Thrombolysis candidates for the treatment of stroke at an emergency department in Japan

Objectives: To study the proportion and characteristics of potential candidates for the intravenous administration of tissue plasminogen activator (IV-tPA) among patients with cerebral infarction in a Japanese emergency department (ED). Methods: A retrospective observational study was performed using patients who had been transported by ambulance between August 1988 and April 2000 to an urban ED of a university hospital located in the Tokyo metropolitan area. Potential candidates for IV-tPA were identified using the criteria of the National Institute of Neurological Disorders and Stroke (NINDS) study. Results: Of all 30,064 patients transported by ambulance, 526 were diagnosed as having cerebral infarction. Among them, 190 patients arrived at the ED within two hours of symptom onset (early ED arrivers). In comparison of their demographics with late ED arrivers (n = 319), atrial fibrillation, male gender, and consciousness disturbance were related with early ED arrivers, while aging and diabetes were related with late ED arrivers. As to the stroke subtype, patients with an embolic infarction accounted for 76.8% among early ED arrivers. Application of exclusion criteria identified 114 patients, who were suitable for the thrombolysis treatment, indicating that the proportion of potential IV-tPA candidates was 21.7% among all cerebral infarction patients and 0.38% among all ED patients. Conclusions: The number of potential IV-tPA candidates among patients transported to the ED by ambulance in Japan was substantial, where the proportion of embolic infarction cases was extremely high.