Background: Temporal changes in baseline characteristics, treatment and clinical outcomes of patients presenting with acute ST elevation myocardial infarction in Canada and the United States have not been examined comprehensively over time.
Objectives: To evaluate baseline characteristics, process of care and clinical outcomes. Also, to explore whether earlier process-of-care differences between Canada and the United States had changed and, if so, whether they influenced clinical outcomes.
Patients and methods: A total of 13, 888 American and 3011 Canadian patients enrolled in 184 American and 38 Canadian hospitals that participated in both the Global Utilization of Streptokinase and Tissue Plasminogen Activator (alteplase) for Occluded Coronary Arteries (GUSTO-I) trial (1990 to 1993) and the Global Utilization of Strategies to Open Occluded Coronary Arteries (GUSTO-III) trial (1995 to 1997) were studied. Logistic regression was used to identify significant prognostic factors, to assess illness severity at hospital presentation and to classify trends between Canada and the United States.
Results: In both countries, illness severity on admission increased, door-to-needle time for thrombolysis was reduced, intensive care unit stay was shortened and hospital stay decreased from GUSTO-I to GUSTO-III. Whereas the administration of oral nitrates, calcium blockers and beta-blockers at discharge converged over time between countries, the disparity in the use of angiography and revascularization widened; the rise in American revascularization rate was most evident in patients without in-hospital ischemia. The 30-day and one-year mortality rates were comparable and declined nonsignificantly in both countries.
Conclusions: Despite increased illness severity and varying medication and procedure rates, there was no increase over time in 30-day or one-year mortality; this remained comparable between countries throughout the seven-year observation period.