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

Vessel deviation during stent retrieval predicts successful recanalization in stent-based mechanical thrombectomy for M2 occlusion

PURPOSE

This study aimed to clarify whether there is a relationship between vessel deviation during stent retrieval and successful recanalization in stent-based mechanical thrombectomy (MT) for M2 occlusion.

METHODS

The video of the MT was reviewed for each of the 25 included patients with M2 occlusion. The vertical distance of vessel deviation at the time of stent retrieval was defined as D, and the diameter of the balloon guide catheter shown on the same screen was defined as B. The D/B ratio was calculated as an index of the vessel deviation. The presence or absence of successful recanalization (thrombolysis in cerebral infarction (TICI) score of 2b/3) was compared based on the D/B ratio and clinical factors.

RESULTS

Of the 25 patients, successful recanalization was achieved in 18 (72%). The median D/B ratio with successful recanalization was 0.9, which was significantly lower than that without successful recanalization (2.5, p < 0.001, Mann-Whitney U test). Combined aspiration catheters were used in 24 cases. In nine (36%) cases, the tip of the aspiration catheter was in M2 during stent retrieval. The median D/B ratio with the position of the aspiration catheter tip in M1 or the internal carotid artery was 1.5, which was significantly higher than that with the position in M2 (0, p = 0.003, Mann-Whitney U test).

CONCLUSION

In stent-based MT for M2 occlusion, cases in which successful recanalization was achieved showed less vessel deviation during stent retrieval. To reduce vessel deviation, advancing the combined aspiration catheter up to M2 is useful.

Intracranial atherosclerotic disease mechanism indicates poor outcomes of thrombectomy in acute cerebral infarction with large vessel occlusion: A matched cohort study

BACKGROUND

Thrombectomy is a standard treatment for acute large vessel occlusion (LVO); however, its effectiveness in treating LVO related to intracranial atherosclerosis disease (ICAD) remains uncertain. This study aimed to compare thrombectomy outcomes in ICAD-related and embolic LVO, focusing on patients with similar symptom severities upon hospital admission.

METHODS

This retrospective study was conducted at Jikei University Hospital and Jikei University Kashiwa Hospital between October 2017 and March 2023. Ischemic stroke patients with LVO who underwent thrombectomy were categorized into ICAD and embolism groups based on the occlusion mechanism. Groups were matched using National Institutes of Health Stroke Scale scores at the time of admission. A modified Rankin Scale score of 5 or 6 at 90 days after symptom onset was defined as a devastating outcome. The procedural outcomes and frequency of devastating outcomes were compared between the ICAD and embolism groups.

RESULTS

The study included 33 matched pairs were included. The ICAD group showed lower rates of successful reperfusion (43 % vs. 82 %, p = 0.001), and longer procedural times (median 88 min vs. 50 min, p < 0.001) than the embolism group. The ICAD group had a significantly higher frequency of devastating outcomes than the non-ICAD group (39 % vs. 15 %, p = 0.027). Multivariate analysis identified ICAD as an independent factor associated with devastating outcomes (OR, 3.804; 95 % confidence interval (95 %CI), 1.148-12.603; p = 0.029).

CONCLUSION

In thrombectomy therapy, reperfusion rates and outcomes are significantly worse in patients with ICAD-LVO than in patients with embolic LVO.

Subarachnoid iodine leakage on dual-energy computed tomography after mechanical thrombectomy is associated with malignant brain edema

BACKGROUND

Dual-energy computed tomography (DE-CT) can differentiate between hemorrhage and iodine contrast medium leakage following mechanical thrombectomy (MT) for acute ischemic stroke (AIS). We determined whether subarachnoid hemorrhage (SAH) and subarachnoid iodine leakage (SAIL) on DE-CT following MT were associated with malignant brain edema (MBE).

METHODS

We analyzed the medical records of 81 consecutive anterior circulation AIS patients who underwent MT. SAH or SAIL was diagnosed via DE-CT performed immediately after MT. We compared the procedural data, infarct volumes, MBE, and modified Rankin scale 0-2 at 90 days between patients with and without SAH and between patients with and without SAIL. Furthermore, we evaluated the association between patient characteristics and MBE.

RESULTS

A total of 20 (25%) patients had SAH and 51 (63%) had SAIL. No difference in diffusion-weighted imaging (DWI)-infarct volume before MT was observed between patients with and without SAH or patients with and without SAIL. However, patients with SAIL had larger DWI-infarct volumes 1 day following MT than patients without SAIL (95 mL vs 29 mL; p=0.003). MBE occurred in 12 of 81 patients (15%); more patients with SAIL had MBE than patients without SAIL (22% vs 3%; p=0.027). Severe SAIL was significantly associated with MBE (OR, 12.5; 95% CI, 1.20-131; p=0.006), whereas SAH was not associated with MBE.

CONCLUSION

This study demonstrated that SAIL on DE-CT immediately after MT was associated with infarct volume expansion and MBE.

Frictional forces in stent retriever procedures: The impact of vessel diameter, angulation, and deployment position

Background

Mechanical thrombectomy has improved the outcome of patients with acute ischemic stroke, but complications such as subarachnoid hemorrhage (SAH) can worsen the prognosis. This study investigates the frictional forces exerted by stent retrievers (SRs) on vessel walls, hypothesizing that these forces contribute to vascular stress and a risk of hemorrhage. We aimed to understand how vessel diameter, curvature, and stent deployment position influence these forces.

Methods

Using a silicone vascular model simulating the middle cerebral artery, we created virtual vessels with diameters of 2.0 mm and 2.5 mm, each with branching angles of 60° and 120°. A Trevo NXT (4 × 28 mm) SR was deployed and retracted through these models, measuring the maximum static frictional force at the moment the SR began to move. The stent deployment position relative to the curvature (straight, distal 1/4, center, and proximal 1/4) was also varied to assess its impact on frictional forces. Each condition was tested 15 times, and the results were statistically analyzed.

Results

The highest frictional force was observed in the 2.0 mm/120° model, followed by the 2.0 mm/60°, 2.5 mm/120°, and 2.5 mm/60° models. Narrower and more sharply curved vessels exhibited significantly higher frictional forces. Friction also increased with more distal stent deployment, particularly in the narrower vessels.

Conclusion

Smaller vessel diameters, greater curvature, and more distal stent deployment positions increase frictional forces during thrombectomy, potentially leading to SAH. These findings highlight the importance of selecting appropriately sized SRs and considering stent deployment positions to minimize vascular stress.

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.

Clinical significance and prevalence of subarachnoid hyperdensities on flat detector CT after mechanical thrombectomy: does it really matter?

BACKGROUND

Subarachnoid hyperdensities after mechanical thrombectomy (MT) are a common finding. However, it is often regarded as clinically insignificant.

OBJECTIVE

With this single-center investigation, to identify the prevalence of subarachnoid hyperdensities following MT, associated predictors, and the impact on the clinical outcome of the patients.

METHODS

383 patients from the stroke registry were analyzed for the presence of subarachnoid hyperdensities on flat detector CT (FDCT) directly after the completion of MT, and on follow-up dual-energy CT, then classified according to a visual grading scale. 178 patients were included with anterior circulation occlusions. Regression analysis was performed to identify significant predictors, and Kruskal-Wallis analysis and Χ2 test were performed to test the variables among the different groups. The primary outcome was the modified Rankin Scale (mRS) score at 90 days and was analyzed with the Wilcoxon-Mann-Whitney rank-sum test.

RESULTS

The prevalence of subarachnoid hyperdensities on FDCT was (66/178, 37.1%) with patients experiencing a significant unfavorable outcome (P=0.035). Significantly fewer patients with subarachnoid hyperdensities achieved a mRS score of ≤3 at 90 days 25/66 (37.9%) vs 60/112 (53.6%), P=0.043). In addition, mortality was significantly higher in the subarachnoid hyperdensities group (34.8% vs 19.6%, P=0.024). Distal occlusions and a higher number of device passes were significantly associated with subarachnoid hyperdensities (P=0.026) and (P=0.001), respectively. Patients who received intravenous tissue plasminogen activator had significantly fewer subarachnoid hyperdensities (P=0.029).

CONCLUSIONS

Postinterventional subarachnoid hyperdensities are a frequent finding after MT and are associated with neurological decline and worse functional outcome. They are more common with distal occlusions and multiple device passes.

Impact of Intracranial Hemorrhage After Endovascular Treatment for Medium Vessel Occlusion

BACKGROUND AND OBJECTIVES

Endovascular treatment (EVT) for medium vessel occlusion (MeVO) raises concern about hemorrhagic complications; however, its clinical impact has not been elucidated. Therefore, we investigated the association between intracranial hemorrhage (ICH) after EVT for MeVO and functional outcomes.

METHODS

We conducted a post hoc analysis of the Japan Registry of NeuroEndovascular Therapy 4, a nationwide registry in Japan from 2015 to 2019 including 13 479 patients who underwent EVT for acute ischemic stroke. This study included 2465 patients with MeVO from 166 participating centers in Japan. We compared patients who underwent EVT for MeVO according to their hemorrhagic complication after EVT (no ICH, asymptomatic ICH, and symptomatic ICH). Outcomes included a modified Rankin scale (mRS) score at 30 days and all-cause mortality within 30 days. We estimated the odds ratios (ORs) and their CIs using a multivariable logistic regression model.

RESULTS

Among 2394 patients analyzed, 302 (12.6%) developed ICH, with 95 (31.5%) being symptomatic. Compared with the no-ICH group (n = 2092), the asymptomatic and symptomatic ICH groups had a lower proportion of patients with an mRS score of 0 to 2 at 30 days (41% vs 34%, vs 7.4%, P for trend <.001), with an adjusted ORs of 0.77 (95% CI, 0.53-1.12) and 0.12 (95% CI, 0.05-0.30) in the asymptomatic and symptomatic ICH groups, respectively. The adjusted common ORs of one-point shift of mRS score at 30 days in the asymptomatic ICH group was 0.76 (95% CI, 0.57-0.99) and that of the symptomatic ICH group was 0.13 (0.07-0.23), compared with the no-ICH group.

CONCLUSION

ICH after EVT for MeVO was associated with worse outcomes, whether they were symptomatic or not. The optimal treatment devices or techniques to reduce ICH after EVT for MeVO are crucial.

Incidence, Risk Factors, and Clinical Implications of Subarachnoid Hyperdensities on Flat-Panel Detector CT following Mechanical Thrombectomy in Patients with Anterior Circulation Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Flat-panel detector CT immediately after mechanical thrombectomy can detect complications, including early hemorrhagic transformation and subarachnoid hyperdensities. The clinical significance of subarachnoid hyperdensities in patients undergoing mechanical thrombectomy remains unclear.

MATERIALS AND METHODS

We studied 223 patients who underwent mechanical thrombectomy for anterior circulation stroke who had flat-panel detector CT performed immediately after the procedure and had follow-up imaging within 24 hours. Subarachnoid hyperdensity severity was categorized into 5 grades (subarachnoid hyperdensities, 0: absent to subarachnoid hyperdensities, IV: extensive). Baseline and procedural characteristics as well as outcome measures were analyzed using group comparisons and multivariable logistic regression analyses.

RESULTS

Overall, 100/223 (45%) patients showed subarachnoid hyperdensities on immediate postinterventional flat-panel detector CT. The factors associated with an increased subarachnoid hyperdensity risk were the following: medium-vessel occlusion or distal-vessel occlusion compared with a large-vessel occlusion, a more distal device position, a higher number of device passes, a larger volume of contrast applied, worse final reperfusion expanded TICI, and after receiving IV thrombolysis. The occurrence of subarachnoid hyperdensity grades II-IV was independently associated with worse functional outcomes (adjusted OR for mRS, 3-6: 2.2; 95% CI 1.1-4.3), whereas patients with subarachnoid hyperdensity grade I had outcomes similar to those in patients without subarachnoid hyperdensities.

CONCLUSIONS

Our study identified risk factors for subarachnoid hyperdensities, most of which reflect increasingly challenging procedures or more peripheral recanalization attempts. The presence of subarachnoid hyperdensity grades II-IV was associated with poorer outcomes, suggesting the need for personalized strategies to reduce its incidence and severity or potentially improve recovery after subarachnoid hyperdensities.

Optimizing Tigertriever adjustable stentriever technique: Operators' experience

The Tigertriever is a novel, radially adjustable stentriever that addresses limitations in traditional mechanical thrombectomy devices by providing enhanced user control over clot integration. This provides the ability to adapt to patient-specific factors such as varying vessel sizes and clot compositions and may be particularly crucial for ensuring efficacy and safety in distal locations. This consensus paper synthesizes the clinical techniques from a consortium of experienced international operators. It outlines the current data on the Tigertriever, discusses the new operator-controlled capabilities, and provides a recommended approach for both proximal and distal mechanical thrombectomy, emphasizing the "FLEX" approach (Fast Controlled Expansion with Relaxation) for optimal integration and reduced clot disruption.

Endovascular thrombectomy versus medical management for moderate-to-severe anterior cerebral artery occlusion stroke

BACKGROUND

There are no established patient selection criteria for endovascular thrombectomy (EVT) for anterior cerebral artery (ACA) stroke.

METHODS

This was a retrospective cohort study of the 2016-2020 National Inpatient Sample in the United States. Isolated ACA-occlusion stroke patients with moderate-to-severe stroke symptoms (NIH stroke scale [NIHSS] ≥ 6) were included. Primary outcome was hospital discharge to home with self-care. Secondary outcomes include in-hospital mortality and intracranial hemorrhage (ICH). Confounders were accounted for by multivariable logistic regression.

RESULTS

6685 patients were included; 335 received EVT. Compared to medical management (MM), EVT patients were younger (mean 67.2 versus 72.2 years; p = 0.014) and had higher NIHSS (mean 16.0 versus 12.5; p < 0.001). EVT was numerically but not statistically significantly associated with higher odds of home discharge compared to MM (aOR 2.26 [95%CI 0.99-5.17], p = 0.053). EVT was significantly associated with higher odds of home discharge among patients with NIHSS 10 or greater (aOR 3.35 [95%CI 1.06-10.58], p = 0.039), those who did not receive prior thrombolysis (aOR 3.96 [95%CI 1.53-10.23], p = 0.005), and those with embolic stroke etiology (aOR 4.03 [95%CI 1.21-13.47], p = 0.024). EVT was not significantly associated with higher rates of mortality (aOR 1.93 [95%CI 0.80-4.63], p = 0.14); however, it was significantly associated with higher rates of ICH (22.4% vs. 8.5%, p < 0.001).

CONCLUSION

EVT was associated with higher odds of favorable short-term outcomes for moderate-to-severe ACA-occlusion stroke in select patients. Future studies are needed to confirm the efficacy of EVT in terms of longer term neurological outcomes.

Delayed Rupture from a Pseudoaneurysm after Mechanical Thrombectomy: A Case Report

Pseudoaneurysm following mechanical thrombectomy (MT) is a rare but possible complication associated with endovascular procedures. This report presents a case of delayed rupture of a pseudoaneurysm after MT with a stent retriever, which was confirmed by open surgery. During hospitalization, an 85-year-old woman had right hemiplegia and aphasia. Magnetic resonance imaging and angiography revealed acute ischemic changes in the left middle cerebral artery because of M2 segment occlusion. MT was performed to address persistent M2 occlusion. Retrieving from distal vessels with the fully deployed Solitaire 4 × 20 mm stent retriever was considered dangerous, we resheathed the stent, but the microcatheter jumped distally. Angiography through microcatheter revealed contrast leakage into the subarachnoid space. The diagnosis was vessel perforation caused by the microcatheter. The lesion was treated with temporary balloon occlusion for 5 minutes using a balloon-guiding catheter, combined with the reversal of heparin anticoagulation by protamine, and a systolic blood pressure reduction to below 120 mm Hg. Anticoagulation was initiated after confirming that postprocedural subarachnoid hemorrhage (SAH) decreased 1 day after the procedure. Fourteen days after the procedure, computed tomography and angiography revealed a massive hematoma with a newly formed small pseudoaneurysm at the site of vessel rupture. Open surgery was performed to close the small artery rupture using a clip. Delayed rupture of the pseudoaneurysm occurred after MT using a stent retriever. If SAH is observed after MT, performing follow-up computed tomography angiography or magnetic resonance angiography is recommended to consider pseudoaneurysm formation.

Post-Thrombectomy Subarachnoid Hemorrhage: Incidence, Predictors, Clinical Relevance, and Effect Modulators

BACKGROUND

Subarachnoid hemorrhage (SAH) following endovascular thrombectomy (EVT) is a poorly understood phenomenon, and whether it is associated with clinical detriment is unclear.

METHODS

This was an explorative analysis of a national database of real-world hospitalizations in the United States. Patients who underwent EVT were included. Patients were divided into SAH and non-SAH groups, and hospitalization outcomes were compared using multivariable logistic regression models. Regression models were also used to identify significant predictors for post-EVT SAH, and significant modulators of SAH's association with hospitalization outcomes were also assessed.

RESULTS

A total of 99,219 EVT patients were identified; 6174 (6.2%) had SAH. Overall, SAH was independently associated with increased odds of in-hospital mortality (21.5% vs. 10.6%, adjusted OR 2.53 [95%CI 2.23-2.87], p < 0.001) and lower odds of routine discharge to home with self-care (18.2% vs. 28.0%, aOR 0.58 [95%CI 0.52-0.65], p < 0.001). Distal/medium vessel occlusion (DMVO), coagulopathy, angioplasty or stenting, concurrent intraparenchymal hemorrhage (IPH), and female sex were associated with higher odds of SAH. DMVO was associated with particularly heightened risk of death (31.8% vs. 7.9%, aOR 6.99 [95%CI 2.99 to 16.3], p < 0.001), which was an effect size significantly larger than other sites of vascular occlusion (interaction p > 0.05).

CONCLUSION

SAH is an uncommon but likely clinically detrimental post-EVT complication. DMVO, coagulopathy, angioplasty or stenting, concurrent IPH, and female sex were independently associated with higher odds of post-EVT SAH. SAH associated with DMVO-EVT may be particularly harmful.

Degree of subarachnoid hemorrhage affects clinical outcome after mechanical thrombectomy for M2 occlusion

PURPOSE

The prognostic relevance of post-mechanical thrombectomy (MT) subarachnoid hemorrhage (SAH) remains controversial. This study aimed to investigate whether the thickness of the SAH clot affects clinical outcomes following MT for M2 occlusion.

METHODS

A retrospective analysis was conducted on a prospective database of patients who underwent MT for isolated M2 occlusion. Patients were categorized into three groups based on the presence and thickness of SAH. Clinical and angiographical characteristics and outcomes were compared.

RESULTS

Of the 36 patients included, SAH was observed in 15 (42%). When comparing patients with no SAH (grade 0) or thin SAH (grade 1) (N = 28) with those who had thick SAH (grade 2) (N = 8), patients with Grade 2 SAH required a higher number of passes and had a more severe angulation at M2. Patients with SAH Grade 2 had significantly worse NIHSS scores at 24 h (median, 4 vs. 14), but only one patient was identified as having a symptomatic intracranial hemorrhage. Patients with SAH Grade 2 were found to have a lower rate of favorable outcome (modified Rankin scale 0-2) (23% vs. 75%, P = 0.0026) and higher mortality (25% vs. 0%, P = 0.0499) at 90 days.

CONCLUSION

The study found that thick SAH prevents clinical recovery after MT for M2 occlusion, even in cases of successful recanalization, and is associated with an unfavorable outcome. Thick SAH after MT is also linked to an increase in the number of passes and severe angulation at the M2 segment.

Distal mechanical thrombectomy using beveled tip aspiration zoom catheters: A preliminary study

INTRODUCTION

Distal medium vessel occlusion (DVO) thrombectomy has been shown to be efficacious with safety profiles comparable to large vessel occlusion (LVO) thrombectomy. A novel, highly-trackable, bevel-tipped Zoom 35 catheter can be used as an aspiration catheter for DVO thrombectomy.

METHODS

This is a retrospective, single-arm, multi-institutional observational study evaluating the efficacy and safety of aspiration thrombectomy for DVO using the Zoom 35 catheter. Patient demographics, presenting and discharge NIHSS, primary and rescue thrombectomy, site of occlusion, TICI score, and intracranial hemorrhage were chart abstracted. Descriptive statistics were used to evaluate the efficacy and safety of thrombectomy.

RESULTS

Fourteen patients (mean age 66.64 ± 13.75 years) were included. The mean NIHSS at presentation was 10.79 ± 5.48, and the mean ASPECTS was 9.00 ± 0.89. Nine patients (64.3%) received tPA. Primary occlusion location was M3 in nine cases (64.3%), M2/M3 junction in two cases (14.3%), A2 in one case (7.1%), A3 in one case (7.1%), and P1 in one case (7.1%). TICI scores were 3 in seven cases (50.0%), 2C in three cases (21.4%), and 2B in four cases (28.6%). There was one postoperative SAH (7.1%) and one asymptomatic ICH (7.1%). Mean discharge NIHSS was 3.38 ± 4.44, with a mean decrease of 7.31 from presentation (p < 0.0001, t-test).

CONCLUSION

Zoom 35 beveled-tip aspiration microcatheters are highly trackable and associated with improved radiographic and clinical outcomes for the treatment of DVO with a good safety profile.

Procedural Blood Pressure and Intracranial Hemorrhage on Dual-Energy Computed Tomography After Endovascular Stroke Treatment

PURPOSE

Optimal systolic blood pressure (SBP) management during endovascular treatment (EVT) for acute ischemic stroke remains a topic of debate. Though BP is associated with worse functional outcome, the relationship between BP and post-procedural intracranial hemorrhage (ICH) is less well-known. We aimed to investigate the association between BP during EVT and post-procedural ICH on dual-energy CT (DECT).

METHODS

We included all patients who underwent EVT for an anterior circulation large vessel occlusion between 2010 and 2019, and received DECT < 3 h post-EVT. All BP measurements during the EVT procedure were used to calculate mean arterial pressure (MAPmean), mean SBP (SBPmean), and SBPmax-min (highest minus lowest). ICH was assessed using virtual post-procedural unenhanced DECT reconstructions and classified as intraparenchymal or extraparenchymal. Symptomatic ICH was scored according to the Heidelberg criteria. The association between different BP parameters and ICH was assessed using multivariable logistic regression.

RESULTS

We included 478 patients. Seventy-six patients (16%) demonstrated ICH on DECT, of which 26 (34%) were intraparenchymal. Symptomatic intraparenchymal and extraparenchymal ICH occurred in 10 (38%) and 4 (8%) patients. SBPmax, SBPmean, and MAPmean were associated with intraparenchymal ICH with an adjusted odds ratio of 1.19 (95%CI, 1.02-1.39), 1.22 (95%CI, 1.03-1.46), and 1.40 (95%CI, 1.09-1.81) per 10 mmHg, while BP was not significantly associated with extraparenchymal ICH. BP did not differ between asymptomatic and symptomatic ICH.

CONCLUSION

Procedural BP is associated with intraparenchymal ICH on post-EVT DECT but not with extraparenchymal ICH. Future studies should evaluate whether individual procedural BP management reduces post-EVT ICH and improves clinical outcome.

First pass effect as an independent predictor of functional outcomes in medium vessel occlusions: An analysis of an international multicenter study

INTRODUCTION

First pass effect (FPE), achievement of complete recanalization (mTICI 2c/3) with a single pass, is a significant predictor of favorable outcomes for endovascular treatment (EVT) in large vessel occlusion stroke (LVO). However, data concerning the impact on functional outcomes and predictors of FPE in medium vessel occlusions (MeVO) are scarce.

PATIENTS AND METHODS

We conducted an international retrospective study on MeVO cases. Multivariable logistic modeling was used to establish independent predictors of FPE. Clinical and safety outcomes were compared between the two study groups (FPE vs non-FPE) using logistic regression models. Good outcome was defined as modified Rankin Scale 0-2 at 3 months.

RESULTS

Eight hundred thirty-six patients with a final mTICI ⩾ 2b were included in this analysis. FPE was observed in 302 patients (36.1%). In multivariable analysis, hypertension (aOR 1.55, 95% CI 1.10-2.20) and lower baseline NIHSS score (aOR 0.95, 95% CI 0.93-0.97) were independently associated with an FPE. Good outcomes were more common in the FPE versus non-FPE group (72.8% vs 52.8%), and FPE was independently associated with favorable outcome (aOR 2.20, 95% CI 1.59-3.05). 90-day mortality and intracranial hemorrhage (ICH) were significantly lower in the FPE group, 0.43 (95% CI, 0.25-0.72) and 0.55 (95% CI, 0.39-0.77), respectively.

CONCLUSION

Over 2/3 of patients with MeVOs and FPE in our cohort had a favorable outcome at 90 days. FPE is independently associated with favorable outcomes, it may reduce the risk of any intracranial hemorrhage, and 3-month mortality.

Clinical outcome after thrombectomy in patients with MeVO stroke: importance of clinical and technical factors

BACKGROUND AND AIMS

Whereas high-level evidence has been proven for safety and efficacy of endovascular treatment (EVT) in large vessel occlusion (LVO) stroke, the evidence for EVT in medium vessel occlusion (MeVO) in both sexes and different age groupremains to be answered. The aim of this study was to evaluate the importance of clinical and technical parameters, focusing on sex, age and EVT procedural factors, on functional outcome in primary MeVO (pMeVO) strokes.

METHODS

144 patients with pMeVO in the MCA territory from the Oslo Acute Reperfusion Stroke Study (OSCAR) were included. Clinical and radiological data were collected including 90-day mRS follow-up.

RESULTS

Successful reperfusion with modified thrombolysis in cerebral infarction (mTICI) ≥ 2b was achieved in 123 patients (84%). Good functional outcome (mRS ≤ 2) at 90-day follow-up was achieved in 84 patients (61.8%). Two or more passes with stent retriever was associated with increased risk of SAH, poor mTICI and poor functional outcome. In average, women had 62 min longer ictus to recanalization time compared to men. Age over 80 years was significantly associated with poor outcome and death.

CONCLUSION

In pMeVO patients, TICI score and number of passes with stent retriever were the main technical factors predicting mRS ≤ 2. Good clinical outcome occurred almost twice as often in patients under 80 years of age compared to patients over 80 years. Women with MeVO strokes had significant longer time from ictus to recanalization; however, this did not affect the clinical outcome.

Diagnosis and management of tandem occlusion in acute ischemic stroke

Approximately 20-30% of patients with acute ischemic stroke, caused by large intracranial vessel occlusion, have a tandem lesion, defined as simultaneous presence of high-grade stenosis or occlusion of the cervical internal carotid artery and thromboembolic occlusion of the intracranial terminal internal carotid artery or its branches, usually the middle cerebral artery. Patients with tandem lesions have usually worse outcomes than patients with single intracranial occlusions, and intravenous thrombolysis is less effective in these patients. Although endovascular thrombectomy is currently a cornerstone therapy in the management of acute ischemic stroke due to large vessel occlusion, the optimal management of extracranial carotid lesions in tandem occlusion remains controversial. Acute placement of a stent in the cervical carotid artery lesion is the most used therapeutic strategy compared with stented balloon angioplasty and thrombectomy alone without carotid artery revascularization; however, treatment strategies in these patients are often more complex than with single occlusion, so treatment decisions can change based on clinical and technical considerations. The aim of this review is to analyze the results of different studies and trials, investigating the periprocedural neurointerventional management of patients with tandem lesions and the safety, efficacy of the different technical strategies available as well as their impact on the clinical outcome in these patients, to strengthen current recommendations and thus optimize patient care.

Low Levels of Low-Density Lipoprotein Cholesterol Increase the Risk of Post-Thrombectomy Delayed Parenchymal Hematoma

PURPOSE

Low levels of low-density lipoprotein cholesterol (LDL-C) have been suggested to increase the risk of hemorrhagic transformation (HT) following acute ischemic stroke. However, the literature on the relationship between LDL-C levels and post-thrombectomy HT is sparse. The aim of our study is to investigate the association between LDL-C and delayed parenchymal hematoma (PH) that was not seen on immediate post-thrombectomy dual-energy computed tomography (DECT).

MATERIALS AND METHODS

A retrospective analysis was conducted on all patients with anterior circulation large vessel occlusion who underwent thrombectomy at a comprehensive stroke center from 2018-2021. Per institutional protocol, all patients received DECT immediately post-thrombectomy and magnetic resonance imaging or CT at 24 hours. The presence of immediate hemorrhage was assessed by DECT, while delayed PH was assessed by 24-hour imaging. Multivariable analysis was performed to identify predictors of delayed PH. Patients with hemorrhage on immediate post-thrombectomy DECT were excluded to select only those with delayed PH.

RESULTS

Of 159 patients without hemorrhage on immediate post-thrombectomy DECT, 18 (11%) developed delayed PH on 24-hour imaging. In multivariable analysis, LDL-C (odds ratio [OR], 0.76; P=0.038; 95% confidence interval [CI], 0.59-0.99; per 10 mg/dL increase) independently predicted delayed PH. High-density lipoprotein cholesterol, triglyceride, and statin use were not associated. After adjusting for potential confounders, LDL-C ≤50 mg/dL was associated with an increased risk of delayed PH (OR, 5.38; P=0.004; 95% CI, 1.70-17.04), while LDL-C >100 mg/dL was protective (OR, 0.26; P=0.041; 95% CI, 0.07-0.96).

CONCLUSION

LDL-C ≤50 mg/dL independently predicted delayed PH following thrombectomy and LDL-C >100 mg/dL was protective, irrespective of statin. Thus, patients with low LDL-C levels may warrant vigilant monitoring and necessary interventions, such as blood pressure control or anticoagulation management, following thrombectomy even in the absence of hemorrhage on immediate post-thrombectomy DECT.

Hemorrhage rates in patients with acute ischemic stroke treated with intravenous alteplase and thrombectomy versus thrombectomy alone

BACKGROUND

Intravenous alteplase treatment (IVT) for acute ischemic stroke carries a risk of intracranial hemorrhage (ICH). However, reperfusion of an occluded vessel itself may contribute to the risk of ICH. We determined whether IVT and reperfusion are associated with ICH or its volume in the Multicenter Randomized Clinical trial of Endovascular treatment for Acute ischemic stroke in the Netherlands (MR CLEAN)-NO IV trial.

METHODS

The MR CLEAN-NO IV trial randomized patients with acute ischemic stroke due to large vessel occlusion to receive either IVT followed by endovascular treatment (EVT) or EVT alone. ICH was classified according to the Heidelberg bleeding classification on follow-up MRI or CT approximately 8 hours-7 days after stroke. Hemorrhage volume was measured with ITK-snap. Successful reperfusion was defined as extended Thrombolysis In Cerebral Infarction (eTICI) score of 2b-3. Multinomial and binary adjusted logistic regression were used to determine the association of IVT and reperfusion with ICH subtypes.

RESULTS

Of 539 included patients, 173 (32%) developed ICH and 30 suffered from symptomatic ICH (sICH) (6%). Of the patients with ICH, 102 had hemorrhagic infarction, 47 had parenchymal hematoma, 44 had SAH, and six had other ICH. Reperfusion was associated with a decreased risk of SAH, and IVT was not associated with SAH (eTICI 2b-3: adjusted OR 0.45, 95% CI 0.21 to 0.97; EVT without IVT: OR 1.6, 95% CI 0.91 to 2.8). Reperfusion status and IVT were not associated with overall ICH, hemorrhage volume, and sICH (sICH: EVT without IVT, OR 0.96, 95% CI 0.41 to 2.25; eTICI 2b-3, OR 0.49, 95% CI 0.23 to 1.05).

CONCLUSION

Neither IVT administration before EVT nor successful reperfusion after EVT were associated with ICH, hemorrhage volume, and sICH. SAH occurred more often in patients for whom successful reperfusion was not achieved.

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.

Type of intracranial hemorrhage after endovascular stroke treatment: association with functional outcome

BACKGROUND

Intracranial hemorrhage (ICH) is a frequent complication after endovascular stroke treatment.

OBJECTIVE

To assess the association of the occurrence and type of ICH after endovascular treatment (EVT) with functional outcome.

METHODS

We analyzed data from the MR CLEAN-NO IV and MR CLEAN-MED trials. Both trials included adult patients with ischemic stroke with a large vessel occlusion in the anterior circulation, who were eligible for EVT. ICH was classified (1) as asymptomatic or symptomatic (concomitant neurological deterioration of ≥4 points on the NIHSS, or ≥2 points on 1 NIHSS item), and (2) according to the Heidelberg Bleeding Classification. We used multivariable ordinal logistic regression analyses to assess the association of the occurrence and type of ICH with the modified Rankin Scale score at 90 days.

RESULTS

Of 1017 included patients, 331 (33%) had an asymptomatic ICH, and 90 (9%) had a symptomatic ICH. Compared with no ICH, both asymptomatic (adjusted common OR (acOR)=0.76; 95% CI 0.58 to 0.98) and symptomatic (acOR=0.07; 95% CI 0.04 to 0.14) ICH were associated with worse functional outcome. In particular, isolated parenchymal hematoma type 2 (acOR=0.37; 95% CI 0.14 to 0.95), combined parenchymal hematoma with hemorrhage outside infarcted brain tissue (acOR=0.17; 95% CI 0.10 to 0.30), and combined hemorrhages outside infarcted brain tissue (acOR=0.14; 95% CI 0.03 to 0.74) were associated with worse functional outcome than no ICH.Strength of the association of ICH with functional outcome depends on the type of ICH. Although the association is stronger for symptomatic ICH, asymptomatic ICH after EVT is also associated with worse functional outcome.

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.

Comparative efficacy and safety of various mechanical thrombectomy strategies for patients with acute ischemic stroke: a Bayesian network meta-analysis

Background

Stent retriever, contact aspiration, and combined treatment are crucial mechanical thrombectomy strategies for patients with acute ischemic stroke (AIS).

Objectives

The aim of this study was to compare and rank three different mechanical thrombectomy strategies for AIS due to large vessel occlusion by means of a Bayesian network meta-analysis.

Design

A systematic review and Bayesian network meta-analysis based on PRISMA guidelines.

Data sources and methods

Relevant randomized controlled trials (RCTs) were identified in Embase, MEDLINE, the Cochrane Library database, and Clinicaltrials.gov from inception to 15 March 2022. We used random effect models to estimate corresponding odds ratios (ORs) and rank probabilities using pairwise and Bayesian network meta-analysis. We applied the grading of recommendations assessment, development, and evaluation (GRADE) methodology to rate the certainty of evidence.

Results

We identified 10 RCTs enrolling 2098 participants. As for modified Rankin Scale (mRS) 0-2, moderate certainty evidence established all mechanical thrombectomy strategies that were more effective than standard medical treatment [combined: log OR 0.9288, 95% credibility intervals (CrI) 0.1268-1.7246; contact aspiration: log OR 0.9507, 95% CrI 0.3361-1.5688; stent retriever: log OR 1.0919, 95% CrI 0.6127-1.5702]. The same applied to mRS 0-3 (combined: log OR 0.9603, 95% CrI 0.2122-1.7157; contact aspiration: log OR 0.7554, 95% CrI 0.1769-1.3279; stent retriever: log OR 1.0046, 95% CrI 0.6001-1.4789). Combined treatment was superior to stent retriever in substantial reperfusion (log OR 0.8921, 95% CrI 0.2105-1.5907, high certainty). Stent retriever had the highest probability of being optimal for mRS 0-2 and mRS 0-3. Standard medical treatment had the lowest risk of subarachnoid hemorrhage. For all other outcomes, combined treatment was most likely the best treatment.

Conclusion

Our results indicated that, with the exception of functional outcome, combined treatment might be the outstanding strategy. Apart from subarachnoid hemorrhage, all three mechanical thrombectomy strategies proved better strategies than standard medical treatment.

Registration

PROSPERO (CRD42022351878).

Distal medium vessel occlusions in acute ischaemic stroke - Stent retriever versus direct aspiration: A systematic review and meta-analysis

BACKGROUND

Acute ischaemic stroke due to distal medium vessel occlusion (AIS-DMVO) causes significant morbidity. Endovascular thrombectomy advancement has made treating AIS-DMVO with stent retrievers (SR) and aspiration catheters (AC) possible, however the optimal technique remains unknown. We performed a systematic review and meta-analysis to investigate the efficacy and safety of SR use compared to purely AC use in patients with AIS-DMVO.

METHODS

We systematically searched PubMed, Cochrane Library and EMBASE, from inception to 2nd September 2022, for studies comparing SR or primary combined (SR/PC) against AC in AIS-DMVO. We adopted the Distal Thrombectomy Summit Group's definition of DMVO. Efficacy outcomes were functional independence (modified Rankin Scale (mRS) 0-2 at 90 days), first pass effect (modified Thrombolysis in Cerebral Infarction scale (mTICI) 2c-3 or expanded Thrombolysis in Cerebral Infarction scale (eTICI) 2c-3 at first pass), successful final recanalisation (mTICI or eTICI 2b-3), and excellent final recanalisation (mTICI or eTICI 2c-3). Safety outcomes were symptomatic intracranial haemorrhage (sICH) and 90-day mortality.

RESULTS

12 cohort studies and 1 randomised-controlled trial were included, involving 1881 patients with 1274 receiving SR/PC and 607 receiving AC only. SR/PC achieved higher odds of functional independence (odds ratio (OR) 1.33, 95% confidence interval (CI) 1.06-1.67) and lower odds of mortality (OR 0.69, 95% CI 0.50-0.94) than AC. Odds of successful/excellent recanalisation and sICH were similar between both groups. Stratified to compare only SR and only AC, the use of only SR, achieved significantly higher odds of successful recanalisation as compared to only AC (OR 1.80, 95% CI 1.17-2.78).

CONCLUSION

There is potential for efficacy and safety benefits in SR/PC use as compared to AC only in AIS-DMVO. Further trials are necessary to validate the efficacy and safety of SR use in AIS-DMVO.

Mechanical Thrombectomy with Tandem Double Stent Retriever in Combination with Intermediate Catheter Aspiration for Refractory Severe Hemorrhagic Cerebral Venous Sinus Thrombosis

OBJECTIVE

We aimed to describe the initial experience of mechanical thrombectomy using tandem double stent retrievers combined with intermediate catheter aspiration to treat refractory severe hemorrhagic (SH)-cerebral venous sinus thrombosis (CVST).

METHODS

All refractory SH-CVST patients treated with mechanical thrombectomy using tandem double stent retriever (SR) combined with intermediate catheter aspiration (MT-TDSA) in our institution were retrospectively reviewed. MT-TDSA is a technique that fully engages the clot with double SRs and retrieves the clot using a double SR in combination with aspiration from an intermediate catheter. Demographics, clinical manifestation, medical history, the location of the occluded venous sinus, intraoperative details, procedure-related complications, and modified Rankin Scale (1, 6, 12 months postoperatively) were collected and analyzed.

RESULTS

Fourteen patients (median age, 43 years) with refractory SH-CVST were treated with MT-TDSA between January 2016 and January 2020. Ten of 14 (71.4%) had a successful intraoperative recanalization rate (>90%) using MT-TDSA. No procedure-related complications occurred. Eleven patients had good clinical outcomes (modified Rankin Scale score 0-2 at 12 months postoperatively).

CONCLUSIONS

MT-TDSA for refractory SH-CVST might improve clot-capturing ability and remove blood clots from cerebral venous sinuses effectively and safely, achieving good clinical outcomes.

First-line thrombectomy strategy for distal and medium vessel occlusions: a systematic review

BACKGROUND

The benefit of mechanical thrombectomy (MT) and efficacy of different first-line MT techniques remain unclear for distal and medium vessel occlusions (DMVOs). In this systematic review, we aimed to compare the performance of three first-line MT techniques in DMVOs.

METHODS

The PubMed database was searched for studies examining the utility of MT in DMVOs (middle cerebral artery M2-3-4, anterior cerebral artery, and posterior cerebral artery). Studies providing data for aspiration thrombectomy (ASP), stent retriever thrombectomy (SR), and combined SR+ASP technique were included. Non-comparative studies were excluded. Safety and efficacy data were collected for each technique. The Nested Knowledge AutoLit platform was utilized for literature search, screening, and data extraction. Pooled data were presented as descriptive statistics.

RESULTS

13 studies comprising 2422 MT procedures were identified. The overall successful recanalization rate was 77.0% (1513/1964) for DMVOs. SR+ASP had a successful recanalization rate of 83.7% (297/355), SR had a 75.6% rate (638/844), while ASP alone had a 74.2% rate (386/520). The overall functional independence rate was 51.3% (851/1659) among DMVOs. The ASP alone group had a functional independence rate of 46.9% (219/467), while functional independence rates of the SR and SR+ASP groups were 51.5% (372/723) and 61.7% (174/282), respectively. Finally, the subarachnoid hemorrhage rates were 1.8% (4/217) for the ASP group, 9.3% (26/281) for the SR group, and 11.9% (41/344) for the SR+ASP group.

CONCLUSIONS

Our systematic review supports the proposition that MT is a safe and effective treatment option for DMVOs. Additionally, while the SR+ASP group had consistently high rates of clot clearance and good neurological outcomes, the SR and SR+ASP groups also had higher rates of subarachnoid hemorrhage, highlighting the need for improved DMVO treatment devices.

Evaluation of Middle Cerebral Artery Symmetry: A Pilot Study for Clinical Application in Mechanical Thrombectomy

BACKGROUND

Endovascular mechanical thrombectomy (MT) has now evolved to become the standard treatment for acute ischemic stroke due to large vessel occlusion. Arterial perforation is a potential complication of MT, and the risk of this event during blind crossing the occlusion site has been elucidated. The intracranial arterial system shows morphological structural symmetry, so we investigated the utility of the bilateral symmetry of the proximal middle cerebral artery (MCA) as a preprocedural evaluation to predict hidden running course distal to the thrombus.

METHODS

This study retrospectively analyzed 191 consecutive patients (mean age, 67.5 ± 15.5 years; 100 women) who underwent time-of-flight-magnetic resonance angiography in our institution. Four landmarks of the MCA were assessed: division pattern, early branching pattern, length, and course pattern. Each geometric property was compared between cerebral hemispheres. Frequencies of symmetry and symmetry breaking were assessed.

RESULTS

In 91% (bifurcation type, 87%; trifurcation type, 4%), branching patterns of the left and right M1 were symmetrical. Early frontal and/or temporal branches were observed in 31%, and the presence/absence of early branches was symmetrical in 70% cases. In 19%, M1 was classified as short M1, and classifications were identical between hemispheres in 74%. Running course of the M1 was symmetrical in 63%. Two or more parameters were symmetrical in 181 cases (95%).

CONCLUSIONS

The symmetry of bilateral M1-2 structures was demonstrated in most cases from the perspectives of 4 parameters. The MCA symmetry can predict the running course of the MCA before crossing the occlusion site and shows potential benefits for neurointerventionalists.

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.

Experimental Validation of Pullout Resistance for Stent Retrievers and Aspiration Catheters

Objective

Stretching or avulsion of a small perforating artery caused by mechanical traction contributes to intracranial hemorrhagic complications in mechanical thrombectomy, especially for medium and small-vessel occlusions. This study aimed to measure the pullout resistance during stent retriever (SR) traction and aspiration catheter (AC) traction with or without thrombi and characterize the mechanical properties of each device.

Methods

We placed the thrombectomy device in the area corresponding to the insular segment of the middle cerebral artery of a silicon carotid artery model. The thrombectomy device was automatically pulled out at a constant velocity using a horizontal motorized test stand, and pullout resistance was continuously measured 2000 times per second using a digital force gauge. Five types of SRs and two types of ACs with or without thrombus were evaluated. The data were divided into four groups for analysis: SR without clot, SR with clot, AC without clot, and AC with clot.

Results

The line graph was a jagged waveform during SR traction, and it was a gentle curve during AC traction. The maximum pullout resistance was higher in the SR with clot group than the other groups. The coefficient of variation was higher in the SR group than the AC group, with or without clot.

Conclusion

The pullout resistance during SR traction was more fluctuated than that during AC traction. In the presence of a thrombus, pullout resistance for SR was substantially increased, whereas AC resistance was less susceptible to thrombi. The differences in characteristics may reflect differences in the frequency of mechanical traction injury between the devices during clinical use.

Delayed Rupture of an Anterior Communicating Artery Pseudoaneurysm Caused by Distal Occlusion Thrombectomy Using a Stent Retriever: A Case Report and Mechanism of Injury

We report a case of delayed rupture of an anterior communicating artery (Acom) pseudoaneurysm following mechanical thrombectomy (MT) of a distal artery occlusion using a stent retriever. An elderly patient with right hemiparesis showed left proximal internal cerebral artery and middle cerebral artery occlusions. During MT, a fragmented thrombus moved to the anterior cerebral artery (ACA). A stent retriever was deployed to the occluded ACA, and the Acom and proximal ACA segment were significantly straightened. Additionally, we attempted a blind exchange mini-pinning (BEMP) technique, but a subarachnoid hemorrhage (SAH) occurred. Bleeding was almost entirely absorbed 9 days after the procedure, but the SAH recurred at 20 days, and computed tomography angiography revealed a new pseudoaneurysm formation in the Acom. We suggest that the proposed mechanism of pseudoaneurysm formation was likely due to the dislocation and avulsion of the Acom perforators when the ipsilateral ACA was pushed and pulled during MT.

Endovascular Thrombectomy for Distal Medium Vessel Occlusions of the Middle Cerebral Artery: A Safe and Effective Procedure

BACKGROUND

Distal medium vessel occlusions (DMVOs) are increasingly recognized as a next target for endovascular thrombectomy (EVT). Our objective was to investigate safety and clinical outcomes of EVT for DMVO of the middle cerebral artery (MCA).

METHODS

We analyzed data of the Lille Reperfusion Registry from January 2017 to September 2020. Patients with a primary or secondary DMVO of the MCA seen on pretreatment angiogram were included. Only patients with a eTICI score 2b50-2b67 on initial angiogram were considered. Baseline characteristics, angiographic clinical, and safety outcomes were compared between patients treated with EVT or standard medical treatment (no-EVT).

RESULTS

Of the 171 patients included, 96 received EVT (46.9% male, 68.7 ± 15.8 years) and 75 received standard medical treatment (44% male, 73.9 ± 13.1 years). EVT patients had a better improvement of the NIHSS score at discharge (adjusted mean difference: 3.71; 95% CI: 1.18-6.24). In the distal M2 occlusions subgroup, EVT was significantly associated with a higher rate of early neurologic improvement (adjusted OR: 3.62 95% CI: 1.31-10.03), NIHSS improvement at discharge (adjusted mean difference: 5.23; 95% CI: 2.18-8.29), and improved modified Rankin Scale score at 3 months (adjusted common OR for 1 point improvement: 3.06; 95% CI: 1.30 to 7.23). Symptomatic intracranial hemorrhage occurred in 3.1% in the EVT group and in 9.5% in the no-EVT group.

CONCLUSIONS

EVT for DMVO of the MCA appears to be safe and may lead to improved clinical outcomes. This effect was especially pronounced in patients with distal M2 occlusions, warranting randomized trials to validate this result.

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.