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

IntroductionPrimary percutaneous coronary intervention (PCI) is the preferred method of reperfusion in ST-segment elevation myocardial infarction patients. Adjunctive pharmacotherapy is, however, still under investigation.ObjectiveTo assess the effect of combined pharmacologic therapy on myocardial perfusion and infarct size in relation to time delays.Materials and methodsWe studied 309 consecutive ST-segment elevation myocardial infarction patients admitted within 12h from symptom onset with (a) chest pain persisting for more than 30min, (b) ST-segment elevation more than 1mm in at least two contiguous leads, and (c) pretreatment with 600mg of clopidogrel, 300mg of aspirin, and 5000U 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.ResultsThe delay between pharmacologic pretreatment and angiography was two times longer in cases of staged transfer (80 vs. 47.5min; 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. 3.9ng/ml; P=0.74).ConclusionPretreatment with a combination of antiplatelet and antithrombotic agents may improve myocardial perfusion and compromise longer delay to a mechanical intervention.