Incidence and Predictors of Early Recanalization After Intravenous Thrombolysis

BACKGROUND AND PURPOSE: After the demonstration of efficacy of bridging therapy, reliably predicting early recanalization (ER; ≤3 hours after start of intravenous thrombolysis) would be essential to limit futile, resource-consuming, interhospital transfers. We present the first systematic review on the incidence and predictors of ER after intravenous thrombolysis alone. METHODS: We systematically searched for studies including patients solely treated by intravenous thrombolysis that reported incidence of ER and its association with baseline variables. Using meta-analyses, we estimated pooled incidence of ER, including according to occlusion site, and summarized the available evidence regarding predictors of no-ER. RESULTS: We identified 26 studies that together included 2063 patients. The overall incidence of partial or complete ER was 33% (95% confidence interval, 27-40). It varied according to occlusion site: 52% (39-64) for distal middle cerebral artery, 35% (28-42) for proximal middle cerebral artery, 13% (6-22) for intracranial carotid artery, and 13% (0-35) for basilar occlusion. Corresponding rates for complete ER were 38% (22-54), 21% (15-29), 4% (1-8), and 4% (0-22), respectively. Proximal occlusion and higher National Institute of Health Stroke Scale were the most consistent no-ER predictors. Other factors, such as long or totally occlusive thrombus and poor collateral circulation, emerged as potential predictors but will need confirmation. CONCLUSION: The overall incidence of ER after intravenous thrombolysis is substantial, highlighting the importance of reliably predicting ER to limit futile, interhospital transfers. Incidence of no-ER is particularly high for proximal occlusion and severe strokes. Given the scarcity of published data, further studies are needed to improve no-ER prediction accuracy.