Efficacy and safety of a high loading dose of clopidogrel administered prehospitally to improve primary percutaneous coronary intervention in acute myocardial infarction: the randomized CIPAMI trial.

Objectives: To compare a loading dose of 600 mg clopidogrel given in the prehospital phase versus clopidogrel administered only after the diagnostic angiogram in patients with STEMI scheduled for primary PCI.

Background: The optimal time and dose for the initiation of clopidogrel therapy in patients with STEMI scheduled for primary PCI has not been studied in prospective randomized trials.

Methods: The primary efficacy endpoint was the TIMI 2/3 patency of the infarct-related artery in the diagnostic angiography immediately prior to PCI.

Results: We randomized 337 patients to prehospital (n = 166) loading dose versus standard therapy (n = 171). The time interval between initiation of clopidogrel therapy and diagnostic angiography was 47 min. TIMI 2/3 patency before PCI was not different between the groups (49.3 vs. 45.1%, P = 0.5). We observed a trend towards a reduction of the combined endpoint death, re-infarction, and urgent target vessel revascularization in the prehospital-treated patients (3.0 vs. 7.0%, P = 0.09), this difference was significant if patients were classified as treated (4/161 vs. 13/174; 2.5 vs. 7.5%, P < 0.05). There was no difference in TIMI major bleeding complications (9.1 vs. 8.2%, P = 0.8).

Conclusions: Early inhibition of the platelet ADP-receptor with a high loading dose of 600 mg clopidogrel given in the prehospital phase in patients with STEMI scheduled for primary PCI is safe, did not increase pre-PCI patency of the infarct vessel, but was associated with a trend towards a reduction in clinical events.