Introduction Improved recanalization rate and immediate flow restoration have been achieved by the latest clot retrieval (thrombectomy) systems in the acute ischemic stroke treatment. However, clot debris generated during mechanical thrombectomy can result in distal embolization. We hypothesise that the catheterization strategies (type and position of the suction catheter) affect the risk of distal embolization
Materials and methods Hard fragment-prone clots (HFC) and soft elastic clots (SEC) were used to create MCA occlusions in the vascular phantom which included collateral circulation via PComA and ACA. Three different treatment strategies using stentrievers (Solitaire FR) included 1) Proximal flow control with an 8Fr balloon guide catheter (BGC) at the cervical ICA, 2) Thromboaspiration via a 5Fr intracranial guide catheter (IGC) in the origin of the MCA, and 3) Thrombectomy through a 6Fr guide catheter (GC) with the tip placed at the carotid-ophthalmic bifurcation (n = 8 per group). Characterization of the emboli smaller than 1000 µm was conducted by using the Coulter Principle. The primary endpoint was the number and size of the clot fragments generated during the procedure and the secondary endpoint was the flow recanalization rate
Results The figure (top) shows the MCA occlusion model with the flow direction (blue arrows). A 5Fr IGC was used in this representative case. Approximately 45% to 60% of the clot debris was presented in the previously unaffected area (ACA), depending on the clot size range (figure, bottom). Similar findings were observed in the BGC and GC with different particle distribution. The results indicated that distribution of clot fragments was not dependent on the treatment strategy. IGC versus BGC technique efficacy appeared to depend on clot mechanics. IGC was the most efficient method for reducing HFC fragments (p < 0.05) among all 3 treatments; whereas, BGC was the best method for preventing SEC fragmentation (p < 0.05). There was a significant increase in the number of particles having a diameter between 8 and 200μm generated during thrombectomy using the SEC as compared to the HFC. The Solitaire FR devices achieved a 100% flow restoration in all cases. The average thrombectomy attempt was 1.1, 1.0 and 1.4 for BGC, IGC and GC, respectively.
Conclusion Efficient clot retrieval observed in the IGC group implied that aspiration location was related to suction efficacy. Successful clot removal with BGC revealed that temporary flow arrest during clot removal and use of large bore catheter minimised the chance of distal embolization.
Disclosures J. Chueh: None. A. Puri: None. A. Wakhloo: 1; C; NIH, Philips Healthcare. 2; C; Stryker Neurovascular. M. Gounis: 1; C; eV3/Covidien, Philips Healthcare, NIH, Silk Road, Stryker Neurovascular. 2; C; fee-per-hour: Stryker Neurovascular, fee-per-hour: Codman Neurovascular.