Abstract 17: Hospital Variation in Thrombolysis Times in Acute Ischemic Stroke Patients: the Contributions of Door-to-Imaging Time and Imaging-to-Needle Time
Background: Given the limited time window available for treatment with tPA in acute ischemic stroke patients, guidelines recommend door-to-imaging time within 25 minutes of hospital arrival and a door-to-needle time (DTN) within 60 minutes. Despite temporal improvements in door-to-image and DTN, tPA treatment times remain suboptimal.
Objectives: To examine the contributions of door-to-image and imaging-to-needle times to delays in timely delivery of tPA to ischemic stroke patients, and to examine between-hospital variation in DTN.
Methods: A cohort analysis of 1,193 ischemic stroke patients treated with intravenous tPA from 2009-2012 at 25 Michigan hospitals participating in the Paul Coverdell National Acute Stroke Registry. The primary outcome was DTN (time in minutes from emergency department arrival to tPA delivery). Multi-level linear regression models included hospital-specific random effects.
Results: Mean patient age was 68 years, median NIHSS score was 11 (IQR 6-17), 51% were female, and 37% were nonwhite. Mean DTN was 82.9 ±35.4 minutes, mean door-to-imaging time was 22.8 ±15.9 minutes and mean imaging-to-needle time was 60.1 ±32.3 minutes. A majority of patients had door-to-imaging within 25 minutes (68.4%) but only a minority had DTN within 60 minutes (28.7%). At the patient level door-to-imaging time was only modestly correlated with DTN (r= 0.41), conversely image-to-needle time was strongly correlated with DTN (r= 0.89) (figure). In the multi-level model the hospital random effect accounted for only 12.7% of variability in door-to-needle time. Neither annual stroke volume nor primary stroke center designation was a significant predictor of better DTN. Patient factors (age, race, sex, arrival mode, onset-to-arrival time, and stroke severity) explained 15.4% of the between-hospital variation in DTN. After adjustment for patient factors, door-to-imaging time explained only 10.8% of the variation in hospital risk-adjusted DTN, while imaging-to-needle time explained 64.6%.
Conclusion: Compared to door-to-imaging time, imaging-to-needle time was more closely correlated with DTN and a much greater contributor to variability in hospital door-to-needle times. More attention to systems changes that can decrease imaging-to-needle time for acute ischemic stroke patients is now needed.
Author Disclosures: K. Sauser: None. D.A. Levine: None. A.V. Nickles: None. M.J. Reeves: None.
- © 2014 by American Heart Association, Inc.