“Is larger always better?” An in vitro comparison of cyclical and static aspiration with different catheters in a neurovascular flow model

BACKGROUND: Recent advances in mechanical thrombectomy for large vessel occlusion suggest that cyclical aspiration (CyA) may enhance clot ingestion and reduce embolic complications compared with static aspiration (StA). We aimed to identify the experimental conditions under which CyA outperforms StA. METHODS: A 3D-printed neurovascular model in a flow loop (137/89 mmHg, 72 bpm) simulated middle cerebral artery M1 segment (MCA-M1) occlusions with soft and stiff clot analogs. CyA (4.5 Hz and Δp=85-105 kPa) was performed with a dual-solenoid device coupled to a vacuum pump. Eighty experiments were randomized into four treatment arms combining aspiration patterns and 0.071″ and 0.088″ aspiration catheters: CyA-71, CyA-88, StA-71, and StA-88. RESULTS: The overall first pass recanalization (FPR) rate was 74% (59/80), with CyA significantly outperforming StA (92% vs 55%, p<0.001). CyA achieved the highest FPR with both 0.088″ and 0.071″ catheters (95% and 90%, respectively), whereas StA-71 achieved 80% and StA-88 30%.Induction of vessel collapse markedly reduced FPR rates (86.2% without collapse vs 20% with collapse, p<0.001). Under StA, collapse was more frequent with larger catheters (StA-088: 70% vs StA-71: 0%, p<0.001), but CyA significantly mitigated this effect (StA-88: 70% vs CyA-88: 5%, p<0.05). No significant differences were found in distal embolization rates. CONCLUSIONS: 0.088″ catheters may be more effective for retrieving clots, except in cases of arterial collapse. CyA improves recanalization rates by reducing the risk of collapse associated with super-large bore catheters. A deeper understanding of catheter sizing and neurovascular anatomy could further optimize outcomes.