Prehospital triage to primary stroke centers and rate of stroke thrombolysis

IMPORTANCE: Implementation of prehospital stroke triage is a public policy intervention that can have an immediate impact on acute stroke care in a region. OBJECTIVE: To evaluate the impact that a citywide policy recommending prehospital triage of patients with suspected stroke to the nearest primary stroke center had on intravenous tissue plasminogen activator (tPA) use in Chicago, Illinois. DESIGN: Retrospective multicenter cohort study from September 1, 2010, to August 31, 2011 (6 months before and after intervention that began March 1, 2011). SETTING: Ten primary stroke center hospitals in Chicago. PATIENTS: All admitted patients with stroke and transient ischemic attack. INTERVENTION: Prehospital triage policy of patients with stroke to primary stroke centers. MAIN OUTCOMES AND MEASURES: Intravenous tPA use (measured as a fraction of patients with ischemic strokes arriving through the emergency department). RESULTS: There were 1075 stroke and transient ischemic attack admissions in the pretriage period and 1172 in the posttriage period. Patient demographic characteristics including age, sex, and risk factors were similar between the 2 periods (mean age, 65 years; 53% female). Compared with the pretriage period, use of emergency medical services increased from 30.2% to 38.1% (P < .001) and emergency medical services prenotification increased from 65.5% to 76.5% (P = .001) after implementation. Rates of intravenous tPA use were 3.8% and 10.1% (P < .001) and onset-to-treatment times decreased from 171.7 to 145.7 minutes (P = .03) in the pretriage and posttriage periods, respectively. Stroke unit admission, symptomatic intracranial hemorrhage rates, and in-hospital mortality were not significantly different between periods. Adjusting for mode of arrival, prehospital notification, and onset-to-arrival time, the posttriage period was independently associated with increased tPA use for patients with ischemic stroke presenting through the emergency department (adjusted odds ratio = 2.21; 95% CI, 1.34-3.64). CONCLUSIONS AND RELEVANCE: Implementation of a prehospital stroke triage policy in Chicago resulted in significant improvements in emergency medical services use and prenotification and more than doubled intravenous tPA use at primary stroke centers.