Experimental Evaluation of the Risk of Distal Embolization during Endovascular Clot Retrieval Using Various Techniques

BACKGROUND: This study was conducted to evaluate various devices and techniques for endovascular thrombectomy that can reduce the risk of intraprocedural distal embolism in a preliminary in vitro setting with different types of thrombi. MATERIALS AND METHODS: Endovascular clot retrieval was performed in a vascular model with collateral circulation. White and red thrombi were prepared using whole blood collected from a pig. A Direct Aspiration First Pass Technique (ADAPT), simple stentretrieving with and without proximal flow arrest by a guiding balloon (SR [B+] and SR [B±]), the AspirationRetriever Technique for Stroke (ARTS), and A stentretrieving into an Aspiration catheter with Proximal balloon (ASAP) were performed three times, respectively. The saline samples that were collected at the distal side during each procedure were examined using a particle counter. The particles were counted and categorized into three groups based on size (100 μm). RESULTS: SR (B−) and SR (B+) could not achieve complete retrieval of the clot, especially using the white thrombus. ASAP was the only method that was able to retrieve the clots in all attempts. In both clot types, SR (B−), SR (B+), and ARTS, which involved a temporary flow restoration through stent deployment, demonstrated the migration of a greater number of particles measuring >100 μm in size than that shown by ADAPT and ASAP. CONCLUSIONS: ASAP was the safest method in terms of intraprocedural clot migration among the five methods evaluated in this study. Temporary flow restoration through stent deployment may affect the dangerous distal clot migration.