Fast Stent Retrieval Improves Recanalization Rates of Thrombectomy: Experimental Study on Different Thrombi

Abstract

BACKGROUND AND PURPOSE: About 20% of patients with acute ischemic stroke due to large-artery occlusion do not achieve recanalization with mechanical thrombectomy. We aimed to determine whether the speed of retrieval of the stent retriever influences the efficacy in removing different clot types.MATERIALS AND METHODS: Sixty mechanical thrombectomies were performed using an in vitro pulsatile cerebrovascular circulation model with controlled pressure and flow rate. Experiments were dichotomized into fast and slow retrieval using a wedging technique, in which the stent retriever and distal catheter are retrieved together. We used 3 different clot types: erythrocyte-rich, fibrin-rich, and friable clots. Primary end points were complete (TICI 3) and successful (TICI 2b-3) recanalizations. Secondary measures were distal and new territory embolizations.RESULTS: Fast retrieval was more frequently associated with complete (RR ¼ 1.83; 95% CI, 1.12-2.99) and successful recanalization (RR ¼ 1.50; 95% CI, 1.03-2.19) than slow retrieval, without a difference in distal embolization (RR ¼ 0.75; 95% CI, 0.29-1.90). There were no emboli in a new territory. The advantage of fast retrieval over slow retrieval differed according to the clot composition, with a stronger effect with fibrin-rich clots with regard to complete (RR ¼ 4.00; 95% CI, 1.11-14.35; Pint ¼ .04) and successful (Pint ¼ .10) recanalization. CONCLUSIONS:In our experimental model, a fast removal improved recanalization rates of mechanical thrombectomy, especially in the case of fibrin-rich clots. An in vivo confirmation is warranted to see whether our findings can have an impact in clinical practice. ABBREVIATIONS: DC ¼ distal catheter; MT ¼ mechanical thrombectomy; RR ¼ relative risk; Pint ¼ P interaction; RBC ¼ red blood cell; SR ¼ stent retriever M echanical thrombectomy (MT) is considered the first-line therapy for selected patients with acute ischemic stroke with a proximal cerebral artery occlusion. [1][2][3] The dramatic technological improvements, such as the combined use of stent retrievers (SRs) and distal catheters (DCs), have led to recanalization rates unreached before. 4,5 With the goal of increasing clot entrapment, techniques in which the thrombus is wedged between the SR and DC have become more popular. [6][7][8] Nevertheless, a successful

Fast Stent Retrieval during Mechanical Thrombectomy Improves Recanalization in Patients with the Negative Susceptibility Vessel Sign

“…5 Moreover, in an in vitro model, when one used a fast retrieval, the extraction of fibrin-rich clots was 4 times greater. 10 This result was confirmed by our in vivo study in which reaching a complete first-pass recanalization (first-pass effect) was 4 times greater with a fast retrieval. Although a first-pass effect is infrequently obtained (20%-35% of patients), it is associated with improved clinical outcome, reduced adverse effects, and decreased mortality.…”

“…A fast retrieval may mobilize the clot suddenly, enhance clot wedging, and minimize loss of apposition during retrieval. 10 The present study aimed to evaluate whether stent-retrieval speed influences recanalization rates and clinical outcome in patients presenting with negative SVS clots.…”

“…9 Recent in vitro experiments have shown that fast retrieval of the clot using a combined technique (contact aspiration 1 stent retriever) can improve recanalization, especially with fibrin-rich clots. 10 Currently, device manufacturers' instructions advise operators to withdraw stent retrievers slowly to avoid potential artery dissection or rupture. Yet, the effect of retrieval speed on mechanical thrombectomy success in vivo has yet to be explored.…”

Thrombus Composition and Efficacy of Thrombolysis and Thrombectomy in Acute Ischemic Stroke

“…37 However, Soize et al found an improvement in recanalization rates using fast compared to slow retrieval. 115 Fast retrieval quickly mobilized the clot which allowed for a higher pulling force. While fast retrieval seems promising in terms of recanalization, perforating arteries cannot be modelled accurately, and the likelihood of damage remains unclear.…”

Novel synthetic clot analogs for in-vitro stroke modelling

“…White clots present with lower attenuation on non-contrast-enhanced CT and increased resistance to both intravenous lysis and mechanical thrombectomy [23]. Technical aspects of MT such as speed retrieval [24] or device selection [15] may be improved based on clot composition [20,23,25]. Namely utilization of stent retriever in MT seems to be less effective in the case of calcified thromboemboli [26].…”