Mechanical Thrombectomy in Acute Embolic Stroke
Preliminary Results With the Revive Device
Background and Purpose—The purpose of this study was to evaluate the safety and technical feasibility of a new thrombectomy device (Revive; Micrus Endovascular) in the endovascular treatment of acute ischemic stroke.
Methods—Ten patients with acute large vessel occlusions were treated with the Revive device between October 2010 and December 2010. Mean National Institutes of Health Stroke Scale on admission was 19.0; mean duration of symptoms was 172 minutes. Recanalization was assessed using the Thrombolysis In Cerebral Infarction score. Clinical outcome (National Institutes of Health Stroke Scale) after thrombectomy was determined on Day 1, at discharge, and at Day 30.
Results—Vessel recanalization (Thrombolysis In Cerebral Infarction 2b or 3) was successful in all patients without device-related complications. Mean National Institutes of Health Stroke Scale 24 hours after the intervention, at discharge, and at Day 30 was 14.0, 11.5, and 5.1, respectively. At Day 30, 6 patients had a clinical improvement of >8 points or an National Institutes of Health Stroke Scale of 0 to 1, 1 patient showed minor improvement, and 3 patients had died. Symptomatic intracranial hemorrhage occurred in 2 patients, of which 1 was fatal.
Conclusions—Thrombectomy with the Revive device in patients with stroke with acute large vessel occlusions demonstrated to be technically safe and highly effective. Clinical safety and efficacy have to be established in larger clinical trials.
The Revive system (FAST Self-Expanding Basket Thrombectomy Device; Micrus Endovascular, San Jose, CA) is a new, European-conformity-marked self-expanding stent for intracranial thrombectomy. The main technical innovation is a closed basket at the distal end of the stent to enhance clot removal (Figure). The deployed stent has a length of 22 mm and a maximum diameter of 4.5 mm and can be delivered through a 0.021-inch microcatheter. We report first procedural and clinical results with the Revive device.
Patient Selection and Acute Stroke Management
Ten patients (mean age, 78.3±6 years) with acute thromboembolic stroke were treated with the Revive device between October 2020 and December 2010 (Table 1). Mean National Institutes of Health Stroke Scale (NIHSS) on admission was 19.0; mean duration of symptoms on admission was 172 minutes.
Selection criteria for endovascular treatment were: NIHSS ≥7, large vessel occlusion, and absence of hemorrhage and extensive ischemia (more than one third of the middle cerebral artery territory) on CT.
Bridging intravenous fibrinolysis was started immediately within 4.5 hours in middle cerebral artery occlusions (n=4) and within 6 hours in terminal internal carotid artery or basilar artery occlusions (n=5) according to internal treatment guidelines. Additional intra-arterial lyses were performed in 2 cases. Intravenous GP2b3a antagonist was given in cases of prolonged thrombectomy (>5 passes, n=2) and in 1 patient who needed stenting of a high-grade internal carotid artery stenosis to get access to a M1/2 occlusion. Patients received no heparin. Mechanical thrombectomy alone was performed outside the mentioned time windows (n=1).
Interventions were performed under general anesthesia. An 8-Fr guiding catheter was placed into the target artery and a 6-Fr catheter (Neuron; Penumbra) was advanced close to the occluded segment. Subsequently, a 0.027-inch microcatheter (Rebar; ev3), running on a 0.016-inch microwire (Terumo GT) was advanced through the occluded vessel segment. Angiographic runs were performed through the microcatheter to document the proper position of the microcatheter tip distal to the thrombus.
The Revive device was subsequently positioned to cover the entire length of the occlusion with the distal tip at least 1 cm beyond the end of the occlusion. The device was deployed by pulling back the microcatheter and angiographic runs were taken to control for flow restoration. The device was kept deployed for 3 to 5 minutes and was withdrawn under continuous aspiration through the Neuron catheter. Thrombectomy was repeated in case of persistent occlusion or incomplete vessel recanalization. Besides the Revive device, no additional endovascular tools were applied.
Successful recanalization of the occluded vessel segment was defined as a Thrombolysis In Cerebral Infarction score of 2b or 3. Patient neurological status was scored with the NIHSS immediately after extubation or at Day 1, at discharge, and at Day 30 by an independent stroke neurologist (P.A.R.). Control CT scans were assessed for infarct size and hemorrhage. Symptomatic intracranial hemorrhage was defined as a ≥4-point NIHSS decline or death.
Technical Feasibility, Safety, and Angiographic Outcome
Interventions were started after a mean of 94 minutes (range, 34 to 150 minutes) after admission. Recanalization of the occluded segment (Thrombolysis In Cerebral Infarction 2b or 3) with the Revive device was successful in all patients (Table 2). There were no complications related to the use of the device.
Mean NIHSS 24 hours after the intervention, at discharge, and at Day 30 was 14.0 (range, 0 to 42), 11.5 (0–34), and 5.1 (0–12), respectively (Table 2). At Day 30, 6 patients had a clinical improvement of >8 points (n=4) or an NIHSS of 0 to 1 (n=2). One patient had minor clinical improvement and 3 patients had died. Of these, 2 deaths were directly related to stroke (1 reperfusion bleeding, 1 brain stem infarction), and 1 patient died due to complicated pneumonia despite good neurological recovery.
Two patients developed a complete territorial infarction. Seven individuals had minor infarctions (less than one third middle cerebral artery territory, n=2, basal ganglia, n=5) and 1 patient had no signs of cerebral ischemia on follow-up imaging. Symptomatic intracranial hemorrhage occurred in 2 patients (Table 2).
In this preliminary trial, the Revive device proved to be technically safe and highly effective. Complete recanalization was achieved in all patients and favorable clinical outcome was present in 60% of the patients. This is remarkable considering the advanced age of the patients, the stroke severity, and the high percentage of long segment occlusions. Our results are superior to recanalization rates of the Penumbra pivotal stroke trial (81.6%5) and the Merci trial (69.5%6), respectively, and even better than the results of the recently published study of Castaño et al and our own experience using the Solitaire stent,1,2 presumably as a result of the closed basket design of the stent tip.
Two patients of this series (Nos. 5 and 6) developed symptomatic intracranial hemorrhage, being fatal in 1 case. Both patients had a prolonged clinical course with fluctuating symptoms for several hours. In the fatal outcome, additional GP2b3a antagonist was administered to prevent rethrombosis after repeated thrombectomy. Thus, hemorrhage in both cases may have been caused by reperfusion injury after delayed revascularization, which was aggravated by antiaggregatory treatment in the fatal outcome.
In conclusion, the Revive device proved to be a technically safe and highly effective tool in the revascularization of acute stroke due to large vessel occlusion. Clinical safety and efficacy remain to be evaluated in larger controlled clinical trials.
M.B. and S.R. received lecture fees from Micrus/Codman Neurovascular.
Devices were provided by Micrus Endovascular.
- Received February 8, 2011.
- Revision received April 5, 2011.
- Accepted April 14, 2011.
- © 2011 American Heart Association, Inc.
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