• infarct size (% of left ventricular mass) as measured by delayed hyperenhancement magnetic resonance imaging at 6 months
  

• Angiographic TIMI Myocardial Perfusion grade and corrected TIMI frame count, assessed immediately after PCI.
  
• Extension of no-reflow areas (% of left ventricular mass), as assessd by delayed enhancement-MRI before hospital discharge.
  
• Extension of microvasculature damage (% of left ventricular mass), as assessed by fist-pass perfusion study by MRI before hospital discharge.
  
• Regional wall motion and left ventricular ejection fraction, as measured by cine MRI and 2D echocardiography at 6 months
  
• Rate of left ventricular remodeling (increase in end-diastolic volume >20%), as measured by cine MRI and 2D echocardiography at 6 months
  
• at 6 month follow up.
  

Strategies directed at improving myocardial perfusion or viability in the setting of acute myocardial infarction (AMI) are currently suboptimal. The consequences of microvascular damage, as assessed by the TIMI myocardial perfusion (TMP) grade or by cardiac magnetic resonance imaging (MR), are serious and affect survival after AMI. Because the size of the infarct is an important predictor of prognosis, precise determination of infarct size allows risk stratification of patients after AMI.

First-pass MR perfusion studies recently developed provide quantification of the absolute measure of myocardial blood flow as well as direct visualization of myocardial perfusion abnormalities, such as areas of “no-reflow”. The hyperenhancement technique (Delayed enhancement) identifies viable and nonviable myocardium as well as no-reflow areas.

A recent pilot study showed that infarct size meausured by scintigraphy at 7 days was 23% vs 14% when abciximab was administered in the cath lab vs emergency room, with a reduction in infarct size of 40%.

The present study will be conducted at the Cardiothoracic Department of the University of Pisa toghether with the Institute of Clinical Physiology (CNR) and two other Cath Labs of the West of Tuscany. Each Cath Lab will treat patients enrolled in peripheral hospitals referring the patients for primary PCI.

The primary objective of the study is to demonstrate that early abciximab administration (before transfer) as compared with late abciximab administration (in the Cath Lab) reduces infarct size as measured by delayed hyperenhancement imaging at 6 months.

The major secondary objectives of this substudy are to demonstrate that early abciximab administration:

1. Improves angiographic TMP grade and cTFC compared with primary PCI group, immediately after PCI.
2. Reduces the extension of no-reflow areas, as assessd by DE-MRI before discharge.
3. Reduces the extension of microvasculature damage as assessed by fist-pass perfusion study by MRI before discharge.
4. Improves regional wall motion and left ventricular ejection fraction (LVEF) as measured by cine MR and 2D echocardiography at 6 months
5. Reduces the occurrence of LV remodeling at 6 month follow up.