Postinterventional subarachnoid haemorrhage after endovascular stroke treatment with stent retrievers

Impact of post-thrombectomy isolated subarachnoid hemorrhage on neurological outcomes in patients with anterior ischemic stroke - a retrospective single-center observational study

PURPOSE

We aimed to investigate the impact of post-thrombectomy isolated subarachnoid hemorrhage (i-SAH) and other types of intracranial hemorrhage (o-ICH) on patient's neurological outcomes.

METHODS

Stroke data from 2018 to 2022 in a tertiary care center were retrospectively analyzed. Patients with large vessel occlusion from ICA to M2 branch were included. Post-thrombectomy intracranial hemorrhages at 24 h were categorized with Heidelberg Bleeding Classification. Neurological impairment of patients was continuously assessed at admission, at 24 h, 48 h and 72 h, and at discharge. Predictors of i-SAH and o-ICH were assessed.

RESULTS

297 patients were included. i-SAH and o-ICH were found in 12.1% (36/297) and 11.4% (34/297) of patients. Overall, NIHSS of i-SAH patients at discharge were comparable to o-ICH patients (median 22 vs. 21, p = 0.889) and were significantly higher than in non-ICH patients (22 vs. 7, p < 0.001). i-SAH often resulted in abrupt deterioration of patient's neurological symptoms at 24 h after thrombectomy. Compared to non-ICH patients, the occurrence of i-SAH was frequently associated with worse neurological outcome at discharge (median NIHSS increase of 4 vs. decrease of 4, p < 0.001) and higher in-hospital mortality (41.7% vs. 23.8%, p = 0.022). Regardless of successful reperfusion (TICI 2b/3), the beneficial impact of thrombectomy appeared to be outweighed by the adverse effect of i-SAH. Incomplete reperfusion and shorter time from symptom onset to admission were associated with higher probability of i-SAH, whereas longer procedure time and lower baseline ASPECTS were predictive for o-ICH occurrence.

CONCLUSION

Post-thrombectomy isolated subarachnoid hemorrhage is a common complication with significant negative impact on neurological outcome.

Impact of Procedure Time on First Pass Effect in Mechanical Thrombectomy for Anterior Circulation Acute Ischemic Stroke

BACKGROUND AND OBJECTIVES

First pass effect (FPE) is a metric increasingly used to determine the success of mechanical thrombectomy (MT) procedures. However, few studies have investigated whether the duration of the procedure can modify the clinical benefit of FPE. We sought to determine whether FPE after MT for anterior circulation large vessel occlusion acute ischemic stroke is modified by procedural time (PT).

METHODS

A multicenter, international data set was retrospectively analyzed for anterior circulation large vessel occlusion acute ischemic stroke treated by MT who achieved excellent reperfusion (thrombolysis in cerebral infarction 2c/3). The primary outcome was good functional outcome defined by 90-day modified Rankin scale scores of 0-2. The primary study exposure was first pass success (FPS, 1 pass vs ≥2 passes) and the secondary exposure was PT. We fit-adjusted logistic regression models and used marginal effects to assess the interaction between PT (≤30 vs >30 minutes) and FPS, adjusting for potential confounders including time from stroke presentation.

RESULTS

A total of 1310 patients had excellent reperfusion. These patients were divided into 2 cohorts based on PT: ≤30 minutes (777 patients, 59.3%) and >30 minutes (533 patients, 40.7%). Good functional outcome was observed in 658 patients (50.2%). The interaction term between FPS and PT was significant ( P = .018). Individuals with FPS in ≤30 minutes had 11.5% higher adjusted predicted probability of good outcome compared with those who required ≥2 passes (58.2% vs 46.7%, P = .001). However, there was no significant difference in the adjusted predicted probability of good outcome in individuals with PT >30 minutes. This relationship appeared identical in models with PT treated as a continuous variable.

CONCLUSION

FPE is modified by PT, with the added clinical benefit lost in longer procedures greater than 30 minutes. A comprehensive metric for MT procedures, namely, FPE 30 , may better represent the ideal of fast, complete reperfusion with a single pass of a thrombectomy device.

The impact of SAH finding on CT to the clinical outcome after mechanical thrombectomy for large vessel occlusion

BACKGROUND AND PURPOSE

Whether subarachnoid haemorrhage (SAH) after mechanical thrombectomy affects the clinical outcomes of patients with acute large-vessel occlusion remains unclear. This study aimed to investigate the clinical impact of SAH on computed tomography (CT) after mechanical thrombectomy.

METHODS

The SKIP study was an investigator-initiated, multicentre, randomised, open-label clinical trial. This study was performed in 23 hospital networks in Japan from January 1, 2017, to July 31, 2019. Among the 204 patients, seven were excluded because they did not undergo mechanical thrombectomy (MT) and had a modified Rankin scale (mRS) score > 2. The main outcome was the association between SAH within 36 h after mechanical thrombectomy and the clinical outcome at 90 days.

RESULTS

Among 197 patients, the median age was 74 (67-79) years, 62.9% were male. Moreover, 26 (13.2%) patients had SAH (seven isolated SAH) on CT within 36 h. The SAH rate did not differ according to IV rt-PA administration (p = 0.4). The rate of favourable clinical outcomes tended to be lower in patients with SAH rather than patients without SAH (11 [42%] vs. 106 [62%], p = 0.08). Among the seven patients with isolated SAH, 6 showed favourable outcomes at 90 days. In the multivariate regression analysis, the presence of SAH within 36 h from onset was not associated with clinical outcome (Odd ratio, 0.59; 95% confidence interval, 0.18-1.95; p = 0.38).

CONCLUSIONS

Among patients with acute stroke treated with MT, SAH, especially isolated SAH findings on CT, were not associated with poor clinical outcomes after 90 days.

TRIAL REGISTRATION NUMBER

UMIN000021488.

Oculomotor palsy and drowsiness due to post-thrombectomy subarachnoid haemorrhage falsely suggesting transtentorial herniation

Introduction

Post-thrombectomy subarachnoid haemorrhage (SAH) can result in oculomotor palsy and drowsiness, which may falsely suggest transtentorial herniation.

Case presentation

We present a case of right oculomotor nerve palsy presenting after endovascular thrombectomy (EVT) for a right middle cerebral artery (MCA) stroke. The patient presented with a significant right MCA syndrome and a National Institutes of Health Stroke Scale (NIHSS) score of 10 with CT perfusion demonstrating a large penumbral lesion and a CT angiogram confirming a right MCA M1 occlusion. After thrombectomy, the patient developed a 9mm dilated non-reactive right pupil, and a new ipsilateral near-complete oculomotor nerve palsy. Repeat code stroke imaging demonstrated perimesencephalic SAH). The patient was managed expectantly and her conscious state and oculomotor palsy gradually resolved with an excellent neurological recovery.

Conclusion

This case underscores the potential for post-thrombectomy perimesencephalic SAH as a rare mimic of symptomatic intracranial haemorrhage with mass effect manifesting as sudden-onset oculomotor nerve palsy.

The clinical utility of dual-energy CT in post-thrombectomy care: Part 1, predictors and outcomes of subarachnoid and intraparenchymal hemorrhage

OBJECTIVES

Dual-energy CT allows differentiation between blood and iodinated contrast. We aimed to determine predictors of subarachnoid and intraparenchymal hemorrhage on dual-energy CT performed immediately post-thrombectomy and the impact of these hemorrhages on 90-day outcomes.

MATERIALS AND METHODS

A retrospective analysis was performed on patients who underwent thrombectomy for anterior circulation large-vessel occlusion and subsequent dual-energy CT at a comprehensive stroke center from 2018-2021. The presence of contrast, subarachnoid hemorrhage, or intraparenchymal hemorrhage immediately post-thrombectomy was assessed by dual-energy CT. Univariable and multivariable analyses were performed to identify predictors of post-thrombectomy hemorrhages and 90-day outcomes. Patients with unknown 90-day mRS were excluded.

RESULTS

Of 196 patients, subarachnoid hemorrhage was seen in 17, and intraparenchymal hemorrhage in 23 on dual-energy CT performed immediately post-thrombectomy. On multivariable analysis, subarachnoid hemorrhage was predicted by stent retriever use in the M2 segment of MCA (OR,4.64;p=0.017;95%CI,1.49-14.35) and the number of thrombectomy passes (OR,1.79;p=0.019;95%CI,1.09-2.94;per an additional pass), while intraparenchymal hemorrhage was predicted by preprocedural non-contrast CT-based ASPECTS (OR,8.66;p=0.049;95%CI,0.92-81.55;per 1 score decrease) and preprocedural systolic blood pressure (OR,5.10;p=0.037;95%CI,1.04-24.93;per 10 mmHg increase). After adjusting for potential confounders, intraparenchymal hemorrhage was associated with worse functional outcomes (OR,0.25;p=0.021;95%CI,0.07-0.82) and mortality (OR,4.30;p=0.023,95%CI,1.20-15.36), while subarachnoid hemorrhage was associated with neither.

CONCLUSIONS

Intraparenchymal hemorrhage immediately post-thrombectomy was associated with worse functional outcomes and mortality and can be predicted by low ASPECTS and elevated preprocedural systolic blood pressure. Future studies focusing on management strategies for patients presenting with low ASPECTS or elevated blood pressure to prevent post-thrombectomy intraparenchymal hemorrhage are warranted.

Evaluation of pure subarachnoid hemorrhage after mechanical thrombectomy in a series of 781 consecutive patients

INTRODUCTION

Subarachnoid hyperdensity is commonly seen on postoperative computed tomography scans within 24 h after mechanical thrombectomy. The impact on patients' outcomes remains uncertain. We present a real-world experience evaluating periprocedural factors associated with the development of subarachnoid hemorrhage (SAH) and its impact on outcomes of patients with acute stroke undergoing mechanical thrombectomy.

METHODS

A single-center, retrospective analysis was performed between January 2016 and August 2021, including all consecutive patients who underwent thrombectomy. Our study aimed to evaluate periprocedural factors associated with subarachnoid hemorrhage within 24 h of the intervention, and the potential impact on patients' outcome.

RESULTS

Of 781 patients, 44 patients (5.63%) demonstrated pure SAH within 24 h of the intervention. Patients from the SAH group were more likely to have tandem occlusion (15.9% vs. 5.2%, p = .003), aspiration using reperfusion pump system (81.4% vs. 66.8%, p = .047), intraoperative complications (9.1% vs. 0.9%; p < .001), longer puncture-to-recanalization times (45 min vs 29 min, p = .042) and a higher median number of passes to achieve recanalization (1 vs. 3, p = .002). There was no statistically significant difference in the long-term functional outcome between the groups.

CONCLUSION

We suggest that dual-energy computed tomography could better distinguish between blood and pure contrast stagnation. Still, SAH was not associated with an unfavorable outcome in stroke patients undergoing thrombectomy.

Brain aneurysm rupture during mechanical thrombectomy for large vessel occlusion: Technical case series and complication avoidance strategies

Endovascular therapy became the mainstream treatment for patients with acute stroke due to emergent large vessel occlusion (LVO). With increasing number of interventions, it is not uncommon for incidental vascular pathologies to be found during mechanical thrombectomy. Overall, intracranial aneurysms can occur in up to 4% of the population, but previous studies suggest a slightly higher prevalence of intracranial aneurysms in stroke patients as they may share common risk factors. We report on three patients with acute stroke secondary to LVO undergoing mechanical thrombectomy with brain aneurysms incidentally discovered and discuss the potential implications and technical considerations of performing revascularization in these scenarios. In the first case, a patient treated with stent-retriever and aspiration developed a carotid-cavernous fistula without clinical repercussion. The second case illustrates an internal carotid artery posterior communicating segment aneurysm rupture with a massive subarachnoid hemorrhage. The third case exemplifies an unruptured middle cerebral artery bifurcation aneurysm related to an M2 occlusion managed with a different strategy, avoiding aneurysm rupture. Intraprocedural aneurysm rupture is a potential complication during mechanical thrombectomy, especially when anatomical challenges are present. Interventionalists should be aware of the potential risk and constraints in this setting in order to mitigate adverse events.

Predictors and Impact of Sulcal SAH after Mechanical Thrombectomy in Patients with Isolated M2 Occlusion

BACKGROUND AND PURPOSE

Data on SAH after M2 mechanical thrombectomy are limited. We aimed to determine the prevalence of sulcal SAH after mechanical thrombectomy for M2 occlusion, its associated predictors, and the resulting clinical outcome.

MATERIALS AND METHODS

The study retrospectively reviewed the data of patients with acute ischemic stroke who underwent mechanical thrombectomy for isolated M2 occlusion. The patients were divided into 2 groups according to the presence of sulcal SAH after M2 mechanical thrombectomy. Angiographic and clinical outcomes were compared. Multivariable analysis was performed to identify independent predictors of sulcal SAH and unfavorable outcome (90-day mRS, 3-6).

RESULTS

Of the 209 enrolled patients, sulcal SAH was observed in 33 (15.8%) patients. The sulcal SAH group showed a higher rate of distal M2 occlusion (69.7% versus 22.7%), a higher of rate of superior division occlusion (63.6% versus 43.8%), and a higher M2 angulation (median, 128° versus 106°) than the non-sulcal SAH group. Of the 33 sulcal SAH cases, 23 (66.7%) were covert without visible intraprocedural contrast extravasation. Distal M2 occlusion (OR, 12.04; 95% CI, 4.56-35.67; P < .001), superior division (OR, 3.83; 95% CI, 1.43-11.26; P = .010), M2 angulation (OR, 1.02; 95% CI, 1.01-1.04; P < .001), and the number of passes (OR, 1.58; 95% CI, 1.22-2.09; P < .001) were independent predictors of sulcal SAH. However, covert sulcal SAH was not associated with an unfavorable outcome (P = .830).

CONCLUSIONS

After mechanical thrombectomy for M2 occlusion, sulcal SAH was not uncommon and occurred more frequently with distal M2 occlusion, superior division, acute M2 angulation, and multiple thrombectomy passes (≥3). The impact of covert sulcal SAH was mostly benign and was not associated with an unfavorable outcome.

Characterization of Subarachnoid Hyperdensities After Thrombectomy for Acute Stroke Using Dual-Energy CT

BACKGROUND AND OBJECTIVES

The presence of post-interventional subarachnoid hyperdensities (SA-HD) is a relatively common finding after mechanical thrombectomy (MT). We aimed to assess the incidence, characteristics, clinical relevance and predictors of SA-HD after MT as categorized through the use of post-interventional Dual Energy-CT (DE-CT).

METHODS

A single-center consecutive series of acute stroke patients treated with MT were retrospectively reviewed. Post-treatment SA-HD were defined as incident extra-axial hyperdensities in a follow-up DE-CT performed within a median of 8 hours after MT. SA-HD were further classified according to their content (isolated contrast extravasation versus blood extravasation) and extension [diffuse (hyperdensities in more than one extraparenchymal compartments) versus non-diffuse]. Adjusted logistic regression models assessed the association of SA-HD with pretreatment and procedural variables and with bad clinical outcome (shift towards worse categories in the ordinal Rankin Scale at 90 days).

RESULTS

SA-HD were observed in 120 (28%) of the 424 included patients (isolated contrast extravasation n=22, blood extravasation n=98). In this group, SA-HD were diffuse in 72 (60%) patients (isolated contrast extravasation n=7, blood extravasation n=65) and non-diffuse in 48 (40%) patients (isolated contrast extravasation n=15, blood extravasation n=33). Diffuse SA-HD were significantly associated with worse clinical outcome in adjusted models (cOR=2.3, 95%CI=1.36-4.00, p=0.002), unlike the specific SA-HD content alone. In contrast with the absence of SA-HD, only the diffuse pattern with blood extravasation was significantly associated with worse clinical outcome (cOR=2.4, 95%CI=1.36-4.15, p=0.002). Diffuse SA-HD patterns were predicted by M2 occlusions, more thrombectomy passes and concurrent parenchymal hematomas.

DISCUSSION

In our cohort of patients imaged within a median of 8 hours after MT, post-interventional SA-HD showed a diffuse pattern in 17% of thrombectomies and were associated with more arduous procedures. Diffuse SA-HD but not local collections of blood or contrast extravasations were associated with an increased risk of poor outcome and death. These findings reinforce the need for improvement in reperfusion strategies.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that in individuals with proximal carotid artery territory occlusions treated with mechanical thrombectomy, diffuse post-interventional subarachnoid hyperdensities on imaging 8 hours post-procedure are associated with worse clinical outcomes at 90 days.

Contrast extravasation and outcome of endovascular therapy in acute ischaemic stroke: a systematic review and meta-analysis

OBJECTIVE

Contrast extravasation (CE) after endovascular therapy (EVT) is commonly present in acute ischaemic stroke (AIS) patients. Substantial uncertainties remain about the relationship between CE and the outcomes of EVT in patients with AIS. Therefore, we aimed to evaluate this association.

DESIGN

A systematic review and meta-analysis of published studies were performed.

DATA SOURCE

We systematically searched the Medline and Embase databases for relevant clinical studies. The last literature search in databases was performed in June 2020.

ELIGIBILITY CRITERIA FOR STUDY SELECTION

We included studies exploring the associations between CE and the outcomes of EVT in patients with AIS undergoing EVT.

DATA EXTRACTION AND SYNTHESIS

Two reviewers extracted relevant information and data from each article independently. We pooled ORs with CIs using a random-effects meta-analysis to calculate the associations between CE and outcomes of EVT. The magnitude of heterogeneity between estimates was quantified with the I² statistic with 95% CIs.

RESULTS

Fifteen observational studies that enrolled 1897 patients were included. Patients with CE had higher risks of poor functional outcome at discharge (2.38, 95% CI 1.45 to 3.89 p=0.001; n=545) and poor functional outcome at 90 days (OR 2.16, 95% CI 1.20 to 3.90; n=1194). We found no association between CE and in-hospital mortality (OR 0.95, 95% CI 0.27 to 3.30; n=376) or 90-day mortality (OR 1.38, 95% CI 0.81 to 2.36; n=697) after EVT. Moreover, CE was associated with higher risks of post-EVT intracranial haemorrhage (ICH) (OR 6.68, 95% CI 3.51 to 12.70; n=1721) and symptomatic ICH (OR 3.26, 95% CI 1.97 to 5.40; n=1092).

CONCLUSIONS

This systematic review and meta-analysis indicates that in patients with AIS undergoing EVT, CE is associated with higher risks of unfavourable functional outcomes and ICH. Thus, we should pay more attention to CE in patients with AIS undergoing EVT.

Subarachnoid Hemorrhage in Mechanical Thrombectomy for Acute Ischemic Stroke: Analysis of the STRATIS Registry, Systematic Review, and Meta-Analysis

Background: The indications for mechanical thrombectomy in acute ischemic stroke continue to broaden, leading neurointerventionalists to treat vessel occlusions at increasingly distal locations farther in time from stroke onset. Accessing these smaller vessels raises the concern of iatrogenic subarachnoid hemorrhage (SAH) owing to increasing complexity in device navigation and retrieval. This study aims to determine the prevalence of SAH following mechanical thrombectomy, associated predictors, and resulting functional outcomes using a multicenter registry and compare this with a systematic review and meta-analysis of the literature. Methods: Data from STRATIS (The Systematic Evaluation of Patients Treated with Neurothrombectomy Devices for Acute Ischemic Stroke) registry were analyzed dichotomized by the presence or absence of SAH after thrombectomy. Only patients with 24-h post-procedural neuroimaging were included (n = 841). Multivariable logistic regression was performed to identify significant predictors of SAH. A systematic review and random-effects meta-analysis was also conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) protocol. Results: The prevalence of post-thrombectomy SAH was 5.23% in STRATIS with 15.9% (1.84% overall) experiencing neurological decline. Distal location of vessel occlusion (OR 3.41 [95% CI: 1.75-6.63], p < 0.001) and more than 3 device passes (OR 1.34 [95% CI: 1.09-1.64], p = 0.01) were associated with a higher probability of SAH in contrast to a reduction with administration of intravenous tissue plasminogen activator (tPA) (OR 0.48 [95% CI: 0.26-0.89], p = 0.02). There was a trend toward a higher discharge NIHSS (8.3 ± 8.7 vs. 5.3 ± 6.6, p = 0.07) with a significantly reduced proportion achieving functional independence at 90 days (modified Rankin Score 0-2: 32.5% vs. 57.8%, p = 0.002) in SAH patients. Pooled analysis of 10,126 patients from 6 randomized controlled trials and 64 observational studies demonstrated a prevalence of 5.85% [95% CI: 4.51-7.34%, I ²: 85.2%]. Only location of vessel occlusion was significant for increased odds of SAH at distal sites (OR 2.89 [95% CI: 1.14, 7.35]). Conclusions: Iatrogenic SAH related to mechanical thrombectomy is more common with treatment of distally-situated occlusions and multiple device passes. While low in overall prevalence, its effect is not benign with fewer patients reaching post-procedural functional independence, particularly if symptomatic.

Clinical impact of the first pass effect on clinical outcomes in patients with near or complete recanalization during mechanical thrombectomy for large vessel ischemic stroke

BACKGROUND AND PURPOSE

The first pass effect has been reported as a mechanical thrombectomy (MT) success metric in patients with large vessel occlusive stroke. We aimed to compare the clinical and neuroimagign outcomes of patients who had favorable recanalization (mTICI 2c or mTICI 3) achieved in one pass versus those requiring multiple passes.

METHODS

In this "real-world" multicenter study, patients with mTICI 2c or 3 recanalization were identified from three prospectively collected stroke databases from January 2016 to December 2019. Clinical outcomes were a favorable functional outcome at 90 days (modified Rankin Scale score 0-2), and the rate of symptomatic intracranial hemorrhage (ICH) any ICH, and 90-day mortality.

RESULTS

Favorable recanalization was achieved in 390/664 (59%) of consecutive patients who underwent MT (age 71.2 ± 13.2 years, 188 [48.2%] women). This was achieved after a single thrombectomy pass (n = 290) or multiple thrombectomy passes (n = 100). The rate of favorable clinical outcome was higher (41% vs. 28 %, p = .02) in the first pass group with a continued trend on multivariate analysis that did not reaching statistical significance (OR 1.68 95% confidence interval [CI] 1.0-2.95, p = .07). Similarly, the odds of any ICH were significantly lower (OR 0.56 CI 0.32-0.97, p = .03). A similar trend of favorable clinical outcomes was noticed on subgroup analysis of patients with M1 occlusion (OR 1.81 CI 1.01-3.61, p = .08).

CONCLUSION

The first-pass reperfusion was associated with a trend toward favorable clinical outcome and lower rates of ICH. These data suggest that the first-pass effect should be the mechanical thrombectomy procedure goal.

Watershed subarachnoid hemorrhage after middle cerebral artery rescue stenting in patients with acute ischemic stroke

Cortical subarachnoid hemorrhage is an infrequent subtype of non-aneurysmal subarachnoid hemorrhage, rarely reported in watershed territories (wSAH) after carotid stenting. It has never been reported after treatment of middle cerebral artery stenosis (MCAS) that is increasingly used in selected patients, as rescue treatment of failed mechanical thrombectomy, due to recent advancements in endovascular interventions. We present a series of patients with MCAS that developed a wSAH after stenting.

Effect of First-Pass Reperfusion on Outcome After Endovascular Treatment for Ischemic Stroke

Background

First‐pass reperfusion (FPR) is associated with favorable outcome after endovascular treatment. It is unknown whether this effect is independent of patient characteristics and whether FPR has better outcomes compared with excellent reperfusion (Expanded Thrombolysis in Cerebral Infarction [eTICI] 2C‐3) after multiple‐passes reperfusion. We aimed to evaluate the association between FPR and outcome with adjustment for patient, imaging, and treatment characteristics to single out the contribution of FPR.

Methods and Results

FPR was defined as eTICI 2C‐3 after 1 pass. Multivariable regression models were used to investigate characteristics associated with FPR and to investigate the effect of FPR on outcomes. We included 2686 patients of the MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) Registry. Factors associated with FPR were as follows: history of hyperlipidemia (adjusted odds ratio [OR], 1.05; 95% CI, 1.01–1.10), middle cerebral artery versus intracranial carotid artery occlusion (adjusted OR, 1.11; 95% CI, 1.06–1.16), and aspiration versus stent thrombectomy (adjusted OR, 1.07; 95% CI, 1.03–1.11). Interventionist experience increased the likelihood of FPR (adjusted OR, 1.03 per 50 patients previously treated; 95% CI, 1.01–1.06). Adjusted for patient, imaging, and treatment characteristics, FPR remained associated with a better 24‐hour National Institutes of Health Stroke Scale (NIHSS) score (−37%; 95% CI, −43% to −31%) and a better modified Rankin Scale (mRS) score at 3 months (adjusted common OR, 2.16; 95% CI, 1.83–2.54) compared with no FPR (multiple‐passes reperfusion+no excellent reperfusion), and compared with multiple‐passes reperfusion alone (24‐hour NIHSS score, (−23%; 95% CI, −31% to −14%), and mRS score (adjusted common OR, 1.45; 95% CI, 1.19–1.78)).

Conclusions

FPR compared with multiple‐passes reperfusion is associated with favorable outcome, independently of patient, imaging, and treatment characteristics. Factors associated with FPR were the experience of the interventionist, history of hyperlipidemia, location of occluded artery, and use of an aspiration device compared with stent thrombectomy.

Is the detectability of the spot sign on CT angiography depending on slice thickness and reconstruction type?

OBJECTIVE

The spot sign is a validated imaging marker widely used in CT angiography (CTA) to detect active bleeding and a higher risk of hematoma expansion in patients with intracerebral hemorrhage (ICH). The aim of this study was to investigate the detectability of spot signs on thin multiplanar projection reconstruction (MPR) images compared to thicker maximum intensity projection (MIP) images.

METHODS

In this retrospective analysis, we assessed imaging data of 146 patients with primary hypertensive/microangiopathic ICH who received emergency non-contrast computed tomography (NCCT) and CTA. Two experienced radiologists, blinded to each other, evaluated images of thin (1 mm) MPR images and thick (3 mm) MIP images on the presence of spot signs and performed a consensus reading. Kappa tests were used for data comparison.

RESULTS

In total, spot signs were observed in 27 cases (=18.5 %) in both thin MPR and thick MIP slices. Detectability of the spot sign did not differ in 1 mm MPR images and 3 mm MIP images (Cohen's kappa, 1.0; p = 0.00). Also, when the readings of the two radiologists were analyzed separately, results for MPR and MIP slices were similar (MPR: Cohen's kappa, 0.81, p = 0.00; MIP: Cohen's kappa, 0.74; p = 0.00).

CONCLUSION

No significant difference in the detectability of the spot sign could be demonstrated when comparing 1 mm MPR images with 3 mm MIP images.

Mechanical thrombectomy in acute ischemic stroke patients with left ventricular assist device

OBJECTIVES

As the number of patients with left ventricular assist device (LVAD) implantation has been increasing, treatment of LVAD-related ischemic stroke is becoming a critical issue. We sought to clarify the features of mechanical thrombectomy in LVAD-related stroke with large vessel occlusion.

METHODS

In a multi-center, retrospective case-control study, we compared 20 LVAD-related strokes with 33 non-LVAD strokes, all of which had large vessel occlusion in the anterior circulation treated with mechanical thrombectomy. A comparative histopathological examination of the retrieved thrombi was also performed.

RESULTS

Successful reperfusion was achieved in 75% of the LVAD-related strokes. The time from onset to reperfusion was similar to that of non-LVAD strokes, but the total number of device passes required for reperfusion (median, 2.5 versus 1, P = 0.01) and the incidences of post-procedural parenchymal and subarachnoid hemorrhage (25% versus 3%, P = 0.02 and 55% versus 15%, P = 0.01, respectively) were higher in LVAD-related strokes. Symptomatic intracranial hemorrhage occurred in 4 patients (20%) with LVAD-related strokes. The histopathological analysis revealed that the ratio of erythrocyte components was significantly lower in thrombi retrieved from patients with LVAD-related stroke than in those with non-LVAD stroke (19 ± 6% versus 41 ± 17%, P = 0.01).

CONCLUSIONS

Mechanical thrombectomy is feasible in patients with LVAD-related stroke. However, repetitive device passes are needed to achieve successful reperfusion mainly because of the structurally organized thrombi, and the higher risk of hemorrhagic complications should be considered, while offering this therapeutic alternative.

Predictors of intracranial hemorrhage in acute ischemic stroke after endovascular thrombectomy

BACKGROUND

Limited data are available regarding the predictors, clinical relevance, and bleeding rate by surgical devices of intracranial hemorrhage after endovascular thrombectomy. This is partially explained by the difference in the classification and definition of hemorrhage among studies. The purpose of this study was to identify the predictors of hemorrhagic transformation and isolated subarachnoid hemorrhage after endovascular thrombectomy.

METHODS

This was a retrospective, multicenter observational cohort study of consecutive patients who underwent endovascular thrombectomy between January 2015 and December 2018. Univariate and logistic regression analyses were performed to determine the predictors, the impact on clinical outcomes, and the bleeding rate by surgical devices of hemorrhagic transformation and isolated subarachnoid hemorrhage.

RESULTS

Among 610 eligible patients, hemorrhagic transformations occurred in 93 (15.2%). Fourteen patients (2.3%) were classified as having symptomatic intracranial hemorrhage. Isolated subarachnoid hemorrhage was found in 60 (9.8%) patients. In the logistic regression analyses, diabetes mellitus (odds ratio: 1.92; 95% confidence interval: 1.06-3.49) was associated with hemorrhagic transformation, and the number of device passes (odds ratio: 1.33; 95% confidence interval: 1.11-1.59) was associated with isolated subarachnoid hemorrhage. Both hemorrhagic transformation and isolated subarachnoid hemorrhage were associated with poor 90-day functional outcomes. There was a significant correlation between treatment with stent retrievers and isolated subarachnoid hemorrhage.

CONCLUSIONS

Patients with diabetes mellitus were vulnerable to hemorrhagic transformation, whereas those who underwent several attempts of thrombectomy were susceptible to isolated subarachnoid hemorrhage. Both hemorrhage types worsened the functional outcome. Treatment with the stent retriever was significantly associated with postprocedural isolated subarachnoid hemorrhage.

Contrast Extravasation After Endovascular Treatment in Posterior Circulation Stroke

OBJECTIVE

Endovascular treatment (EVT) is a promising clinical technology. However, some patients with posterior circulation stroke might not experience neurological function recovery after EVT. We reviewed the recent experience with EVT to clarify the clinical and radiographic factors that contribute to optimal neurological outcomes.

METHODS

We analyzed the data from 108 consecutive patients with acute posterior circulation stroke who had undergone EVT from January 2016 to December 2018. A favorable outcome was defined as a modified Rankin scale score of 0-3 at 3 months. We evaluated the association and predictive value of the clinical and radiographic factors that contribute to good neurological outcomes.

RESULTS

Of the 108 included patients, 43 had a favorable clinical outcome at day 90. Univariate analysis revealed a significant association between the 90-day favorable outcome and the baseline values of systolic blood pressure, time of stroke onset, contrast extravasation, symptomatic intracranial hemorrhage, general anesthesia, Alberta stroke program early computed tomography score for the posterior circulation, and the National Institutes of Health stroke scale (NIHSS) score. Contrast extravasation (odds ratio [OR], 5.094; 95% confidence interval [CI], 1.22-21.261), symptomatic intracranial hemorrhage (OR, 11.24; 95% CI, 1.309-96.517), general anesthesia (OR, 5.094; 95% CI, 1.22-21.26), and baseline NIHSS score (OR, 1.087; 95% CI, 1.023-1.309) were found to be independent predictors of a favorable outcome at day 90. Contrast extravasation alone predicted for unfavorable clinical outcomes and mortality with high specificity.

CONCLUSION

In the present retrospective case series, contrast extravasation, symptomatic intracranial hemorrhage, the use of general anesthesia, and baseline NIHSS score were related to a favorable prognosis for patients with posterior circulation stroke after EVT. Contrast extravasation was an independent and strong predictor of unfavorable clinical outcomes.

The impact of general anesthesia, baseline ASPECTS, time to treatment, and IV tPA on intracranial hemorrhage after neurothrombectomy: pooled analysis of the SWIFT PRIME, SWIFT, and STAR trials

BACKGROUND

Despite the proven benefit of neurothrombectomy, intracranial hemorrhage (ICH) remains the most serious procedural complication. The aim of this analysis was to identify predictors of different hemorrhage subtypes and evaluate their individual impact on clinical outcome.

METHODS

Pooled individual patient-level data from three large prospective multicenter studies were analyzed for the incidence of different ICH subtypes, including any ICH, hemorrhagic transformation (HT), parenchymal hematoma (PH), subarachnoid hemorrhage (SAH), and symptomatic intracranial hemorrhage (sICH). All patients (n=389) treated with the Solitaire device were included in the analysis. A multivariate stepwise logistic regression model was used to identify predictors of each hemorrhage subtype.

RESULTS

General anesthesia and higher baseline Alberta Stroke Program Early CT score (ASPECTS) were associated with a lower probability of any ICH (OR 0.36, p=0.003), (OR 0.80, p=0.032) and HT (OR 0.54, p=0.023), (OR 0.78, p=0.001), respectively. Longer time from onset to treatment was associated with a higher likelihood of HT (OR 1.08, p=0.001) and PH (OR 1.11, p=0.015). Intravenous tissue plasminogen activator (IV-tPA) was also a strong predictor of PH (OR 7.63, p=0.013). Functional independence at 90 days (modified Rankin Scale (mRS) 0-2) was observed significantly less frequently in all hemorrhage subtypes except SAH. None of the patients who achieved functional independence at 90 days had sICH.

CONCLUSIONS

General anesthesia and smaller baseline ischemic core are associated with a lower probability of HT whereas IV-tPA and prolonged time to treatment increase the risk of PH after neurothrombectomy.

TRIAL REGISTRATION NUMBERS

SWIFT-NCT01054560; post results, SWIFT PRIME-NCT01657461; post results, STAR-NCT01327989; post results.

True First-Pass Effect

Background and Purpose- It has been hypothesized that in stroke patients, complete reperfusion (modified Thrombolysis in Cerebral Infarction; mTICI 3) after a single thrombectomy pass is a predictor for favorable outcome (modified Rankin Scale score, 0-2), but a true first-pass effect defined as improved clinical outcome after complete reperfusion with one versus multiple passes has not yet been specifically addressed in the literature. Methods- We compared clinical outcome of 164 consecutive patients with occlusions in the anterior circulation and known symptom onset, in whom we achieved complete reperfusion (mTICI 3), depending on whether complete reperfusion was achieved after a single thrombectomy pass (n=62) or multiple thrombectomy passes (n=102). To adjust for confounding factors such as prolonged time spans between symptom onset and reperfusion, additional administration of intra-arterial thrombolysis, and clot localization, we also compared clinical outcome of our first-pass group with a matched cohort (n=54) and a superselective subgroup of first-pass patients (only M1 occlusions, no additional intra-arterial thrombolysis; n=46) with its matched cohort (n=24). Results- Multivariable analysis of our cohort of 164 nonmatched patients revealed that there was a significant association between first-pass complete reperfusion and favorable clinical outcome (P=0.013). This was confirmed in our case-control analyses (P=0.010 and P=0.042). In our matched cohorts, favorable clinical outcome was seen almost twice as often if complete reperfusion was achieved after one pass (62% and 67% versus 36% and 37%), and odds for favorable outcome were 2.4 to 3.2× higher (CIs, 1.1-4.8 and 1.0-9.9). Conclusions- First-pass complete reperfusion is an independent factor for favorable outcome and should be aimed for in mechanical thrombectomy.

Endovascular treatment for large vessel occlusion stroke in patients with ventricular assist devices

Background

Embolic stroke with large vessel occlusion (LVO) is a major adverse event during ventricular assist device (VAD) support. In this study we aimed to clarify the efficacy of, and problems associated with, endovascular treatment (EVT) of LVO in patients with VAD support.

Methods

We retrospectively reviewed EVT for LVO in patients with VAD support between 2006 and 2017 at our institute and evaluated baseline characteristics, treatment variables, outcomes, and complications.

Results

The study cohort comprised 12 consecutive patients (age 35.4±20.4 years), with 15 LVO events involving 20 arterial occlusions, who had undergone EVT. The median Alberta Stroke Program Early CT score was 10 and good collaterals were observed in 10 of 17 occluded middle cerebral artery areas. No study patients had received intravenous thrombolysis therapy. EVT was performed on 18 of the 20 occluded arteries and mechanical thrombectomy on 13 vessels. The successful reperfusion (modified Thrombolysis in Cerebral Infarction grade ≥2 b) rate was 67% in all EVTs and 85% with mechanical thrombectomy. Histological analysis showed fibrin-rich thrombi in four of five samples. Seven of 12 patients (58%) maintained their neurological function (modified Rankin Scale score ≤2 or equal to pre-stroke score) at 90 days. Periprocedural complications comprised two symptomatic intracranial hemorrhages and the 90-day mortality rate was 13%. Seven of 10 cardiac transplant candidates (70%) returned to the waiting list and three of them received transplants.

Conclusions

Endovascular therapy for acute LVO stroke is feasible even in patients with VAD support.

Preventing vessel perforations in endovascular thrombectomy: feasibility and safety of passing the clot with a microcatheter without microwire: the wireless microcatheter technique

BACKGROUND

To place a stent retriever for thrombectomy in acute ischemic stroke, the clot has to be passed first. A microwire is usually used for this maneuver. As an alternative, a wireless microcatheter can be used to pass the clot.

OBJECTIVE

To analyze the feasibility and complication rates of passing the clot using either a microwire or a wireless microcatheter.

METHODS

A retrospective non-randomized analysis of 110 consecutive patients with acute ischemic stroke in the anterior circulation was performed, in whom video recordings of mechanical thrombectomies were available. In total, 203 attempts at mechanical recanalization were performed.

RESULTS

Successful recanalization (TICI 2b-3) was achieved in 97.3% of patients. In 71.8% of attempts the clot was successfully passed using a wireless microcatheter only. When a microwire was used initially, clot passage was successful in 95.3% of attempts. Complication rates for angiographically detectable subarachnoid hemorrhage were 6.1% when a microwire was used to pass the clot compared with 0% when a wireless microcatheter was used (p<0.001). Complication rates for angiographically occult circumscribed subarachnoid contrast extravasation observed on post-interventional CT scans were 18.2% when a microwire was used to pass the clot and 4.5% when a wireless microcatheter was used (p<0.001).

CONCLUSIONS

In most cases of mechanical recanalization the clot can be passed with a wireless microcatheter instead of a microwire. In our study this method significantly reduced the risk for vessel perforation and subarachnoid hemorrhage. We therefore recommend the use of this technique whenever possible.

Relevance of standard intravenous thrombolysis in endovascular stroke therapy of a tertiary stroke center

The majority of patients undergoing endovascular stroke treatment (EST) in randomized controlled trials received additional systemic thrombolysis ("combination or bridging therapy (C/BT)"). Nevertheless, its usefulness in this subtype of acute ischemic stroke (AIS) is discussed controversially. Of all consecutive AIS patients, who received any kind of reperfusion therapy in a tertiary university stroke center between January 2015 and March 2016, those with large vessel occlusions (LVO) and EST with or without additional C/BT, were compared primarily regarding procedural aspects. Data were extracted from an investigator-initiated, single-center, prospective and blinded end-point study. 70 AIS patients with EST alone and 118 with C/BT were identified. Significant baseline differences existed in pre-existing cardiovascular disease (52.9% (EST alone) vs. 35.6% (C/BT), p = 0.023), use of anticoagulation (30.6% vs. 5.9%, p < 0.001), and frequency of unknown time of symptom onset (65.7% vs. 32.2%, p < 0.001), in-hospital stroke (18.6% vs. 1.7%, p < 0.001), pre-treatment ASPECT scores (7.9 vs. 8.9, p = 0.004), and frequency of occlusion in the posterior circulation (18.6% vs. 5.1%, p = 0.003). Pre-interventional procedural time intervals tended to be shorter in the C/BT group, reaching statistical significance in door-to-image time (30.3 (EST alone) vs. 22.2 min (C/BT), p < 0.001). Good clinical outcome (mRS d90) was reached more often in the C/BT group (24.5% vs. 11.8%, p = 0.064). Rates of symptomatic intracranial hemorrhages (sICH) were comparable (4.3% (EST alone) vs. 6.8% (C/BT), p = 0.481). Additional systemic thrombolysis did not delay EST. On the contrary, application of IVRTPA seemed to be a positive indicator for faster EST without increased side effects.

Improvement of Endovascular Stroke Treatment: A 24-Hour Neuroradiological On-Site Service Is Not Enough

Background and Purpose

With the advent of endovascular stroke treatment (EST) with mechanical thrombectomy, stroke treatment has also become more challenging. Purpose of this study was to investigate whether a fulltime neuroradiological on-site service and workflow optimization with a structured documentation of the interdisciplinary stroke workflow resulted in improved procedural times.

Material and Methods

Procedural times of 322 consecutive patients, who received EST (1) before (n = 96) and (2) after (n = 126) establishing a 24-hour neuroradiological on-site service as well as (3) after implementation of a structured interdisciplinary workflow documentation (“Stroke Check”) (n = 100), were analysed.

Results

A fulltime neuroradiological on-site service resulted in a nonsignificant improvement of procedural times during out-of-hours admissions (p ≥ 0.204). Working hours and out-of-hours procedural times improved significantly, if additional workflow optimization was realized (p ≤ 0.026).

Conclusions

A 24-hour interventional on-site service is a major prerequisite to adequately provide modern reperfusion therapies in patients with acute ischemic stroke. However, simple measures like standardized and focused documentation that affect the entire interdisciplinary pre- and intrahospital stroke rescue chain seem to be important.

Necessary Catheter Diameters for Mechanical Thrombectomy with ADAPT

BACKGROUND AND PURPOSE

Large-bore catheters allow mechanical thrombectomy in ischemic stroke by engaging and retrieving clots without additional devices (direct aspiration first-pass technique [ADAPT]). The purpose of this study was to establish a model for minimal catheter diameters needed for ADAPT.

MATERIALS AND METHODS

We established a theoretic model for the calculation of minimal catheter diameters needed for ADAPT. We then verified its validity in 28 ADAPT maneuvers in a porcine in vivo model. To account for different mechanical thrombectomy techniques, we factored in ADAPT with/without a hypothetic 0.021-inch microcatheter or 0.014-inch microwire inside the lumen of the aspiration catheter and aspiration with a 60-mL syringe versus an aspiration pump.

RESULTS

According to our calculations, catheters with an inner diameter of >0.040 inch and >0.064 inch, respectively, are needed to be effective in the middle cerebral artery (2.5-mm diameter) or in the internal carotid artery (4 mm) in an average patient. There was a significant correlation between predicted and actual thrombectomy results (P = .010). Our theoretic model had a positive and negative predictive value of 78% and 79%, respectively. Sensitivity and specificity were 88% and 64%, respectively.

CONCLUSIONS

Our theoretic model allows estimating the minimal catheter diameters needed for successful mechanical thrombectomy with ADAPT, as demonstrated by the good agreement with our animal experiments. Our model will be helpful to interventionalists in avoiding selecting catheters that are likely too small to be effective.

[Mechanical thrombectomy: Acute complications and delayed sequelae]

BACKGROUND

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

AIM

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Clinical Impact of Ventilation Duration in Patients with Stroke Undergoing Interventional Treatment under General Anesthesia: The Shorter the Better?

BACKGROUND AND PURPOSE

Whether general anesthesia for neurothrombectomy in patients with ischemic stroke has a negative impact on clinical outcome is currently under discussion. We investigated the impact of early extubation and ventilation duration in a cohort that underwent thrombectomy under general anesthesia.

MATERIALS AND METHODS

We analyzed 103 consecutive patients from a prospective stroke registry. They met the following criteria: CTA-proved large-vessel occlusion in the anterior circulation, ASPECTS above 6 on presenting cranial CT, revascularization by thrombectomy with the patient under general anesthesia within 6 hours after onset of symptoms, and available functional outcome (mRS) 90 days after onset.

RESULTS

The mean ventilation time was 128.07 ± 265.51 hours (median, 18.5 hours; range, 1-1244.7 hours). Prolonged ventilation was associated with pneumonia during hospitalization and unfavorable functional outcome (mRS ≥3) and death at follow-up (Mann-Whitney U test; P ≤ .001). According to receiver operating characteristic analysis, a cutoff after 24 hours predicted unfavorable functional outcome with a sensitivity and specificity of 60% and 78%, respectively. Our results imply that delayed extubation was not associated with a less favorable clinical outcome compared with immediate extubation after the procedure.

CONCLUSIONS

Short ventilation times are associated with a lower pneumonia rate and more favorable clinical outcome. Cautious interpretation of our data implies that whether patients are extubated immediately after the procedure is irrelevant for clinical outcome as long as ventilation does not exceed 24 hours.

Weekend effect in endovascular stroke treatment: do treatment decisions, procedural times, and outcome depend on time of admission?

Background

Epidemiologic studies identified a ‘weekend effect’ or ‘out-of-hours effect’, which implies that procedural and clinical outcomes of patients with stroke, who are admitted out-of-hours, are less favorable than for patients admitted during working-hours.

Objective

To determine (1) whether our procedural times and clinical outcome were affected by an out-of-hours effect and (2) whether the decision in favor of, or against, endovascular stroke treatment (EST) depends on the time of admission.

Methods

Between February 2010 and January 2015, 6412 consecutive patients presenting with symptoms of acute ischemic stroke were evaluated for EST eligibility according to established local protocols and generally accepted consensus criteria, and dichotomized into working-hours and out-of-hours cohorts according to admission times. Within both groups, patients given EST were identified and the rate of treatment decision, procedural times, and clinical outcome were compared and analyzed.

Results

Clinical and radiological features of patients admitted in working-hours and out-of-hours did not differ significantly. Procedural times and clinical outcome were not affected by an out-of-hours effect (p≥0.054). 221/240 (92.1%) out-of-hours patients and 154/166 (92.8%) working-hours patients who were eligible for EST were transferred to the angiography suite for EST (p=0.798). The rationale not to treat patients who were eligible for EST did not differ between working-hours and out-of-hours admission (p=0.756).

Conclusions

It is possible to produce competitive procedural times regardless of the time of admission and to prevent a treatment decision bias when standard operating procedures are applied consistently.

Stent Retriever Thrombectomy of Small Caliber Intracranial Vessels Using pREset LITE: Safety and Efficacy

Purpose

Few devices are approved for thrombectomy of distal vessel branches, and clinical experience is limited. Here we report our experience with pREset LITE for thrombectomy of small intracranial vessels.

Methods

From an institutional database we selected consecutive patients treated with pREset LITE for an occlusion of small (≤ 2 mm), intracranial target vessels. Recanalization success was measured by applying the modified Thrombolysis In Cerebral Infarction (mTICI) score. To assess safety, we recorded device-related procedural events and potentially device-related hemorrhages on follow-up imaging. Infarcts in the dependent territory served as a measure for efficacy.

Results

Of 536 patients treated between August 2013 and March 2015, 76 met the inclusion criteria. pREset LITE was used in 90 branches with an average diameter of 1.6 mm (1.3–2.0 mm). An mTICI score ≥ 2b was achieved in 70.0 %. Procedural events consisted of 5.6 % significant vasospasm, 2.2 % suspected dissections, 2.2 % downstream emboli, and 1.1 % self-limiting extravasations. On posttreatment imaging 2.2 % parenchymal hemorrhages type I (PHI) and 13.3 % focal subarachnoid hemorrhage (SAH) were potentially device related, but all of these events remained asymptomatic. After successful recanalization, 33.3 % developed no ischemia in the dependent territory while 41.7 % developed a partial infarct, and 25 % developed a complete infarct. Successful recanalization significantly increased the chance to develop no or only partial infarct compared with a complete infarction (p = 0.003, p = 0.013).

Conclusions

Thrombectomy of small vessels with pREset LITE is feasible with good recanalization and reasonable safety margins. Successful recanalization significantly reduces the risk of infarction in the dependent territory. The impact on the overall clinical outcome remains to be determined.

Mechanical thrombectomy in acute ischemic stroke: Consensus statement by ESO-Karolinska Stroke Update 2014/2015, supported by ESO, ESMINT, ESNR and EAN

The original version of this consensus statement on mechanical thrombectomy was approved at the European Stroke Organisation (ESO)-Karolinska Stroke Update conference in Stockholm, 16–18 November 2014. The statement has later, during 2015, been updated with new clinical trials data in accordance with a decision made at the conference. Revisions have been made at a face-to-face meeting during the ESO Winter School in Berne in February, through email exchanges and the final version has then been approved by each society. The recommendations are identical to the original version with evidence level upgraded by 20 February 2015 and confirmed by 15 May 2015. The purpose of the ESO-Karolinska Stroke Update meetings is to provide updates on recent stroke therapy research and to discuss how the results may be implemented into clinical routine. Selected topics are discussed at consensus sessions, for which a consensus statement is prepared and discussed by the participants at the meeting. The statements are advisory to the ESO guidelines committee. This consensus statement includes recommendations on mechanical thrombectomy after acute stroke. The statement is supported by ESO, European Society of Minimally Invasive Neurological Therapy (ESMINT), European Society of Neuroradiology (ESNR), and European Academy of Neurology (EAN).