Functional aspects of meningeal lymphatics in ageing and Alzheimer's disease

Ageing is a major risk factor for many neurological pathologies, but its mechanisms remain unclear. Unlike other tissues, the parenchyma of the central nervous system (CNS) lacks lymphatic vasculature and waste products are removed partly through a paravascular route. (Re)discovery and characterization of meningeal lymphatic vessels has prompted an assessment of their role in waste clearance from the CNS. Here we show that meningeal lymphatic vessels drain macromolecules from the CNS (cerebrospinal and interstitial fluids) into the cervical lymph nodes in mice. Impairment of meningeal lymphatic function slows paravascular influx of macromolecules into the brain and efflux of macromolecules from the interstitial fluid, and induces cognitive impairment in mice. Treatment of aged mice with vascular endothelial growth factor C enhances meningeal lymphatic drainage of macromolecules from the cerebrospinal fluid, improving brain perfusion and learning and memory performance. Disruption of meningeal lymphatic vessels in transgenic mouse models of Alzheimer's disease promotes amyloid-β deposition in the meninges, which resembles human meningeal pathology, and aggravates parenchymal amyloid-β accumulation. Meningeal lymphatic dysfunction may be an aggravating factor in Alzheimer's disease pathology and in age-associated cognitive decline. Thus, augmentation of meningeal lymphatic function might be a promising therapeutic target for preventing or delaying age-associated neurological diseases.

How Do Meningeal Lymphatic Vessels Drain the CNS?

The many interactions between the nervous and the immune systems, which are active in both physiological and pathological states, have recently become more clearly delineated with the discovery of a meningeal lymphatic system capable of carrying fluid, immune cells, and macromolecules from the central nervous system (CNS) to the draining deep cervical lymph nodes. However, the exact localization of the meningeal lymphatic vasculature and the path of drainage from the cerebrospinal fluid (CSF) to the lymphatics remain poorly understood. Here, we discuss the potential differences between peripheral and CNS lymphatic vessels and examine the purported mechanisms of CNS lymphatic drainage, along with how these may fit into established patterns of CSF flow.

Lower complication rates associated with transradial versus transfemoral flow diverting stent placement

BACKGROUND

Currently, there are no large-scale studies in the neurointerventional literature comparing safety between transradial (TRA) and transfemoral (TFA) approaches for flow diversion procedures. This study aims to assess complication rates in a large multicenter registry for TRA versus TFA flow diversion.

METHODS

We retrospectively analyzed flow diversion cases for cerebral aneurysms from 14 institutions from 2010 to 2019. Pooled analysis of proportions was calculated using weighted analysis with 95% CI to account for results from multiple centers. Access site complication rate and overall complication rate were compared between the two approaches.

RESULTS

A total of 2,285 patients who underwent flow diversion were analyzed, with 134 (5.86%) treated with TRA and 2151 (94.14%) via TFA. The two groups shared similar patient and aneurysm characteristics. Crossover from TRA to TFA was documented in 12 (8.63%) patients. There were no access site complications in the TRA group. There was a significantly higher access site complication rate in the TFA cohort as compared with TRA (2.48%, 95% CI 2.40% to 2.57%, vs 0%; p=0.039). One death resulted from a femoral access site complication. The overall complications rate was also higher in the TFA group (9.02%, 95% CI 8.15% to 9.89%) compared with the TRA group (3.73%, 95% CI 3.13% to 4.28%; p=0.035).

CONCLUSION

TRA may be a safer approach for flow diversion to treat cerebral aneurysms at a wide range of locations. Both access site complication rate and overall complication rate were lower for TRA flow diversion compared with TFA in this large series.

Pipeline Embolization Device for the Treatment of Intracranial Pseudoaneurysms

BACKGROUND

Intracranial pseudoaneurysms (PSAs) are associated with high rupture and mortality rates and have traditionally been treated by parent vessel sacrifice. There has been recent interest in using flow-diverting devices for treatment of these complex lesions while preserving flow through the parent artery. The objective of this study is to examine the safety and efficacy of these devices in the treatment of intracranial PSA.

METHODS

We performed a multi-institutional retrospective study of intracranial PSAs treated with the Pipeline Embolization Device (PED) between 2014 and 2017 at 7 institutions. Complications and clinical and radiographic outcomes were reviewed.

RESULTS

A total of 19 patients underwent PED placement for intracranial PSA. Iatrogenic injury and trauma comprised most etiologies in our series. The mean pseudoaneurysm diameter was 8.8 mm, and 18 of 19 PSAs (95%) involved the internal carotid artery (ICA). Multiple PEDs were deployed in a telescoping fashion in 7 patients (37%). Of the 18 patients with follow up imaging, 14 (78%) achieved complete pseudoaneurysm obliteration and 2 achieved near-complete obliteration (11%). Two patients (11%) were found to have significant pseudoaneurysm progression on short-term follow-up and required ICA sacrifice. No patients experienced new neurologic deficits or deterioration secondary to PED placement. No patients experienced bleeding or rebleeding from PSA.

CONCLUSIONS

In well-selected patients, the use of flow-diverting stents may be a feasible alternative to parent vessel sacrifice. Given the high morbidity and mortality associated with PSA, we recommend short- and long-term radiographic follow-up for patients treated with flow-diverting stents.

Pattern of pressure gradient alterations after venous sinus stenting for idiopathic intracranial hypertension predicts stent-adjacent stenosis: a proposed classification system

Objective

Venous sinus stenting (VSS) is a safe and effective treatment for idiopathic intracranial hypertension (IIH) with angiographic venous sinus stenosis. However, predictors of stent-adjacent stenosis (SAS) remain poorly defined.

Methods

We performed a retrospective review of 47 patients with IIH and intracranial venous stenosis who underwent VSS with pre- and post-stent venography. Patient characteristics, treatments and outcomes were reviewed. Changes in pressure gradient after VSS were classified according to pattern of gradient resolution into types I–III.

Results

Type I gradient resolution, in which mean venous pressure (MVP) in the transverse sinus (TS) decreases towards MVP in the sigmoid sinus (SS), occurred in 18 patients (38.3%). Type II gradient resolution pattern, in which SS MVP increases towards that in the TS, occurred in 7patients (14.9%). Type III pattern, in which MVP equilibrates to a middle value, occurred in 22patients (46.8%). SAS occurred in 0%, 28.6%, and 22.7% of patients in types I, II and III, respectively. Compared with patients with type I gradient resolution, SAS was more common in those with type II (p=0.0181) and type III (p=0.0306) patterns.

Conclusions

The pattern of change in the trans-stenosis venous pressure gradient may be predictive of SAS and is a useful tool for classifying the response of the venous obstruction to stenting. A type I pattern appears to represent the ideal response to VSS. Some patients with type II and III changes, particularly if they have other predictors of recurrent stenosis, may benefit from longer initial stent constructs.

The Era of Onyx Embolization: A Systematic and Literature Review of Preoperative Embolization Before Stereotactic Radiosurgery for the Management of Cerebral Arteriovenous Malformations

INTRODUCTION

The current treatment paradigm for intracranial arteriovenous malformations (AVMs) focuses on reducing the risk of intracranial hemorrhage using various therapeutic means including embolization, stereotactic radiosurgery (SRS), and microsurgical resection. To improve AVM obliteration rates with SRS, pre-radiosurgical embolization has been trialed in a number of studies to reduce the volume of the AVM nidus prior to radiosurgery. This study aimed to review the efficacy of pre-radiosurgical embolization in the pre-Onyx era compared to the current Onyx era.

METHODS

A systematic review was performed using PubMed to identify studies with 20 or more AVM patients, embolization material, and obliteration rates for both embolization + stereotactic radiosurgery (E+SRS) and SRS-only groups.

RESULTS

Seventeen articles consisting of 1133 eligible patients were included in this study. A total of 914 (80.7%) patients underwent embolization prior to SRS. Onyx was used as the embolysate in 340 (37.2%) patients in the E+SRS cohorts. Mean obliteration rate for the embolized cohort was 46.9% versus 46.5% in the SRS-only cohort. When comparing obliteration rates based on embolysate material, obliteration rate was 42.1% with Onyx+SRS and 50.0% in the non-Onyx embolysate + SRS cohort.

CONCLUSIONS

Onyx (ethylene vinyl-alcohol copolymer dissolved in dimethyl sulfoxide and suspended in micronized tantalum powder) has been increasingly used for the embolization of intracranial AVMs with increased success regarding its ease of use from a technical standpoint and performs similarly to other embolysate materials.

Rerupture Following Flow Diversion of a Dissecting Aneurysm of the Vertebral Artery: Case Report and Review of the Literature

BACKGROUND

Dissecting aneurysms of the posterior cerebral circulation can wield significant treatment challenges with devastating clinical outcomes. Despite an expanded therapeutic armamentarium, these vascular lesions remain relatively difficult to diagnose and portend high associated morbidity and mortality.

METHODS

A ruptured, fusiform, dissecting aneurysm of the mid V4 segment of the right vertebral artery (VA) distal to the posterior inferior cerebellar artery origin resulted in a Hunt and Hess grade 5, Fisher scale score 4 subarachnoid hemorrhage. The lesion incorporated 360 degrees of the vessel wall and extended across an area measuring 11 mm in length and 6.8 mm in width at maximum dimension. The vascular lesion was treated with 2 overlapping Pipeline Embolization Devices.

RESULTS

Digital subtraction angiography demonstrated an origin of the right posterior inferior cerebellar artery mildly stenosed by the dissecting aneurysm. The left VA was markedly hypoplastic. After deployment of 2 overlapping Pipeline Embolization Devices, the aneurysm neck was well covered with appropriate positioning of the stent construct with good apposition to the vessel wall. There was contrast stasis within the aneurysm. The patient was managed with dual antiplatelet therapy. He demonstrated initial clinical and radiographic improvement. However, on the night of the second postprocedure day, the patient succumbed to rerupture of the aneurysm.

CONCLUSIONS

The literature posits that nonsaccular, fusiform, and dissecting aneurysms of the vertebrobasilar circulation can be occluded with consistency and success using flow diversion techniques. Endovascular treatment of a ruptured dissecting aneurysm of the VA is technically feasible and can be performed with or without parent artery occlusion. Outcomes following flow diversion of the posterior circulation may depend on the location of the dissection and viability of collateral circulation. In the present case, adequate coverage of the aneurysm did not portend a positive outcome.

Decreased calcification of a petroclival meningioma after gamma knife radiosurgery

Stereotactic radiosurgery (SRS) has been well reported in the treatment of certain calcified intracranial lesions such as meningiomas. However, reduction in the calcified portion of the tumour after SRS treatment has not been reported. We present the case of a 76-year-old man with a right petroclival lesion consistent on imaging with a calcified meningioma. The lesion progressed on serial neuroimaging studies, and the patient elected to undergo Gamma Knife radiosurgery. No complications were encountered during the radiosurgery. The patient underwent follow-up imaging at 4 and 8 months, during which the lesion was seen to remain stable in overall size, but with marked decrease in the calcified component. Stereotactic radiosurgery can lead to the reduction of all aspects of meninigomas including the calcified component. The radiobiological effects of high dose ionising radiation may result in bony changes and, thereby, decrease intratumoural calcification of an intracranial tumour.

Predictors and outcomes of first pass efficacy in posterior circulation strokes: Insights from STAR collaboration

Background: First-pass efficacy (FPE) has been established as an important predictor of favorable functional outcomes after endovascular thrombectomy (ET) in anterior circulation strokes. In this retrospective cohort study, we investigate predictors and clinical outcomes of FPE in posterior circulation strokes (pcAIS). Methods: The Stroke Thrombectomy and Aneurysm Registry database was used to identify pcAIS patients who achieved FPE. Their baseline characteristics and outcomes were compared with the non-FPE group. The primary outcome was a 90-day modified Rankin Scale (mRS) of 0-3. Univariate (UVA) and multivariate (MVA) analyses were done to evaluate predictors of FPE. Safety outcomes included distal emboli, vessel rupture, symptomatic intracranial hemorrhage, and mortality. Results: Of 359 patients, 179 (50%) achieved FPE. Clot burden, occlusion site, and ET technique-related variables were similar between the two groups except for shorter procedure time with FPE. The primary outcome was significantly better with FPE (56.4% vs. 32.8%, p < 0.001). Complications were similar except for a higher rate of distal emboli in non-FPE group (11.1% vs. 3.2%, p = 0.032). Atrial fibrillation (Afib) had increased odds (aOR: 2.06, 95% CI; 1.24, 3.4, p = 0.005) and prior ischemic stroke had decreased odds (aOR: 0.524, 95% CI; 0.28, 0.97, p = 0.04) of FPE. Afib was the only independent predictor of FPE on MVA (1.94, 95% CI; 1.1, 3.43, p = 0.022). Conclusions: Higher rate of FPE in Afib-related pcAIS could possibly be explained by the differences in clot composition and degree of in-situ atherosclerotic disease burden. Future studies are warranted to explore the relationship of clot composition with ET outcomes.

Resolution of venous pressure gradient in a patient with idiopathic intracranial hypertension after ventriculoperitoneal shunt placement: A proof of secondary cerebral sinovenous stenosis

Background:

The relationship between idiopathic intracranial hypertension (IIH) and cerebral sinovenous stenosis (CSS) remains unclear. The effects of cerebrospinal fluid (CSF) diversion on venous sinus physiology have not been rigorously investigated. We describe the effect of ventriculoperitoneal shunt (VPS) placement on sinovenous pressures in the setting of IIH and CSS.

Case Description:

A patient in their 30 s presented with headache and transient visual obscurations for few months and was diagnosed with IIH. Catheter cerebral venography showed focal stenosis of the right transverse sinus (TS) with a trans-stenosis pressure gradient (TSG) of 20 mmHg. The patient was treated with VPS. During the procedure, we performed a real-time measurement of ventricular CSF and cerebral sinovenous pressures. VPS selectively reduced the TS pressure and abolished the preoperative TS-TSG within 20 min of CSF diversion without altering the sigmoid sinus (SS) pressure. Our findings suggest that CSS can be an epiphenomenon, rather than the primary etiology in some patients with IIH.

Conclusion:

IIH is a challenging condition, in certain patients the radiographic stenosis and trans-stenosis gradient were an epiphenomenon because of the increased intracranial pressure that resulted in reversible TS-SS stenosis.

Carotid artery revascularization using the Walrus balloon guide catheter: safety and feasibility from a US multicenter experience

INTRODUCTION

The Walrus balloon guide catheter (BGC) is a new generation of BGC, designed to eliminate conventional limitations during mechanical thrombectomy.

OBJECTIVE

To report a multi-institutional experience using this BGC for proximal flow control (PFC) in the setting of carotid artery angioplasty/stenting (CAS) in elective (eCAS) and tandem strokes (tCAS).

METHODS

Prospectively maintained databases at 8 North American centers were queried to identify patients with cervical carotid disease undergoing eCAS/tCAS with a Walrus BGC.

RESULTS

110 patients (median age 68, 64.6% male), 80 (72.7%) undergoing eCAS and 30 (27.3%) tCAS procedures, were included (median cervical carotid stenosis 90%; 46 (41.8%) with contralateral stenosis). Using a proximal flow-arrest technique in 95 (87.2%) and flow-reversal in 14 (12.8%) procedures, the Walrus was navigated into the common carotid artery successfully in all cases despite challenging arch anatomy (31, 28.2%), with preferred femoral access (103, 93.6%) and in monitored anesthesia care (90, 81.8%). Angioplasty and distal embolic protection devices (EPDs) were used in 91 (83.7%) and 58 (52.7%) procedures, respectively. tCAS led to a modified Thrombolysis in Cerebral Infarction 2b/3 in all cases. Periprocedural ischemic stroke (up to 30 days postoperatively) rate was 0.9% (n=1) and remote complications occurred in 2 (1.8%) cases. Last follow-up modified Rankin Scale score of 0-2 was seen in 95.3% of eCAS cohort, with no differences in complications in the eCAS subgroup between PFC only versus PFC and distal EPD (median follow-up 4.1 months).

CONCLUSION

Walrus BGC for proximal flow control is safe and effective during eCAS and tCAS. Procedural success was achieved in all cases, with favorable safety and functional outcomes on short-term follow-up.

The Effect of Extracranial-to-Intracranial Bypass on Cerebral Vasoreactivity: A 4D Flow MRI Pilot Study

BACKGROUND AND PURPOSE

Extracranial-to-intracranial (EC-IC) surgical bypass improves cerebral blood flow (CBF) and cerebrovascular vasoreactivity (CVR) for patients with carotid occlusion. Bypass graft patency and contribution of the graft to the postoperative increase in CVR are challenging to assess. To assess the effectiveness of 4D flow magnetic resonance imaging (MRI) to evaluate bypass graft patency and flow augmentation through the superficial temporal artery (STA) before and after EC-IC bypass.

METHODS

Three consecutive patients undergoing EC-IC bypass for carotid occlusion were evaluated pre- and postoperatively using CVR testing with pre- and poststimulus 4D flow-MRI for assessment of the bypass graft and intracranial vasculature.

RESULTS

Preoperatively, 2 patients (patients 1 and 3) did not augment flow through either native STA. The third, who had evidence of extensive native EC-IC collateralization on digital subtraction angiography (DSA), did augment flow through the STA preoperatively (CVR = 1). Postoperatively, all patients demonstrated CVR > 1 on the side of bypass. The patient who had CVR > 1 preoperatively demonstrated the greatest increase in resting postoperative graft flow (from 40 to 130 mL/minute), but the smallest CVR, with a poststimulus graft flow of 160 mL/minute (CVR = 1.2). The 2 patients who did not demonstrate augmentation of graft flow preoperatively augmented postoperatively from 10 to 20 mL/minute (CVR = 2.0) and 10-80 mL/minute (CVR = 8.0), respectively. Intracranial flow was simultaneously interrogated. Two patients demonstrated mild reductions in resting flow velocities in all interrogated vessels immediately following bypass. The patient who underwent CVR testing on postoperative day 48 demonstrated a stable or increased flow rate in most intracranial vessels.

CONCLUSION

Four-dimensional flow MRI allows for noninvasive, simultaneous interrogation of the intra- and extracranial arterial vasculature during CVR testing, and reveals unique paradigms in cerebrovascular physiology. Observing these flow patterns may aid in improved patient selection and more detailed postoperative evaluation for patients undergoing EC-IC bypass.

Comparison of Simultaneous Bilateral Internal Carotid Artery (ICA) 3-Dimensional Rotational Venography (3D-RV) versus Separate Bilateral ICA 3D-RV and Postprocessing 3D-3D Fusion

BACKGROUND

Preoperative venogram of the superior sagittal sinus (SSS) is helpful to plan the surgical resection strategy in patients with parasagittal meningiomas invading the SSS.

METHODS

Catheter 3-dimensional rotational venography (3D-RV) allows for SSS patency assessment and detection of alternative venous cortical drainage routes in patients with contraindication for magnet resonance venography. It is unknown if separate bilateral internal carotid artery 3D-RV followed by postprocessing 3D-3D fusion (technique 1) achieves the same imaging results as simultaneous bilateral internal carotid artery 3D-RV without postprocessing fusion (technique 2) needed.

RESULTS

In this report we were able to confirm in 2 patients that both techniques achieve comparable imaging quality with similar amount of contrast use.

CONCLUSIONS

Although technique 2 requires less radiation, technique 1 is favored due to the need for only 1 vessel access site and catheter with reduced risk for access site and ischemic complications.

Abstract P504: Outcomes and Predictors of Successful First Pass in MCA Occlusions Using ADAPT Thrombectomy Technique - Insights From STAR

Introduction: Successful first pass (SFP) has been identified as a key benchmark of the success of mechanical thrombectomy (MT). However, studies that evaluate the predictors and outcomes of SFP using ADAPT (A Direct Aspiration first Pass Technique) are limied by the small number of patients or single center design.

Methods: We used data from the prospectively collected data from 28 stroke centers that are included in the Stroke Thrombectomy and Aneurysm Registry (STAR). Patients with middle cerebral artery (MCA) occlusions at the level of M1 or M2 segments were included. SFP was defined by achieving modified Thrombolysis in Cerebral Infarction (mTICI) score≥2b with a single aspiration attempt. A multivariable logistic regression analysis was used to assess the predictors of SFP and evaluate the relationship between SFP and favorable 90-day outcome (90-day modified Rankin scale ≤2).

Results: Out of 6123 patients included in STAR, 1002 (16.4%) underwent MT of M1 or M2 occlusion using ADAPT technique. SFP was achieved in 390 (38.9%) patients. SFP patients were older (72 vs. 69, P=0.007), had higher Alberta Stroke Program Early CT Score (ASPECTS) on presentation (9 vs. 8, P=0.018) (Table 1). On multivariable analysis, neither age (aOR 1.006, 95% CI 0.996-1.016, P=0.252) nor ASPECTS (aOR 1.055, 95% CI 0.976-1.141, P=0.179) were independent predictor of SFP. Importantly, SFP was independently associated with favorable 90-day outcome (aOR 2.769, 95% CI 1.988-3.858, P<0.001) after controlling for age, sex, ASPECTS, history of atrial fibrillation, NIHSS on presentation, onset to groin time and IV-tPA.

Conclusion: In this cohort of patients with M1 or M2 occlsuion undergoing MT using ADAPT technique, patients who had SFP were older and had better ASPECTS. However, both age and ASPECTS were not independently associated with SFP. Also, patients who had SFP were almost 3 times more likely to achieve favorable 90-day outcome.

Abstract P11: Clinical Utility of Aspects in Late Window Stroke Thrombectomy Patients: Insights From Star

Introduction: Recent trials have proven safety and efficacy of mechanical thrombectomy for patients presenting with emergent large vessel occlusion beyond 6 hours of symptom onset. While evidence supports using baseline CT scan to evaluate the candidacy for mechanical thrombectomy for patients presenting in the early window, late window trials have used advanced imaging such as CT and MR perfusion. We aim to assess outcomes of MT stratified by admission Alberta Stroke Program Early CT Score (ASPECTS).

Methods: We used data from the prospectively maintained registries of 28 stroke centers in the Stroke Thrombectomy and Aneurysm (STAR) collaboration. Demographics, comorbidities, LVO site, ASPECTS, MT technique, radiographic and clinical outcome data were collected. Patients with M1 or ICA occlusion were included in these analyses. Multivariable analysis was performed using a generalized linear model with logit link to assess for variables associated with favorable outcomes.

Results: 3356 patients in the STAR database were reviewed and 347 (10.3%) of those underwent MT in the late window (table). Median age was 69, 189 (54.5%) were female, and 181 (52.2%) were white. 295 patients ASPECTS ≥6. In this group, 200 (68.8%) had M1 occlusion, and the remaining had ICA occlusion. Aspiration thrombectomy was used in 139 (47.1%) of patients. Successful reperfusion was achieved (mTICI≥2b) in 264 (76.1%). sICH was observed in 15 (5.1%). Excellent functional outcome (mRS 0-2) was observed in 124 (42%) patients. ASPECTS score was independently associated with favorable outcomes (aOR 1.2, 95% CI 1.1-1.4, P=0.006).

Conclusion: Excellent outcomes are observed in patients with good ASPECT score presenting in the late window irrespective of perfusion criteria. Admission CT scan could be used to triage patients presenting with emergent large vessel occlusion beyond 6 hours of symptom onset.

Abstract P6: Impact of Ethnicity on the Outcomes of Mechanical Thrombectomy- Insights From Star

Introduction: Previous studies have reported that Hispanic stroke patients have limited access to mechanical thrombectomy (MT) compared to other ethnic groups. This has resulted in worse stroke outcomes in this group. However, limited data is available about the outcomes of MT in Hispanic patients.

Methods: We used data from the Stroke Thrombectomy and Aneurysm Registry (STAR) that combined the prospectively maintained databases of 28 thrombectomy-capable stroke centers in the US, Europe, and Asia. Consecutive patients who underwent MT were included in these analyses and patients were divided into 2 groups (Hispanics vs. non-Hispanics). Baseline features, time from symptom onset, thrombolysis receipt, final thrombolysis in cerebral infarction (TICI) score, symptomatic hemorrhage, and 90-day functional outcomes (measured by modified Rankin scale-mRS) were compared between Hispanic and non-Hispanics patients. A generalized linear model with logit link was used to assess the relationship between ethnicity and favorable outcomes at 90-day (mRS 0-2) controlling for confounders.

Results: We included 2015 patients in these analyses. Of those, 285 (14.1%) were Hispanic. As shown in table 1, Hispanic patients were older (72 vs. 70, p=0.007), more likely to have diabetes (41.1% vs. 26.5%, p<0.001), and more likely to have hypertension (81.8% vs. 73.7%, p=0.004). Importantly, Hispanics had a shorter procedure duration with a similar rate of successful recanalization (TICI≥2B). On multivariable analysis, Hispanic ethnicity was associated with a lower probability of favorable 90-day outcome (aOR 0.659, 95% CI 0.494-0.879, P=0.005) after controlling for age, stroke risk factors and location of occlusion.

Conclusion: Hispanic patients receiving MT have higher rate of stroke risk factors including diabetes and hypertension. Moreover, Hispanic ethnicity was independently associated with lower probability of favorable 90-day outcome.