On- versus Off-Hour Patient Cohorts at a Primary Stroke Center: Onset-to-Treatment Duration and Clinical Outcomes after IV Thrombolysis

David Asuzu, Karin Nyström, Hardik Amin, Joseph Schindler, Charles Wira, David Greer, Nai Fang Chi, Janet Halliday, Kevin N. Sheth

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Background The symptom onset-to-treatment (OTT) duration predicts symptomatic intracerebral hemorrhage (sICH) and adverse outcomes after ischemic stroke. Previous studies found disparities in OTT durations and clinical outcomes between stroke patients with symptom onset during on-hours versus off-hours, which led to the initiation of nationwide efforts to provide consistent 24-hour stroke care. Goal Our objective is to compare OTT durations and clinical outcomes in ischemic stroke patients whose symptoms originated during on- versus off-hours at a primary stroke center. Methods We analyzed clinical data from 210 consecutive patients receiving intravenous recombinant tissue plasminogen activator therapy between January 2009 and December 2013 at Yale-New Haven Stroke Center, a primary stroke center. Stroke severity was assessed by baseline National Institutes of Health Stroke Scale (NIHSS) scores. Clinical outcomes were assessed by presence of sICH and by stroke-related fatalities. OTT durations and clinical outcomes were compared using Mann-Whitney tests, 2-sample tests of proportions, and 2-sample t-tests after testing for equal variance. Findings We found no significant differences in OTT durations between on-hour and off-hour patient cohorts (137 minutes versus 145 minutes, P =.53). There were also no differences in stroke severity (mean NIHSS score 12.4 versus 11.3, P =.27), sICH rates (4.6% versus 6.5%, P =.56), or stroke fatality rates (9.2% versus 9.8%, P =.89) between the 2 cohorts. Conclusions Our results represent progress in emergency response and acute stroke care, and reinforce ongoing nationwide efforts to increase stroke awareness and provide consistent quality care for patients with acute stroke.

Original languageEnglish
Pages (from-to)447-451
Number of pages5
JournalJournal of Stroke and Cerebrovascular Diseases
Issue number2
Publication statusPublished - Feb 1 2016


  • IV thrombolysis
  • Ischemic stroke
  • acute stroke care
  • onset to treatment

ASJC Scopus subject areas

  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine
  • Rehabilitation
  • Surgery


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