Is time really brain in stroke therapy?: A meta-analysis of mechanical thrombectomy up to 155 h post ictus

Background and objectives: Mechanical thrombectomy (MT) has been established as the gold standard of treatment for patients with Acute Ischemic Stroke (AIS) who present up to 6 h after the onset of the stroke. Recently, the DEFUSE-3 and DAWN trials established the safety of starting the MT procedure up to 16 and 24 h after the patient was last seen well, respectively. The purpose of this study is to assess the safety and functional effects of thrombectomy in individuals with AIS detected at a late stage (> 24 h).

Materials and methods: PubMed, Web of Science, Embase, and Cochrane databases were thoroughly searched for research on MT in patients in the extremely late time window after AIS. The primary outcomes were symptomatic cerebral hemorrhage, 90-day mortality, Thrombolysis in Cerebral Infarction (TICI) 2b-3, and Modified Rankin Scale (mRS) 0-2.

Results: Our study included fifteen studies involving a total of 1,221 patients who presented with AIS and an extended time window. The primary outcome of interest was the favorable functional outcome, mRS 0-2 at 90 days. The pooled proportion for this outcome was 45% (95% confidence interval 34-58%). Other outcomes included the TICI 2b or 3 (successful recanalization), which was reported in 12 studies and had a 79% incidence in the study population (95% CI 68-87%). Complications included: symptomatic intracranial hemorrhage (sICH), which revealed an incidence of 7% in the study population (95% CI 5-10%); and 90-day mortality, which reported a 27% incidence (95% CI 24-31%). In addition, we conducted a comparative analysis between endovascular treatment and standard medical therapy.

Conclusion: Our meta-analysis provides evidence that supports the need of further randomized and prospective clinical trials to better assess the effectiveness and safety of MT in these patients.