Aspiration tubing diameter is a key determinant of vacuum pressure and is associated with procedural outcome in mechanical thrombectomy for large vessel occlusion: An experimental and cohort study.

BACKGROUND: We (1) evaluated the effect of aspiration tubing diameter on intraluminal pressure and (2) compared thrombectomy outcomes in patients treated using small diameter tubing versus those treated using large diameter vacuum tubing. METHODS: Intraluminal negative pressure was measured in a validated benchtop set up where consistency of negative pressure (inHg) was measured between static and dynamic aspiration. Static aspiration refers to activation of vacuum once the catheter is engaged with the clot. Dynamic aspiration refers to activation of vacuum when the catheter is slightly proximal to the clot. Four different sizes of vacuum tubing were trialed. We performed a retrospective analysis of consecutive patients who underwent mechanical thrombectomy. Procedural and functional outcomes were compared. RESULTS: The large diameter aspiration tubing held a consistent high negative pressure in static and dynamic aspiration (p = 0.152). Tubing types I to III were associated with a significant fall off in negative pressure between static and dynamic technique (p < 0.05). Two-hundred and five patients were included in the retrospective analysis; 124 (60%) underwent thrombectomy using small diameter vacuum tubing, and 81 (40%) using the large tubing. Mean thrombectomy time was shorter with the larger tubing [25.9 (17.9) minutes] versus the small tubing [37.5 (28.5) minutes, p = 0.002]. A greater proportion of patients had a thrombolysis in cerebral infarction score ≥2b in the group treated using the large tubing (78, 99%) than those with the small tubing (96, 78%, p < 0.001). CONCLUSION: Vacuum tubing diameter is linearly associated with intraluminal aspiration pressure. These findings have clinical significance as shown by increased recanalization rates and decreased thrombectomy times when large-diameter aspiration tubing is used. Shifting the paradigm toward a flow-based technique using large-bore vacuum tubing ought to be considered.

Push and Fluff technique for optimization of clot integration with stent-retriever: An in vitro model.

BACKGROUND: For stent-retriever (SR) thrombectomy, technical developments such as the Push and Fluff technique (PFT) appear to have a significant impact on procedural success. This study aimed to (1) quantify the enhancement in clot traction when using PFT as compared to the standard unsheathing technique (SUT) and (2) to evaluate the performance of PFT in new versus established users of the technique. METHODS: Operators were divided between established PFT and SUT users. Each experiment was labeled according to the SR size, utilized technique, and operator experience. A three-dimensional-printed chamber with a clot simulant was used. After each retriever deployment, the SR wire was connected to a force gauge. Tension was applied by pulling the gauge until clot disengagement. The maximal force was recorded. RESULTS: A total of 167 experiments were performed. The median overall force to disengage the clot was 1.11 pounds for PFT and 0.70 pounds for SUT (an overall 59.1% increment with PFT; p < 0.001). The PFT effect was consistent across different retriever sizes (69% enhancement with the 3 × 32mm device, 52% with the 4 × 28mm, 65% with the 4 × 41mm, 47% with the 6 × 37mm). The ratio of tension required for clot disengagement with PFT versus SUT was comparable between physicians who were PFT versus SUT operators (1.595 [0.844] vs. 1.448 [1.021]; p: 0.424). The PFT/SUT traction ratio remained consistent from passes 1 to 4 of each technique in SUT users. CONCLUSION: PFT led to reproduceable improvement in clot engagement with an average ∼60% increase in clot traction in this model and was found not to have a significant learning curve.