Extending the Treatment Window for Intravenous Thrombolysis in Acute Ischemic Stroke: An Updated Systematic Review and Meta-Analysis.

Abstract

BACKGROUND AND OBJECTIVES: Intravenous thrombolysis (IVT) is the standard treatment for acute ischemic stroke within 4.5 hours of onset. However, imaging-based selection may extend the treatment window. This systematic review and meta-analysis evaluated the efficacy and safety of IVT administered beyond 4.5 hours after stroke onset or last known well (LKW) in patients selected based on imaging findings. METHODS: A comprehensive search of PubMed, Scopus, and Cochrane Library was performed to identify randomized controlled trials comparing IVT with alteplase or tenecteplase (TNK) administered >4.5 hours after stroke onset/LKW vs standard care. Primary outcomes were 3-month excellent (modified Rankin Scale [mRS] 0-1) functional outcome and symptomatic intracranial hemorrhage (sICH). Secondary outcomes included good (mRS 0-2) functional outcome, recanalization, and 3-month mortality. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random-effects models. Subgroup analysis assessed differences between alteplase and TNK. RESULTS: Fourteen studies involving 4,944 patients were included. The mean age was 69.8 years, 58.2% were male, the median National Institutes of Health Stroke Scale score was 9, and 12.3% received preplanned endovascular thrombectomy (EVT). A total of 2,492 patients received IVT in an extended time window (4.5-24 hours). Compared with standard care, extended IVT was associated with higher odds of achieving an excellent functional outcome (OR: 1.43 [95% CI 1.25-1.63]), a good functional outcome (OR: 1.25 [95% CI 1.11-1.40]), and recanalization (OR: 3.28 [95% CI 2.09-5.16]). There was no difference in 3-month mortality (OR: 1.21 [95% CI 0.95-1.53]). However, IVT increased the risk of sICH (OR: 2.51 [95% CI 1.47-4.28]). Sensitivity analysis excluding patients who received EVT showed no impact on the outcomes. TNK exhibited similar efficacy to alteplase but showed potentially lower odds of sICH (OR: 1.96, 95% CI 1.06-3.64) compared with alteplase (OR: 5.29, 95% CI 1.80-15.57); however, the subgroup difference was not significant (p = 0.11). DISCUSSION: Among patients selected based on imaging, 4.5-24 hours after stroke onset/LKW, IVT improves outcomes despite an increased risk of sICH. TNK showed similar efficacy to alteplase, with a possible lower risk of sICH; however, direct comparisons in future trials are needed.