The TIMI Risk Score for Unstable Angina/Non-ST-elevation MI: A Method for Prognostication and Therapeutic Decision Making - TIMI Risk Score for Unstable Angina/Non-ST-elevation MI
The TIMI Risk Score for Unstable Angina/Non-ST-elevation MI: A Method for Prognostication and Therapeutic Decision Making.
Which clinical markers are independent predictors of a combined endpoint of death, new or recurrent MI or recurrent severe ischemia requiring urgent coronary artery revascularization within 2 weeks after presentation with unstable angina/non-ST-elevation MI?
Patients Enrolled: 3,910
Multivariate analysis of 3,910 patients enrolled in TIMI IIB and ESSENCE trials.
The seven independent predictor variables of the combined endpoints included age > 65 years, three or more risk factors for coronary heart disease, known prior coronary stenosis of at least 50%, ST-segment elevation or depression on presenting electrocardiography, two or more anginal episodes in the preceding 24 hours, aspirin use within a week of presentation and elevated serum markers of myocardial injury. By aggregating patients with 0 to as many as 7 markers, a corresponding stepwise increase in the overall risk of mortality, myocardial infarction and urgent revascularization was observed. Patients with no or one variable had a mortality rate of 1.2%, those with four variables had 2.5% and those with six or seven markers had a mortality rate of 6.5%. The rate of the composite endpoint varied from as low as 4.7% in patients with no or one marker to a level of 40.9% in those with six or seven of the markers noted. The analysis also compared the relative benefit of low molecular weight heparin (enoxaparin) vs. unfractionated heparin in patients at various risk levels. The greatest benefit of low molecular weight heparin compared to unfractionated heparin occurred in patients with multiple risk variables, particularly those with four or more of the seven high-risk markers.
This study provides a practical and fairly easy to use method by which practitioners can risk stratify patients presenting with acute coronary syndromes. Tools such as this can assist clinicans as they make decisions about which populations will benefit most from acute coronary interventions, more advanced antitrombin therapies or the use of newer antiplatelet agents.
Although this tool provides several insights, there are a number of unanswered questions. First, patients presenting for the first time will not bring prior knowledge of underlying coronary stenoses. Second, debate surrounding which cardiac enzyme to monitor, and at what time interval, continues to fuel disagreements on how MI is defined.
1. Antman EM, Cohen M, Bernink PJ, et al. JAMA 2000;284:876-8.
Keywords: Myocardial Infarction, Acute Coronary Syndrome, Multivariate Analysis, Platelet Aggregation Inhibitors, Biological Markers, Coronary Stenosis, Enoxaparin, Heparin, Low-Molecular-Weight, Risk Factors, Electrocardiography
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