A 2-hour thrombolysis in myocardial infarction score outperforms other risk stratification tools in patients presenting with possible acute coronary syndromes: comparison of chest pain risk stratification tools.

BACKGROUND: Accelerated diagnostic pathways for risk stratification of patients presenting to the emergency department with potential acute coronary syndromes may identify very-low-risk patients safe for early discharge to outpatient care.
METHODS: Patients presenting with potential acute coronary syndrome to the emergency department were prospectively enrolled between November 2007 and April 2010. Patient characteristics in conjunction with 0- and 2-hour biomarkers and electrocardiograms were analyzed according to a 2-hour thrombolysis in myocardial infarction (TIMI) score and 9 other accelerated diagnostic pathways. The primary outcome was acute coronary syndrome by 30 days.
RESULTS: Of 1,000 patients, 362 (36.2%) had a primary outcome. A pathway comprising electrocardiogram, prior ischemic heart disease, 0/2-hour troponin/creatine kinase MB fraction/myoglobin identified the highest proportion (25.0%) as low risk, with 96.1% sensitivity for the primary outcome. A pathway comprising electrocardiogram, history of ischemic heart disease, typical vs atypical symptoms, 0/2-hour troponin was the safest, with 99.7% sensitivity for the primary outcome, but only 9.0% were low risk. A pathway comprising the TIMI score with 0/2-hour troponin and electrocardiograms identified 15.5% as low risk, with a sensitivity of 99.2% for the primary outcome. This compares with standard care in which none were for outpatient care but, 3.3% had a primary outcome postdischarge within 30 days.
CONCLUSION: In this relatively high-risk population, a 2-hour TIMI score safely identified significant numbers of patients suitable for early discharge to outpatient care.