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.