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Patients with pre-stroke disability, defined as a modified Rankin Scale (mRS) ≥3, were excluded from most trials of endovascular thrombectomy (EVT) for acute stroke. We sought to evaluate the prognostic factors associated with favorable outcome in stroke patients with known disability undergoing EVT, and the impact of successful reperfusion.Consecutive acute stroke patients with pre-stroke disability, undergoing EVT, were retrospectively collected between 2016 to 2019 from a Canadian cohort and a multicenter French cohort (Endovascular Treatment in Ischemic Stroke registry-ETIS). Favorable outcome was defined as an mRS equal to pre-stroke mRS. Patients achieving successful reperfusion (defined as a modified Thrombolysis in Cerebral Infarction score of 2b/3) were compared with patients without successful reperfusion to determine if successful EVT was associated with better functional outcomes.Among 6220 patients treated with EVT, 280 (4.5%) patients with a pre-stroke mRS ≥3 were included. Sixty-one patients (21.8%) had a favorable outcome and 146 (52.1%) died at 3 months. Patients with successful reperfusion had a higher proportion of favorable 90-day mRS (27.6% versus 19.6%, p = 0.025) and a lower mortality (48.3% versus 69.6%, p = 0.008) than patients without successful reperfusion. After adjusting for baseline prognostic factors, successful reperfusion defined by TICI ≥2b was associated with favorable functional outcome (OR 3.16 CI95% [1.11-11.5]; p 0.048).In patients with pre-stroke disability, successful reperfusion is associated with a greater proportion of favorable outcome and lower mortality.

OBJECTIVE Anterior cranial fossa dural arteriovenous fistulas (DAVFs) have been almost exclusively considered as surgical lesions. However, new advances in endovascular technology have made the endovascular treatment (EVT) of ethmoidal DAVFs feasible. The aim of this study was to report the clinical and angiographic outcomes of patients harboring DAVFs of the anterior cranial fossa who had undergone EVT as a first-line approach. METHODS This was a retrospective study of a consecutive series of patients harboring anterior cranial base DAVFs who had undergone EVT as a first-line approach at four institutions. Angiographic follow-up was performed at 6 months. Immediate and late serious clinical events were assessed during follow-up, including death and stroke. Special emphasis was given to visual status before and after the treatment. RESULTS Between 2008 and 2020, 37 patients with ethmoidal DAVFs were admitted to the participating centers. In 2 patients, EVT was not attempted; therefore, 35 patients underwent EVT as a first-line procedure. An isolated transarterial approach was performed in 19 (54.3%) patients. The transvenous approach was performed exclusively in 12 (34.3%) patients, and combined access was used in 4 (11.4%) patients. The most frequently used arterial access route was the ophthalmic artery in 82.6% of the patients. Immediately, complete angiographic occlusion was achieved in 31 (91.2%) of 34 patients whose treatment was accomplished. Six-month control angiography revealed that 30 (88.2%) DAVFs were totally occluded. Complications occurred in 3 (8.8%) patients, including 1 (2.9%) patient who had central retinal artery occlusion. No significant difference in complications or occlusion rates was noted between the transarterial and transvenous approaches. CONCLUSIONS Most anterior cranial base DAVFs can be successfully treated via an endovascular approach. Neurological and visual complications are rare, even if the ophthalmic artery is used as the primary access route. Efforts should be focused on prospectively comparing the results of EVT and surgical management.

Background and purpose: First pass effect (FPE), the occurrence of complete reperfusion after one pass with no rescue attempt during endovascular therapy (EVT), is associated with the best clinical outcome after an acute ischemic stroke (AIS). Previous studies evaluating FPE occurrence according to EVT technical strategies, occlusion locations, or thrombus composition have provided controversial results. Here, we performed a correlation analysis between FPE occurrence and AIS thrombus cellular composition, as assessed using quantitative biochemical assays. Patients and methods: Homogenates of AIS thrombi from 250 patients were prepared by mechanical grinding. Platelet, red blood cell (RBC), and leukocyte contents of AIS thrombi were respectively estimated by quantification of GP (glycoprotein) VI, heme, and DNA in thrombus homogenates. FPE was defined as a modified Thrombolysis in Cerebral Infraction (mTICI) score of 2C or 3 after a single EVT device pass. Results: AIS thrombi successfully removed after a single pass were poorer in GPVI (0.098 ± 0.023 vs 0.111 ± 0.024 ng/mg, p Discussion and conclusion: Thrombus platelet content may hamper thrombus removal by EVT. This result suggests that adjunctive therapies or functionalization of retrieval devices targeting platelets may improve EVT efficacy.

Background: Acute ischemic stroke (AIS) patients with a history of hypertension experience worse outcomes, which may be explained by a deleterious impact of the renin-angiotensin system (RAS) overactivation. We sought to investigate whether prestroke antihypertensive treatments (AHT) influenced baseline stroke severity and neurological outcomes, in patients with AIS successfully treated by endovascular therapy. Methods: We performed a post hoc analysis of the BP TARGET trial (Blood Pressure Target in Acute Stroke to Reduce Hemorrhage After Endovascular Therapy) and included hypertensive patients with available data regarding AHT at admission, categorized as RAS inhibitors (ACE [angiotensin-converting enzyme] inhibitors, ARBs [angiotensin 2 receptor blockers], and β-blockers) and non-RAS inhibitors (calcium channel blockers and diuretics). Associations of each AHT with National Institutes of Health Stroke Scale (NIHSS) score at baseline were investigated in linear mixed model adjusted for the number of treatments and center. Associations of each AHT with 24-hour NIHSS change, intracranial hemorrhage were performed using linear mixed model adjusted for baseline NIHSS, the number of treatments, center, age, and sex and adjusted for age, sex, diabetes, and current smoking for favorable outcome. All analyses were performed on cases-available data regarding the low number of missing data. Results: Overall, 203 patients with at least one AHT were included. Patients under non-RAS inhibitor treatments had a higher NIHSS score at baseline (adjusted mean difference=3.28 [95% CI, 1.33–5.22]; P =0.001). Conversely, patients under RAS inhibitor treatments had a lower baseline NIHSS score (adjusted mean difference=−2.81 [95% CI, −5.37 to −0.25]; P =0.031). Intracranial hemorrhage occurrence was significantly more frequent in patients under non-RAS inhibitor treatments (adjusted odds ratio of 2.48 [95% CI, 1.12–5.47]; P =0.025). Conversely, the use of RAS inhibitor treatments before AIS was not associated with higher odds of radiographic intracranial hemorrhage. Patients with non-RAS inhibitor treatments had less improvement of NIHSS at 24 hours compared with patients without (adjusted mean difference, 2.83 [95% CI, −0.16 to 5.81]; P =0.063). Baseline RAS inhibitor or noninhibitor treatments were not associated with favorable outcome. Conclusions: We showed an opposite effect of baseline AHT, based on their effect on the RAS. Patients treated with RAS inhibitor agents before AIS exhibited less severe AIS compared with patients under non-RAS inhibitor treatments, developed less intracranial hemorrhage at 24 hours and had a trend toward better NIHSS score at 24 hours. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03160677.

To elucidate the pathogenesis of vein of Galen malformations (VOGMs), the most common and severe congenital brain arteriovenous malformation, we performed an integrated analysis of 310 VOGM proband-family exomes and 336,326 human cerebrovasculature single-cell transcriptomes. We found the Ras suppressor p120 RasGAP (RASA1) harbored a genome-wide significant burden of loss-of-functionde novovariants (p=4.79×10-7). Rare, damaging transmitted variants were enriched in Ephrin receptor-B4 (EPHB4) (p=1.22×10-5), which cooperates with p120 RasGAP to limit Ras activation. Other probands had pathogenic variants inACVRL1,NOTCH1,ITGB1, andPTPN11.ACVRL1variants were also identified in a multi-generational VOGM pedigree. Integrative genomics defined developing endothelial cells as a key spatio-temporal locus of VOGM pathophysiology. Mice expressing a VOGM-specificEPHB4kinase-domain missense variant exhibited constitutive endothelial Ras/ERK/MAPK activation and impaired hierarchical development of angiogenesis-regulated arterial-capillary-venous networks, but only when carrying a “second-hit” allele. These results illuminate human arterio-venous development and VOGM pathobiology and have clinical implications.

Resistance to fibrinolysis, levels of procoagulant/antifibrinolytic neutrophil extracellular traps (NETs), and the severity of acute ischemic stroke (AIS) are increased by COVID-19. Whether NETs are components of AIS thrombi from COVID-19 patients and whether COVID-19 impacts the susceptibility of these thrombi to thrombolytic treatments remain unknown, however.We aimed to characterize AIS thrombi from COVID-19 patients by immunohistology and to compare their response to thrombolysis to that of AIS thrombi from non-COVID-19 patients.For this monocentric cohort study, 14 thrombi from COVID-19 AIS patients and 16 thrombi from non-COVID-19 patients, all recovered by endovascular therapy, were analyzed by immunohistology or subjected to ex vivo thrombolysis by tissue-type plasminogen (tPA)/plasminogen.COVID-19 AIS thrombi were rich in neutrophils and contained NETs, but not spike protein. Thrombolysis assays revealed a mean resistance profile to tPA/plasminogen of COVID-19 AIS thrombi similar to that of non-COVID-19 AIS thrombi. The addition of DNase 1 successfully improved thrombolysis by potentiating fibrinolysis irrespective of COVID-19 status. Levels of neutrophil, NETs, and platelet markers in lysis supernatants were comparable between AIS thrombi from non-COVID-19 and COVID-19 patients.These results show that COVID-19 does not impact NETs content or worsen fibrinolysis resistance of AIS thrombi, a therapeutic hurdle that could be overcome by DNase 1 even in the context of SARS-CoV-2 infection.

The anterior cerebral artery (ACA) and the anterior communicating artery (AComA) are important arteries of the telencephalon and are prominent location for cerebral aneurysms. Their embryological development is closely linked, and explains the possible variants seen in adults. In this paper, we present details related to the development of these two arteries, focusing on some variants such as the infra-optic course of the ACA, the unpaired ACA, and the persistent primitive olfactory artery.

Background: Management of extracranial internal carotid artery steno-occlusive lesion during endovascular therapy remains debated. Stent occlusion within 24 hours of endovascular therapy is a frequent event after acute carotid artery stenting, and we currently lack large population results. We investigated the incidence, predictors, and clinical impact of stent occlusion after acute carotid artery stenting in current clinical practice. Methods: Patients treated by endovascular therapy with acute carotid artery stenting between 2015 and 2019 in 5 large-volume endovascular-capable centers were retrospectively analyzed. Patients were separated in 2 groups according to the stent patency at 24 hours after carotid artery stenting. We compared baseline characteristics, treatment modalities, and clinical outcome depending on 24-hour stent patency. Primary end point was favorable outcome, defined as a modified Rankin Scale score 0–2 at 3 months. Results: A stent occlusion was observed in 47/225 patients (20.9%). Patients with stent patency had a lower baseline National Institutes of Health Stroke Scale (median [interquartile range]: 13 [7–17] versus 18 [12–21]) and had more often stroke of atherothrombotic origin (77.0% versus 53.2%). A higher stent patency rate was found for patients treated with P2Y 12 antagonists at the acute phase (odds ratio [OR]‚ 2.95 [95% CI‚ 1.10–7.91]; P =0.026) and treated with angioplasty (OR‚ 2.42 [95% CI‚ 1.24–4.67]; P =0.008). A better intracranial angiographic reperfusion was observed in patients with 24-hour stent patency compared with patients without stent patency (OR‚ 8.38 [95% CI‚ 3.07–22.78]; P P P =0.009). Conclusions: One out of 5 patients treated with carotid artery stenting during endovascular therapy presented a stent occlusion within 24 hours. This event was associated with worse functional outcome. Stroke etiology, P2Y 12 antagonist administration, quality of intracranial reperfusion, and angioplasty were associated with 24-hour stent patency.

BackgroundThe concept of intra-aneurysmal flow disruption has emerged as a new paradigm for the treatment of primarily bifurcation aneurysms. The purpose of this study was to determine the clinical and angiographic outcomes of patients treated with the new ARTISSE intrasaccular device (ISD).MethodsSelected patients with bifurcation aneurysms that matched the indications of the ARTISSE ISD defined by the manufacturer were treated in a single center. Clinical and angiographic follow-up was conducted at 6 and 36 months. Aneurysm occlusion was assessed using the Raymond–Roy classification scale.ResultsNine subjects with nine unruptured bifurcation aneurysms were enrolled. Mean aneurysm size was 7.2±1.2 mm (range 5.5–9.7 mm). An adequate aneurysm occlusion (defined as a complete occlusion or a neck remnant) was achieved in 6/9 patients (66.7%) at 6 months and 4/7 patients (57.1%) at 36 months follow-up. Two of the nine subjects experienced a major stroke (22.2%), including one on postoperative day 1 due to a procedure-related parent vessel occlusion and subsequent ischemic stroke. The other major stroke occurred within the 36-month follow-up period during treatment of a separate aneurysm with coils, leading to perforation with hemorrhagic stroke causing a permanent neurological deficit.ConclusionThe ARTISSE ISD was successfully deployed in all nine cases. There were, however, several procedure-related complications and results in terms of angiographic aneurysm occlusion were modest.

Background and purpose Recent clinical trials demonstrated the benefit of thrombectomy beyond 6 h based on the automated measurement of infarct volume exclusively with the RAPID software. We aimed to compare eight tools commonly used for the measurement of infarct volume and see whether they would lead to similar thrombectomy decisions based on the Diffusion-weighted-imaging or computerized-tomography-perfusion Assessment with clinical mismatch in the triage of Wake-up and late-presenting strokes undergoing Neurointervention with Trevo (DAWN) trial imaging inclusion criteria. Materials and Methods The diffusion-weighted-imaging (DWI) infarct volume of 36 patients was measured with 3 automated tools (including RAPID) and 5 non-automated tools. The agreement for the measurements of DWI infarct volume and the resulting thrombectomy decisions were assessed with intraclass correlation coefficient (ICC) and Fleiss’ Kappa (K) statistics. Results The correlation for the measurement of DWI infarct volume between all 9 tools was excellent (ICC > 0.8). After dichotomization, agreement was substantial for any of the cut-points used in DAWN trial. Discrepancies involving at least one of the tools for thrombectomy decisions based on DAWN criteria occurred in one third of cases. Compared with RAPID, the use of any other tool for treatment decision based on DAWN criteria would have led to contradictory decisions in 6% to 19% of cases. Conclusion There are several currently available tools for the measurement of DWI infarct volume with excellent correlation. Despite the high agreement demonstrated in our study, frequent discrepancies between measurements in some dichotomized configurations led to frequent diverging thrombectomy decisions when applying DAWN criteria.

BACKGROUND AND PURPOSE: CTA has shown limited accuracy and reliability in distinguishing tandem occlusions and pseudo-occlusions on initial acute stroke imaging. The utility of early and delayed contrast-enhanced MRA in this setting is unknown. We aimed to assess the accuracy and reliability of early and delayed contrast-enhanced MRA for carotid bulb patency in patients with acute ischemic stroke. MATERIALS AND METHODS: We retrospectively reviewed patients who had ICA occlusion and underwent thrombectomy with preprocedural early and delayed contrast-enhanced MRA in a single comprehensive stroke center. During 2 sessions, 10 raters independently assessed 32 cases with early contrast-enhanced MRA (with an additional delayed contrast-enhanced MRA sequence during the second reading session). Their judgments were compared with DSA as a reference standard. Accuracy and interrater agreement were measured. Five raters undertook a third reading session to assess intrarater agreement. RESULTS: Accuracy for the assessment of carotid bulb patency with early contrast-enhanced MRA was limited (69%; 95% CI, 59%–79%), with moderate interrater agreement (κ = 0.42; 95% CI, 0.27–0.55). The second reading with an additional delayed contrast-enhanced MRA sequence improved both accuracy (82%; 95% CI, 73%–91%; P < .001) (raters corrected 43%–77% of incorrect diagnoses with early contrast-enhanced MRA alone; mean = 59%) and interrater agreement (κ = 0.56; 95% CI, 0.41–0.73; P = .07). Intrarater agreement was almost perfect, substantial, and moderate for 3, 1, and 1 raters. CONCLUSIONS: Early contrast-enhanced MRA has limited accuracy and repeatability for the evaluation of carotid bulb patency in acute ischemic stroke. The additional delayed contrast-enhanced MRA sequence may improve accuracy and reliability.

The middle meningeal artery is the major human dural artery. Its origin and course can vary a great deal in relation, not only with the embryologic development of the hyostapedial system, but also because of the relationship of this system with the ICA, ophthalmic artery, trigeminal artery, and inferolateral trunk. After summarizing these systems in the first part our review, our purpose is to describe, in this second part, the anatomy, the possible origins, and courses of the middle meningeal artery. This review is enriched by the correlation of each variant to the related embryologic explanation as well as by some clinical cases shown in the figures. We discuss, in conclusion, some clinical conditions that require detailed knowledge of possible variants of the middle meningeal artery.

Background and Purpose: Higher rates of strokes have been observed in patients with coronavirus disease 2019 (COVID-19), but data regarding the outcomes of COVID-19 patients suffering from acute ischemic stroke due to large vessel occlusion (LVO) are lacking. We report our initial experience in the treatment of acute ischemic stroke with LVO in patients with COVID-19. Methods: All consecutive patients with COVID-19 with acute ischemic stroke due to LVO treated in our institution during the 6 first weeks of the COVID-19 outbreak were included. Baseline clinical and radiological findings, treatment, and short-term outcomes are reported. Results: We identified 10 patients with confirmed COVID-19 treated for an acute ischemic stroke due to LVO. Eight were men, with a median age of 59.5 years. Seven had none or mild symptoms of COVID-19 at stroke onset. Median time from COVID-19 symptoms to stroke onset was 6 days. All patients had brain imaging within 3 hours from symptoms onset. Five patients had multi-territory LVO. Five received intravenous alteplase. All patients had mechanical thrombectomy. Nine patients achieved successful recanalization (mTICI2B-3), none experienced early neurological improvement, 4 had early cerebral reocclusion, and a total of 6 patients (60%) died in the hospital. Conclusions: Best medical care including early intravenous thrombolysis, and successful and prompt recanalization achieved with mechanical thrombectomy, resulted in poor outcomes in patients with COVID-19. Although our results require further confirmation, a different pharmacological approach (antiplatelet or other) should be investigated to take in account inflammatory and coagulation disorders associated with COVID-19.

Pediatric interventional neuroradiology is a rewarding but demanding specialty. It cannot be classified as a miniaturized technical procedure simply because it deals with small vessels in small patients but remains a field requiring specific knowledge combining clinical, anatomical, physiologic, and technical features. Complications that occur remain terrible experiences in this population whose patients have not personally requested to be treated for their vascular malformations. The aim of this article is to evoke the various possible groups of complications that may occur during a pediatric endovascular procedure in order to make physicians aware of these problems and help them to avoid them.

Central vein disease (CVD) is a well-known complication of central venous cannulations, indwelling dialysis catheters, and arteriovenous grafts. Brachiocephalic vein (BCV) stenosis or thrombotic occlusion can occur in dialysis patients, and the presence of an ipsilateral arteriovenous fistula can cause cerebral venous hypertension due to retrograde flow in the ipsilateral jugular vein. A 53-year-old man receiving hemodialysis (left brachiocephalic hemodialysis fistula) presented with impaired consciousness and seizures related to status epilepticus due to left temporal multifocal hemorrhages. Brain computed tomography and angiogram showed left cortical vein congestion without intracranial arteriovenous shunt. Complementary left brachial angiogram showed a left BCV stenosis and jugular and cerebral high-flow venous reflux with cortical venous reflux from the hemodialysis fistula. The left arm shunt resulted in severe cerebral venous hypertension due to ipsilateral stenosis of the BCV. BCV angioplasty immediately resolved the cerebral reflux. Patients with hemodialysis fistulas are at a higher risk of developing these intracerebral hemorrhage complications.

To study the genotypes and phenotypes of cerebral arteriovenous fistulas that drain or do not drain through the vein of Galen, and true vein of Galen aneurysmal malformations, in order to determine whether genotyping could help improve classification of these malformations and their management. We carried out a retrospective review of genetic and phenotypic data in databases of four centers. All children with cerebral arteriovenous fistula or vein of Galen aneurysmal malformations aged below 18 years at onset were included. We recorded the nature of the genetic variant or absence of variant, age at onset, type of malformation, symptoms at onset (hemorrhage, neurological deficit, hydrocephalus, incidental, and heart failure), type of venous drainage and the long-term outcome. One hundred and fifteen children were included. Autosomal dominant variants were identified in 39% of patients. The most frequent variant affected was the gene (25%) followed by (8%) and the HHT-associated genes (5%). HHT gene variants were only observed in pial arteriovenous fistula not draining into the vein of Galen; on the contrary, variants were only seen in genuine vein of Galen aneurysmal malformation. variants were identified in all types of shunts. variants seem specific to the vein of Galen aneurysmal malformation, variants are associated with either pial arteriovenous fistulas or with genuine VGAM and HHT gene variants seem specific to pial arteriovenous fistulas. The genetic data helps to classify these malformations and to guide treatment toward lowest risk of post-operative cerebral ischemic-hemorrhagic complications.

More than 40% of endovascular therapy (EVT) fail to achieve complete reperfusion of the territory of the occluded artery in patients with acute ischemic stroke (AIS). Understanding factors influencing EVT could help overcome its limitations. Our objective was to study the impact of thrombus cell composition on EVT procedures, using a simulation system for modeling thrombus-induced large vessel occlusion (LVO) in flow conditions. In an open comparative trial, we analyzed the behavior of size-standardized platelet-rich and red blood cells (RBC)-rich thrombi during simulated stent retriever-mediated EVT procedures. Sixteen simulated EVT procedures were performed (8 RBC- vs. 8 platelet-rich thrombi). Platelet-rich thrombi were associated with a higher number of stent retriever passes (p = 0.03) and a longer procedure duration (p = 0.02) compared to RBC-rich thrombi. Conversely, RBC-rich thrombi released more embolic fragments than platelet-rich thrombi (p = 0.004). Both RBC-rich and platelet-rich thrombi underwent drastic compaction after being injected into the in vitro circulation model, and histologic analyses showed that these EVT-retrieved thrombi displayed features comparable to those previously observed in thrombi from patients with AIS patients having LVO, including a marked structural dichotomy between RBC- and platelet-rich areas. Our results show that the injection of in vitro-produced thrombi in artificial cerebrovascular arterial networks is suitable for testing recanalization efficacy and the risk of embolization of EVT devices and strategies in association with thrombus cell composition.

To report the occurrence of non-ischemic cerebral enhancing (NICE) lesions following mechanical thrombectomy (MT) through the retrospective French nationwide registry of NICE lesions. All thrombectomy capable stroke centers (TSC) in France were invited to fill out a questionnaire disseminated through a trainee-led research network (JENI-RC: Jeunes en Neuroradiologie Interventionnelle-Research Collaborative). NICE lesions were defined according to previous literature as delayed onset punctate, nodular, or annular foci enhancements with peri-lesion edema and vascular distribution in the territory of the MT with no other confounding disease. All 43 TSC French centers responded. Three patients were reported by 3 different centers over a total of 34,824 MT (2015-2020). Patient no. 1 developed symptomatic NICE lesions 8 weeks after MT with combination of aspiration and stentriever for a right middle cerebral artery occlusion. Patient no. 2 developed asymptomatic NICE lesions 5 weeks after MT with direct thromboaspiration for a right middle cerebral artery occlusion. Patient no. 3 developed symptomatic NICE lesions 6 weeks after MT with direct thromboaspiration, and combination of aspiration and stentriever for a basilar artery occlusion. This study provides evidence that NICE lesions following MT are a possible rare complication with a similar presentation as previously described following endovascular aneurysm treatment. Both radiologists and neurologists should be aware of this adverse event and make use of MRI contrast agents in case of unexplained symptoms/images during follow-up after MT.

Background and Purpose: Approximately half of the patients with acute ischemic stroke due to anterior circulation large vessel occlusion do not achieve functional independence despite successful reperfusion. We aimed to determine influence of reperfusion strategy (bridging therapy, intravenous thrombolysis alone, or mechanical thrombectomy alone) on clinical outcomes in this population. Methods: From ongoing, prospective, multicenter, observational Endovascular Treatment in Ischemic Stroke registry in France, all patients with anterior circulation large vessel occlusion who achieved successful reperfusion (modified Thrombolysis in Cerebral Infarction 2b-3) following reperfusion therapy were included. Primary end point was favorable outcome, defined as 90-day modified Rankin Scale score ≤2. Patient groups were compared using those treated with bridging therapy as reference. Differences in baseline characteristics were reduced after propensity score-matching, with a maximum absolute standardized difference of 14% for occlusion site. Results: Among 1872 patients included, 970 (51.8%) received bridging therapy, 128 (6.8%) received intravenous thrombolysis alone, and the remaining 774 (41.4%) received MT alone. The rate of favorable outcome was comparable between groups. Excellent outcome (90-day modified Rankin Scale score 0–1) was achieved more frequently in the bridging therapy group compared with the MT alone (odds ratio after propensity score-matching, 0.70 [95% CI, 0.50–0.96]). Regarding safety outcomes, hemorrhagic complications were similar between the groups, but 90-day mortality was significantly higher in the MT alone group compared with the bridging therapy group (odds ratio, 1.60 [95% CI, 1.09–2.37]). Conclusions: This real-world observational study of patients with anterior circulation large vessel occlusion demonstrated a similar rate of favorable outcome following successful reperfusion with different therapeutic strategies. However, our results suggest that bridging therapy compared with MT alone is significantly associated with excellent clinical outcome and lower mortality. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03776877.

Background and Purpose: The influence of prior antiplatelet therapy (APT) uses on the outcomes of patients with acute ischemic stroke treated with endovascular therapy is unclear. We compared procedural and clinical outcomes of endovascular therapy in patients on APT or not before stroke onset. Methods: We analyzed 2 groups from the ongoing prospective multicenter Endovascular Treatment in Ischemic Stroke registry in France: patients on prior APT (APT+) and patients without prior APT (APT−) treated by endovascular therapy, with and without intravenous thrombolysis. Multilevel mixed-effects logistic models including center as random effect were used to compare angiographic (rates of reperfusion at the end of procedure, procedural complications) and clinical (favorable and excellent outcome, 90-day all-cause mortality, and hemorrhagic complications) outcomes according to APT subgroups. Comparisons were adjusted for prespecified confounders (age, admission National Institutes of Health Stroke Scale score, Alberta Stroke Program Early CT Score, intravenous thrombolysis, and time from onset to puncture), as well as for meaningful baseline between-group differences. Results: A total of 2939 patients were analyzed, of whom 877 (29.8%) were on prior APT. Patients with prior APT were older, had more frequent vascular risk factors, cardioembolic stroke mechanism, and prestroke disability. Rates of complete reperfusion (37.9% in the APT− group versus 42.7 % in the APT+ group; aOR, 1.09 [95% CI, 0.88–1.34]; P =0.41) and periprocedural complication (16.9% versus 13.3%; aOR, 0.90 [95% CI, 0.7–1.2]; P =0.66) did not differ between the two groups. Symptomatic intracerebral hemorrhage (aOR, 0.93 [95% CI, 0.63–1.37]; P =0.73), 3 months favorable clinical outcome (modified Rankin Scale score of 0–2; aOR, 0.98 [95% CI, 0.77–1.25]; P =0.89), and mortality (aOR, 0.95 [95% CI, 0.72–1.26]; P =0.76) at 90 days did not differ between the groups. Conclusions: Prior APT does not influence angiographic and functional outcomes following endovascular therapy and should not be taken into account for acute revascularization strategies.

Background and Purpose: Identification of acute ischemic stroke (AIS) cause is crucial for guidance of secondary prevention. Previous studies have yielded inconsistent results regarding possible correlations between AIS cause and thrombus composition, as assessed by semiquantitative histological analysis. Here, we performed a correlation analysis between AIS cause and AIS thrombus cellular composition and content, as assessed using quantitative biochemical assays. Methods: Homogenates of 250 patients with AIS thrombi were prepared by mechanical grinding. Platelet, red blood cell, and leukocyte content of AIS thrombi were estimated by quantification of GP (glycoprotein) VI, heme, and DNA in thrombus homogenates. AIS cause was defined as cardioembolic, noncardioembolic, or embolic stroke of undetermined source, according to the TOAST classification (Trial of ORG 10172 in Acute Stroke Treatment). Results: Cardioembolic thrombi were richer in DNA (35.8 versus 13.8 ng/mg, P P =0.045) than noncardioembolic ones. The area under the receiver operating characteristic curve of DNA content to discriminate cardioembolic thrombi from noncardioembolic was 0.72 (95% CI, 0.63–0.81). With a threshold of 44.7 ng DNA/mg thrombus, 47% of thrombi from undetermined cause would be classified as cardioembolic with a specificity of 90%. Conclusions: Thrombus DNA content may provide an accurate biomarker for identification of cardioembolic thrombi in patients with AIS with embolic stroke of undetermined source. Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT03268668.

Background and Purpose: Hypotension during endovascular therapy for acute ischemic stroke is associated with worse functional outcomes (FO). Given its important role in intracranial hemodynamics, we investigated whether hypotension during endovascular therapy had the same effect on FO according to the posterior communicating artery (PComA) patency. Methods: We performed a post hoc analysis of the ASTER trial (Contact Aspiration Versus Stent Retriever for Successful Revascularization). Patients were included if they had middle cerebral artery occlusions. Primary outcome was favorable FO, defined by a modified Rankin Scale scores between 0 and 2 at 3 months. Results: One hundred forty-eight patients with middle cerebral artery occlusion were included. In patients with no PComA, an increase in minimum mean arterial pressure was positively associated with favorable FO (odds ratio per 10 mm Hg increase, 1.59 [95%CI, 1.11–2.25]; P =0.010), whereas no association was found in patients with a PComA (odds ratio, 0.77 [95% CI, 0.54–1.08]; P =0.12). Patients with no PComA and longer cumulative time with mean arterial pressure P =0.010) and 0.74 (95% CI, 0.60–0.91; P =0.003), but not in patients with a PComA. Conclusions: Hypotension during endovascular therapy for middle cerebral artery occlusion is consistently associated with worse FO in patients with no PComA but not in those with a PComA. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02523261.

OBJECTIVETreatment of posterior fossa arteriovenous malformations (PFAVMs) remains controversial as it is always challenging and may lead to major complications. Nonetheless, these lesions are more likely to bleed and generate poorer outcomes than other brain AVMs. The aim of this study was to evaluate the effect of endovascular treatment on long-term outcomes and identify the patient subgroups that might benefit from endovascular treatment.METHODSThe authors performed a retrospective analysis of all consecutive cases of PFAVM managed at the Fondation Rothschild Hospital between 1995 and 2018. Clinical, imaging, and treatment data were prospectively gathered; these data were analyzed with respect to long-term outcomes.RESULTSAmong the 1311 patients with brain AVMs, 114 (8.7%) had a PFAVM, and 88 (77.2%) of these patients had a history of bleeding. Of the 114 PFAVMs, 101 (88.6%) were treated (83 ruptured and 18 unruptured). The mean duration of follow-up was 47.6 months (range 0–240 months). Good neurological outcome at last follow-up was achieved in 79 cases (78.2%). Follow-up angiography showed obliteration of the PFAVM in 68.3% of treated cases. The presence of direct vertebrobasilar perforator feeders was associated with neurological deterioration (OR 5.63, 95% CI 11.15–30.76) and a lower obliteration rate (OR 15.69, 95% CI 2.52–304.03) after endovascular treatment. Other predictors of neurological deterioration and obliteration rate were consistent with the Spetzler-Martin grading system.CONCLUSIONSAdvances in endovascular techniques have enabled higher obliteration rates in the treatment of PFAVMs, but complication rates are still high. Subgroups of patients who might benefit from treatment must be carefully selected and the presence of direct vertebrobasilar perforator feeders must call into question the indication for endovascular treatment.

Background and Purpose— Parenchymal hematoma (PH) is a rare but dreadful complication of acute ischemic stroke with unclear underlying mechanisms. We aimed to study the incidence and predictors of PH after mechanical thrombectomy. Methods— Data from a prospective observational multicenter registry was screened to identify acute ischemic stroke patients with an anterior circulation large vessel occlusion who underwent mechanical thrombectomy. Clinical, imaging, and procedural characteristics were used for the analysis, including brain imaging systematically performed at 24 hours. PH occurrence was assessed according to ECASS (European Collaborative Acute Stroke Study) criteria. Univariate and multivariable analyses were performed to identify predictors of PH. Results— A total of 1316 patients were included in the study. PH occurred in 153 out of 1316 patients (11.6%) and was associated with a lower rate of favorable outcome and increased mortality. On multivariable analysis, age (per 1 year increase, odds ratio [OR], 1.01; 95% CI, 1.00–1.03; P =0.05), current smoking (OR, 2.02; 95% CI, 1.32–3.09; P P P P P Conclusions— PH occurred at a rate of 11.6% after mechanical thrombectomy, with high morbidity and mortality. Our study identified clinical, radiological, and procedural predictors of PH occurrence that can serve as the focus of future periprocedural management studies with the aim of reducing its occurrence. Clinical Trial Registration— URL: https://www.clinicaltrials.gov . Unique identifier: NCT03776877.

To evaluate outcomes of thrombectomy in patients with a basilar artery occlusion (BAO) and mild symptoms, defined by an initial National Institutes of Health Stroke Scale (NIHSS) score ≤6.We performed a retrospective analysis of a multicenter prospective cohort of consecutive patients with acute ischemic stroke with BAO who underwent thrombectomy. We compared baseline and procedural characteristics, as well as outcomes between patients with BAO with an NIHSS score ≤6 and6. Multivariate analyses were performed to determine baseline and procedural predictors of good outcome (modified Rankin Scale score 0-2) among patients with an NIHSS score ≤6.A total of 269 patients were included: 50 (19%) had an initial NIHSS score ≤6 and 219 (81%) had an NIHSS score6. Patients with mild strokes (NIHSS score ≤6) had better outcomes (68% of modified Rankin Scale score 0-2 vs. 27% for NIHSS score6; P0.0001), lower mortality (14% vs. 48; P0.0001) and fewer parenchymal hematomas at day 1 (0% vs. 10%; P = 0.016). A multivariate analysis identified the following predictors for good outcome among patients with BAO with an NIHSS score ≤6: younger age, fewer passes, a cardioembolic cause, and the absence of need for angioplasty/stenting.Thrombectomy seems to be safer and more effective for mild BAO strokes with NIHSS score ≤6 than for more severe patients. Even although thrombectomy showed high rates of recanalization, a substantial proportion (32%) nevertheless had a poor long-term clinical outcome. The number of passes, patient's age, and stroke cause seem to be predictors of clinical outcome.

Immediate reocclusion after mechanical thrombectomy (MT) for acute ischemic stroke (AIS) is a rare but devastating condition associated with poor functional outcome. The aim of this study was to gain insights into the mechanisms underlying immediate reocclusion, and to evaluate the efficacy and safety of the glycoprotein IIb/IIIa antagonist abciximab, for its treatment. Clinical data were collected from April 2015 to April 2019 in a monocentric prospective registry of AIS patients treated by MT. All patients with immediate reocclusion were retrospectively selected and subdivided into 2 groups according to abciximab treatment status.

Background and Purpose: The aim of this study was to characterize neurological complications after flow diverter (FD) treatment on a long follow-up cohort and identify predictive factors associated with these complications.Methods: This study was conducted on a monocentric cohort of patients treated for intracranial aneurysms by FD.Results: Between September 2008 and July 2018, 413 patients were treated for 514 aneurysms: 18% of the patients presented with at least one neurological complication during a median follow-up of 446 days (IQR 186–1,210). Sixty-one patients presented with ischemic complications, 13 with hemorrhagic ones and 10 with compressive processes. Among 89 neurological complications 64.5% were peri-operative (occurring within the 30 days following the procedure) and 35.5% were delayed after 1 month.Conclusions: Overall, neurological complications after FD implantation were overrepresented by cerebrovascular ischemic events occurring during the peri-operative period, but also in a delayed manner after 1 year. Long-term follow-up is relevant after aneurysm intervention using FD.

International audience; BACKGROUND: High systolic blood pressure after successful endovascular therapy for acute ischaemic stroke is associated with increased risk of intraparenchymal haemorrhage. However, no randomised controlled trials are available to guide optimal management. We therefore aimed to assess whether an intensive systolic blood pressure target resulted in reduced rates of intraparenchymal haemorrhage compared with a standard systolic blood pressure target. METHODS: We did a multicentre, open-label, randomised controlled trial at four academic hospital centres in France. Eligible individuals were adults (aged ≥18 years) with an acute ischaemic stroke due to a large-vessel occlusion that was successfully treated with endovascular therapy. Patients were randomly assigned (1:1) to either an intensive systolic blood pressure target group (100-129 mm Hg) or a standard care systolic blood pressure target group (130-185 mm Hg), by means of a central web-based procedure, stratified by centre and intravenous thrombolysis use before endovascular therapy. In both groups, the target systolic blood pressure had to be achieved within 1 h after randomisation and maintained for 24 h with intravenous blood pressure lowering treatments. The primary outcome was the rate of radiographic intraparenchymal haemorrhage at 24-36 h and the primary safety outcome was the occurrence of hypotension. Analyses were done on an intention-to-treat basis. BP-TARGET is registered with ClinicalTrials.gov, number NCT03160677, and the trial is closed at all participating sites. FINDINGS: Between June 21, 2017, and Sept 27, 2019, 324 patients were enrolled in the four participating stroke centres: 162 patients were randomly assigned to the intensive target group and 162 to the standard target group. Four (2%) of 162 patients were excluded from the intensive target group and two (1%) of 162 from the standard target group for withdrawal of consent or legal reasons. The mean systolic blood pressure during the first 24 h after reperfusion was 128 mm Hg (SD 11) in the intensive target group and 138 mm Hg (17) in the standard target group. The primary outcome was observed in 65 (42%) of 154 patients in the intensive target group and 68 (43%) of 157 in the standard target group on brain CT within 24-36 h after reperfusion] (adjusted odds ratio 0·96, 95% CI 0·60-1·51; p=0·84). Hypotensive events were not significantly different between both groups and occurred in 12 (8%) of 158 patients in the intensive target and five (3%) of 160 in the standard target group. Mortality within the first week after randomisation occurred in 11 (7%) of 158 patients in the intensive target group and in seven (4%) of 160 in the standard target group. INTERPRETATION: An intensive systolic blood pressure target of 100-129 mm Hg after successful endovascular therapy did not reduce radiographic intraparenchymal haemorrhage rates at 24-36 h as compared with a standard care systolic blood pressure target of 130-185 mm Hg. Notably, these results are applicable to patients with successful reperfusion and systolic blood pressures of more than 130 mm Hg at the end of procedure. Further studies are needed to understand the association between blood pressure and outcomes after reperfusion. FUNDING: French Health Ministry. Copyright

International audience; Objectives: The aim of this study was to determine whether individual operator characteristics have an impact on reperfusion and procedural complication rates.Background: Mechanical thrombectomy (MT) is a Level IA treatment in acute ischemic stroke (AIS) patients. The operator's effect has been found to be an independent predictor for clinical outcome and technical performance in interventional cardiology.Methods: From the ETIS (Endovascular Treatment in Ischemic Stroke) study, a prospective, multicenter, observational real-world MT registry, the authors included all AIS patients consecutively treated by MT between January 2012 and March 2017 in 3 high-volume comprehensive stroke centers by 19 operators. We assessed the effect of individual operator characteristics on successful reperfusion, defined as modified Thrombolysis In Cerebral Infarction 2b/3 at the end of MT, and procedural complications using multivariable hierarchical logistic regression models.Results: A total of 1,541 patients with anterior and posterior AIS were enrolled (mean age 67 years; median NIHSS 16). There was a significant operator effect on successful reperfusion, with an intraclass correlation coefficient of 0.036 (p = 0.046), but not on complications (intraclass correlation coefficient = 0). There was a dose-response relationship between annual operator volume and successful reperfusion rate (p = 0.003) with an adjusted odds ratio for successful reperfusion equal to 2.52 (95% confidence interval: 1.37 to 4.64) for patients treated by an operator with an annual volume ≥40 MT/year compared with those treated by an operator with

Background and Purpose: Acute ischemic stroke and large vessel occlusion can be concurrent with the coronavirus disease 2019 (COVID-19) infection. Outcomes after mechanical thrombectomy (MT) for large vessel occlusion in patients with COVID-19 are substantially unknown. Our aim was to study early outcomes after MT in patients with COVID-19. Methods: Multicenter, European, cohort study involving 34 stroke centers in France, Italy, Spain, and Belgium. Data were collected between March 1, 2020 and May 5, 2020. Consecutive laboratory-confirmed COVID-19 cases with large vessel occlusion, who were treated with MT, were included. Primary investigated outcome: 30-day mortality. Secondary outcomes: early neurological improvement (National Institutes of Health Stroke Scale improvement ≥8 points or 24 hours National Institutes of Health Stroke Scale 0–1), successful reperfusion (modified Thrombolysis in Cerebral Infarction grade ≥2b), and symptomatic intracranial hemorrhage. Results: We evaluated 93 patients with COVID-19 with large vessel occlusion who underwent MT (median age, 71 years [interquartile range, 59–79]; 63 men [67.7%]). Median pretreatment National Institutes of Health Stroke Scale and Alberta Stroke Program Early CT Score were 17 (interquartile range, 11–21) and 8 (interquartile range, 7–9), respectively. Anterior circulation acute ischemic stroke represented 93.5% of cases. The rate modified Thrombolysis in Cerebral Infarction 2b to 3 was 79.6% (74 patients [95% CI, 71.3–87.8]). Thirty-day mortality was 29% (27 patients [95% CI, 20–39.4]). Early neurological improvement was 19.5% (17 patients [95% CI, 11.8–29.5]), and symptomatic intracranial hemorrhage was 5.4% (5 patients [95% CI, 1.7–12.1]). Patients who died at 30 days exhibited significantly lower lymphocyte count, higher levels of aspartate, and LDH (lactate dehydrogenase). After adjustment for age, initial National Institutes of Health Stroke Scale, Alberta Stroke Program Early CT Score, and successful reperfusion, these biological markers remained associated with increased odds of 30-day mortality (adjusted odds ratio of 2.70 [95% CI, 1.21–5.98] per SD-log decrease in lymphocyte count, 2.66 [95% CI, 1.22–5.77] per SD-log increase in aspartate, and 4.30 [95% CI, 1.43–12.91] per SD-log increase in LDH). Conclusions: The 29% rate of 30-day mortality after MT among patients with COVID-19 is not negligible. Abnormalities of lymphocyte count, LDH and aspartate may depict a patient’s profiles with poorer outcomes after MT. Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT04406090.

BackgroundEndovascular therapy (EVT) for acute ischemic stroke (AIS) can be challenging in older patients with supra-aortic tortuosity. Rescue carotid puncture (RCP) can be an alternative in case of supra-aortic catheterization failure by femoral access, but data regarding RCP are scarce. We sought to investigate the feasibility, effectiveness and safety of RCP for AIS treated by EVT.MethodsPatients treated by EVT with RCP were included from January 2012 to December 2019 in the Endovascular Treatment in Ischemic Stroke (ETIS) multicentric registry. Main outcomes included reperfusion rates ( ≥ TICI2B), 3 month functional outcome (modified Rankin Scale) and 3 month mortality. We also performed an additional systematic review of the literature according to the PRISMA checklist to summarize previous studies on RCP.Results25 patients treated by EVT with RCP were included from the ETIS registry. RCP mainly concerned elderly patients (median age 85 years, range 73–92) with supra-aortic tortuosity (n=16 (64%)). Intravenous thrombolysis (IVT) was used for nine patients (36%). Successful reperfusion was achieved in 64%, 87.5% of patients were dependent at 3 months, and 3 month mortality was 45.8%. The systematic review yielded comparable results. In pooled individual data, there was a shift toward better functional outcome in patients with successful reperfusion (median (IQR) 4 (2–6) vs 6 (4–6), p=0.011).ConclusionRCP mainly concerned elderly patients admitted for AIS with anterior LVO with supra-aortic tortuosity. The procedure seemed feasible, notably for patients treated with IVT, and led to significant reperfusion rates at the end of procedure, but with pronounced unfavorable outcomes at 3 months. RCP should be performed under general anesthesia to avoid life-threatening complications and ensure airways safety. Finally, RCP led to low rates of closure complications, emphasizing that this concern should not withhold RCP, if indicated.

International audience; Mechanical thrombectomy is now the standard of care for acute ischemic stroke patients with large vessel occlusions, and can be performed with several devices and techniques. One of these techniques, direct aspiration (DA), consists of navigating a large-bore catheter up to the face of the clot and initiating forceful suction. This comprehensive review has three objectives: (1) to describe the direct aspiration technique; (2) to present the available evidence regarding predictive factors of DA success and performance compared with other techniques; and (3) to discuss the forthcoming improvements in distal aspiration.

Background and Purpose: Although the efficacy of endovascular treatment (EVT) in patients with anterior circulation ischemic stroke (AIS) is well documented, early neurological deterioration after EVT remains a serious issue associated with poor outcome. Besides obvious causes, such as lack of reperfusion, procedural complications, or parenchymal hemorrhage, early neurological deterioration may remain unexplained (UnEND). Our aim was to investigate predictors of UnEND after EVT in patients with AIS. Methods: Patients who underwent EVT for AIS, with an initial National Institutes of Health Stroke Scale score >5, Alberta Stroke Program Early CT Score ≥6, and included in a multicenter prospective observational registry were analyzed. Predictors of UnEND, defined as ≥4-point increase in the National Institutes of Health Stroke Scale score between baseline and day 1 after EVT, were determined via center-adjusted analyses. Results: Among the 1925 included in the analysis, 128 UnEND (6.6%) were recorded. In multivariate analysis, predictors of UnEND were diabetes mellitus (odds ratio [OR], 2.17 [95% CI, 1.32–3.56]), prestroke modified Rankin Scale score ≥2 (OR, 2.22 [95% CI, 1.09–4.55]), general anesthesia (OR, 2.55 [95% CI, 1.51–4.30]), admission systolic blood pressure (OR, 1.10 [95% CI, 1.01–1.20]), age (OR, 1.38 [95% CI, 1.14–1.67]), number of passes (OR, 1.16 [95% CI, 1.04–1.28]), direct admission or not to a comprehensive stroke center (OR, 0.49 [95% CI, 0.30–0.81]), and initial National Institutes of Health Stroke Scale score (OR, 0.65 [95% CI, 0.52–0.81]). Conclusions: Severely impaired AIS patients with nonmodifiable factors are more likely to develop UnEND. Some modifiable predictors of UnEND such as the number of EVT passes could be the object of improvement in AIS management.

Background and Purpose: Reports are emerging regarding the association of acute ischemic strokes with large vessel occlusion and coronavirus disease 2019 (COVID-19). While a higher severity of these patients could be expected from the addition of both respiratory and neurological injury, COVID-19 patients with strokes can present with mild or none respiratory symptoms. We aimed to compare anterior circulation large vessel occlusion strokes severity between patients with and without COVID-19. Methods: We performed a comparative cohort study between patients with COVID-19 who had anterior circulation large vessel occlusion and early brain imaging within 3 hours from onset, in our institution during the 6 first weeks of the COVID-19 outbreak and a control group admitted during the same calendar period in 2019. Results: Twelve COVID-19 patients with anterior circulation large vessel occlusion and early brain imaging were included during the study period and compared with 34 control patients with anterior circulation large vessel occlusion and early brain imaging in 2019. Patients in the COVID-19 group were younger ( P =0.032) and had a history of diabetes mellitus more frequently ( P =0.039). Patients did not significantly differ on initial National Institutes of Health Stroke Scale nor time from onset to imaging ( P =0.18 and P =0.6, respectively). Patients with COVID-19 had more severe strokes than patients without COVID-19, with a significantly lower clot burden score (median: 6.5 versus 8, P =0.016), higher rate of multivessel occlusion (50% versus 8.8%, P =0.005), lower DWI-ASPECTS (Diffusion-Weighted Imaging–Alberta Stroke Program Early CT Scores; median: 5 versus 8, P =0.006), and higher infarct core volume (median: 58 versus 6 mL, P =0.004). Successful recanalization rate was similar in both groups ( P =0.767). In-hospital mortality was higher in the COVID-19 patients’ group (41.7% versus 11.8%, P =0.025). Conclusions: Early brain imaging showed higher severity large vessel occlusion strokes in patients with COVID-19. Given the massive number of infected patients, concerns should be raised about the coming neurovascular impact of the pandemic worldwide.

Acute ischemic stroke (AIS) secondary to the occlusion of a large intracranial vessel (LVO) is a recognized public health problem. Mechanical thrombectomy (MT) has gained full acceptance: Class A, Level 1 in 2015 after the publication of numerous trials. Further meta-analyses have scrutinized extensively those results and international recommendations and guidelines have been given. Nevertheless, multiple-specific points remain to be clarified and are or will be under investigations.This review of the most recent literature (mostly publications after 2015) will cover the actual common practice for MT, especially focusing on the devices available (and their validation), how they are commonly used, relate the most relevant results, and detail some emerging technologies.The authors will express their own view on the current practice and emphasize on the areas where questions remain and hypothesize what specific improvements are necessary and prone to occur.

The stapedial artery is an embryonic artery that represents the precursor of some orbital, dural, and maxillary branches. Although its embryologic development and transformations are very complex, it is mandatory to understand the numerous anatomic variations of the middle meningeal artery. Thus, in the first part of this review, we describe in detail the hyostapedial system development with its variants, referring also to some critical points of ICA, ophthalmic artery, trigeminal artery, and inferolateral trunk embryology. This basis will allow the understanding of the anatomic variants of the middle meningeal artery, which we address in the second part of the review.