Background: There is controversy regarding the optimal size of stent retriever for achieving timely recanalization in acute ischemic stroke patients.
Objective: To determine the relationship between stent retriever diameter and procedure time, and rates of recanalization, and functional independence among acute ischemic stroke patients undergoing mechanical thrombectomy.
Methods: We analyzed data from consecutive acute ischemic stroke patients treated with mechanical thrombectomy derived from a prospective database. Baseline demographic and clinical characteristics, NIHSS score on admission and discharge, intracranial hemorrhage occurrence, and mRS at discharge were analyzed. Thrombolysis In Cerebral Infarction (TICI) scale was used to grade pre and post procedure angiographic recanalization. Procedural time was defined by the time interval between microcatheter placement and recanalization. We compared the rates of thrombectomy attempts, complete recanalization (TICI grade of 3), and functional independence (defined by mRS 0-2) between patients treated with 6 mm and 3-4 mm diameter stent retrievers.
Results: A total of 230 acute ischemic stroke patients (mean age 71.8 ±12.5; 46.6% women) were treated with stent retrievers. Thrombectomy was performed with a 6mm diameter stent retriever in 107 patients and 3 or 4 mm diameter stent retriever in 123 patients. There were no statistically significant differences in demographics or baseline characteristics, or admission NIHSS score between the two groups. There was a trend towards a fewer number of thrombectomy attempts required with a 6mm diameter stent retriever (p=0.06). There was a higher rate of complete recanalization in patients treated with 6mm diameter stent retriever compared with 3 or 4 mm diameter stent retriever (72% vs 57.7% p=0.02). There was no statistically significant difference in rates of functional independence between the two groups (24.3% vs 25.2% p=0.84) at discharge.
Conclusion: Among acute ischemic stroke patients undergoing mechanical thrombectomy, use of a 6 mm diameter stent retriever was associated with a higher rate of complete recanalization and a lower number of thrombectomy attempts compared with 3-4 mm diameter stent retrievers.