Evaluation of using a double helical, closed-cell stent-retriever (Skyflow) for thrombectomy procedures in acute arterial occlusion: A preclinical study and a clinical trial

Abstract

Background and purpose: Stent retriever thrombectomy is the standard therapeutic approach for ischemic stroke with acute large-vessel occlusion. This study evaluated the safety and efficacy of a new thrombectomy device (Skyflow) in the treatment of acute ischemic stroke.

Methods: After an arterial occlusion model was established, stent-retriever thrombectomy was performed. Digital subtraction angiography (DSA) and autopsy were carried out immediately after thrombectomy in six animals in the acute experimental group. Simulated stent-retriever thrombectomy was performed for three animals in the subacute experimental group, and follow-up angiography and vascular pathological examination were assessed 90 days after the operation. In the clinical trial, 192 patients with intracranial anterior circulation large vessel occlusion, within 8 ​h of symptom onset, were included to undergo thrombectomy with either Skyflow or Solitaire FR stent retriever. Efficacy and safety endpoints were recorded (including successful reperfusion, favorable clinical outcomes, time from puncture to reperfusion, instrument operation success rates and National Institutes of Health Stroke Scale (NIHSS) scores at 7 days for efficacy endpoints, and symptomatic intracranial hemorrhage (sICH), subarachnoid hemorrhage (SAH) and all-cause mortality rates for safety endpoints).

Results: All blood vessels achieved successful recanalization in the animal models. In the clinical trial, successful recanalization was attained in 88.4% of patients of the Skyflow group, which was comparable to that of the Solitaire FR group (82.5%) in the full analysis set of the clinical trial. There were no severe complications on DSA, an animal autopsy, or vessel pathological examination in animal experiments. Additionally, no statistically significant difference was observed between the Skyflow and Solitaire FR groups in the clinical trial regarding the safety endpoints.

Conclusion: This study showed that the new Skyflow stent retriever is safe and effective for the treatment of acute large vessel occlusion, as demonstrated in our animal study and human trial.

Keywords: Acute ischemic stroke; Efficacy; Safety; Skyflow stent-retriever; Thrombectomy.

Fig. 1

Diagram of the Skyflow device. A large mesh in the middle and small meshes in the proximal and distal parts of the stent as well as a double helical structure are highlighted in Panel A. Integral stent retriever structure is shown in Panel B. Pushing wire (L1) with a variable-diameter structure coiled with platinum alloy coil in the distal part (L2). The diameters of the stent were 3 ​mm for TD320; 4 ​mm for TD420, TD430, and TD440; and 6 ​mm for TD620 and TD630 (D). The stent retriever’s effective lengths were 20 ​mm for TD320, TD420, and TD620; 30 ​mm for TD430 and TD630; and 40 ​mm for TD440 (L). The radiopaque platinum alloy is shown in M.

Fig. 2

Acute experiment of a swine model undergoing thrombectomy with the Skyflow stent retriever. (A) Digital subtraction angiograms (DSAs) showing the right subclavian ascending branch artery clot embolization. (B) Skyflow stent retriever deployment in the occluded segment of the artery through the microcatheter. (C) Angiogram showing complete recanalization of the occluded artery after the first pass of thrombectomy.

Fig. 3

Vessel pathology of the left common carotid artery in an animal of the subacute experimental group. No inflammatory cell infiltration, thrombosis, tear, or dissection in the untreated segment (A) and distal (B), middle (C), and proximal (D) parts of the thrombectomy segments. Endothelial cells on the lumen surface were intact for all vessel segments.

Fig. 4

DSA of a patient undergoing thrombectomy using Skyflow device. (A) left middle cerebral artery (LMCA) occlusion before thrombectomy. (B) The stent was well deployed and expanded (arrows, radiopaque markers of the stent), and there was blood flowing through the occlusive segment. (C) The LMCA was completely recanalized after stent removal (TICI 3).