Predictors of infarct artery patency after prehospital thrombolysis: the multicentre, prospective, observational OPTIMAL study.

Objective: To identify predictors of early TIMI 3 flow patency of the infarct-related artery after prehospital thrombolysis in patients with ST-segment elevation myocardial infarction (STEMI) using data from a "real-world" population, and to develop a nomogram for triaging patients to emergency angiography.

Design: Multicentre, observational, prospective, cohort study.

Setting: 79 Hospitals in France with a prehospital mobile intensive care unit and a coronary care unit with 24 h access to coronary angiography.

Patients: 997 Patients with STEMI.

Interventions: All patients received prehospital thrombolysis within 6 h of symptom onset and angiography was performed within 6 h of thrombolysis.

Main Outcome Measures: Coronary patency (TIMI flow).

Results: The median age of the population was 59 years and the sample comprised 18% women. After multivariable logistic regression analysis, predictors of TIMI 3 flow in the infarct-related artery were current/previous smoking (odds ratio (OR) = 1.60, 95% confidence interval 1.15 to 2.22), < or =5 leads with ST-segment elevation before thrombolysis (OR = 1.59, 1.12 to 2.25), Killip class I (OR = 1.96, 1.05 to 3.67), chest pain relief (OR = 1.62, 1.17 to 2.25) and ST-segment resolution > or =70% (OR = 1.76, 1.29 to 2.38). A nomogram was developed to assess the probability of TIMI 3 flow, according to smoking status, number of leads with ST elevation before thrombolysis, Killip class, chest pain relief and ST-segment resolution.

Conclusions: This study provides quantitative data for predicting success of prehospital thrombolysis. The nomogram is a simple tool for predicting likelihood of coronary patency, based on clinical and electrocardiographic data. It may help to identify patients who require emergency angiography and rescue percutaneous coronary intervention.