Thrombolytic Therapy Rates and Stroke Severity

Background and Purpose— We tested the hypothesis that higher proportions of patients with minor stroke being treated with thrombolysis contribute to increasing overall rates of thrombolysis. Methods— We included 1743 ischemic stroke patients (age 18–80 years) treated with thrombolysis, recorded in the Swedish stroke register Riks-Stroke between 2007 and 2010. Minor stroke was defined as National Institutes of Health Stroke Scale score ≤5. Results— The proportion with minor stroke among patients treated with thrombolysis increased from 22.1% in 2007 to 28.7% in 2010 ( P =0.021). The rate of increase did not differ significantly between men and women, age groups, or hospital types (university hospitals, other large hospitals, or community hospitals). Hospitals with high proportions of thrombolysis patients with minor stroke were more likely to have high thrombolysis frequencies ( R =0.55; P <0.001). Conclusions— In recent years, an increase in the proportion of patients with minor stroke treated with thrombolysis has contributed to rising overall thrombolysis rates in Sweden. At the hospital level, high rates of thrombolysis are associated with a high proportion of minor stroke being treated.