciximab.

Intracoronary adiponectin at reperfusion reduces infarct size in a porcine myocardial infarction model.

Reperfusion injury (RI) remains an important limitation of myocardial revascularization. The aim of the present study was to evaluate the influence of the intracoronary injection of adiponectin on RI and cardiomyocyte death in a porcine myocardial infarction model. Acute infarction in 14 Polish domestic pigs was induced by inflation of an over the wire balloon (OTW) catheter in the medial left anterior descending artery for 60 min. The study group consisted of 7 pigs in which intracoronary adiponectin (50 µg) was infused through the OTW catheter immediately before reperfusion. The control group (n=7) was administered placebo. Animals were sacrificed after two days of follow-up. The infarct area (IA) was stained with tetrazoline and the area at risk (AAR) with intracoronary administration of Evans Blue dye before euthanasia. Hearts in each group had similar AARs (46.2±9.9% vs. 48.4±6.2% of the whole myocardium, p=ns). The IA/AAR% and IA were smaller in the study group when compared to the control (24.7±4.0% vs. 45.3±22.5%, p=0.005; and 11.7±4.9% vs. 20.5±5.6%, p=0.01, respectively). These outcomes corresponded well with the peak troponin levels after 12 h (109.9±60.9 ng/ml vs. 185.5±39.4 ng/ml, p=0.017). After two days there was a significantly higher LVEF in the study group (51.4±8.5% vs. 33.9±8.6%, p=0.002). There was also a trend toward lower apoptosis enhancement in the viable myocardium in the study group (3.11±2.3 vs. 8.92±6.3; p=0.07). The administration of adiponectin into the infarct- related artery is safe and feasible. The treatment significantly reduced the infarct size.