Objective: To determine what proportion of patients with acute myocardial infarction are not eligible for thrombolytic therapy and to assess their natural history.
Design: Retrospective chart review.
Setting: A large community-based hospital.
Patients: All patients with acute myocardial infarction hospitalized during a 27-month period.
Measurements: Of 1471 patients with acute myocardial infarction, 230 (16%) received thrombolytic therapy according to the protocol and an additional 97 (7%) received nonprotocol thrombolytic therapy, primary coronary balloon angioplasty, or both because of contraindications. The other 1144 patients (78%) did not receive reperfusion therapy.
Main results: The patients who did not receive thrombolytic therapy were older, more likely to be women, and more likely to have a history of hypertension, previous myocardial infarction, or chronic angina (all comparisons, P less than 0.002). An average of 1.9 reasons for exclusion were identified per patient among the ineligible patients. Mortality was fivefold higher among ineligible patients (19%; Cl, 16% to 21%) than among protocol-treated patients (4%; Cl, 1% to 6%) (P less than 0.001). In-hospital mortality rates for excluded patients were 28% (Cl, 23% to 32%) in elderly patients (age, greater than 76 years; n = 396); 29% (Cl, 23% to 35%) in patients with stroke or bleeding risk (n = 209); 17% (Cl, 14% to 20%) in patients with delayed presentation (greater than 4 hours after the onset of chest pain; [n = 599]); 14% (Cl, 11% to 16%) in patients with an ineligible electrocardiogram (ECG) (n = 673); and 26% (Cl, 21% to 32%) in patients with a miscellaneous reason for exclusion (n = 243). Independent predictors of increased mortality were: age greater than 76 years, stroke or other bleeding risk, ineligible ECG, or the presence of two or more exclusion criteria.
Conclusions: Thrombolytic therapy is currently used in the United States for only a minority of patients with acute myocardial infarction: those who have low-risk prognostic characteristics.