Benefit from thrombolysis in acute MI was predicted in the emergency department

To develop a clinical prediction guide that identifies, in the emergency department, patients with acute myocardial infarction (MI) who are likely to benefit from thrombolytic therapy. Design Derivation and validation of a thrombolytic predictive guide using patientspecific data from 13 clinical trials. Setting Clinical trial data were from 107 hospitals in the United States. Patients 4911 patients who were s 75 years of age (median age 58 y), had onset of chest pain or other ischemic symptoms of acute ischemia within 9 hours of presentation, systolic blood pressure £ 190 mm Hg, ST-segment elevation & 1 mm in a 2 contiguous leads on the electrocardiogram (EGG), and no contraindications to thrombolytic therapy. For mortality outcomes, the database of patients was randomly al-located (2:1 ratio) to a development data set (n = 3263) and a test data set (n = 1648). Description of prediction guide Logistic regression was used to develop component predictive instruments for each of 5 outcomes that included clinically important and statistically significant variables. 2 ECG-based variables were produced to show 2 indicators of the effect of thrombolytic therapy: acute infarction size based on ST segments, and a sign that the infarction was still early in its course based on T-wave changes. Main outcome measures Predictors of 30-day mortality, 1-year mortality, cardiac arrest within 48 hours of the first EGG, intracranial hemorrhage, and bleeding requiring transfusion. The areas under receiveroperating characteristic (ROC) curves were calculated to evaluate the performance of each component instrument in both the derivation and validation sets. Main results The overall Thrombolytic Predictive Instrument Database comprised 4911 patients. 3483 patients (71%) received thrombolytic therapy. The predictors for 30-day mortality were patient age {(odds ratio [OR] 1.75/10 y), systolic blood pressure in anterior or posterior acute MI (OR 0.76/10 mm Hg), history of diabetes (OR 2.52), heart rate (OR 1.31/10 beats per min), Q waves without ST-segment elevation in inferior acute iMI (OR 1.38), right bundlebranch block (OR 1.78), and use of thrombolytic therapy (OR 0.30)}*. The predicted probabilities of dying within 30 days ranged from 0.2% to 80%. For all outcomes, the areas under the ROC curves ranged from 0.77 for cardiac arrest to 0.84 for 30-day mortality. Conclusion A thrombolytic predictive guide was helpful in quantifying the probability that an individual patient with acute myocardial infarction would benefit from thrombolytic therapy or have an adverse outcome caused by thrombolytic therapy.