Simple Risk Stratification at Admission to Identify Patients With Reduced Mortality From Primary Angioplasty

Abstract

Background— Randomized trials comparing fibrinolysis with primary angioplasty for acute ST-elevation myocardial infarction have demonstrated a beneficial effect of primary angioplasty on the combined end point of death, reinfarction, and disabling stroke but not on all-cause death. Identifying a patient group with reduced mortality from an invasive strategy would be important for early triage. The Thrombolysis in Myocardial Infarction (TIMI) risk score is a simple validated integer score that makes it possible to identify high-risk patients on admission to hospital. We hypothesized that a high-risk group might have a reduced mortality with an invasive strategy. Methods and Results— We classified 1527 patients from the Danish Multicenter Randomized Study on Fibrinolytic Therapy Versus Acute Coronary Angioplasty in Acute Myocardial Infarction (DANAMI-2) trial with information for all variables necessary for calculating the TIMI risk score as low risk (TIMI risk score, 0 to 4) or high risk (TIMI risk score ≥5) and investigated the effect of primary angioplasty versus fibrinolysis on mortality and morbidity in the 2 groups. Follow-up was 3 years. We classified 1134 patients as low risk and 393 as high risk. There was a significant interaction between risk status and effect of primary angioplasty ( P =0.008). In the low-risk group, there was no difference in mortality (primary angioplasty, 8.0%; fibrinolysis, 5.6%; P =0.11); in the high-risk group, there was a significant reduction in mortality with primary angioplasty (25.3% versus 36.2%; P =0.02). Conclusions— Risk stratification at admission based on the TIMI risk score identifies a group of high-risk patients who have a significantly reduced mortality with an invasive strategy of primary angioplasty.