The investigators examined the mechanism underlying the lack of benefit from distal protection and thrombus aspiration (DP-TA) in 126 patients with ST-elevation Myocardial Infarction (STEMI) in a prospective, randomized trial.

Patients with first-diagnosed STEMI were randomly assigned to distal protection and thrombus aspiration (DP-TA) pretreatment during percutaneous coronary intervention (PCI) or conventional PCI (c-PCI).

The primary endpoint was the remodeling index (RI), measured by cardiac magnetic resonance imaging (CMR) post-PCI and 6 months after PCI.

Secondary endpoints, determined by CMR within 3 to 5 days after PCI, included the infarct ratio (infarct size to entire left ventricular [LV] size ) by delayed-enhancement (DE), area at risk (AAR) ratio (AAR to LV size) by T2 high-signal intensity , microvascular occlusion index (MVO) ratio (MVO to LV size) by DE, and myocardial salvage index (MSI, [AAR-infarct size] x 100/AAR).

Inclusion Criteria:

• 30 and less than 80 years presenting with STEMI
• more than 30 minutes but less than 12 hours after symptom onset
• with ≥ 2 mm of ST-segment elevation in 2 or more contiguous leads or with a presumably new left bundle-branch block
• for whom primary PCI was intended

Exclusion Criteria:

• included thrombolytic therapy before PCI;
• spontaneous restoration of coronary flow (> TIMI grade II or III);
• cardiogenic shock (Killip class IV);
• major surgery or active bleeding within 6 weeks;
• aspirin, thienopyridine, or heparin allergy;
• neutropenia (<1000 neutrophils/mm3), thrombocytopenia (<100000 platelets/mm3), hepatic dysfunction, or renal insufficiency (serum creatinine level >2.5 mg/dL [221 μmol/L]);
• noncardiac condition with expected survival less than 1 year;
• current participation in other investigations.

6 months