Can the clot meniscus and claw signs predict thrombectomy and clinical outcomes in patients with stroke? A systematic review and meta-analysis

Background The angiographic shape of an occlusion, like the clot meniscus sign and the claw sign, has been reported to potentially impact the recanalization rate and clinical outcome in patients undergoing mechanical thrombectomy for acute ischemic strokes. Method Following PRISMA guidelines, a systematic literature search was conducted across PubMed, Scopus, Embase and Web of Science databases. Patients were grouped into clot meniscus/claw sign positive and negative groups based on the definitions obtained from each study. Primary outcomes included technical success, with a meta-analysis performed using a random-effects model to calculate proportions and odds ratios (OR) with 95% confidence intervals (Cl). Results We included seven studies recruiting 1572 patients. The results indicated that the positive and negative groups had comparable first-pass effect (OR 1.95; 95% CI 0.76 to 5.01; P=0.167) and final recanalization (OR 1.36; 95% CI 0.81 to 2.27; P=0.248) rates. However, the rate of having a favorable functional outcome was significantly higher in the positive group than in the negative sign group (OR 1.91; 95% CI 1.25 to 2.92; P<0.003). Within the sign-positive population, the use of contact aspiration was associated with a significantly higher rate of recanalization compared with using a stent retriever (OR 0.18; 95% CI 0.07 to 0.49; P<0.001). This result did not translate into a clinical impact, as both stent retriever and contact aspiration showed comparable rates of functional independence at 3 months (OR 0.22; 95% CI 0.02 to 2.33; P=0.210). Conclusion The presence of the clot meniscus/claw sign is not associated with recanalization outcomes after thrombectomy. However, it might be a good sign to predict which thrombectomy technique might be associated with better recanalization, although current evidence may need further confirmation.