Penumbra system: a novel mechanical thrombectomy device for large-vessel occlusions in acute stroke

Percutaneous aspiration of aortic valve vegetation in a patient with aortic valve endocarditis

Key Clinical Message

Percutaneous aspiration for debulking of vegetations in right-sided infective endocarditis has been well-described, however, this technique can be employed successfully for left-sided vegetations in select high-risk patients.

Abstract

We report a case of percutaneous aspiration of an aortic valve vegetation in a patient with prosthetic valve endocarditis. This novel approach was selected after patient declined surgical intervention for an enlarging vegetation despite antibiotic therapy. The procedure was successful, resulting in the complete removal of solid vegetation without complications.

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.

Successful Treatment of Acute Limb Ischemia Secondary to Iatrogenic Distal Embolization Using Catheter Directed Aspiration Thrombectomy

Objective: Acute limb ischemia (ALI) due to thromboembolism is a limb- and life-threatening condition regularly encountered by vascular surgeons. Iatrogenic distal embolization is occasionally seen as a complication of various endovascular procedures. We present a series of four patients who developed ALI due to arterial embolization during cardiovascular procedures that were successfully treated via catheter directed aspiration embolectomy. Methods: Retrospective review of demographics, risk factors, and procedural outcomes was completed for 4 patients who presented with ALI due to distal embolization following cardiovascular procedures. All patients were successfully treated with catheter directed aspiration embolectomy using the Penumbra Indigo System (Penumbra Inc., Alameda, California). All patients had high-quality angiography demonstrating successful embolectomy and end-procedure patency. Results: Three patients presented with Rutherford 2A and one with Rutherford 2B ALI secondary to intraoperative distal embolization. Three patients presented with ALI secondary to distal embolization during peripheral vascular interventions, and one following emergent intra-aortic balloon pump (IABP) placement for myocardial infarction. All emboli were located in the infra-inguinal vasculature. Median post-operative ABIs were 0.94 (n = 4). Median length of stay was 2 days. There were no mortalities and no need for adjunctive fasciotomy, amputation, or bypass for limb salvage. All patients improved clinically after intervention, and returned to their reported pre-hospitalization functional status. Conclusion: All procedures achieved technical success with catheter-directed aspiration thrombectomy with or without adjunctive lysis. Catheter-directed aspiration embolectomy with the Penumbra Indigo System for ALI following an iatrogenic embolic event is a safe, less-invasive treatment option. The use of this technology may reduce the need for traditional open thrombectomy or thrombolytic therapy to address ALI.

Use of microcatheters for suction thrombectomy of acute distal occlusions

We report our initial experience of using a microcatheter for contact aspiration of acute distal occlusions for recanalization. Endovascular technique and a case using Excelsior XT-27 microcatheter are presented. After manual suction within distal middle cerebral artery segments using a 50-ml syringe, instant and complete recanalization was obtained. Microcatheter suction thrombectomy using a 50-ml syringe can be considered a feasible treatment option for acute distal small artery occlusions.

Temporal Changes in Care Processes and Outcomes for Endovascular Treatment of Acute Ischemic Stroke: Retrospective Registry Data from Three Korean Centers

BACKGROUND AND PURPOSE

The purpose of the current study is to evaluate the influence of temporal patterns related to the availability of new endovascular treatment (EVT) devices on care processes and outcomes among patients with AIS.

MATERIALS AND METHODS

We enrolled 720 consecutive patients (January 2011 to May 2016) in a retrospective registry, ASIAN KR, from three Korean hospitals, who received EVT for acute ischemic stroke (AIS) caused by cervicocephalic arterial occlusions. We performed period-to-period analyses based on stent retriever reimbursement and the availability of second-generation direct-aspiration devices (Period 1: January 2011-July 2014 vs. Period 2: August 2014-May 2016); time metrics and outcomes were compared when the onset-to-puncture time was <720 min among patients with EVT for intracranial occlusion.

RESULTS

Period 2 had better post-EVT outcomes (3-month modified Rankin Scale 0-2 or equal to prestroke score, 48.3% vs. 60.2%, P=0.004), more successful reperfusion rates (modified Treatment In Cerebral Ischemia 2b-3, 74.2% vs. 82.2%, P=0.019), fewer subarachnoid hemorrhages (modified Fisher grade 3-4, 5.5% vs. 2.0%, P=0.034) and lower hemorrhagic transformation rates (any intracerebral hemorrhage, 35.3 vs. 22.7%, P=0.001) than Period 1. Compared to Period 1, Period 2 had a shorter door-to-puncture time (median 109 vs. 90 min, P<0.001), but longer onset-to-door time (129 vs. 143 min, P=0.057).

CONCLUSION

Recent temporal improvements in post-EVT AIS outcomes in Korea are likely due to a combination of enhanced hospital care processes and administration of newer thrombectomy devices.

Primary Endovascular Treatment of Acute Ischemic Stroke Using Stent Retrievers: Initial Egyptian Experience

BACKGROUND

Several mechanical thrombectomy (MT) devices have been designed with the goal of improving the recanalization rates of major intracranial artery occlusions.

OBJECTIVE

In this single-center experience, we analyzed the acute ischemic stroke (AIS) treatment with Primary MT; safety and efficacy and clinical results in our patients with large vessel occlusion (LVO).

METHODS

During a five-year period (from September 2011 to July 2016), out of 996 patients who presented to our center with a diagnosis of AIS, 113 (11.4%) patients (55 men and 58 women) underwent primary mechanical recanalization within three hours from onset of signs and symptoms for anterior and 12 hours for posterior circulation (with computer tomography angiography/perfusion ELVO). Successful recanalization (thrombolysis in cerebral infarction 2b-3), good outcome (modified Rankin scale score 0-2) and overall mortality rate, and symptomatic intracranial hemorrhage [sICH: parenchymal hematoma Type 1 or Type 2; National Institutes of Health Stroke Scale (NIHSS) score increment ≥4 points] were prospectively assessed.

RESULTS

The mean age of the patients was 62 ± 11.73 years, with a baseline mean admission NIHSS score of 16.7 ± 3.2. The mean time from onset to puncture (time to treatment) was 208.55 ± 53.49. Successful recanalization was achieved in 104 (92%) cases. Good outcome was observed in 89 (78.8%) patients, and mortality was 11.5% (n = 13). sICH occurred in five (4.4%) patients.

CONCLUSION

MT, within the first 4.5 hours, as primary treatment of acute LVO stroke provides high rate of recanalization and favorable clinical outcomes with low procedural complications.

Direct Microsurgical Embolectomy for Acute Occlusion of the Internal Carotid Artery and Middle Cerebral Artery

BACKGROUND

Surgical embolectomy is the most promising therapy for physically removing emboli from major cerebral arteries. However, it requires an experienced surgical team, time-consuming steps, and is not incorporated into acute stroke therapy.

METHODS

We established seamless collaboration between services, refined surgical techniques, and conducted a prospective trial of emergency surgical embolectomy. Surgical indications included the presence of acute hemispheric symptoms, absence of low-density area on computed tomography, evidence of internal carotid artery terminus or proximal middle cerebral artery occlusion, and availability of resources to start surgery within 3 hours of symptom onset. The indications were confirmed by an interdisciplinary team. We assessed revascularization rates, time from admission to surgery and from surgery to recanalization, procedural complications, and clinical outcomes.

RESULTS

Between 2005 and 2014, 14 consecutive patients with acute proximal middle cerebral artery or internal carotid artery terminus occlusion underwent emergency surgical embolectomy. All patients showed complete recanalization. Twelve patients survived and 7 had fair functional outcome (Rankin Scale score, ≤3). No significant procedural adverse events occurred. The mean times from admission to start of surgery, from surgery to recanalization, and from onset to recanalization were 14 minutes, 79 minutes, and 223 minutes, respectively.

CONCLUSIONS

Our results suggest that microsurgical embolectomy can rapidly, safely, and effectively retrieve clots and deserves reappraisal, although the choice largely depends on local institutional expertise.

In vitro experiments of cerebral blood flow during aspiration thrombectomy: potential effects on cerebral perfusion pressure and collateral flow

Background

Mechanical thrombectomy with stent retriever devices is associated with significantly better outcomes than thrombolysis alone in the treatment of acute ischemic stroke. Thrombus aspiration achieves high patency rates, but clinical outcomes are variable. The aim of this study was to examine the effect of different suction conditions on perfusate flow during aspiration thrombectomy.

Methods

A computational fluid dynamics model of an aspiration device within a patent and occluded blood vessel was used to simulate flow characteristics using fluid flow solver software. A physical particulate flow model of a patent vessel and a vessel occluded by thrombus was then used to visualize flow direction and measure flow rates with the aspiration catheter placed 1–10 mm proximal of the thrombus, and recorded on video.

Results

The mathematical model predicted that, in a patent vessel, perfusate is drawn from upstream of the catheter tip while, in an occluded system, perfusate is drawn from the vessel proximal to the device tip with no traction on the occlusion distal of the tip. The in vitro experiments confirmed the predictions of this model. In the occluded vessel aspiration had no effect on the thrombus unless the tip of the catheter was in direct contact with the thrombus.

Conclusions

These experiments suggest that aspiration is only effective if the catheter tip is in direct contact with the thrombus. If the catheter tip is not in contact with the thrombus, aspirate is drawn from the vessels proximal of the occlusion. This could affect collateral flow in vivo.

Emergent intracranial surgical embolectomy in conjunction with carotid endarterectomy for acute internal carotid artery terminus embolic occlusion and tandem occlusion of the cervical carotid artery due to plaque rupture

Acute internal carotid artery (ICA) terminus occlusion is associated with extremely poor functional outcomes or mortality, especially when it is caused by plaque rupture of the cervical ICA with engrafted thrombus that elongates and extends into the ICA terminus. The goal of this study was to evaluate the efficacy and safety of surgical embolectomy in conjunction with carotid endarterectomy (CEA) for acute ICA terminus occlusion associated with cervical plaque rupture resulting in tandem occlusion. A retrospective review of medical records was performed. Clinical and radiographic characteristics were evaluated, including details of surgical technique, recanalization grade, recanalization time, complications, modified Rankin Scale (mRS) score at 3 months, and National Institutes of Health Stroke Scale (NIHSS) score improvement at 1 month. Three patients (mean age 77.3 years; median presenting NIHSS Score 22, range 19–26) presented with abrupt tandem occlusion of the cervical ICA and ICA terminus and were selected for surgery after confirmation of embolic high-density signal at the ICA terminus on CT and diffusion-weighted imaging (DWI)/magnetic resonance angiography (MRA) mismatch. All patients underwent craniotomy for surgical embolectomy of the ICA terminus embolus followed by cervical exposure, aspiration of long residual proximal embolus ranging from the cervical to cavernous ICA, and removal of ruptured unstable plaque by CEA. Postoperative MRA demonstrated Thrombolysis In Myocardial Infarction (TIMI) 3 recanalization in all patients (100%) without evidence of additional infarction according to DWI. Mean recanalization time from hospital arrival was 234 minutes and from start of surgery, 151 minutes. Serial postoperative CT and MRI studies showed no symptomatic hemorrhage, brain edema, or progression of infarction. The patients' mRS scores at 3 months were 3, 3, and 1. All 3 patients demonstrated marked improvements in NIHSS scores (median 17 points; range 13–23 points) at 1 month. Considering the dismal prognosis associated with ICA terminus occlusion, especially when accompanied by cervical plaque rupture, emergent surgical embolectomy in conjunction with CEA might be an effective and decisive treatment option with a high complete recanalization rate and acceptable safety profile.

Endovascular therapy for ischemic stroke

The utility of intravenous tissue plasminogen activator (IV t-PA) in improving the clinical outcomes after acute ischemic stroke has been well demonstrated in past clinical trials. Though multiple initial small series of endovascular stroke therapy had shown good outcomes as compared to IV t-PA, a similar beneficial effect had not been translated in multiple randomized clinical trials of endovascular stroke therapy. Over the same time, there have been parallel advances in imaging technology and better understanding and utility of the imaging in therapy of acute stroke. In this review, we will discuss the evolution of endovascular stroke therapy followed by a discussion of the key factors that have to be considered during endovascular stroke therapy and directions for future endovascular stroke trials.

Endovascular treatment of acute ischemic stroke

Early recanalization of the occluded artery leads to better clinical outcomes in patients with acute ischemic stroke (AIS) through protection of the time-sensitive penumbra. Intravenous administration of pharmacologic thrombolytic agents has been a standard treatment for AIS. To get better rates of recanalization, enhance the time window, and diminish the possibility of intracranial hemorrhage, endovascular thrombectomy was launched, with first authorization of the Merci clot retriever, a corkscrew-like apparatus, followed by approval of the Penumbra thromboaspiration system. Both devices lead to a high rate of recanalization. On the other hand, time to recanalization was on an average of 45 minutes, with most of the patients attaining only partial recanalization. More lately, retrievable stents have shown promise in decreasing the time to recanalization, and attaining a superior rate of complete clot resolution. The retrievable stent can be released within the clot to engage it within the struts of the stent, and afterwards it is taken back by pulling it under flow arrest. Neurointerventional techniques have a persistently ever-increasing and stimulating role in the management of AIS, as indicated by the advent of several important techniques. Stent retrievers have the capability to be ascertained as the most important approach to endovascular stroke treatment.

Surgical embolectomy for middle cerebral artery occlusion after thrombolytic therapy: A report of two cases

Background:

Occlusion of the intracranial main trunk results in a poor functional outcome and a high mortality rate. Accordingly, some revascularization procedures such as intravenous administration of recombinant tissue plasminogen activator (rt-PA), endovascular surgery, or surgical embolectomy in the very acute stage have been attempted.

Case Description:

We describe two patients with middle cerebral artery occlusion due to cardiogenic embolism. One patient was subjected to surgical embolectomy shortly after intravenous rt-PA and the other was subjected to same after intra-arterial urokinase. Complete recanalization without new cerebral infarction territory was achieved in both patients.

Conclusion:

Based on our experience, we think that surgical embolectomy is an effective and safe procedure and should be attempted when no response to early thrombolytic therapy is obtained.

Machine learning for outcome prediction of acute ischemic stroke post intra-arterial therapy

Introduction

Stroke is a major cause of death and disability. Accurately predicting stroke outcome from a set of predictive variables may identify high-risk patients and guide treatment approaches, leading to decreased morbidity. Logistic regression models allow for the identification and validation of predictive variables. However, advanced machine learning algorithms offer an alternative, in particular, for large-scale multi-institutional data, with the advantage of easily incorporating newly available data to improve prediction performance. Our aim was to design and compare different machine learning methods, capable of predicting the outcome of endovascular intervention in acute anterior circulation ischaemic stroke.

Method

We conducted a retrospective study of a prospectively collected database of acute ischaemic stroke treated by endovascular intervention. Using SPSS®, MATLAB®, and Rapidminer®, classical statistics as well as artificial neural network and support vector algorithms were applied to design a supervised machine capable of classifying these predictors into potential good and poor outcomes. These algorithms were trained, validated and tested using randomly divided data.

Results

We included 107 consecutive acute anterior circulation ischaemic stroke patients treated by endovascular technique. Sixty-six were male and the mean age of 65.3. All the available demographic, procedural and clinical factors were included into the models. The final confusion matrix of the neural network, demonstrated an overall congruency of ∼80% between the target and output classes, with favourable receiving operative characteristics. However, after optimisation, the support vector machine had a relatively better performance, with a root mean squared error of 2.064 (SD: ±0.408).

Discussion

We showed promising accuracy of outcome prediction, using supervised machine learning algorithms, with potential for incorporation of larger multicenter datasets, likely further improving prediction. Finally, we propose that a robust machine learning system can potentially optimise the selection process for endovascular versus medical treatment in the management of acute stroke.

Neurothrombectomy in the treatment of acute ischaemic stroke

Major ischaemic stroke is a leading cause of morbidity and mortality in industrialized countries. For patients with acute stroke, fast and effective vessel recanalization is important for successful treatment. Neurothrombectomy--that is, angiographically performed mechanical thrombus removal from intracranial arteries--results in higher recanalization rates than with pharmaceutical thrombolysis alone, but the value of this treatment in terms of clinical outcome remains to be established. This article summarizes the history of intra-arterial stroke treatment, outlines the recent developments and the different techniques used, and discusses the results of current studies on neurothrombectomy. Owing to the high morphological and clinical variability of stroke, careful patient selection in future randomized controlled trials will be crucial for assessment of the true potential of neurothrombectomy.

Optimizing prediction scores for poor outcome after intra-arterial therapy in anterior circulation acute ischemic stroke

BACKGROUND AND PURPOSE

Intra-arterial therapy (IAT) promotes recanalization of large artery occlusions in acute ischemic stroke. Despite high recanalization rates, poor clinical outcomes are common. We attempted to optimize a score that combines clinical and imaging variables to more accurately predict poor outcome after IAT in anterior circulation occlusions.

METHODS

Patients with acute ischemic stroke undergoing IAT at University of Texas (UT) Houston for large artery occlusions (middle cerebral artery or internal carotid artery) were reviewed. Independent predictors of poor outcome (modified Rankin Scale, 4-6) were studied. External validation was performed on IAT-treated patients at Emory University.

RESULTS

A total of 163 patients were identified at UT Houston. Independent predictors of poor outcome (P≤0.2) were identified as score variables using sensitivity analysis and logistic regression. Houston Intra-Arterial Therapy 2 (HIAT2) score ranges 0 to 10: age (≤59=0, 60-79=2, ≥80 years=4), glucose (<150=0, ≥150=1), National Institute Health Stroke Scale (≤10=0, 11-20=1, ≥21=2), the Alberta Stroke Program Early CT Score (8-10=0, ≤7=3). Patients with HIAT2≥5 were more likely to have poor outcomes at discharge (odds ratio, 6.43; 95% confidence interval, 2.75-15.02; P<0.001). After adjusting for reperfusion (Thrombolysis in Cerebral Infarction score≥2b) and time from symptom onset to recanalization, HIAT2≥5 remained an independent predictor of poor outcome (odds ratio, 5.88; 95% confidence interval, 1.96-17.64; P=0.02). Results from the cohort of Emory (198 patients) were consistent; patients with HIAT2 score≥5 had 6× greater odds of poor outcome at discharge and at 90 days. HIAT2 outperformed other previously published predictive scores.

CONCLUSIONS

The HIAT2 score, which combines clinical and imaging variables, performed better than all previous scores in predicting poor outcome after IAT for anterior circulation large artery occlusions.

Aspiration thrombectomy in concert with stent thrombectomy

In the SWIFT and TREVO 2 trials, aspiration thrombectomy was not able to be performed. Outside these studies, in post-market application, the interventionist can use aspiration thrombectomy in addition to stent device thrombectomy. This technique is described in detail in the present report. Combined aspiration/stentriever thrombectomy may improve recanalization efforts, simplify a second thrombectomy attempt if necessary and may limit distal embolization.

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.

What is meant by "TICI"?

BACKGROUND

In 2003, Higashida et al proposed the Thrombolysis In Cerebral Infarction scale to evaluate angiographic intracranial flow. Our aim is to review how subsequently published studies define TICI.

MATERIALS AND METHODS

We used the ISI Web of Knowledge and SciVerse Scopus databases to search for "TICI" and "thrombolysis in cerebral infarction" and for articles that cited the original TICI paper from January 2004 through May 2012. Articles were categorized according to their definition of the TICI categories, typically grades 0-4, with grade 2 (partial reperfusion) subdivided into 2a and 2b, and rate of contrast entry to the perfused area. In addition, we catalogued the type of redefinitions of TICI subcategory 2 and additions of new categories.

RESULTS

Of 236 articles screened, 74 were included. Eight (11%) explicitly followed the TICI scale as originally defined. Thirty-seven (50%) cited Higashida but did not define their scale. Fifteen (21%) used and explained modified scales. Thirteen (18%) used the term TICI, but did not define the scale and did not cite Higashida. Eighteen (24%) specified a 2a subcategory. Nine defined grade 2a as <67% filling, 6 defined it as <50%, and 3 did not offer a percentage. Two studies added a 2c subcategory. Fifty-two (70%) used a cutoff level to define "successful reperfusion." Of these, 65% used TICI ≥2, 33% used TICI ≥2b, and 2% used TICI = 3.

CONCLUSIONS

There is substantial variability in the definition and/or application of the TICI scale in the literature. This variability could considerably impact our understanding of results of revascularization studies.

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.

The combined use of mechanical thrombectomy devices is feasible for treating acute carotid terminus occlusion

BACKGROUND

Mechanical thrombectomy devices have recently been developed and approved for recanalization of intracranial arterial occlusion. Here, we investigated the feasibility of combined stent-assisted and clot aspiration mechanical thrombectomy for effective recanalization of acute carotid terminus occlusion (CTO).

METHODS

Ten consecutive patients with acute ischemic stroke secondary to CTO who underwent intra-arterial (IA) treatment with both stent retrieval and negative-pressured clot aspiration systems were enrolled. Periprocedural and radiologic findings and clinical outcomes were evaluated.

RESULTS

The median age was 69 years (range, 47-86 years), and the median initial NIHSS score was 17.5 (range, 12-33). Mechanical thrombectomy was performed using a combination of the Solitaire stents and Penumbra system. Thrombolysis in cerebral ischemia [TICI] grade II-III was achieved in eight patients (80.0 %); complete recanalization of the CTO (TICI III) was achieved in three of those patients. Any type of intracranial hemorrhages occurred in four patients (40.0 %), but parenchymal hematoma type 2 was not observed. Four patients died within 3 months (40.0 %).

CONCLUSIONS

Combined mechanical thrombectomy treatment was effective for recanalization of acute CTO. The combination of Solitaire and Penumbra devices can be considered as a treatment option for CTO.

Reduction in distal emboli with proximal flow control during mechanical thrombectomy: a quantitative in vitro study

BACKGROUND AND PURPOSE

To evaluate the impact of proximal flow control on efficacy and safety of mechanical thrombectomy in an in vitro middle cerebral artery occlusion.

METHODS

Three independent variables, including clot type, device (Merci Retriever, Solitaire FR, and Trevo devices), and use of a balloon guide catheter, were used to ascertain the impact of proximal flow control on the size and number of distal emboli generated during thrombectomy. Secondary end points were the recanalization rate and amount of flow restored.

RESULTS

Use of the balloon guide catheter during thrombectomy of the fragile, hard clot significantly reduced the formation of large distal emboli with a diameter >1 mm, regardless of the device used (P<0.01). Applying aspiration via the balloon guide catheter in place of the conventional guide catheter resulted in a significant increase of flow reversal (P<0.0001). Prior to thrombectomy, deployment of the stent-trievers produced immediate flow restoration through the soft and hard clot occlusions, 69.2 ± 27.3 and 45.5 ± 22.8 mL/min, respectively, that was preserved after the balloon inflation because of collateral flow via the posterior communication artery. After deployment but before thrombectomy, no flow was restored when using the Merci Retriever. After thrombectomy, complete flow restoration was achieved in a majority of cases. The Merci Retriever required more thrombectomy attempts to achieve hard clot removal compared with the stent-trievers when the conventional guide catheter was used (1.5 versus 1.1).

CONCLUSIONS

The risk of distal embolization was significantly reduced with the use of the balloon guide catheter.

Critical use of balloon angioplasty after recanalization failure with retrievable stent in acute cerebral artery occlusion

OBJECTIVE

Sudden major cerebral artery occlusion often resists recanalization with currently available techniques or can results in massive symptomatic intracranial hemorrhage (sICH) after thrombolytic therapy. The purpose of this study was to examine mechanical recanalization with a retrievable self-expanding stent and balloon in acute intracranial artery occlusions.

METHODS

Twenty-eight consecutive patients with acute intracranial artery occlusions were treated with a Solitaire retrievable stent. Balloon angioplasty was added if successful recanalization was not achieved after stent retrieval. The angiographic outcome was assessed by Thrombolysis in Cerebral Infarction (TICI) and the clinical outcomes were assessed by the National Institutes of Health Stroke Scale (NIHSS) and the modified Rankin Scale (mRS).

RESULTS

At baseline, mean age was 69.4 years and mean initial NIHSS score was 12.5. A recanalization to TICI 2 or 3 was achieved in 24 patients (85%) after stent retrieval. Successful recanalization was achieved after additional balloon angioplasty in 4 patients. At 90-day follow-up, 24 patients (85%) had a NIHSS improvement of ≥4 and 17 patients (60%) had a good outcome (mRS ≤2). Although there was sICH, there was one death associated with the procedure.

CONCLUSION

Mechanical thromboembolectomy with a retrievable stent followed by additional balloon angioplasty is a safe and effective first-line therapy for acute intracranial artery occlusions especially in case of unsuccessful recanalization after stent thrombectomy.

Trevo versus solitaire a head-to-head comparison between two heavy weights of clot retrieval

BACKGROUND AND PURPOSE

Recent reports have indicated that mechanical thrombectomy may have potential to treat acute ischemic stroke. However, few comparative studies of neurothrombectomy devices are reported. This study aims to compare the safety and effectiveness of two retrievable stent systems in acute ischemic stroke patients.

METHODS

A prospective study comparing the clinical, radiological, and functional outcome of 33 patients with an angiographically verified occlusion of the anterior cerebral circulation. Patients were treated either with Trevo Retriever(TM) or Solitaire Stent(TM) according to the neurointerventionalist preference. Successful recanalization was defined as TICI grade 2a to 3. Good outcome was defined as a modified Rankin Scale score ≤ 2 at 3 months.

RESULTS

Revascularization was achieved in 10 patients (77%) in the Trevo group and in 12 (60%) of the Solitaire group (P = .456). Rate of symptomatic ICH was 0% for Trevo versus 15% for Solitaire (P = .261). Four patients (30%) died during the 3-month follow-up period in the Trevo versus 5 patients (25%) in the solitaire group (P = 1.000). Rate of good outcome was 38% and 40% for Trevo and Solitaire respectively (P = .435).

CONCLUSIONS

Our study showed no significant differences between both stentrievers. Moderately high recanalization rates are possible with both, however larger series may depict safety-related variations.

Population-based estimates of neuroendovascular procedures: results of a state-wide study

BACKGROUND

The Brain Attack Coalition identified the availability of neuroendovascular procedures as an essential component of a comprehensive stroke center.

OBJECTIVE

To provide population-based estimates of neuroendovascular procedures.

METHODS

State-wide estimates of cervicocerebral angiograms, endovascular ischemic stroke treatments, carotid angioplasty and stent placements, intracranial angioplasty and stent placements, endovascular treatment of intracranial aneurysms, and endovascular treatment of intracranial arteriovenous malformations (AVMs) were obtained. We calculated the annual incidence rates of various neuroendovascular and neurosurgical procedures (per 100,000 persons). For the denominator, total persons in each year were categorized in 10-year age intervals.

RESULTS

The incidence of carotid endarterectomy (387.6 per 100,000 persons) and carotid stent placement (34.7 per 100,000 persons) peaked at 75-84 years. The incidence of aneurysm embolization also peaked in that population bracket (67.9 per 100,000 persons), yet there was a dramatic reduction in the incidence of surgical aneurysm treatment (3.6 per 100,000 persons) in those aged 75-84 years. There was a prominent reduction in the incidence of all procedures in the population aged ≥85 years, except for intravenous/intra-arterial thrombolytic use in ischemic stroke. The incidence of ischemic stroke increased almost by 50% in the population aged ≥85 years compared to those aged 75-84 years. However, the incidence of endovascular procedures for acute ischemic stroke decreased from 22.8 per 100,000 persons in the population aged 75-84 years to 13.2 per 100,000 persons in the population aged ≥85 years.

CONCLUSIONS

A marked disproportion of neuroendovascular procedures performed and disease prevalence was noted in persons aged ≥85 years, an increasing segment of the population according to recent Census.

Use of stentrievers in acute stroke: tips, tricks, and current results

Stentrievers are stent-like devices used in the treatment of acute ischemic stroke. They have demonstrated efficacy in restoring the intracranial blood flow with low procedural times. This article is a synopsis of the available devices and different techniques. An extensive review of the literature summarizing all the data that have been published demonstrating their clinical impact and complications is also presented.

A meta-analysis of observational intra-arterial stroke therapy studies using the Merci device, Penumbra system, and retrievable stents

BACKGROUND AND PURPOSE

The time from arterial puncture to successful recanalization is an important milestone toward timely recanalization. With the significant improvement in recanalization rates by using thrombectomy devices, procedural time to recanalization is becoming a determinant factor in choosing among available devices. We aimed to assess the impact of time to recanalization on the outcome of intra-arterial stroke therapies.

MATERIALS AND METHODS

We conducted a meta-analysis of studies reporting procedural times in patients with stroke treated with the MD, PS, and RS.

RESULTS

We identified 16 eligible studies: 4 on the MD (n = 357), 8 on the PS (n = 455), and 4 on RS (n = 113). Merci device studies described total procedural duration, while PS and RS studies described puncture-to-recanalization times. With a random-effects model, mean procedural duration for the MD was 120 minutes (95% CI, 105.7-134.2 minutes). Mean puncture to recanalization time for the PS was 64.6 minutes (95% CI, 44.4-84.8 minutes) and 54.7 minutes for RS (95% CI, 47.3-62.2 minutes). Successful recanalization was achieved in 211 of 357 patients (59.1%) in the MD studies (95% CI, 49.3-77.7), 394 of 455 (86.6%) in the PS studies (95% CI, 84.1-93.8), and 105 of 113 (92.9%) in the RS studies (95% CI, 90.9-99.9). Functional independence (mRS ≤2) was achieved in 31.5% of patients in the MD studies, 36.6% in the PS studies, and 46.9% in the RS studies.

CONCLUSIONS

The use of the PS and RS was associated with comparable procedural time to recanalization. Available data did not allow this parameter to be determined for trials using the MD. Retrievable stents achieved the highest rate of successful recanalization and functional outcome and the lowest mortality.

Mechanical revascularization for acute ischemic stroke: a single-center, retrospective analysis

BACKGROUND

Endovascular mechanical revascularization (thrombectomy) is an increasingly used method for intracranial large vessel recanalization in acute stroke. The purpose of the study was to analyze the recanalization rate, clinical outcome, and complication rate in our stroke patients treated with mechanical revascularization.

METHODS

A total of 57 patients with large vessel stroke (within 3 h for anterior and 12 h for posterior circulation) were treated with mechanical revascularization at a single center during 24 months. The primary goal of endovascular treatment using different mechanical devices was recanalization of the occluded vessel. Recanalization rate (reported as thrombolysis in cerebral infarction [TICI] score), clinical outcome (reported as National Institutes of Health Stroke Scale [NIHSS] score and modified Rankin scale [mRS] score), as well as periprocedural complications were analyzed.

RESULTS

The mean age of the patients was 63.1 ± 12.9 years, with baseline median NIHSS score of 14 (interquartile range, 9.5-19). Successful recanalization (TICI 2b or 3) was achieved in 41 (72 %) patients. Twenty patients (35 %) presented with favorable outcome (mRS ≤2) 30 days after stroke. Overall, significant neurological improvement (≥4 NIHSS point reduction) occurred in 36 (63 %) patients. A clinically significant procedure-related adverse events (vessel disruption, peri/postprocedural intracranial bleeding) defined with decline in NIHSS of ≥4 or death occurred in three (5 %) patients.

CONCLUSIONS

The study showed a high recanalization rate with improved clinical outcome and a low rate of periprocedural complications in our stroke patients treated with mechanical revascularization. Therefore, we could conclude that endovascular revascularization (primary or in combination with a bridging thrombolysis) was an effective and safe procedure for intracranial large vessel recanalization in acute stroke.

Endovascular acute stroke treatment performed by vascular interventional radiologists: is it safe and efficacious?

PURPOSE

To evaluate the safety and efficacy of neurointerventional procedures in acute stroke patients performed by a team of vascular interventional radiologists in close cooperation with diagnostic neuroradiologists and stroke neurologists and to compare the results with those of previous reports from centres with specialised interventional neuroradiologists.

MATERIAL AND METHODS

A total of 39 patients with acute ischemic stroke due to large-vessel occlusion not responding to or not eligible for intravenous thrombolysis were treated with either intra-arterial thrombolysis or mechanical thrombectomy (Penumbra System or solitaire FR thrombectomy system, respectively) and included in our prospective study. Outcomes were measured using the modified Rankin scale after 90 days, and recanalization was assessed by thrombolysis using the myocardial infarction score.

RESULTS

Mean patient age was 68.3 ± 14.2 years; the average National Institutes of Health Stroke Scale score at hospital admission was 17.2 (SD = 6.2 [n = 38]). Successful recanalization was achieved in 74.4 % of patients. Median time from clinical onset to recanalization was 5 h 11 min. Procedure-related complications occurred in 5 % of patients, and 7.5 % had a symptomatic intracerebral hemorrhage. Of the patients, 22.5 % died within the first 90 postprocedural days, 5 % of these from cerebral causes. Patients who were successfully recanalized had a clinical better outcome at follow-up than those in whom treatment failed. Of the patients, 35.9 % had an mRS score ≤2 after 90 days.

CONCLUSION

Our results are in line with those in the published literature and show that a treatment strategy with general interventional radiologists performing neurointerventional procedures in acute stroke patients with large vessel occlusions can be achieved to the benefit of patients.

Improvement of stent retriever design and efficacy of mechanical thrombectomy in a flow model

PURPOSE

In vitro experiments were performed to evaluate the efficacy of mechanical intracranial thrombectomy comparing the newly developed Aperio stent retriever and standard devices for stroke treatment.

METHODS

The Aperio (A), with an increased working length of 4 cm and a special cell design for capturing and withholding clots, was compared to three benchmark devices: the Solitaire retrievable stent (B), the Merci X6 (C), and the Merci L5 retriever (D). In a vascular glass model with pulsatile flow, reminiscent of the M1 segment of the middle cerebral artery, we repeatedly induced occlusion by generating thrombi via a modified Chandler loop system. The numbers of recanalization attempts, peripheral embolizations, and recanalizations at the site of occlusion were recorded during 10 retrieval experiments with each device.

RESULTS

Eleven devices were able to remove the blood clots from the occluded branch. In 34 of 40 experiments, restoration of flow was obtained in 1-3 attempts. The main differences between the study devices were observed in terms of clot withholding and fragmentation during retrieval. Although there was only one fragmentation recorded for device A, disengagement of the whole clot or peripheral embolization of fragments occurred more frequently (5-7 times) with devices B, C, and D.

CONCLUSION

In a vascular model, the design of device A was best at capturing and withholding thrombi during retrieval. Further study will be necessary to see whether this holds true in clinical applications.

Acute stroke treatment using the Penumbra endovascular mechanical thrombolysis device: a single-centre experience

PURPOSE

Ischaemic stroke due to occlusion of large cerebral vessels has a poor prognosis. The clinical outcome is related to efficacy and timing of recanalisation of the occluded arteries. We report our experience with a thrombus aspiration device (Penumbra), and focus on pre- and postprocedural management.

MATERIALS AND METHODS

We retrospectively reviewed 18 consecutive patients with acute ischaemic stroke due to the occlusion of large cerebral vessels who were treated with mechanical thrombolysis at our centre between September 2009 and July 2010. Preprocedural symptoms were quantified using the National Institutes of Health Stroke Scale (NIHSS). Mechanical thrombolysis was performed with the Penumbra system. Intravenous thrombolysis was done only if <3 h had elapsed since symptom onset. Associated vessel stenoses were treated with stenting. All patients underwent neurological examination and postprocedural magnetic resonance angiography (MRA) at 3 and 6 months.

RESULTS

Mechanical thrombolysis using the Penumbra system was performed in all cases. A total of 83% of treated vessels had a value of 2/3 according to the Thrombolysis in Cerebral Infarction (TICI) scale. In seven patients (39%) intravenous thrombolysis was unsuccessful, and salvage mechanical thrombolysis followed. Three patients died after the procedure (16.7%). Five patients (27.8%) required a stenting procedure. All patients reported a significant improvement in symptoms (mean baseline NIHSS 19.6±5.6; mean postprocedural NIHSS, 7.8±5.5 p<0.0001)

CONCLUSIONS

Our preliminary experience with the Penumbra mechanical thrombolysis system confirms previously reported results showing the efficacy and safety of the device in treating acute stroke caused by the occlusion of large intracranial vessels.

Manual aspiration thrombectomy through balloon-tipped guide catheter for rapid clot burden reduction in endovascular therapy for ICA L/T occlusion

INTRODUCTION

Timely recanalization during endovascular procedures for acute ischemic stroke can be challenging in cases with large clot burden, such as those encountered in the terminal internal carotid T- or L-type occlusion.

METHODS

A novel but simple technique to achieve fast reduction in clot burden in stroke patients with occlusion of the internal carotid artery termination is described where manual suction using a 60-ml syringe applied through an 8-F balloon guide catheter positioned in the cervical carotid vasculature with proximal flow arrest allows subsequent revascularization of the residual middle cerebral artery clot.

RESULTS

The use of manual suction through a balloon-tipped guide catheter in internal carotid artery L- or T-type occlusion is illustrated. This resulted in a significant reduction of the clot burden and facilitated further interventions leading to full recanalization.

CONCLUSION

Manual suction using a 60-ml syringe through a balloon guide catheter is a useful and feasible technique that facilitates thrombectomy of large burden cerebral clots.

Mechanical thrombectomy for acute ischemic stroke using the MERCI retriever and penumbra aspiration systems

OBJECTIVE

Intracranial large-vessel ischemia is associated with poor clinical outcome and increased mortality. Early reperfusion of ischemic tissue remains the goal of treatment of stroke. Intravenous tissue plasminogen activator (IV tPA) has been shown to improve clinical outcomes for patients who experience ischemic stroke, but it has been shown to be less efficacious for large-vessel occlusions. Mechanical clot extraction provides a therapeutic option for those who are ineligible for, or who do not respond to, conventional ischemic stroke treatment.

METHODS

We reviewed the initial studies of the Merci Retriever and Penumbra System for mechanical clot extraction. Baseline patient characteristics, as well as revascularization rates and clinical outcome, were examined.

RESULTS

Baseline National Institutes of Health Stroke Scale scores were greater than those observed in previous IV tPA studies, consistent with large-vessel occlusion. Successful recanalization occurred more frequently than with IV tPA and was associated with improved clinical outcome and mortality. Symptomatic intracranial hemorrhage and mortality rates were greater than those seen with IV tPA.

CONCLUSIONS

Mechanical clot extraction can be performed safely in patients with large-vessel occlusions, and successful recanalization resulted in better clinical outcomes than those without. Mechanical thrombectomy provides a therapeutic option for ischemic stroke patients who are ineligible for, or who do not respond to, IV thrombolytics. Further studies, including randomized clinical trials, are needed to validate these findings.

Trevo System: single-center experience with a novel mechanical thrombectomy device

BACKGROUND AND PURPOSE

Recent reports have indicated that mechanical thrombectomy may have the potential to treat acute ischemic stroke. This study aims to describe the safety and effectiveness of Trevo Retriever, using Stentriever technology, in revascularization of patients with acute ischemic stroke.

METHODS

Prospective study evaluating the clinical, radiological, and functional outcome of 13 patients with an angiographically verified occlusion of the anterior cerebral circulation. All patients underwent thrombectomy with TR as monotherapy or in combination with intra-arterial thrombolysis, within the first 8 hours from the onset of symptoms. Successful revascularization was defined as thrombolysis in cerebral ischemia grade 2a to 3. Good outcome was defined as modified Rankin Scale score ≤ 2.

RESULTS

Median baseline National Institutes of Health Stroke Scale score was 19(16-22). The occlusion site was middle cerebral artery in 8 patients and internal carotid artery in 5 patients. Revascularization was achieved in 10 of 13 patients (77%). The mean time from groin puncture to recanalization was 95 ± 31 minutes. No significant intra-procedural complications occurred. Four patients (30%) died during the 90-day follow-up period and 4 patients (30%) achieved functional independence.

CONCLUSION

Early clinical experience suggests that the TR can allow safe and effective revascularization in certain subjects with acute ischemic stroke.