Evaluation of the Solitaire system in a canine arterial thromboembolic occlusion model: is it safe for the endothelium?

The association of plasma osteoprotegerin levels and functional outcomes post endovascular thrombectomy in acute ischemic stroke patients: a retrospective observational study

Background

Osteoprotegerin (OPG), also known as osteoclastogenesis inhibitory factor, is a tumor necrosis factor receptor superfamily component. There is an established relationship between OPG and cardiovascular disease. We hypothesized that plasma OPG levels are associated with functional outcomes in acute ischemic stroke patients who have undergone endovascular thrombectomy (EVT).

Methods

From April 2014 through December 2020, a total of 360 acute ischemic stroke patients who underwent EVT were prospectively included in this retrospective observational study. Plasma OPG was measured after fasting for 12 postoperative hours after EVT. A modified Rankin Scale (mRS) was used to assess functional outcomes 3 months after index stroke occurrence. Univariate and multivariate binary logistic regression and ordinal logistic regression analyses were performed to investigate the association of plasma OPG levels with poor functional outcomes.

Results

Overall, 145 (40.2%) patients had poor (mRS > 2) outcomes. The mean ± standard deviation plasma OPG level was 200.2 ± 74.4 pg/mL. Multivariate analysis after adjusting for sex, body mass index, and variables with p < 0.1 in the preceding univariate analysis revealed high plasma OPG levels were independently associated with poor functional outcomes (highest tertile vs. lowest tertile of OPG; odds ratios (OR) 2.121, 95% confidence interval (CI) [1.089-4.191], p = 0.037 in binary logistic regression, OR 2.102, 95% CI [1.301-3.412], p = 0.002 in ordinal logistic regression analysis).

Conclusions

This study demonstrated that higher plasma OPG levels were associated with poor functional outcomes in acute ischemic stroke patients who underwent EVT.

The Jrecan Device: Preclinical Data of a Novel Thrombectomy Device in Acute Thromboembolism Model of Beagle Dogs

Objective

The aim of this study is to investigate the safety and efficiency of a Jrecan^® flow restoration system, a novel thrombectomy device, in an arterial thromboembolic occlusion model of Beagle dogs.

Methods

A total of 12 Beagle dogs with acute thromboembolism were randomized to receive mechanical thrombectomy with either Jrecan^® flow restoration device or Trevo^TM PROVUE Device (2:1). The efficacy and safety of the two devices, including recanalization rate, the presence of distal embolism, vasospasm, vessel perforation, and vessel injuries were evaluated through DSA and microscopic examination.

Result

A 100% recanalization rate (mTICI 2b/3) was achieved in both groups. Endothelial and subendothelial injuries occurred in all target vessels. Focal disruption of internal elastic lamina was observed in 4 cases. The mean vessel injury score of the Jrecan^® group was 1.16 ± 0.48, significantly lower than that of the Trevo^TM group (1.54 ± 0.8) (P < 0.001).

Conclusion

The Jrecan^® and Trevo^TM devices demonstrated an equally high recanalization rate in Beagle dogs with acute thromboembolism. However, histological findings revealed that the Jrecan^® stent seemed to be safer than the Trevo^TM device during clot retrieval, which might be related to a more appropriate radial force provided by the Jrecan^® stent that resulted from its wider cell design.

Combined Approach to Eptifibatide and Thrombectomy in Acute Ischemic Stroke Because of Large Vessel Occlusion: A Matched-Control Analysis

BACKGROUND

In patients undergoing mechanical thrombectomy (MT), adjunctive antithrombotic might improve angiographic reperfusion, reduce the risk of distal emboli and reocclusion but possibly expose patients to a higher intracranial hemorrhage risk. This study evaluated the safety and efficacy of combined MT plus eptifibatide for acute ischemic stroke.

METHODS

This was a propensity-matched analysis of data from 2 prospective trials in Chinese populations: the ANGEL-ACT trial (Endovascular Treatment Key Technique and Emergency Workflow Improvement of Acute Ischemic Stroke) in 111 hospitals between November 2017 and March 2019, and the EPOCH trial (Eptifibatide in Endovascular Treatment of Acute Ischemic Stroke) in 15 hospitals between April 2019 and March 2020. The primary efficacy outcome was good outcome (modified Rankin Scale score 0-2) at 3 months. Secondary efficacy outcomes included the distribution of 3-month modified Rankin Scale scores and poor outcome (modified Rankin Scale score 5-6) and successful recanalization. The safety outcomes included any intracranial hemorrhage, symptomatic intracranial hemorrhage, and 3-month mortality. Mixed-effects logistic regression models were used to account for within-hospital clustering in adjusted analyses.

RESULTS

Eighty-one combination arm EPOCH subjects were matched with 81 ANGEL-ACT noneptifibatide patients. Compared with the no eptifibatide group, the eptifibatide group had significantly higher rates of successful recanalization (91.3% versus 81.5%; P=0.043) and 3-month good outcomes (53.1% versus 33.3%; P=0.016). No significant difference was found in the remaining outcome measures between the 2 groups. All outcome measures of propensity score matching were consistent with mixed-effects logistic regression models in the total population.

CONCLUSIONS

This matched-control study demonstrated that MT combined with eptifibatide did not raise major safety concerns and showed a trend of better efficacy outcomes compared with MT alone. Overall, eptifibatide shows potential as a periprocedural adjunctive antithrombotic therapy when combined with MT. Further randomized controlled trials of MT plus eptifibatide should be prioritized.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03844594 (EPOCH), NCT03370939 (ANGEL-ACT).

Preclinical modeling of mechanical thrombectomy

Mechanical thrombectomy to treat large vessel occlusions (LVO) causing a stroke is one of the most effective treatments in medicine, with a number needed to treat to improve clinical outcomes as low as 2.6. As the name implies, it is a mechanical solution to a blocked artery and modeling these mechanics preclinically for device design, regulatory clearance and high-fidelity physician training made clinical applications possible. In vitro simulation of LVO is extensively used to characterize device performance in representative vascular anatomies with physiologically accurate hemodynamics. Embolus analogues, validated against clots extracted from patients, provide a realistic simulated use experience. In vitro experimentation produces quantitative results such as particle analysis of distal emboli generated during the procedure, as well as pressure and flow throughout the experiment. Animal modeling, used mostly for regulatory review, allows estimation of device safety. Other than one recent development, nearly all animal modeling does not incorporate the desired target organ, the brain, but rather is performed in the extracranial circulation. Computational modeling of the procedure remains at the earliest stages but represents an enormous opportunity to rapidly characterize and iterate new thrombectomy concepts as well as optimize procedure workflow. No preclinical model is a perfect surrogate; however, models available can answer important questions during device development and have to date been successful in delivering efficacious and safe devices producing excellent clinical outcomes. This review reflects on the developments of preclinical modeling of mechanical thrombectomy with particular focus on clinical translation, as well as articulate existing gaps requiring additional research.

Catheterization of Ventral Caudal Artery in Rats: A Modified Technique for Repeatable Angiography and Intervention

BACKGROUND

The use of digital silhouette angiography (DSA) has been restricted due to lack of a technique that allows for repeated intra-arterial inspections over a prolonged period. Current studies are focused on the arteries that can be cannulated multiple times. We intended to develop and test a technique that would enable repeated performance of various catheterizations and transcatheter operations for a prolonged period, at the same site, with fewer postsurgical complications.

METHODS

Thirty rats were randomly divided into five groups. Ventral caudal artery cannulation was performed via the transtail approach after grouping for subsequent experiments. Histological staining and scanning electron microscopy were used to assess endothelial injuries.

RESULTS

The rats survived post catheterization of ventral caudal artery and establishment of animal models. The average time of ventral caudal artery cannulation was significantly shorter than that of the femoral (p < 0.01) and common carotid arteries (p < 0.01). In rats, the transtail artery technique effectively allowed selective arterial catheterization and angiography. Histological staining and scanning electron microscopy of the abdominal aorta revealed disruption of the intima and denuded wavy endothelial surface.

CONCLUSIONS

We describe a novel method for artery sheath catheterization through the ventral caudal artery in rats; it may be possible to perform serial DSA studies and interventional operations with a single sheath channel in rats over a prolonged period. We believe that this approach will improve the utility of rats as models of human diseases and enable the broader use of rodent models for endovascular therapy research.

Preclinical testing platforms for mechanical thrombectomy in stroke: a review on phantoms, in-vivo animal, and cadaveric models

Preclinical testing platforms have been instrumental in the research and development of thrombectomy devices. However, there is no single model which fully captures the complexity of cerebrovascular anatomy, physiology, and the dynamic artery-clot-device interaction. This article provides a critical review of phantoms, in-vivo animal, and human cadaveric models used for thrombectomy testing and provides insights into the strengths and limitations of each platform. Articles published in the past 10 years that reported thrombectomy testing platforms were identified. Characteristics of each test platform, such as intracranial anatomy, artery tortuosity, vessel friction, flow conditions, device-vessel interaction, and visualization, were captured and benchmarked against human cerebral vessels involved in large-vessel occlusion stroke. Thrombectomy phantoms have been constructed from silicone, direct 3D-printed polymers, and glass. These phantoms represent oversimplified patient-specific cerebrovascular geometry but enable adequate visualization of devices and clots under appropriate flow conditions. They do not realistically mimic the artery-clot interaction. For the animal models, arteries from swine, canines, and rabbits have been reported. These models can reasonably replicate the artery-clot-device interaction and have the unique value of evaluating the safety of thrombectomy devices. However, the vasculature geometries are substantially less complex and flow conditions are different from human cerebral arteries. Cadaveric models are the most accurate vascular representations but with limited access and challenges in reproducibility of testing conditions. Multiple test platforms should be likely used for comprehensive evaluation of thrombectomy devices. Interpretation of the testing results should take into consideration platform-specific limitations.

Histological evaluation of acute ischemic stroke thrombi may indicate the occurrence of vessel wall injury during mechanical thrombectomy

Background

Several animal studies have demonstrated that mechanical thrombectomy (MT) for acute ischemic stroke (AIS) may cause vessel wall injury (VWI). However, the histological changes in human cerebral arteries following MT are difficult to determine.

Objective

To investigate the occurrence of VWI during MT by histological and immunohistochemical evaluation of AIS clots.

Methods

As part of the multicenter STRIP registry, 277 clots from 237 patients were analyzed using Martius Scarlett Blue stain and immunohistochemistry for CD34 (endothelial cells) and smooth muscle actin (smooth muscle cells).

Results

MT devices used were aspiration catheters (100 cases), stentriever (101 cases), and both (36 cases). VWI was found in 33/277 clots (12%). There was no significant correlation between VWI and MT device. The degree of damage varied from grade I (mild intimal damage, 24 clots), to grade II (relevant intimal and subintimal damage, 3 clots), and III (severe injury, 6 clots). VWI clots contained significantly more erythrocytes (p=0.006*) and less platelets/other (p=0.005*) than non-VWI clots suggesting soft thrombus material.

Thrombolysis correlated with a lower rate of VWI (p=0.04*). VWI cases showed a significantly higher number of passes (2 [1–4] vs 1 [1–3], p=0.028*) and poorer recanalization outcome (p=0.01*) than cases without VWI.

Conclusions

Histological markers of VWI were present in 12% of AIS thrombi, suggesting that VWI might be related to MT. VWI was associated with soft thrombus consistency, higher number of passes and poorer revascularization outcome. There was no significant correlation between VWI and MT device.

Changes in Procoagulant Blood Biomarkers After Mechanical Thrombectomy

OBJECTIVES

There is limited knowledge of the relationship between mechanical thrombectomy (MT) and endothelial inflammation in large-vessel occlusion (LVO) acute ischemic stroke (AIS). Intimal arterial damage releases tissue factor, a precipitant of the clotting cascade and thrombosis. We report changes in blood coagulation markers after MT treated with and without tissue plasminogen activator for AIS.

MATERIALS AND METHODS

Cases of LVO-AIS treated with MT were included. Blood coagulation marker levels were measured within 10 h of stroke onset as a baseline and then 48 h later. Assayed biomarkers included: tissue factor procoagulant activity (TFPCA), factor VII (FVII), activated factor VII (FVIIa), factor VIII (FVIII), d-dimer, thrombin-antithrombin complex (TAT), plasminogen activator inhibitor-1 (PAI-1), and tissue factor pathway inhibitor (TFPI). Biomarker levels of MT with tissue plasminogen activator (TPA) or without (non-TPA) are reported.

RESULTS

Biomarker levels from five patients with LVO-AIS treated with MT (three non-TPA, two TPA) were included. In non-TPA cases, TFPCA and PAI-1 increased while FVII, FVIIa, TAT, d-dimer, and TFPI decreased from baseline to 48 h. In TPA cases, TFPCA, FVIIa, d-dimer, TFPI, and PAI-1 decreased while FVIII increased from baseline to 48 h.

CONCLUSIONS

TFPCA increased after MT in non-TPA but decreased in TPA treated patients. This finding suggests that MT is associated with elevated inflammation and procoagulation which may be reduced with TPA treatment. With further validation, the increase in TFPCA levels could help guide anticoagulant management of patients with MT without TPA.

Evaluation of the Partial Re-Sheathing Technique with the Solitaire Stent Retrieval System In Vitro Model and a Representative Case

Objective

Vascular injuries are severe complications associated with endovascular thrombectomy. In the present study, we evaluated the re-sheathing technique with the Solitaire stent retrieval system to overcome these complications.

Methods

We examined the diameter and resistance to retrieval of the Solitaire FR device (6 × 20 mm) during full and partial deployment in vitro model. We also examined a representative case in which the re-sheathing technique was used.

Results

We found that the Solitaire device spread elliptically during partial deployment. As the length of the partially deployed device decreased, the maximum diameter also decreased. The distal half of the stent retained 80% of the maximum diameter of the partially deployed Solitaire. The resistance to retrieval was significantly higher during full deployment (mean ± standard deviation; 0.32 ± 0.04 kg) than during half deployment (0.22 ± 0.04 kg) (Mann-Whitney U test; p = 0.006). The re-sheathing technique was used in the representative case due to the high resistance to retrieval, which enabled recanalization without extravasation.

Conclusion

In cases of high resistance to retrieval, minimal re-sheathing may be useful for capturing the thrombus without increasing the risk of vascular injury.

Multicenter randomized clinical trial of endovascular treatment for acute ischemic stroke. The effect of periprocedural medication: acetylsalicylic acid, unfractionated heparin, both, or neither (MR CLEAN-MED). Rationale and study design

BACKGROUND

Despite evidence of a quite large beneficial effect of endovascular treatment (EVT) for ischemic stroke caused by anterior circulation large vessel occlusion, many patients do not recover even after complete recanalization. To some extent, this may be attributable to incomplete microvascular reperfusion, which can possibly be improved by antiplatelet agents and heparin. It is unknown whether periprocedural antithrombotic medication in patients treated with EVT improves functional outcome. The aim of this study is to assess the effect of acetylsalicylic acid (ASA) and unfractionated heparin (UFH), alone, or in combination, given to patients with an ischemic stroke caused by an intracranial large vessel occlusion in the anterior circulation during EVT.

METHODS

MR CLEAN-MED is a multicenter phase III trial with a prospective, 2 × 3 factorial randomized, open label, blinded end-point (PROBE) design, which aims to enroll 1500 patients. The trial is designed to evaluate the effect of intravenous ASA (300 mg), UFH (low or moderate dose), both or neither as adjunctive therapy to EVT. We enroll adult patients with a clinical diagnosis of stroke (NIHSS ≥ 2) and with a confirmed intracranial large vessel occlusion in the anterior circulation on CTA or MRA, when EVT within 6 h from symptom onset is indicated and possible. The primary outcome is the score on the modified Rankin Scale (mRS) at 90 days. Treatment effect on the mRS will be estimated with ordinal logistic regression analysis, with adjustment for main prognostic variables. Secondary outcomes include stroke severity measured with the NIHSS at 24 h and at 5-7 days, follow-up infarct volume, symptomatic intracranial hemorrhage (sICH), and mortality.

DISCUSSION

Clinical equipoise exists whether antithrombotic medication should be administered during EVT for a large vessel occlusion, as ASA and/or UFH may improve functional outcome, but might also lead to an increased risk of sICH. When one or both of the study treatments show the anticipated effect on outcome, we will be able to improve outcome of patients treated with EVT by 5%. This amounts to more than 50 patients annually in the Netherlands, more than 1800 in Europe, and more than 1300 in the USA.

TRIAL REGISTRATION

ISRCT, ISRCTN76741621 . Dec 6, 2017.

Etiology of recurrent large vessel occlusions treated with repeated thrombectomy

BACKGROUND

Repeated mechanical thrombectomy for acute stroke treatment in individual patients has been proven feasible. However, less is known about the etiology of recurrent vessel occlusions after prior thrombectomy. We aimed to understand if the etiology of such recurrent events differs from the first stroke.

METHODS

Retrospectively, we identified all patients at our center who received a repeated mechanical thrombectomy between 2007 and 2019. Clinical data were retrieved from medical records. Etiology of stroke was evaluated retrospectively, and angiographic studies were revisited.

RESULTS

Twenty-three patients (1.5%) were identified. Median age was 68 years (IQR 56-77). Median NIHSS at first admission was 11 points (IQR 5-15). In nine cases (39.1%), the recurrent vessel occlusion was located exactly at the same position as the prior occlusion. Overall, five (21.7%) patients had a remarkable extracranial pathology as likely cause of stroke recurrence. In 16 patients (69.6%), the etiology of the first stroke and its recurrence was considered as likely being the same, mostly of cardioembolic or unknown origin. In the seven remaining patients (30.4%), the cause of stroke possibly differed from the first event, with five patients (21.7%) having a postinterventional intracranial intimal lesion as possible cause of stroke.

CONCLUSION

Incidence of repeated thrombectomy was low. However, the high number of patients with known origin of stroke etiology raises the question how their monitoring may be optimized. The number of patients with remarkable extracranial pathologies or intracranial endothelial lesions supports current clinical practice to pay attention to final angiographic series.

Delayed mid-basilar artery stenosis following paediatric acute mechanical thrombectomy: a rare complication from a rare case

There is limited literature on the use of mechanical thrombectomy with stent-retrievers in paediatric stroke, especially in the posterior circulation. We report a paediatric case of acute basilar artery occlusion successfully treated by mechanical thrombectomy using stent-retriever but complicated by delayed basilar artery stenosis. This case emphasises prudent selection of thrombectomy device and meticulous long-term follow-up when employed in paediatric stroke.

Large animals in neurointerventional research: A systematic review on models, techniques and their application in endovascular procedures for stroke, aneurysms and vascular malformations

Neuroendovascular procedures have led to breakthroughs in the treatment of ischemic stroke, intracranial aneurysms, and intracranial arteriovenous malformations. Due to these substantial successes, there is continuous development of novel and refined therapeutic approaches. Large animal models feature various conceptual advantages in translational research, which makes them appealing for the development of novel endovascular treatments. However, the availability and role of large animal models have not been systematically described so far. Based on comprehensive research in two databases, this systematic review describes current large animal models in neuroendovascular research including their primary use. It may therefore serve as a compact compendium for researchers entering the field or looking for opportunities to refine study concepts. It also describes particular applications for ischemic stroke and aneurysm therapy, as well as for the treatment of arteriovenous malformations. It focuses on most promising study designs and readout parameters, as well as on important pitfalls in endovascular translational research including ways to circumvent them.

Neurosonography After Mechanical Thrombectomy for Acute Stroke Treatment

BACKGROUND AND PURPOSE

Mechanical thrombectomy has been shown to be effective for acute stroke treatment, but lesions of cerebral vessels can develop thereafter. Such lesions of recanalized vessels and altered cerebral hemodynamics after mechanical thrombectomy are poorly investigated. In particular for neurosonography, data are sparse. We aimed to describe hemodynamic changes and incidence of de-novo stenosis after mechanical thrombectomy with neurosonography.

METHODS

Retrospective analysis of patients after successful mechanical thrombectomy for acute stroke therapy who received one neurosonography at baseline and during follow up. Peak systolic velocity (PSV) of all intracranial recanalized and reference vessels was extracted for analysis. Patients with an isolated increase or decrease of PSV (50% or 50 cm/second for anterior and 30% or 30 cm/second for posterior circulation) were identified and characterized.

RESULTS

Eighty-eight patients (mean age 64.4; 34.1% female) were included in this study. In 9 (10.2%) patients, the vessel occlusion was located in the posterior, and in 79 (89.9%) patients the vessel occlusion was located in the anterior circulation. With predominance to the recanalized vessel, mean PSV decreased at both, the recanalized and the reference vessel during follow up. In 3 (3.4%) patients, an isolated increase of PSV was observed in the recanalized vessel, and in 6 (6.8%) patients an isolated decrease of PSV was observed in the recanalized vessel.

CONCLUSION

Sonographic incidence of de-novo stenosis following mechanical thrombectomy seems to be low, in line with prior angiographic studies. However, as measured by neurosonography, cerebral hemodynamic in the recanalized vessel is dynamic after thrombectomy. This result is of interest for further prospective analysis.

Magnetic wires: A novel design for neuroendovascular coil retrieval

The present study aimed to evaluate the operation, application and safety of a novel prototype device designed for the retrieval of a migrated coils, an intraprocedural complication of endovascular aneurysm treatment, compared with the widely used Solitaire AB stent retriever. The prototype retrieval device, referred to as magnetic wires, consisted of two microwires that were joined by a small magnetic ring near to the tips. To retrieve a coil, the wires are advanced through the dislodged coil one at a time and then capture the target coil in a chopstick-like manner, as their tips are attracted to the magnet. In vitro tests were performed five times for each retrieval device using a pulsing flow circulator to compare retrieval effectiveness. In vivo efficacy testing was performed in 5 male piglets. The left and right carotid arteries were used to assess the magnetic wires and the Solitaire retriever, respectively. While the two devices successfully retrieved coils in vitro at a rate of 100%, the magnetic wires did so in a shorter time. In vivo, the magnetic wires successfully captured the migrated coils in 3/5 cases (60%), whereas the Solitaire AB stent retriever was successful 4/5 cases (80%). Endothelial injury was observed following magnetic wires retrieval in 1/5 cases (20%) and following use of the Solitaire AB stent retriever in 3/5 cases (60%). These results demonstrate the feasibility and safety of this novel prototype coil retrieval device, which with further development has the potential to be an optimal device for the retrieval of dislodged coils.

Retrograde semi-retrieval technique for combined stentriever plus aspiration thrombectomy in acute ischemic stroke

The endovascular treatment of acute ischemic stroke has become a standard procedure. The combination of multiple neuroendovascular devices provides more possibilities for the improvement of the thrombectomy technique. We describe a modified retrieval technique using a distal intracranial catheter (DIC) for the semi-retrieval of stentriever during the thrombectomy procedure. The retrograde semi-retrieval technique involves completely unfolding the stent retriever by pulling a Navien catheter and the partial re-sheath of a retrievable stent forming a tapered configuration by pushing the Navien catheter, which results in the thrombi being embedded into the strut, securing the clot within the stent and there being a shorter distance for the clot to travel. This technique may lessen the occurrence of thrombus fragmentation and injury to the vessel wall. The retrograde semi-retrieval technique is an optional thrombectomy technique that may improve the efficiency of this procedure in the treatment of acute ischemic stroke.

[Mechanical thrombectomy: Acute complications and delayed sequelae]

BACKGROUND

Due to the positive evidence for mechanical thrombectomy (mTE), it will be increasingly used in future. Profound knowledge of potential complications, prevention and management of complications is necessary to safely implement mTE into clinical practice.

AIM

Description of specific complications of mTE and their clinical relevance, measures for prevention and management. Summary of the current knowledge on long-term side effects of mTE.

MATERIAL AND METHODS

Analysis of current trial results and selected case series to address specific topics. Summary of own practical clinical experience.

RESULTS

Vascular injury (1-5%) and emboli (5-9%) are the most relevant intraprocedural complications but the clinical outcome is variable. Measures for prevention and management are described in detail. Vasospasms frequently occur (20-26%) but rarely need specific treatment and do not affect the clinical course. In the case of restrictive indications the frequency of symptomatic hemorrhage is similar to that for medicinal treatment (up to 8%). Contrast medium enhancement in the area of the infarction on post-treatment imaging should not be mistaken for hemorrhages. Focal subarachnoid contrast medium enhancement or hemorrhage occurs in up to 24% of cases and is predominantly benign. In follow-up imaging stenoses or occlusions can be detected in 4-10% of the treated vessels, most of which are asymptomatic. They are considered to be caused by microtrauma to the vascular wall.

CONCLUSION

Clinically relevant complications of mTE are rare. Preventive measures and effective management of complications may even increase safety. Stenoses occasionally occur as a long-term side effect but are asymptomatic in the majority of cases.

The Effectiveness of Additional Treatment Modalities after the Failure of Recanalization by Thrombectomy Alone in Acute Vertebrobasilar Arterial Occlusion

Objective

Acute vertebrobasilar artery occlusion (AVBAO) is a devastating disease with a high mortality rate. One of the most important factors affecting favorable clinical outcome is early recanalization. Mechanical thrombectomy is an emerging treatment strategy for achieving a high recanalization rates. However, thrombectomy alone can be insufficient to complete recanalization, especially for acute stroke involving large artery atheromatous disease. The purpose of this study is to investigate the safety and efficacy of mechanical thrombectomy in AVBAO.

Methods

Fourteen consecutive patients with AVBAO were treated with mechanical thrombectomy. Additional multimodal treatments were intra-arterial (IA) thrombolysis, balloon angioplasty, or permanent stent placement. Recanalization by thrombectomy alone and multimodal treatments were assessed by the Thrombolysis in Cerebral Infarction (TICI) score. Clinical outcome was determined using the National Institutes of Health Stroke Scale (NIHSS) at 7 days and the modified Rankin Scale (mRS) at 3 months.

Results

Thrombectomy alone and multimodal treatments were performed in 10 patients (71.4%) and 4 patients (28.6%), respectively. Successful recanalization (TICI 2b-3) was achieved in 11 (78.6%). Among these 11 patients, 3 (27.3%) underwent multimodal treatment due to underlying atherosclerotic stenosis. Ten (71.4%) of the 14 showed NIHSS score improvement of >10. Overall mortality was 3 (21.4%) of 14.

Conclusion

We suggest that mechanical thrombectomy is safe and effective for improving recanalization rates in AVBAO, with low complication rates. Also, in carefully selected patients after the failure of recanalization by thrombectomy alone, additional multimodal treatment such as IA thrombolysis, balloons, or stents can be needed to achieve successful recanalization.

Shear-Activated Nanoparticle Aggregates Combined With Temporary Endovascular Bypass to Treat Large Vessel Occlusion

Background and Purpose—

The goal of this study is to combine temporary endovascular bypass (TEB) with a novel shear-activated nanotherapeutic (SA-NT) that releases recombinant tissue-type plasminogen activator (r-tPA) when exposed to high levels of hemodynamic stress and to determine if this approach can be used to concentrate r-tPA at occlusion sites based on high shear stresses created by stent placement.

Methods—

A rabbit model of carotid vessel occlusion was used to test the hypothesis that SA-NT treatment coupled with TEB provides high recanalization rates while reducing vascular injury. We evaluated angiographic recanalization with TEB alone, intra-arterial delivery of soluble r-tPA alone, or TEB combined with 2 doses of intra-arterial infusion of either the SA-NT or soluble r-tPA. Vascular injury was compared against stent-retriever thrombectomy.

Results—

Shear-targeted delivery of r-tPA using the SA-NT resulted in the highest rate of complete recanalization when compared with controls ( P =0.0011). SA-NT (20 mg) had a higher likelihood of obtaining complete recanalization as compared with TEB alone (odds ratio 65.019, 95% confidence interval 1.77, >1000; P =0.0231), intra-arterial r-tPA alone (odds ratio 65.019, 95% confidence interval 1.77, >1000; P =0.0231), or TEB with soluble r-tPA (2 mg; odds ratio 18.78, 95% confidence interval 1.28, 275.05; P =0.0322). Histological analysis showed circumferential loss of endothelium restricted to the area where the TEB was deployed; however, there was significantly less vascular injury using a TEB as compared with stent-retriever procedure (odds ratio 12.97, 95% confidence interval 8.01, 21.02; P <0.0001).

Conclusions—

A novel intra-arterial, nanoparticle-based thrombolytic therapy combined with TEB achieves high rates of complete recanalization. Moreover, this approach reduces vascular trauma as compared with stent-retriever thrombectomy.

Mechanical thrombectomy with the Trevo ProVue device in ischemic stroke patients: does improved visibility translate into a clinical benefit?

PURPOSE

To investigate the efficacy and safety of the Trevo ProVue (TPV) stent retriever in stroke patients with large artery occlusions, with particular attention to the full structural radiopacity of the TPV.

MATERIALS AND METHODS

Case files and images of TPV treatments were reviewed for clinical and technical outcome data, including revascularization rates, device and procedure related complications, and outcome at discharge and after 90 days.

RESULTS

76 patients were treated with TPV. Mean National Institutes of Health Stroke Scale (NIHSS) score was 18 and 68% had additional intravenous thrombolysis. 63 occlusions were in the anterior circulation: 44 M1 (58%), 8 M2 (11%), 8 internal carotid artery-terminus (11%), 2 internal carotid artery- left (3%), 1 A2 (1%), and 13 vertebrobasilar (17%). 58 of 76 (76%) were solely treated with TPV; the remainder were treated with additional stent retrievers. Mean number of passes in TPV only cases was 2.2 (SD 1.2). In rescue cases, 3.2 (SD 2.2) passes were attempted with the TPV followed by 2.6 rescue device passes (SD 2). TPV related adverse events occurred in 4/76 cases (5%) and procedural events in 6/76 cases (8%). Mean procedural duration was 64 min (SD 42). Thrombolysis in Cerebral Infarction (TICI) 2b/3 recanalization was achieved in 69/76 patients (91%), including 50% TICI 3. Of 56 survivors (74%), 37 (49%) showed a favorable outcome at 90 days (Solitaire With the Intention for Thrombectomy trial criteria), statistically associated with age, baseline NIHSS, onset to revascularization time, and TICI 2b-3 reperfusion. TPV radiopacity allowed for visual feedback, changing the methodology of stent retriever use in 44/76 cases (58%).

CONCLUSIONS

Neurothrombectomy with TPV is feasible, effective, and safe. The recanalization rate compares favorably with reported data in the literature. Improved structural radiopacity may facilitate neurothrombectomy or influence the course of action during retrieval.

One-year MR angiographic and clinical follow-up after intracranial mechanical thrombectomy using a stent retriever device

BACKGROUND AND PURPOSE

Little is known about the consequences of arterial wall damage that may be due to mechanical endovascular thrombectomy. Our aim was to perform 1-year MR angiographic and clinical follow-up of patients treated with mechanical endovascular thrombectomy using the Solitaire device.

MATERIALS AND METHODS

Patients with stroke treated between August 2010 and July 2012 were prospectively evaluated with a minimum follow-up of 1 year after mechanical endovascular thrombectomy. Angiographic follow-up was performed on a 3T MR imaging scanner and included intracranial artery TOF MRA and supra-aortic artery gadolinium-enhanced MRA. Images were assessed to detect arterial abnormalities (stenosis, occlusion, dilation) and were compared with the final post-mechanical endovascular thrombectomy run to differentiate delayed and pre-existing abnormalities. Clinical evaluation was performed with the mRS and the 36-Item Short-Form Health Survey questionnaire quality-of-life scale.

RESULTS

Thirty-nine patients were angiographically assessed at the mean term of 19 ± 4 months. MRA showed intracranial artery abnormalities in 10 patients, including 5 delayed intracranial artery abnormalities in 4 patients (4 stenoses and 1 dilation), 4 cases of pre-existing intracranial artery stenosis, and 2 occlusions. Pre-existing etiologic cervical artery stenosis or occlusion was observed in 2 patients. All these patients remained asymptomatic during the follow-up period. A significant clinical improvement was observed at 1-year follow-up in comparison with 3-month follow-up (P < .0001), with a good outcome achieved in 62.5% of patients and an acceptable quality of life restored.

CONCLUSIONS

One-year follow-up identifies delayed asymptomatic arterial abnormalities in patients treated with the Solitaire device.