A case-control study of tissue plasminogen activator for acute ischemic stroke

Background: Randomized trials demonstrate that intravenous tissue plasminogen activator (tPA) improves outcome in acute ischemic stroke (AIS). To assess translation of this efficacy into effectiveness in routine clinical practice we performed a case-control study of tPA treatment for AIS in a single hospital. Methods: 151 tPA-treated AIS patients (1996-2005) were matched 1:1 with blinding to outcome to controls from a prospective registry based on age, gender, pre-stroke Oxford handicap scale (OHS), stroke severity, and subtype. The outcomes were in-hospital death, symptomatic intracranial hemorrhage (SICH), length-of-stay (LOS), discharge OHS and long-term survival. Results: In-hospital mortality (23% vs. 24%) or long-term survival (median follow-up of 2 years) was not different between cases and controls (p=0.83). SICH occurred in 7.8% (95% CI 4.2-13.5%) of tPA-treated patients. Median LOS was non-significantly shorter for cases (13 [7-29] vs. 16 [8-32] days, p=0.14) but significantly shorter in tPA-treated vs. non-treated women (14 [7-28] vs. 20 [11-34] days, p=0.04). At discharge 6.6% (95% CI 1.1-12.0%) more tPA-treated patients than controls had no disability (OHS ≤1, p=0.02). However, there was no difference in discharge independence rates or proportion discharged home. Conclusion: We demonstrate minor improvements in early recovery after stroke with tPA but the impact is less dramatic than that reported in randomized trials. This may relate to timing of treatment and the type of patients treated.