Investigation of Current and Super‐Bore 088″ Treatment Strategies of Soft and Stiff Clots at Internal Carotid Artery and Middle Cerebral Artery Occlusion Sites in an In Vitro Thrombectomy Model

Background: Various mechanical thrombectomy devices including stent retrievers (STRs), contact aspiration (CA) catheters, and balloon guide catheters (BGCs) are used in both isolation and combination for the treatment of acute ischemic stroke. A new generation of Super-Bore 088″ aspiration catheters are being trialed clinically. We evaluated the in vitro revascularization performance of current and novel thrombectomy approaches in treating soft (red blood cell-rich) and stiff (fibrin/platelet-rich) clots at internal carotid artery (ICA) and middle cerebral artery (MCA) occlusion sites. Methods: National University of Ireland Galway Research Ethics Committee approved the study. Two human blood clot phenotypes were used to form ICA-terminus (20-mm) and MCA-M1 segment (10-mm) occlusions in an in vitro thrombectomy model. Thrombectomy setups tested were CA: Millipede 088, SOFIA Plus+conventional guide catheter, SOFIA Plus+BGC and C ombination; Millipede 088+STR, SOFIA Plus+BGC+STR, SOFIA Plus+conventional guide catheter+STR. Ten replicates of each experiment were performed totaling 120 tests. Revascularization endpoints were first-pass effect, final modified Thrombolysis in Cerebral Infarction (mTICI) 2c/3, and procedural-related distal emboli. Results: Millipede 088 CA achieved the highest first-pass effect rate in ICA-terminus (60%) and MCA-M1 segment (100%) occlusions and lowest number of procedural-related distal emboli compared with all other device setups, followed by the combined Millipede 088+STR technique. Amongst the conventional techniques, higher first-pass effect rates were observed with the combined technique using a BGC (40%) than 6F CA (20%) in ICA-terminus occlusions whereas the reverse was seen in MCA-M1 segment occlusions, with 6F CA performing better than combined approaches (60% versus 50%). BGCs may provide a revascularization benefit in ICA-terminus occlusions. Rates of first-pass effect and final mTICI 2c/3 were better for stiff clots compared with soft clots for all treatment approaches at both occlusion sites. Conclusion: Millipede 088 CA was the most effective technique for all clot types and occlusion locations. Across conventional techniques, CA seems to be more effective in MCA-M1 segment occlusions, while the combined technique performed better in ICA occlusions. Clot composition influences the success of each technique.