abbreviation for thrombolysis in myocardial infarction risk score. A simple integer score for bedside risk stratification of patients with acute myocardial infarction (MI). Point values are assigned to each of a set of independent prognostic variables (e.g., age, diabetes mellitus, history of hypertension, history of angina, ST segment elevation), and the sum of points is the score. Several studies have validated the score as a measure of risk of all-cause mortality and recurrent MI; predictors have varied slightly between studies.