Risk factors for intracranial hemorrhage after mechanical thrombectomy: a systematic review and meta-analysis

<b>Background</b>: Intracerebral hemorrhage (ICH) is the most feared complication of mechanical thrombectomy (MT). This study aims to provide a comprehensive overview of ICH risk factors. <b>Methods</b>: The authors systematically searched Pubmed and Embase (from inception to November 2018) for studies evaluating independent predictors for symptomatic ICH (sICH), parenchymal hematoma (PH), hemorrhagic infarction (HI), and any ICH after MT. <b>Results</b>: This analysis included a total of 42 studies involving 10,001 patients. The combined rate was 8% (7–10%) for sICH, 13% (10–15%) for PH, 25% (20–29%) for HI, and 35% (31–39%) for any ICH. Meta-analysis identified the following predictors of sICH: female sex (OR 2.98, 95%CI 1.23–7.25, I² = 26.3%), treatment interval (OR 1.01, 95%CI 1–1.03, I² = 69.20%), tirofiban use (OR 3.16, 95%CI 2.11–4.73, I² = 0%), and ASPECTS score on admission (OR 0.63, 95%CI 0.54–0.74, I² = 0%). Predictors of any ICH were diabetes mellitus (OR 1.95, 95%CI 1.29–2.94, I² = 35.7%), deep white matter on diffusion-weighted imaging (OR 3.11, 95%CI 1.56–6.20, I² = 0%), and intravenous recombinant tissue plasminogen activator (rt-PA) (OR 2.57, 95%CI 1.28–5.17, I² = 0%). <b>Conclusion</b>: Many predictors of ICH were identified, however, given the lack of robust evidence, larger cohort studies should be prioritized to confirm these predictors.