Evolution of thrombectomy approaches and devices for acute stroke: a technical review

Ultra-distal access of the M1 segment with the 5 Fr Navien distal access catheter in acute (anterior circulation) stroke: is it safe and efficient?

BACKGROUND AND AIM

The importance of mechanical thrombectomy in acute stroke treatment has grown over recent years. Mechanical thrombectomy comprises many different techniques. Technical improvements in the catheter material have led to the development of large-bore distal access catheters which can enter tortuous intracranial vessels. This has promising applications for endovascular stroke treatment. This study evaluated the safety and success rate of ultra-distal access of the middle cerebral artery (MCA) M1 segment with the 5 Fr Navien 58 distal access catheter in the treatment of acute stroke in combination with stent retrievers.

METHODS

We retrospectively analyzed 81 patients with an acute stroke of the anterior circulation in whom ultra-distal access to the M1 segment was carried out using the Navien 58 catheter with an anchoring technique with a stent retriever for mechanical thrombectomy. Technical complications, success rates of catheter placement, success rates of thrombectomy using the modified Thrombolysis In Cerebral Infarction (mTICI) score, and the procedure times were evaluated.

RESULTS

Ultra-distal access with the Navien 58 was successful in 75% (61/81) of cases. Recanalization success with a mTICI score of 2b and better was achieved in 83% overall (67/81), in 90% (55/61) of cases with successful ultra-distal access and in 60% (12/20) of cases without ultra-distal access. No severe adverse effects such as dissections or perforations occurred as a result of the ultra-distal catheter placement in the M1 segment. In 4% (3/81) of the cases a reversible MCA vasospasm occurred.

CONCLUSIONS

Ultra-distal placement of the Navien 58 distal access catheter into the M1 segment in acute anterior circulation stroke can be achieved consistently, is safe in practice, and results in good recanalization success rates.

The Evolution of Mechanical Thrombectomy for Acute Stroke

OPINION STATEMENT

The natural history of an acute ischemic stroke from a large vessel occlusion (LVO) is poor and has long challenged stroke therapy. Recently, endovascular therapy has demonstrated superiority to medical management in appropriately selected patients. This advance has revolutionized acute care for LVO and mandates a reevaluation of the entire chain of stroke care delivery, including patient selection, intervention, and post-procedural care. Since endovascular therapy is a therapy specifically targeting LVO, its application should be restricted to those patients only. Clinical and radiologic parameters need to be considered in patient selection. Data supports that all patients over the age of 18 years presenting with a National Institutes of Health Stroke Scale (NIHSS) of 6 or greater within 6 hours of symptom onset should be considered for emergent endovascular therapy. Radiologically, those with a LVO of the internal carotid artery (ICA) or middle cerebral artery (MCA) M1 portion, intermediate or good collaterals and without large established infarct should be considered endovascular candidates. Selection beyond these parameters remains an open question and is being actively evaluated. In all cases, revascularization should be attempted with a new generation device (stentriever or direct aspiration), as these techniques are most likely to deliver adequate reperfusion. Post-revascularization, patients are closely monitored in an intensive care setting followed by discharge to rehabilitation, if required, or directly home. Patients should be evaluated in delayed fashion to assess recovery (typically at 3 months post-treatment). Ultimately, the poor natural history of ischemic stroke from LVO and the potential significant benefit from endovascular therapy over medical management alone necessitate a national response to ensure we identify and treat all eligible patients as rapidly and effectively as possible.

Evolution of endovascular stroke therapies and devices

Acute ischemic stroke is caused by occlusion of a cerebral artery, resulting in loss of brain tissue and neurologic deficits. However, a portion of the ischemic brain can be salvaged if blood flow is restored within an appropriate time frame. The past year has seen the publication of five positive randomized controlled trials demonstrating substantial benefit of mechanical thrombectomy in select patients with large vessel cerebrovascular occlusion. This progress is related to several factors, but most importantly, dramatic improvements in speed and rates of recanalization with the latest generation devices. In this article, we review the evolution of endovascular acute ischemic stroke therapies and key design features of the most widely used devices.

The Penumbra 5MAX ACE Catheter Is Safe, Efficient, and Cost Saving as a Primary Mechanical Thrombectomy Device for Large Vessel Occlusions in Acute Ischemic Stroke

BACKGROUND

Reperfusion of large vessel occlusions in acute stroke can improve patient outcomes. The purposes of this study were to assess the safety and efficacy of the Penumbra 5MAX ACE catheter for revascularization of large vessels and to compare its cost to the cost of stent retrievers.

METHODS

In this retrospective, single-center case review study, data were captured on consecutive patients treated with the Penumbra 5MAX ACE as first-line therapy during an 11-month period. Good functional outcome was defined as a modified Rankin Scale score of ≤2 at discharge. Results were directly compared with previously published data for stent retrievers, and length of stay was analyzed in relation to revascularization.

RESULTS

The 31 patients studied had a mean age of 66.3 ± 17.8 years and a mean National Institutes of Health Stroke Scale score of 19.4 ± 5.7. Intravenous tissue recombinant plasminogen activator therapy was initiated in 35.5% (11/31) of patients. A Thrombolysis in Cerebral Infarction (TICI) grade of 2b-3 reperfusion after endovascular therapy was achieved in 26/31 (83.9%) of cases; TICI grade 3 was achieved in 19/31 (61.3%) patients. The average time from groin puncture to TICI grade 2b-3 reperfusion was 40 minutes. The average estimated cost for aspiration with the 5MAX ACE alone was $4,916 per case compared with an estimated cost of $9,620 if a stent retriever was used as the primary device. Our actual average cost per case, including all adjunctive devices used in the neurointerventional procedure, was $6,997. Good functional outcome was achieved in 19/31 (61.3%) patients. Two patients experienced symptomatic intracerebral hemorrhage (6.5%), and 1 (3.2%) patient died. The length of stay was significantly shorter among patients with TICI grade 2b-3 reperfusion compared to patients with TICI grade <2 (6.8 ± 5.34 days vs 15.8 ± 11.32 days, respectively; P<0.05).

CONCLUSION

These findings suggest that direct aspiration with the large-bore 5MAX ACE catheter can be considered a first-line approach to mechanical thrombectomy for large vessel occlusions. Our results demonstrated high rates of successful reperfusion in a timely manner with excellent clinical outcomes, although our sample size was small. In addition, this direct-aspiration technique has important cost-savings potential compared to stent retrievers.

Patterns and Clinical Impact of Angiographically Visible Distal Emboli During Thrombectomy With Solitaire for Acute Ischemic Stroke

BACKGROUND:

Revascularization rates with stent retrievers after acute ischemic stroke are 69% to 86%, but favorable clinical outcomes occur in just 43% to 58% of cases. New distal emboli may negatively impact clinical outcomes.

OBJECTIVE:

To determine the prevalence and angiographic pattern of distal emboli associated with mechanical thrombectomy using the Solitaire Flow Restoration device and evaluate their correlation with clinical outcome.

METHODS:

We retrospectively reviewed the cerebral angiography of all patients with acute ischemic stroke who underwent mechanical thrombectomy with the use of the Solitaire FR device from 2012 to 2013. Angiographic microcatheter runs prior to Solitaire deployment and after thrombectomy were compared to identify new distal filling defects. Clinical outcome was assessed at discharge and after 90 days.

RESULTS:

Successful revascularization using the Solitaire device occurred in 36 of 39 patients (92%). Three distinct patterns were identified: new distal emboli in the same vascular territory (n = 3), new distal emboli in a new vascular territory (n = 3), and distal emboli that resolved after proximal revascularization (n = 7). Thirteen patients had distal emboli before and after Solitaire runs, and 13 showed no evidence of distal emboli. Favorable outcome (modified Rankin scores 0-2) was seen in 54% of all patients and 83% of patients with new distal emboli; thus, there was no correlation between new emboli and unfavorable clinical outcome (P = .67).

CONCLUSION:

We report an incidence rate of at least 15% of new emboli associated with use of the Solitaire device during thrombectomy in our series. Filling defects after Solitaire use were not associated with poor outcomes at discharge or 90-day follow-up.

Mechanical Thrombectomy Using the New ERIC Retrieval Device Is Feasible, Efficient, and Safe in Acute Ischemic Stroke: A Swiss Stroke Center Experience

BACKGROUND AND PURPOSE

Intravenous thrombolysis and mechanical thrombectomy predominantly using stent retrievers have been shown to effectively restore cerebral blood flow and improve functional outcome in patients with acute ischemic stroke. We sought to determine the safety and feasibility of mechanical thrombectomy using the new ERIC retrieval device.

MATERIALS AND METHODS

We identified 36 consecutive patients from our Stroke Center registry with acute ischemic stroke who were treated with the new ERIC retriever from September 2013 to December 2014. Patients with ischemic stroke meeting the following criteria were eligible: onset-to-treatment time of ≤4.5 hours or wake-up stroke (n = 10) with relevant CT perfusion mismatch, NIHSS score of ≥4, and proof of large-vessel occlusion in the anterior circulation on CT angiography. We assessed the baseline characteristics including age, sex, comorbidities, stroke severity, site of vessel occlusion, presence of tissue at risk, and treatment-related parameters such as onset-to-treatment time, recanalization grade, and outcome.

RESULTS

The mean age was 70 ± 13 years, and the median NIHSS score on admission was 18 (interquartile range, 10-20). Seventeen of 36 patients were on platelet inhibitors or anticoagulants before endovascular treatment (47.2%); 20 patients received intravenous thrombolysis (55.5%). The ERIC was used as the sole retriever in 28 patients (77.8%) and as a rescue device in 8. Excellent recanalization was achieved in 30/36 patients (83.3%) with TICI 3 in 19/36 and 2b in 11/36, respectively. Median procedural time in these patients was 90 minutes (interquartile range, 58-133 minutes). No intraprocedural complications occurred.

CONCLUSIONS

In this observational study, the new ERIC retrieval device was technically feasible, safe, and effective in acute ischemic stroke with large-vessel occlusion.

Primary stentriever versus combined stentriever plus aspiration thrombectomy approaches: in vitro stroke model comparison

BACKGROUND

Artificial stroke models can be used for testing various thrombectomy devices.

OBJECTIVE

To determine the value of combined stentriever-aspiration thrombectomy compared with the stentriever-alone approach.

METHODS

We designed an in vitro model of the intracranial circulation with a focus on the middle cerebral artery (MCA) that closely resembles the human intracranial circulation. After introducing fresh clot in the MCA, we used conventional biplane angiography and microangiographic fluoroscopy to compare recanalization rates and occurrence of emboli in new, unaffected territory for thrombectomy approaches in which a stentriever (Solitaire flow restoration stentriever, Covidien) was used alone or in combination with continuous manual aspiration through a Navien catheter (Covidien).

RESULTS

In a total of 22 experiments (11 for each approach), successful clot delivery to the MCA was achieved in all cases. Successful angiographic recanalization (thrombolysis in cerebral infarction score of 2b-3) was achieved more frequently with the combined stentriever-aspiration approach than with the stentriever-alone approach (in 10 vs 4 experiments, p=0.023). Emboli in new territory occurred in three experiments with the stentriever-alone approach, and none were seen with the combined approach (p=0.21).

CONCLUSIONS

The combined stentriever-aspiration approach to thrombectomy leads to better angiographic recanalization rates than use of the stentriever alone. Further experiments are needed to test the value of balloon-guide catheters and aspiration performed using other types of catheters and modes of aspiration.

Intra-arterial therapy for acute ischemic stroke: a golden age

OPINION STATEMENT

With the recent publication of multiple trials demonstrating the superiority of the endovascular treatment of patients presenting with stroke from large vessel occlusion (LVO) over medical management, the emergent care of these patients is entering a new era. This realization justifies an aggressive treatment approach with these stroke patients, given the poor natural history of the disease. In general, treatment should occur as quickly as is reasonably possible. Patients with NIHSS >8 should be considered, and if <6 h from onset imaging selection achieved with CT and CTA. Those with ASPECTS >5, LVO and intermediate or good collaterals should be treated emergently. For patients with clinical deficits presenting in later timeframes MRI should be used to define core infarct size and therefore treatment eligibility. MRI might also be considered for the workup of stroke patients in centers that can offer it rapidly. Recanalization should be attempted with a stentriever or using a direct aspiration technique, with the patient under conscious sedation rather than general anesthesia, if that is a safe option. Angiographically, the goal is reperfusion of mTICI 2b/3. Post-procedure, the patient should be admitted to an intensive care setting and assessed for inpatient rehabilitation placement as soon as stable. Continuous institutional process improvement ensures that optimization of treatment times and logistics is an ongoing endeavor. Finally, patient outcomes should be assessed at three months, most commonly using the modified Rankin score.

Force and aspiration analysis of the ADAPT technique in acute ischemic stroke treatment

Introduction

The development of new revascularization devices has significantly improved recanalization rates and time to reperfusion. A direct aspiration first-pass (ADAPT) technique for stroke thrombectomy was recently shown to be an effective and rapid way to achieve revascularization. The technique focuses on engaging and removing a clot without the use of a separator or retriever by relying on the force and aspiration generated by the catheter. We sought to compare the physical and fluid dynamic properties (force and aspiration) of commercially available catheters to determine the most effective catheter for the ADAPT technique.

Methods

Benchtop models were employed to compare aspiration for each catheter by submersing the catheter into a graduated cylinder and aspirating water. The volume of fluid aspirated and flow rates were calculated. Force of aspiration at the tip of each catheter was measured using a vacuum pressure gauge while the catheter was attached to a standard aspiration pump. Force was then calculated.

Results

The Penumbra 5MAX ACE catheter had the greatest aspiration rate of all the catheters at 245 mL/min. The Penumbra 5 MAX catheter aspirated 212 mL/min, followed by the Navien 058 and DAC 057 with 198 mL/min and 197 mL/min, respectively. The Penumbra 5MAX ACE generated the greatest tip force (18.25 g) and the 5MAX had the least amount of force (14.77 g).

Conclusions

The physical and fluid dynamic properties of currently available catheters suggest that the 5MAX ACE is the optimal catheter to use in direct aspiration for stroke therapy.

Evolution of endovascular mechanical thrombectomy for acute ischemic stroke

Acute ischemic stroke (AIS) is a common medical problem associated with significant morbidity and mortality worldwide. A small proportion of AIS patients meet eligibility criteria for intravenous thrombolysis (IVT) with recombinant tissue plasminogen activator, and its efficacy for large vessel occlusion is poor. Therefore, an increasing number of patients with AIS are being treated with endovascular mechanical thrombectomy when IVT is ineffective or contraindicated. Rapid advancement in catheter-based and endovascular device technology has led to significant improvements in rates of cerebral reperfusion with these devices. Stentrievers and modern aspiration catheters have now surpassed earlier generation devices in the degree and rapidity of revascularization. This progress has been achieved with no concurrent increase in risk of major complications or mortality, both when used alone or in combination with IVT. The initial randomized controlled trials comparing endovascular therapy to IVT for AIS failed to show superior outcomes with endovascular treatment, but key limitations of each trial may limit the significance of these results to current practice. While endovascular devices and operator experience continue to evolve, we are optimistic that this will be accompanied by improvements in patient outcomes. This review highlights the major endovascular devices used in current practice and the trials which have investigated their efficacy.

Multicenter clinical experience in over 125 patients with the Penumbra Separator 3D for mechanical thrombectomy in acute ischemic stroke

Background

The aim of this study was to assess reperfusion and clinical outcome of treatment with the self-expanding retrievable Separator 3D in revascularization of acute ischemic stroke. The three-dimensional (3D) device secures thrombus with direct aspiration and supports debulking of the clot.

Methods

At two centers, 129 consecutive stroke patients with National Institutes of Health Stroke Scale (NIHSS) scores ≥5 were treated with mechanical thrombectomy using the Separator 3D as a component of the Penumbra System within 8 h of symptom onset; modified Treatment in Cerebral Infarction (mTICI) revascularization scores, NIHSS score on admission and discharge, mortality rates, and modified Rankin Scale (mRS) outcomes at 90 days were evaluated.

Results

A total of 129 vessels in 129 patients were treated. Occlusions were located in the middle cerebral artery (MCA, 48%), internal carotid artery (ICA, 33%), cervical ICA–MCA (3%), and vertebrobasilar arteries (16%). Intravenous thrombolytic therapy with recombinant tissue plasminogen activator was given to 78% of patients. Median NIHSS was 15 prior to treatment. Reperfusion to mTICI 2b or 3 was successful in 96/129 (74%) target arterial lesions, with more than half of cases (51%) achieving mTICI 3. The mean time from arterial puncture to revascularization was 65 min. At 90 days, the symptomatic intracranial hemorrhage rate was 4%, all cause mortality was 32%, and 43/99 patients (43%) achieved functional independence with an mRS score of ≤2.

Conclusions

The results suggest that the Separator 3D enables safe and effective revascularization of occluded large arteries in acute stroke intervention, leading to a high rate of functional independence at 90 days.

Comparison of endovascular treatment approaches for acute ischemic stroke: cost effectiveness, technical success, and clinical outcomes

INTRODUCTION

The use of mechanical thrombectomy for the treatment of acute ischemic stroke has significantly advanced over the last 5 years. Few data are available comparing the cost and clinical and angiographic outcomes associated with available techniques. The aim of this study is to compare the cost and efficacy of current endovascular stroke therapies.

METHODS

A single-center retrospective review was performed of the medical record and hospital financial database of all ischemic stroke cases admitted from 2009 to 2013. Three discrete treatment methodologies used during this time were compared: traditional Penumbra System (PS), stent retriever with local aspiration (SRLA) and A Direct Aspiration first Pass Technique (ADAPT). Statistical analyses of clinical and angiographic outcomes and costs for each group were performed.

RESULTS

222 patients (45% men) underwent mechanical thrombectomy. Successful revascularization was defined as Thrombolysis In Cerebral Infarction (TICI) 2b/3 flow, which was achieved in 79% of cases with PS, 83% of cases with SRLA, and 95% of cases with ADAPT. The average total cost of hospitalization for patients was $51,599 with PS, $54,700 with SRLA, and $33 ,11 with ADAPT (p<0.0001). Average times to recanalization were 88 min with PS, 47 min with SRLA, and 37 min with ADAPT (p<0.0001). Similar rates of good functional outcomes were seen in the three groups (PS 36% vs SRLA 43% vs ADAPT 47%; p=0.4).

CONCLUSIONS

The ADAPT technique represents the most technically successful yet cost-effective approach to revascularization of large vessel intracranial occlusions.

Outcomes of manual aspiration thrombectomy for acute ischemic stroke refractory to stent-based thrombectomy

BACKGROUND AND PURPOSE

The optimal treatment for patients with acute stroke refractory to stent-based thrombectomy (SBT) is unclear. This study aimed to report clinical outcomes of manual aspiration thrombectomy (MAT) for the treatment of acute ischemic stroke refractory to SBT.

METHODS

We retrospectively analyzed clinical and angiographic data of 30 patients who underwent MAT with a Penumbra reperfusion catheter because of refractory occlusion after SBT with a Solitaire stent as first-line endovascular therapy. Refractory occlusion was defined by a lack of successful revascularization (defined as Thrombolysis In Cerebral Infarction ≥2b) after five retrieval attempts. A good outcome was defined as a modified Rankin scale score of ≤2 at 3 months.

RESULTS

Successful revascularization was achieved in 83.3% (25/30) of the patients who underwent MAT after failed SBT. There was no arterial rupture or dissection or symptomatic intracranial hemorrhage. Two embolic occlusions in a new arterial territory and five subarachnoid hemorrhages occurred, neither of which caused neurological worsening. At the 3-month follow-up, 36.7% (11/30) of patients exhibited a good outcome. The mortality rate was 6.7% (2/30) at 3 months.

CONCLUSIONS

This study suggests that MAT with the Penumbra reperfusion catheter can further increase the revascularization rate without serious complications in patients with acute stroke with refractory occlusions after SBT with a Solitaire stent.