Midterm clinical and angiographic follow-up for the first Food and Drug Administration-approved prospective, Single-Arm Trial of Primary Stenting for Stroke: SARIS (Stent-Assisted Recanalization for Acute Ischemic Stroke)

Rescue Stenting for Refractory Large Vessel Occlusions in the Thrombectomy Era: Intracranial Use of Coronary Stents in Low-mid Economic Settings

Background: Failed mechanical thrombectomy due to a refractory emergent large vessel occlusion (RELVO) in patients presenting with an acute stroke poses a major challenge to the outcomes.

Objective: We demonstrate the use of coronary stents in the intracranial circulation as rescue stenting for an already expensive mechanical thrombectomy procedure in a mid-low socioeconomic setting.

Methods: A retrospective, multicenter study was conducted between December 2015 and January 2021. The studied cohort were patients who required the use of a rescue stenting using a coronary stent for emergent large vessel occlusion to avoid failed recanalization. Failed recanalization was defined as failed vessel recanalization after at least two passes. Patient demographic data, procedure specifics, type of stent used, and procedural outcomes were collected.

Results: A total of 26 patients with acute ischemic stroke were included from eight different centers across India. Out of 26 patients, 19 (73.0%) were male and seven were female (26.9%). The mean age was 53.6 years, the youngest patient was 23 years old and the eldest was 68 years old. Seven patients (26.9%) had posterior circulation stroke due to occlusion of the vertebral or basilar artery and 19 patients (73.0%) had anterior circulation stroke median NIHSS at presentation was 16 (range 10 to 28) in anterior circulation stroke and 24 (range 16 to 30) in posterior circulation stroke. Intravenous thrombolysis with tissue plasminogen activator (IV tPA) was given in three patients (11.5%). The hospital course of two patients was complicated by symptomatic intracranial hemorrhage (sICH), which was fatal. Favorable revascularization outcome and favorable functional outcome was achieved in 22 patients (84.6%), three patients passed away (11.5%), and one patient was lost to follow up.

Conclusions: Overall, our study finds that rescue stenting using coronary stents can potentially improve outcomes in refractory large vessel occlusions while minimizing costs in low-mid economic settings.

Preliminary Experience of Neuroform Atlas Stenting as a Rescue Treatment after Failure of Mechanical Thrombectomy Caused by Residual Intracranial Atherosclerotic Stenosis

Objective

The low-profile Neuroform Atlas stent can be deployed directly without an exchange maneuver by navigating into the Gateway balloon. This retrospective study assessed the safety and efficacy of Neuroform Atlas stenting as a rescue treatment after failure of mechanical thrombetomy (MT) for large artery occlusion.

Methods

Between June 2018 and December 2019, a total of 31 patients underwent Neuroform Atlas stenting with prior Gateway balloon angioplasty after failure of conventional MT caused by residual intracranial atherosclerotic stenosis (ICAS). Primary outcomes were successful recanalization and patency of the vessel 24 hours after intervention. Secondary outcomes were vessel patency after 14 days and 3-month modified Rankin Scale. Peri-procedural complications, intracerebral hemorrhage (ICH), and 3-month mortality were reviewed.

Results

With a 100% of successful recanalization, median value of stenosis was reduced from 79.0% to 23.5%. Twenty-eight patients (90.3%) showed tolerable vessel patency after 14 days. New infarctions occurred in three patients (9.7%) over a period of 14 days; two patient (6.5%) underwent stent occlusion at 24 hours, and the other patient (3.2%) with delayed stent occlusion had a non-symptomatic dot infarct. There were no peri-procedural complications. Two patients (6.5%) developed an ICH immediately after the procedure with one of them is symptomatic.

Conclusion

Neuroform Atlas stenting seems to be an effective and safe rescue treatment modality for failed MT with residual ICAS, by its high successful recanalization rate with tolerable patency, and low peri-procedural complication rate. Further multicenter and randomized controlled trials are needed to confirm our findings.

Acute ischemic stroke endovascular therapy

Endovascular therapy (EVT) has become the standard treatment for large-vessel occlusion (LVO) acute ischemic stroke (AIS). EVT is now indicated in patients up to 24h from their last known well, provided that the patient meets specific clinical and imaging criteria. Improvements in thrombectomy devices, techniques, and operator experience have allowed successful EVT of ICA terminus, M1-MCA occlusions as well as proximal M2-MCA, basilar artery occlusions, and revascularization of tandem lesions. Mechanical thrombectomy failures still occur due to several factors, however, highlighting the need for further device and technical improvements. An ongoing debate exists regarding the need for pre-EVT thrombolytic agents, thrombectomy techniques, distal occlusions, anesthesia methods, the role of advanced neuroimaging, the treatment of patients with larger infarct core, and those presenting with milder stroke symptoms. Many of these questions are the subject of current or upcoming clinical trials. This review aims to provide an outline and discussion about the established recommendations and emerging topics regarding EVT for LVO AIS.

Endovascular treatment of acute ischemic stroke

Endovascular treatment of acute ischemic stroke has become the first choice of treatment in large cerebral vessel occlusions, with a very high efficacy in terms of revascularization and reducing disability of affected patients. Revolutionizing acute therapy, it induced important paradigm shifts in the concepts of time and salvageable brain. In this review we focus on the current concepts of patient selection, imaging, techniques and perspectives of endovascular stroke treatment.

Epidemiology, Natural History, and Clinical Presentation of Large Vessel Ischemic Stroke

Large vessel occlusions (LVOs), variably defined as blockages of the proximal intracranial anterior and posterior circulation, account for approximately 24% to 46% of acute ischemic strokes. Commonly refractory to intravenous tissue plasminogen activator (tPA), LVOs place large cerebral territories at ischemic risk and cause high rates of morbidity and mortality without further treatment. Over the past few years, an abundance of high-quality data has demonstrated the efficacy of endovascular thrombectomy for improving clinical outcomes in patients with LVOs, transforming the treatment algorithm for affected patients. In this review, we discuss the epidemiology, pathophysiology, natural history, and clinical presentation of LVOs as a framework for understanding the recent clinical strides of the endovascular era.

Trends in the Incidence and Treatment of Cerebrovascular Diseases in Korea : Part II. Cerebral Infarction, Cerebral Arterial Stenosis, and Moyamoya Disease

OBJECTIVE

To analyze trends in the incidence and treatment of diseases associated with ischemic stroke, namely, cerebral infarction (CI), cerebral arterial stenosis (CASTN), and moyamoya disease (MMD), based on Korean National Health Insurance Service (NHIS) data from 2008 to 2016.

METHODS

Data was extracted from the national health-claim database provided by the NHIS for 2008-2016 using International Classification of Diseases codes. The crude and age-standardized incidences of each disease (CI, CASTN without a history of CI, and MMD) were calculated; additional analyses were conducted according to age and sex. Trends in the number of patients undergoing treatment according to treatment method were analyzed for each disease using the Korean Classification of Diseases procedure codes.

RESULTS

In 2016, the total number of adults with newly diagnosed CI was 83939, reflecting a 9.4% decrease from that in 2008. The agestandardized incidence of CI in adults was 153.2 per 100000 person-years in 2016, reflecting a 37.2% decrease from that in 2008, while that of CASTN was 167.3 per 100000 person-years in 2016, reflecting a 73.3% increase from that in 2008. Among treated cases, the number of patients who underwent intra-arterial (IA) treatment, including IA fibrinolysis and mechanical thrombectomy, showed the most prominent increase, increasing at an annual rate of 25.8%. For CASTN, the number of cases treated with carotid artery stenting or balloon angioplasty (CAS) showed the most prominent increase, increasing at a rate of 69.8% over the 9-year period. For MMD, the total number of patients with newly diagnosed MMD and that with adult MMD demonstrated significantly increasing trends, while the number of pediatric patients with newly diagnosed MMD declined by 18.0% over the 9-year period. The age-standardized incidences of pediatric and adult MMD in 2016 were 2.4 and 3.4 per 100000 person-years, respectively.

CONCLUSION

Although the incidence of CI showed a declining trend over a 9-year period, the number and proportion of patients treated for CI increased. Meanwhile, the incidence of CASTN and the number of patients treated for CASTN have demonstrated increasing trends since 2008. On the other hand, the number of patients diagnosed with pediatric MMD decreased, despite no significant change in the incidence. In contrast, the number of patients and the incidence of adult MMD increased. These trends reflect changes in the population structure, gains in the accessibility of imaging examinations, and the development of endovascular techniques.

A systematic review and meta-analysis of observational evidence for the use of bailout self-expandable stents following failed anterior circulation stroke thrombectomy

BACKGROUND

The crucial role of thrombectomy in the management of emergent large vessel occlusive stroke is not disputed but there is a technical failure rate in a significant minority of patients whose outcomes are often poor. Our objective was to perform a systematic review and meta-analysis to assess the safety and efficacy of permanent self-expandable stent deployment as a bailout procedure in cases of failed anterior circulation thrombectomy.

METHODS

Two independent reviewers searched the Pubmed (Medline) database for studies reporting outcomes following failed endovascular thrombectomy with subsequent rescue therapy employing self-expandable stents.

RESULTS

Eight studies (one prospective, seven retrospective) originating from Europe, Asia, and America comprising 160 patients met the inclusion criteria. Estimated baseline National Institutes of Health Stroke Scale score was 17.1 (95% CI 15.7 to 18.4). Following failed thrombetcomy and stent deployment, the rate of favorable outcome (modified Rankin Scale score 0-2) was 43% (95% CI 34% to 53%). Pooled mortality was 21% (95% CI 13% to 33%). Successful recanalization (Thrombolysis in Cerebral Infarction (TICI) 2b-3 or Thrombolysis in Myocardial Infarction (TIMI) 2-3) was 71% (95% CI 63% to 77%). Symptomatic intracerebral hemorrhage was seen in 12% (95% CI 7% to 18%). The Solitaire stent (Medtronic) was the most commonly deployed stent following failed thrombectomy attempts (66%; 95% CI 31% to 89%). Pre- or post-stent angioplasty was performed in 39%of patients (95% CI 29% to 48%). Glycoprotein IIb/IIIa inhibitors were used in 89% (95% CI 71% to 97%). 95% of patients received postprocedural antiplatelet therapy.

CONCLUSION

A rescue stent procedure seems reasonable as a last resort following failed thrombectomy but currently the level of evidence is limited. Prospective registries may aid in guiding future recommendations.

Bail-out intracranial stenting with Solitaire AB device after unsuccessful thrombectomy in acute ischemic stroke of anterior circulation

BACKGROUND

Recent trials established the efficacy of mechanical stent-retriever thrombectomy for treatment of stroke patients with large vessel occlusion (LVO) in the anterior circulation. However, stent-retriever thrombectomy may not accomplish successful recanalization in all patients. The aim of this study is to report the role of bail-out permanent stenting after failure of mechanical thrombectomy.

METHODS

Among 430 patients included in a prospectively maintained database, we analysed 325 cases of anterior circulation LVO. Mechanical thrombectomy (mTICI 2b-3) was effective in 213/325 (65%) and failed in 112/325 (35%). Bail-out intracranial stenting was performed in 17/325 (5.2%) patients. In all cases a fully retrievable detachable stent was used (Solitaire AB, Medtronic).

RESULTS

No intraprocedural technical complications occurred. Successful reperfusion (mTICI 2b/3) was achieved in 12/17 patients (70.6%). Three (17.6%) patients died: one extensive infarction in the internal carotid artery territory, one large intracerebral haemorrhage, and one massive pulmonary embolism. Haemorrhagic conversion, both symptomatic and asymptomatic, occurred in 2/17 (11.7%). Good clinical outcome (mRS 0-2) at 3-months was achieved in 41.2% of patients.

CONCLUSION

Bail-out intracranial stenting after unsuccessful thrombectomy is technically feasible and the associated haemorrhagic risk seems acceptable in selected patients. We suggest that bail-out intracranial stenting, is safe and effective in selected patients with LVO stroke who failed to respond to thrombectomy.

Reperfusion therapy in acute ischemic stroke: dawn of a new era?

Following the success of recent endovascular trials, endovascular therapy has emerged as an exciting addition to the arsenal of clinical management of patients with acute ischemic stroke (AIS). In this paper, we present an extensive overview of intravenous and endovascular reperfusion strategies, recent advances in AIS neurointervention, limitations of various treatment paradigms, and provide insights on imaging-guided reperfusion therapies. A roadmap for imaging guided reperfusion treatment workflow in AIS is also proposed. Both systemic thrombolysis and endovascular treatment have been incorporated into the standard of care in stroke therapy. Further research on advanced imaging-based approaches to select appropriate patients, may widen the time-window for patient selection and would contribute immensely to early thrombolytic strategies, better recanalization rates, and improved clinical outcomes.

Feasibility of Permanent Stenting with Solitaire FR as a Rescue Treatment for the Reperfusion of Acute Intracranial Artery Occlusion

BACKGROUND AND PURPOSE

The Solitaire FR can be used not only as a tool for mechanical thrombectomy but also as a detachable permanent stent. Our aim was to assess the feasibility and safety of permanent stent placement with the Solitaire FR compared with other self-expanding stents for intracranial artery recanalization for acute ischemic stroke.

MATERIALS AND METHODS

From January 2011 through January 2016, we retrospectively selected 2979 patients with acute ischemic stroke. Among them, 27 patients who underwent permanent stent placement (13 patients with the Solitaire FR [Solitaire group] and 14 patients with other self-expanding stents [other stent group]) were enrolled. The postprocedural modified TICI grade and angiographic and clinical outcomes were assessed. The safety and efficacy of permanent stent placement of the Solitaire FR for acute large-artery occlusion were evaluated.

RESULTS

Stent placement was successful in all cases. Modified TICI 2b-3 reperfusion was noted in 84.6% of the Solitaire group and in 78.6% of the other stent group. Procedural time was significantly shorter in the Solitaire group than in the other stent group (P = .022). Shorter procedural time was correlated with favorable outcome (ρ = 0.46, P = .035). No significant differences were found in the modified TICI grade, NIHSS score, mRS, and hemorrhagic transformation rate between the 2 groups. The acute in-stent thrombosis rate at discharge was significantly lower when a glycoprotein IIb/IIIa inhibitor was injected during the procedure (P = .013).

CONCLUSIONS

Permanent stent placement with the Solitaire FR compared with other self-expanding stents appears to be feasible and safe as a rescue tool for refractory intra-arterial therapy.

Percutaneous transluminal angioplasty and stenting for symptomatic intracranial arterial stenosis: a systematic review and meta-analysis

OBJECTIVES

The cumulative safety and efficacy measures of percutaneous transluminal angioplasty and stenting (PTAS) for secondary stroke prevention in patients with symptomatic intracranial arterial stenosis (sICAS) have not previously been evaluated using a meta-analytical approach.

METHODS

We conducted a systematic review and random effects meta-analysis of all available randomized controlled trials (RCTs) evaluating the safety and efficacy of PTAS (in comparison with medical therapy) for sICAS.

RESULTS

Three RCTs (678 total patients) were included in the quantitative analysis. PTAS was associated with a higher risk of recurrent ischemic stroke in the territory of qualifying artery both within 30 days [risk ratio (RR) = 2.21, 95% confidence interval (CI) 1.10-4.43] and 1 year (RR = 1.92, 95% CI 1.10-3.36). PTAS was also related to a higher risk of any ischemic stroke within 30 days from the index event (RR = 2.08, 95% CI 1.17-3.71). The risk for intracranial hemorrhage was found to be higher in PTAS patients both within 30 days (RR = 10.60, 95% CI 1.98-56.62) and 1 year (RR = 8.15, 95% CI 1.50-44.34). The composite outcome of any stroke or death within 1 year (RR = 2.29, 95% CI 1.13-4.66) and 2 years (RR = 1.52, 95% CI 1.04-2.21) was higher in PTAS than in medical therapy. PTAS was associated with a higher risk of any stroke or death within 2 years in the sICAS subgroup located in posterior circulation (RR = 2.37, 95% CI 1.27-4.42).

CONCLUSIONS

PTAS is associated with adverse early and long-term outcomes and should not be recommended in patients with sICAS. Further research to identify subgroups of patients who could also serve as candidates for future interventional trials along with efforts to reduce procedure-related complications are needed.

Changing Management of Acute Ischaemic Stroke: the New Treatments and Emerging Role of Endovascular Therapy

OPINION STATEMENT

Urgent reperfusion of the ischaemic brain is the aim of stroke treatment, and the last two decades have seen a rapid advancement in the medical and endovascular treatment of acute ischaemic stroke. Intravenous tissue plasminogen activator (tPA) was first introduced as a safe and effective thrombolytic agent followed by the introduction of newer thrombolytic agents as well as anticoagulant and antiplatelet agents, proposed as potentially safer drugs with more favourable interaction profiles. In addition to chemo-thrombolysis, other techniques including transcranial sonothrombolysis and microbubble cavitation have been introduced which are showing promising results, but await large-scale clinical trials. These developments in medical therapies which are undoubtedly of great importance due to their potential widespread and immediate availability are paralleled with gradual but steady improvements in endovascular recanalisation techniques which were initiated by the introduction of the MERCI (Mechanical Embolus Removal in Cerebral Ischemia) and Penumbra systems. The introduction of the Solitaire device was a significant achievement in reliable and safe endovascular recanalisation and was followed by further innovative stent retrievers. Initial trials failed to show a solid benefit in endovascular intervention compared with IV-tPA alone. These counterintuitive results did not last long, however, when a series of very well-designed randomised controlled trials, pioneered by MR-CLEAN, EXTEND-IA and ESCAPE, emerged, confirming the well-believed daily anecdotal evidence. There have now been seven positive trials of endovascular treatment for acute ischaemic stroke. Now that level I evidence regarding the superiority of endovascular recanalisation is abundantly available, the clinical challenge is how to select patients suitable for intervention and to familiarise and educate stroke care providers with this recent development in stroke care. It is important for the interventional services to be provided only in comprehensive stroke centres and endovascular interventions attempted by experienced well-trained operators, at this stage as an adjunct to the established medical treatment of IV-tPA, if there are no contraindications.

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.

A Novel Canine Model of Acute Vertebral Artery Occlusion

Background

The extended time window and theoretic reduction in hemorrhage make mechanical strategies an attractive approach for the treatment of patients with ischemic stroke. However, a limited availability of suitable animal models of cerebrovascular thrombosis has hampered the study of novel endovascular interventions. The aim of the present study was to develop a new technique for site-specific placement of a thrombus in a canine model that would allow for the evaluation of mechanical thrombectomy and clot retrieval methods and the visualization of thrombus dislocation or fragmentation during angiographic manipulation.

Methods

Angiography and embolization with a preformed thrombus were performed in 12 canines. Under fluoroscopic guidance, an embolism protection device (EPD) was anchored to the middle segment of the left vertebral artery (VA) via the left femoral arterial sheath. A preformed radiopaque clot was injected through the guide catheter into the left VA, via the contralateral femoral artery, proximal to the EPD. After 15 min of occlusion, the EPD was removed and persistent occlusion of the VA was documented angiographically.

Results

Angiography performed during the observation period confirmed the persistence of VA occlusion in each case, and displacement of the radiopaque clots did not occur during the 3-hour observation period. The technique allowed selective embolization of targeted vessels without thrombus fragmentation.

Conclusion

This study demonstrates, for the first time, a canine model of post-circulation embolism induced by autologous blood clot placement. This model can be rapidly formed and easily operated, and the site of thrombosis can be readily controlled.

State-of-the-art endovascular treatment of acute ischemic stroke

Stroke is the third leading cause of death in the USA. An estimated 795,000 new or recurrent stroke events occur annually, mostly ischemic in nature. Arterial recanalization and subsequent reperfusion performed shortly after symptom onset can help to restore brain function in acute ischemic stroke (AIS). The only treatment currently approved by the United States Food and Drug Administration is intravenous tissue plasminogen activator, administered within 4.5 h of symptom onset. However, this short window often precludes effective intervention. Mechanical neurothrombectomy devices offer many potential advantages over pharmacologic thrombolysis, including more rapid achievement of recanalization, enhanced efficacy in treating large-vessel occlusions, and a potentially lower risk of hemorrhagic events. The goal of this chapter is to describe the state-of-the-art neurothrombectomy devices and stenting techniques for endovascular treatment of acute ischemic stroke, as well as to highlight recent advances in reperfusion therapies. Ongoing clinical trials, some with randomized, controlled designs, are included.

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.

Thrombolysis and reperfusion: advanced understanding of early management strategies in acute ischemic stroke

Currently, intravenous (IV) thrombolysis within 3 hours from stroke onset is the only approved treatment in acute ischemic stroke (AIS). Although effective, the definition of therapeutic time window and appropriate patient selection still remains controversial. Notably, early endovascular treatment strategies may serve as an adjunct therapy for time window extension in AIS. In this article, we review the safety and efficacy of IV thrombolysis in AIS as it pertains to the optimal time window, the selection of eligible patients, and in combination with endovascular treatment. Combined clinical application of IV thrombolysis and endovascular therapy may improve the therapeutic outcomes for AIS patients.

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

While intravenous administration of tissue plasminogen activator (tPA) remains the only FDA-approved treatment modality for acute ischemic stroke, many patients do not meet the criteria for intravenous tPA and are offered intra-arterial therapy. Rapid advances in devices and approaches have marked the evolution of thrombectomy over the past decade from rudimentary mechanical disruption, followed by intra-arterial thrombolytic infusions to increasingly effective thrombectomy devices. We review the critical advancements in thrombectomy technique that have evolved and the key anatomic and technical challenges they address, from first-generation Merci retrieval systems to second-generation Penumbra aspiration systems and third-generation stent retrievers, as well as nuances of their uses to maximize their effectiveness. We also highlight more recent advances that offer patients hope for more expedient vessel recanalization.

The quest for arterial recanalization in acute ischemic stroke-the past, present and the future

Ischemic stroke is one of the major causes of mortality and long-term disability. In the recent past, only very few treatment options were available and a considerable proportion of stroke survivors remained permanently disabled. However, over the last 2 decades rapid advances in acute stroke care have resulted in a corresponding improvement in mortality rates and functional outcomes. In this review, we describe the evolution of systemic thrombolytic agents and various interventional devices, their current status as well as some of the future prospects. We reviewed literature pertaining to acute ischemic stroke reperfusion treatment. We explored the current accepted treatment strategies to attain cerebral reperfusion via intravenous modalities and compare and contrast them within the boundaries of their clinical trials. Subsequently we reviewed the trials for interventional devices for acute ischemic stroke, categorizing them into thrombectomy devices, aspiration devices, clot disruption devices and thrombus entrapment devices. Finally we surveyed several of the alternative reperfusion strategies available. We also shed some light on the controversies surrounding the current strategies of treatment of acute ischemic stroke. Acute invasive interventional strategies continue to improve along with the noninvasive modalities. Both approaches appear promising. We conducted a comprehensive chronological review of the existing treatments as well as upcoming remedies for acute ischemic stroke.

Endovascular treatment of acute ischemic stroke

Endovascular stroke therapy has revolutionized the management of patients with acute ischemic stroke in the last decade and has facilitated the development of sophisticated stroke imaging techniques and a multitude of thrombectomy devices. This article reviews the scientific basis and current evidence available to support endovascular revascularization and provides brief technical details of the various methods of endovascular thrombectomy with case examples.

Mechanical thrombectomy devices for endovascular management of acute ischemic stroke: Duke stroke center experience

Background:

Mechanical thrombectomy devices are gaining popularity in large vessel occlusions where chemical thrombolysis is usually futile. MERCI, Multi-MERCI, Penumbra and SWIFT trails have elevated the status of mechanical thrombectomy from being a complementary treatment modality to mainstream stroke intervention. The aim of this study was to compare our immediate recanalization rates with available mechanical devices.

Materials and Methods:

A retrospective review from March 2009 to August 2012 was performed on patients who underwent mechanical thrombectomy for large vessel occlusion. Cases where IATPA and/or balloon angioplasty was performed without mechanical thrombectomy were excluded from the study. Recanalization rates were assessed immediately post-procedure by follow-up angiography. TICI scores were used to quantify the extent of recanalization and the residual clot burden.

Results:

Twenty two procedures were performed on 20 patients using Merci (MER):5; Penumbra (PEN):11; Solitaire-FR (SOL):6. Two patients underwent intervention using both Merci and Penumbra devices. The M:F ratio was 1.2:1. The most common vascular territory involved was the right MCA (9/20) followed by left MCA (5/20), left ICA (2/20), basilar (3/20) and vertebral arteries (1/20). The average door to needle time was 210 minutes [MER: 184.4; PEN: 249.2; SOL: 162]. Additional procedures were performed in 63.4% (14/22) of the patients [MER: 80% (4/5); PEN: 72.7% (8/11) and SOL: 33.3% (2/6)]. Vasospasm was observed in MER: 20% (1/5); PEN: 9.1% (1/11); SOL: 0% (0/6)]. Complete recanalization was achieved in 59.1% (13/22) [MER: 40% (2/5); PEN: 45.5% (5/11); SOL: 100% (6/6)]. The rate of complete recanalization was statistically significant for the Solitaire group vs. the MERCI group (P=0.0062) as well as the Penumbra group (0.0025). The average pre-procedure TICI was 0.4 [MER: 0.6; PEN: 0.3; SOL: 0.3], while the average post-procedure TICI was 2.5 [MER: 2.4; PEN: 2.3; SOL: 3.0].

Conclusions:

The study reveals a higher rate of angiographic recanalization using the Solitaire-FR device, requiring a lesser number of passes and other associated procedures as compared to MERCI and Penumbra. Thus, Stentrievers (Solitaire-FR) are advantageous in faster device delivery and quick flow restoration. However, future prospective randomized large trials are required to confirm these early results.

Evidence-based changes in devices and methods of endovascular recanalization therapy

The devices and methods of endovascular recanalization therapy (ERT) have been rapidly developed and changed since PROACT II trial. Emerging as a treatment option in addition to intravenous or intra-arterial thrombolysis, mechanical thrombectomy is currently being further developed and investigated as a potential first-line and stand-alone treatment. This review highlights and summarizes the recent clinical series and trials of the available devices and methods of ERT focusing on the multimodal approach.

Multimodal endovascular management of acute ischemic stroke in patients over 75 years old is safe and effective

Introduction

Greater attention has been directed to endovascular recanalization of acute ischemic stroke in septuagenarians and above.

Technique

A retrospective chart review was conducted to include patients treated for acute ischemic stroke from 2006 to 2012. All patients underwent initial neurological assessment and non-contrast head CT. Patients treated from 2009 to 2012 additionally received emergent CT angiogram and CT perfusion. 51 patients met the clinical and radiographic criteria and underwent multimodal endovascular revascularization for acute ischemic events.

Results

All patients underwent cerebral angiography and met angiographic criteria for endovascular thrombolysis. 34 patients (67%) were older than 80 years of age. 23 patients (45%) received intravenous tissue plasminogen activator prior to admission. Eight (16%) patients underwent stent placement after intra-arterial thrombolysis, 10 (20%) underwent balloon angioplasty and seven (14%) underwent both angioplasty and stent placement. 21 (41%) required only intra-arterial thrombolytics. An improvement in Thrombolysis in Myocardial Infarction score was noted in 34 patients (67%). The average modified Rankin Scale score on discharge was 3.9. Symptomatic intracranial hemorrhage occurred in three patients (6%); none required surgery. One patient (1.9%) had a postoperative retroperitoneal hematoma, which was managed conservatively. Two fatalities resulted from intraoperative vessel rupture (3.9%), with a combined morbidity and mortality of 27.5%.

Conclusions

Multimodal endovascular recanalization of acute ischemic stroke is a relatively safe treatment option in patients older than 75 years of age. Careful patient selection by clinical and radiographic inclusion criteria is necessary for the successful management of stroke in this age group.

Techniques and results: intracranial stenting

Recanalization rates with conventional pharmacologic thrombolysis and thrombectomy devices in the treatment of large-vessel occlusions are low. Moreover, these patients do not have favorable clinical outcomes. Better recanalization devices and approaches are needed. In this review, we describe current stents used in the intracranial circulation and their application in the treatment of acute ischemic stroke due to large-vessel occlusion.

Stenting in the treatment of acute ischemic stroke: literature review

Recanalization of acute large artery occlusions is a strong predictor of good outcome. The development of thrombectomy devices resulted in a significant improvement in recanalization rates compared to thrombolytics alone. However, clinical trials and registries with these thrombectomy devices in acute ischemic stroke (AIS) have shown recanalization rates in the range of 40-81%. The last decade has seen the development of nickel titanium self-expandable stents (SES). These stents, in contrast to balloon-mounted stents, allow better navigability and deployment in tortuous vessels and therefore are optimal for the cerebral circulation. SES were initially used for stent-assisted coil embolization of intracranial aneurysms and for treatment of intracranial stenosis. However, a few authors have recently reported feasibility of deployment of SES in AIS. The use of these devices yielded higher recanalization rates compared to traditional thrombectomy devices. Encouraged by these results, retrievable SES systems have been recently used in AIS. These devices offer the advantage of resheathing and retrieving of the stent even after full deployment. Some of these stents can also be detached in case permanent stent placement is needed. Retrievable SES are being used in Europe and currently tested in clinical trials in the United States. We review the recent literature in the use of stents for the treatment of AIS secondary to large vessel occlusion.