Effect of a combination of antiplatelet and antithrombotic pretreatment on myocardial perfusion in patients with an acute ST-segment elevation myocardial infarction undergoing a primary percutaneous coronary intervention.

INTRODUCTION:Primary percutaneous coronary intervention (PCI) is the preferred method of reperfusion in ST-segment elevation myocardial infarction patients. Adjunctive pharmacotherapy is, however, still under investigation. OBJECTIVE:To assess the effect of combined pharmacologic therapy on myocardial perfusion and infarct size in relation to time delays. MATERIALS AND METHODS:We studied 309 consecutive ST-segment elevation myocardial infarction patients admitted within 12 h from symptom onset with (a) chest pain persisting for more than 30 min, (b) ST-segment elevation more than 1 mm in at least two contiguous leads, and (c) pretreatment with 600 mg of clopidogrel, 300 mg of aspirin, and 5000 U of intravenous heparin. Group I (n=90) included patients transferred directly to cathlab (immediate transfer) and group II (n=219) included patients transferred by referring hospitals (staged transfer). The results of thrombolysis in myocardial infarction (TIMI) flow before and after PCI, ST-segment resolution (STSR), troponin T level, and myocardial blush grade were analyzed in relation to delay to intervention. RESULTS:The delay between pharmacologic pretreatment and angiography was two times longer in cases of staged transfer (80 vs. 47.5 min; P<0.0001). Despite the longer delay, higher rates of preangiography total STSR (26.4 vs. 15.5%; P=0.039) and initial TIMI flow 3 (20.1 vs. 11.1%; P=0.059) were observed in those patients. Differences in the rate of total STSR (70.3 vs. 66.7%; P=0.52), TIMI flow 3 (91.3 vs. 88.9%; P=0.33), and myocardial blush grade (60.7 vs. 63.3%; P=0.66) were no longer observed after PCI. Similarly, the peak troponin T level was also comparable (3.6 vs. 3.9 ng/ml; P=0.74). CONCLUSION:Pretreatment with a combination of antiplatelet and antithrombotic agents may improve myocardial perfusion and compromise longer delay to a mechanical intervention.