Preclinical (in vivo) efficacy and safety assessment of the Russian-made Grasper stent retriever

Objective: To evaluate the efficacy and safety profile of the Grasper stent retriever, manufactured in Russia, in a preclinical model of large intracranial vessel occlusion. Furthermore, to determine the impact of clot phenotype and procedural burden on thrombectomy outcomes.

Materials and methods. The study was conducted in vivo on 14 pigs, resulting in 41 episodes of occlusion. Three morphotypes of autologous clots were tested, including red, mixed, and white. Reperfusion was assessed using an adapted TICI (aTICI) scale. First pass effect (FPE) was defined as achieving aTICI 2c-3 after the first pass. Number of passes, puncture-to-reperfusion time, embolization to new territories (ENT), and angiographic vessel injury were analyzed.

Results. FPE (aTICI 2c-3) was achieved in 51.2% of cases. Final successful reperfusion (aTICI 2b-3) was obtained in 100%, with aTICI 2c-3 in 92.7%. No perforations, contrast extravasation, or mortality occurred; dissections (4.9%) were associated with ≥ 4 passes. ENT was observed in 24.4% and was more frequent with ≥ 3 passes (40.0 vs 15.4%). Outcomes were clot-dependent: FPE reached 71.4% for red clots (mean 1.79 passes) versus 23.1% for white clots (3.31 passes; p < 0.05).

Conclusion. The Grasper stent retriever demonstrated high recanalization efficacy with a favorable safety profile. Procedural burden is a key mediator of embolic and vascular complications. The clot phenotype influences the first pass effect and thus should be considered when selecting an initial thrombectomy strategy.

1. Jang KM, Choi HH, Nam TK, Byun JS. Clinical outcomes of first-pass effect after mechanical thrombectomy for acute ischemic stroke: a systematic review and meta-analysis. Clin Neurol Neurosurg. 2021;211:107030. doi: 10.1016/j.clineuro.2021.107030

2. Mueller-Kronast NH, Zaidat OO, Froehler MT, et al. Systematic evaluation of patients treated with neurothrombectomy devices for acute ischemic stroke: primary results of the STRATIS registry. Stroke. 2017;48(10):2760–2768. doi: 10.1161/sTROKEAHA.117.016456.

3. Zaidat OO, Castonguay AC, Linfante I, Gupta R, Martin CO, Holloway WE, et al. First pass effect: a new measure for stroke thrombectomy devices. Stroke. 2018;49(3):660–666. doi: 10.1161/STROKEAHA.117.020315.

4. Almekhlafi MA, Marquering HA, Majoie CB, Liebeskind DS. Thrombolysis in cerebral infarction scoring at the core lab. J Neurosonol Neuroimag. 2018;10(2):95–99. doi: 10.31728/jnn.2018.00031.

5. Memon MZ, Daniel DD, Chaudhry MR, Grewal M, Saini V, Lukas J, et al. Clinical impact of the first pass effect on clinical outcomes in patients with near or complete recanalization during mechanical thrombectomy for large vessel ischemic stroke. J Neuroimaging. 2021;31(4):743–750. doi: 10.1111/jon.12864