Modification of the Thrombolysis in Myocardial Infarction risk score for patients presenting with chest pain to the emergency department

Objective: To develop a modified Thrombolysis in Myocardial Infarction (TIMI) score to effectively risk stratify patients presenting to the ED with chest pain.

Methods: A prospective observational study was conducted at two metropolitan EDs. Data were obtained during patient interview. The primary outcome was major adverse cardiovascular events (MACE) within 30 days of presentation. Two separate modifications of the TIMI score were developed. These scores were compared to the original TIMI in terms of the area under the receiver operating characteristic curve and diagnostic accuracy statistics (sensitivity, specificity, positive and negative predictive values).

Results: Of 1760 patients, 364 (20.7%) experienced 30 day MACE. The first modified TIMI score was a simplified TIMI (s-TIMI) including four variables: age ≥65 years, three or more risk factors, high-sensitivity troponin (hs-cTnI) and electrocardiogram changes. The second score included the same four variables plus two Global Registry of Acute Coronary Events (GRACE) variables (systolic blood pressure and estimated glomerular filtration rate). This score was termed the GRACE TIMI (g-TIMI). s-TIMI had a lower sensitivity compared to the original TIMI score (93.41 and 96.98%), but higher specificity (45.49 and 24.50%). The g-TIMI had a sensitivity of 98.90% and specificity of 14.90%.

Conclusions: Attempts to modify the TIMI score yielded two scores with added predictive utility in comparison to the original TIMI model. The addition of GRACE variables (g-TIMI) increased sensitivity for MACE, but decreased the specificity of the model. The s-TIMI score yielded good specificity but had sensitivity that would not be acceptable by emergency physicians. The s-TIMI may be useful as part of an accelerated chest pain protocol.