Impact of time-to-treatment on myocardial perfusion after primary percutaneous coronary intervention with Gp IIb-IIIa inhibitors

BACKGROUND: Primary angioplasty has been shown to be superior to thrombolysis. However, previous reports have shown a negative impact of longer time-to-treatment on myocardial perfusion and survival even with mechanical reperfusion. However, these deleterious effects might potentially be overcome by an extensive use of glycoprotein (Gp) IIb-IIIa inhibitors. Thus, the aim of the current study was to evaluate the prognostic role of the interval from symptoms onset to reperfusion in a large cohort of patients undergoing primary angioplasty with Gp IIb-IIIa inhibitors. METHODS: Our population is represented by 1560 patients undergoing primary angioplasty for ST-segment elevation myocardial infarction (STEMI) included in the EGYPT (Early Glycoprotein IIb-IIIa Inhibitors in Primary Angiography) database. Myocardial perfusion was evaluated by angiography or ST-segment resolution, whereas infarct size was estimated by using peak creatine kinase and creatine kinase-MB (CK-MB). Follow-up data were collected between 30 days and 1 year after primary angioplasty. RESULTS: Time-to-treatment was significantly associated with age and female sex, diabetes and previous myocardial infarction (MI), but inversely related to smoking. Time-to-treatment affected the rate of postprocedural thrombolysis in myocardial infarction (TIMI) 3 flow (P<0.0001), myocardial blush grade 2-3 (P=0.052), complete ST-resolution (P<0.0001) and distal embolization (P=0.038). This relationship was confirmed after correction for baseline confounding factors for postprocedural TIMI 3 flow (P=0.008) and complete ST-segment resolution (P=0.003). Furthermore, time-to-treatment significantly affected enzymatic infarct size, even after correction for baseline confounding factors [odds ratio (OR) 95% confidence interval (95% CI)=1.002 (1.001-1.003), P=0.004]. At 208±160 days follow-up, time-to-treatment was associated with a significantly higher mortality (P=0.006). The impact was confirmed when time-to-treatment was evaluated as a continuous variable (P<0.001), even after correction for baseline confounding factors [age, sex, diabetes, smoking, hypertension, previous myocardial infarction (MI), preprocedural TIMI 3 flow, multivessel disease, coronary stenting and early Gp IIb-IIIa inhibitors] (P=0.001). CONCLUSION: This study showed that time-to-treatment is a major determinant of mortality in ST-segment elevation myocardial infarction patients undergoing primary angioplasty. Impaired epicardial and myocardial perfusion and larger infarct size associated with longer ischemia time contribute to explain this finding.