Background: There is growing interest in assessing therapy for acute myocardial infarction. Because thrombolysis was not a study therapy in the GISSI-3 trial, the decision about thrombolysis was left to the responsible physicians. We evaluated the data on thrombolytic therapy among patients with acute myocardial infarction enrolled in the GISSI-3 trial to study the relation between rate of prescription and the characteristics of patients and participating coronary care units.
Methods: Complete clinical data were available for 17,944 patients randomized between June 1991 and July 1993 from 200 coronary care units in Italy. Demographic and clinical information were obtained for each patient, and each coronary care unit was classified according to patient volume, level of technology, and wide geographic area in which it was located. A multivariate logistic regression was performed with administration of thrombolytic therapy as the dependent variable and previously defined clinical and structural variables as independent variables.
Results: The most important factor in administration of thrombolytic therapy was that less than 6 hours elapse from symptom onset to hospital admission (odds ratio [OR] 14.05; 95% confidence interval [CI] 12.3 to 16.0). Next were location of coronary care unit in southern Italy (OR 1.81; 95% CI 1.62 to 2.01), presence of ST elevation at entrance electrocardiogram ECG (OR 1.47; 95% CI 1.35 to 1.61), absence of previous myocardial infarction (OR 1.35; 95% CI 1.22 to 1.49), and presence of catheterization laboratory or cardiac surgery program or both in the same hospital (OR 1.24; 95% CI 1.14 to 1.35). Coronary care units with high or low patient volume did not show different rates of administration of thrombolytic agents.
Conclusions: The GISSI-3 experience confirmed a high rate of prescription of thrombolytic therapy to patients admitted within 6 hours of symptom onset and those with ST-segment elevation on entrance electrocardiogram. It demonstrated that patients admitted to coronary care units with catheterization laboratories or cardiac programs or both have higher chances of receiving thrombolytic treatment than those admitted to hospitals without these capabilities.