Mode of Onset Modifies the Effect of Time to Endovascular Reperfusion on Clinical Outcomes after Acute Ischemic Stroke: An Analysis of the DAWN Trial.

OBJECTIVE: We aimed to assess the impact of time to endovascular thrombectomy (EVT) on clinical outcomes in the DAWN trial, while also exploring the potential effect modification of mode of stroke onset on this relationship. METHODS: The association between every 1-h treatment delay with 90-day functional independence (modified Rankin Scale [mRS] score 0-2), symptomatic intracranial hemorrhage, and 90-day mortality was explored in the overall population and in three modes of onset subgroups (wake-up vs. witnessed vs. unwitnessed). RESULTS: Out of the 205 patients, 98 (47.8%) and 107 (52.2%) presented in the 6 to 12 hours and 12 to 24 hours time window, respectively. Considering all three modes of onset together, there was no statistically significant association between time last seen well to randomization with either functional independence or mortality at 90 days in either the endovascular thrombectomy (mRS 0-2 1-hour delay OR 1.07; 95% CI 0.93-1.24; mRS 6 OR 0.84; 95% CI 0.65-1.03) or medical management (mRS 0-2 1-hour delay OR 0.98; 95% CI 0.80-1.14; mRS 6 1-hour delay OR 0.94; 95% CI 0.79-1.09) groups. Moreover, there was no significant interaction between treatment effect and time (p = 0.439 and p = 0.421 for mRS 0-2 and 6, respectively). However, within the thrombectomy group, the models that tested the association between time last seen well to successful reperfusion (modified Treatment in Cerebral Infarction ≥2b) and 90-day functional independence showed a significant interaction with mode of presentation (p = 0.013). This appeared to be driven by a nominally positive slope for both witnessed and unwitnessed strokes versus a significantly (p = 0.018) negative slope in wake-up patients. There was no association between treatment times and symptomatic intracranial hemorrhage. INTERPRETATION: Mode of onset modifies the effect of time to reperfusion on thrombectomy outcomes, and should be considered when exploring different treatment paradigms in the extended window. ANN NEUROL 2024;96:356-364.

Middle meningeal artery patency after surgical evacuation for chronic subdural hematoma.

BACKGROUND: Chronic subdural hematoma (CSDH) often requires surgical evacuation, but recurrence rates remain high. Middle meningeal artery (MMA) embolization (MMAE) has been proposed as an alternative or adjunct treatment. There is concern that prior surgery might limit patency, access, penetration, and efficacy of MMAE, such that some recent trials excluded patients with prior craniotomy. However, the impact of prior open surgery on MMA patency has not been studied. METHODS: A retrospective analysis was conducted on patients who underwent MMAE for cSDH (2019-2022), after prior surgical evacuation or not. MMA patency was assessed using a six-point grading scale. RESULTS: Of the 109 MMAEs (84 patients, median age 72 years, 20.2% females), 58.7% were upfront MMAEs, while 41.3% were after prior surgery (20 craniotomies, 25 burr holes). Median hematoma thickness was 14 mm and midline shift 3 mm. Hematoma thickness reduction, surgical rescue, and functional outcome did not differ between MMAE subgroups and were not affected by MMA patency or total area of craniotomy or burr-holes. MMA patency was reduced in the craniotomy group only, specifically in the distal portion of the anterior division (p = 0.005), and correlated with craniotomy area (p < 0.001). CONCLUSION: MMA remains relatively patent after burr-hole evacuation of cSDH, while craniotomy typically only affects the frontal-distal division. However, MMA patency, evacuation method, and total area do not affect outcomes. These findings support the use of MMAE regardless of prior surgery and may influence future trial inclusion/exclusion criteria. Further studies are needed to optimize the timing and techniques for MMAE in cSDH management.

The delicate nature of a constructive peer review: pearls from the editorial board.

Peer review stands as a cornerstone of academic publishing, especially in the era of evidence-based neurosurgery - the scientific literature relies on proficient peer reviewers. Providing a constructive peer review is an art and learned skill that requires knowledge of study design and expertise in the neurosurgical subspeciality. Peer reviewers guard against arbitrary decision-making and are essential in ensuring that published manuscripts are of the highest quality. However, there remains a scarcity in the formal training relating to the peer review process. The objective of this article is therefore to shed light on this process through the lens of the Editorial Board. We encourage our invited peer reviewers to make use of this guide when appraising potential manuscripts.

Middle Meningeal Artery Embolization for Chronic Subdural Hematoma: Predictors of Clinical and Radiographic Failure from 636 Embolizations.

Background Knowledge regarding predictors of clinical and radiographic failures of middle meningeal artery (MMA) embolization (MMAE) treatment for chronic subdural hematoma (CSDH) is limited. Purpose To identify predictors of MMAE treatment failure for CSDH. Materials and Methods In this retrospective study, consecutive patients who underwent MMAE for CSDH from February 2018 to April 2022 at 13 U.S. centers were included. Clinical failure was defined as hematoma reaccumulation and/or neurologic deterioration requiring rescue surgery. Radiographic failure was defined as a maximal hematoma thickness reduction less than 50% at last imaging (minimum 2 weeks of head CT follow-up). Multivariable logistic regression models were constructed to identify independent failure predictors, controlling for age, sex, concurrent surgical evacuation, midline shift, hematoma thickness, and pretreatment baseline antiplatelet and anticoagulation therapy. Results Overall, 530 patients (mean age, 71.9 years ± 12.8 [SD]; 386 men; 106 with bilateral lesions) underwent 636 MMAE procedures. At presentation, the median CSDH thickness was 15 mm and 31.3% (166 of 530) and 21.7% (115 of 530) of patients were receiving antiplatelet and anticoagulation medications, respectively. Clinical failure occurred in 36 of 530 patients (6.8%, over a median follow-up of 4.1 months) and radiographic failure occurred in 26.3% (137 of 522) of procedures. At multivariable analysis, independent predictors of clinical failure were pretreatment anticoagulation therapy (odds ratio [OR], 3.23; P = .007) and an MMA diameter less than 1.5 mm (OR, 2.52; P = .027), while liquid embolic agents were associated with nonfailure (OR, 0.32; P = .011). For radiographic failure, female sex (OR, 0.36; P = .001), concurrent surgical evacuation (OR, 0.43; P = .009), and a longer imaging follow-up time were associated with nonfailure. Conversely, MMA diameter less than 1.5 mm (OR, 1.7; P = .044), midline shift (OR, 1.1; P = .02), and superselective MMA catheterization (without targeting the main MMA trunk) (OR, 2; P = .029) were associated with radiographic failure. Sensitivity analyses retained these associations. Conclusion Multiple independent predictors of failure of MMAE treatment for chronic subdural hematomas were identified, with small diameter (<1.5 mm) being the only factor independently associated with both clinical and radiographic failures. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Chaudhary and Gemmete in this issue.

Postoperative de novo epilepsy after resection of brain arteriovenous malformations: A national database study of 536 patients.

OBJECTIVE: We aimed to assess the incidence and risk factors for de novo epilepsy after arteriovenous malformation (AVM) resection and compare them with a nonresection cohort after propensity score matching, utilizing a national database. METHODS: Utilizing the TriNetX Research Network, we queried cases from January 1, 2004 to March 1, 2022. We included patients of all ages who underwent supratentorial AVM resection, presenting without seizures on or before surgery and without being on antiseizure medications at least 1 day before surgery. The primary outcome was seizures manifesting at least 6 weeks after surgery. Patient characteristics and outcomes were compared between the cohorts with and without postoperative epilepsy. Further cohorts were created to compare cohorts with and without embolization or rupture. After propensity score matching, we compared an additional cohort of patients with an AVM diagnosis who did not undergo resection. RESULTS: Of the 536 patients (mean age = 38.9 ± 19.6, 52% females) presenting without seizure who underwent AVM resection, 99 (18.5%) developed de novo epilepsy, with a 1-year cumulative incidence of 13.8%. Patients with epilepsy had higher rates of intracerebral hemorrhage, and intracerebral hemorrhage was less common in the embolization cohort. Patients in the ruptured cohort were older and more often males. After propensity score matching with 18 588 patients with AVM diagnosis but no resection, each group consisted of 529 patients, and de novo epilepsy at 1 year was significantly higher in the AVM resection cohort compared to the nonresection cohort (11.5% vs. 3.4%, p < .001). SIGNIFICANCE: This analysis of 536 patients provides evidence that de novo epilepsy after brain AVM resection occurs at a 1-year cumulative incidence of 13.8%, with a total of 19.4% developing de novo epilepsy. Intracerebral hemorrhage was inconsistently associated with postoperative de novo epilepsy. De novo epilepsy was significantly less frequent after AVM diagnosis without resection.

Safety and efficacy of the p48 MW and p64 flow modulation devices: a systematic review and meta-analysis.

OBJECTIVE: Flow diverters (FDs) have demonstrated increasing safety and efficacy in treating various types of intracranial aneurysms. Although the underlying mechanism of action of all FDs is similar, differences are noted in their intrinsic characteristics, materials, and deployment techniques. The p64 flow modulation device (p64) and the newer p48 movable wire flow modulation device (p48 MW) are not yet available in the US but have been increasingly used mainly in Europe, demonstrating optimistic results. The authors performed a systematic review and meta-analysis of the literature to evaluate the safety and efficacy of the p64 and p48 MW FDs. METHODS: A literature review (between January 1960 and November 2022) of the PubMed, Scopus, Embase, Web of Science, and Cochrane Central Register of Controlled Trials databases was conducted. The primary efficacy outcome was the proportion of complete angiographic occlusion at last follow-up. Complete occlusion was defined as Raymond-Roy class 1 and O'Kelly-Marotta grade D. The primary safety outcomes were the composite safety rate of ischemic and hemorrhagic events (intra- and postprocedure) and the all-cause mortality rate. Data were analyzed using a random-effects proportions meta-analysis, and statistical heterogeneity was assessed. RESULTS: Twenty studies with 1781 patients harboring 1957 aneurysms were included in the analysis. Seventeen studies were conducted in Europe. Sixteen studies evaluated the performance of the p64 (MW). Patient ages ranged between 20 and 89 years, and most were female (78.7%). Aneurysm size ranged between 1 and 50 mm. Most aneurysms were unruptured (92.8%) and in the anterior circulation (93.1%). Single antiplatelet therapy pre- and postprocedure was used in 2 studies. Follow-up ranged from 2 to 14.5 months. For the p64 and p48 MW, complete angiographic occlusion rates were 77% (95% CI 68%-85%) and 67% (95% CI 49%-81%), adjunctive coil usage rates were 7% (95% CI 4%-12%) and 4% (95% CI 0%-24%), primary safety composite rates were 2% (95% CI 1%-4%) and 3% (95% CI 1%-11%), and mortality rates were 0.49% (95% CI 0%-1%) and 2% (95% CI 1%-6%), respectively. CONCLUSIONS: The p64 and p48 MW have primarily been used in Europe thus far. This analysis found that both devices have an acceptable efficacy and favorable safety profile. However, further studies are needed to evaluate the efficacy and safety of prescribing a single antiplatelet regimen after implantation of the newer-generation FDs with antithrombotic coating surface modification.

Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and Infarct.

BACKGROUND: The effect of endovascular thrombectomy that is performed more than 6 hours after the onset of ischemic stroke is uncertain. Patients with a clinical deficit that is disproportionately severe relative to the infarct volume may benefit from late thrombectomy. METHODS: We enrolled patients with occlusion of the intracranial internal carotid artery or proximal middle cerebral artery who had last been known to be well 6 to 24 hours earlier and who had a mismatch between the severity of the clinical deficit and the infarct volume, with mismatch criteria defined according to age (<80 years or ≥80 years). Patients were randomly assigned to thrombectomy plus standard care (the thrombectomy group) or to standard care alone (the control group). The coprimary end points were the mean score for disability on the utility-weighted modified Rankin scale (which ranges from 0 [death] to 10 [no symptoms or disability]) and the rate of functional independence (a score of 0, 1, or 2 on the modified Rankin scale, which ranges from 0 to 6, with higher scores indicating more severe disability) at 90 days. RESULTS: A total of 206 patients were enrolled; 107 were assigned to the thrombectomy group and 99 to the control group. At 31 months, enrollment in the trial was stopped because of the results of a prespecified interim analysis. The mean score on the utility-weighted modified Rankin scale at 90 days was 5.5 in the thrombectomy group as compared with 3.4 in the control group (adjusted difference [Bayesian analysis], 2.0 points; 95% credible interval, 1.1 to 3.0; posterior probability of superiority, >0.999), and the rate of functional independence at 90 days was 49% in the thrombectomy group as compared with 13% in the control group (adjusted difference, 33 percentage points; 95% credible interval, 24 to 44; posterior probability of superiority, >0.999). The rate of symptomatic intracranial hemorrhage did not differ significantly between the two groups (6% in the thrombectomy group and 3% in the control group, P=0.50), nor did 90-day mortality (19% and 18%, respectively; P=1.00). CONCLUSIONS: Among patients with acute stroke who had last been known to be well 6 to 24 hours earlier and who had a mismatch between clinical deficit and infarct, outcomes for disability at 90 days were better with thrombectomy plus standard care than with standard care alone. (Funded by Stryker Neurovascular; DAWN ClinicalTrials.gov number, NCT02142283 .).

Telescoping flow diverters for a pediatric fusiform distal anterior cerebral artery aneurysm: technical case report.

BACKGROUND AND IMPORTANCE: Pediatric intracranial aneurysms are rare, with fusiform aneurysms of the distal anterior circulation even more so. A limited number of prior reports detail the management of this pathology. CLINICAL PRESENTATION: We report a case of a 15-year-old boy presenting with new-onset headache found to have a 3.1 cm × 1.4 cm × 1.4 cm fusiform partially thrombosed aneurysm of the A2 segment of the left anterior cerebral artery. Subsequent treatment with flow diversion resulted in the placement of five telescoping PEDs (2.5 mm × 20 mm, 2.75 mm × 20 mm, 2.75 mm × 20 mm, 3 mm × 25 mm, and 3 mm × 20 mm) from the left pericallosal artery to the left A1 segment. Catheter-based angiography at 6 months post-placement indicated normal vessel caliber, no residual aneurysm, and no in-stent stenosis. The patient's headache resolved after treatment. CONCLUSION: Telescoping PEDs are a feasible low-risk treatment option for long-segment fusiform distal ACA aneurysms in children that can have optimal clinical and radiographic outcomes.

Conventional Angiography in the Assessment of Recently Symptomatic Patients with Ipsilateral Carotid Stenosis.

BACKGROUND AND PURPOSE: Benefits of revascularization for moderate and severe (≥50%) carotid stenosis were established based on digital subtraction angiography (DSA). We aimed to assess the discrepancy between invasive and non-invasive angiography in a consecutive, prospective cohort of patients with recent stroke and non-invasive imaging suggesting ≥50% ipsilateral carotid stenosis. MATERIALS AND METHODS: We reviewed prospectively-collected data for consecutive patients admitted with recent stroke/TIA and ≥50% ipsilateral carotid stenosis on non-invasive imaging over 28 months. All patients underwent DSA to confirm the degree of stenosis per NASCET criteria. All patients with <50% stenosis by DSA were treated with medical therapy only and their recurrent event rates were assessed at 6 months. RESULTS: 148 symptomatic patients with ≥50% ipsilateral carotid stenosis on CTA (82%) and MRA (18%) underwent DSA to confirm degree of stenosis. Median age was 73 years and 64% were male. DSA demonstrated <50% stenosis in 28 patients (19%). Median presenting NIHSS was 1 (IQR 0-3). Median carotid stenosis evaluated by non-invasive imaging was 70% (IQR 60-85%) and by DSA was 40% (IQR 30-45%). One of 28 patients (4%) experienced recurrent nondisabling stroke (NIHSS 1) after stopping dual antiplatelet therapy. CONCLUSION: In nearly one-in-five cases with recent stroke due to ipsilateral carotid stenosis deemed to be candidates for revascularization based on CTA or MRA, DSA led to institution of medical therapy only due to insufficiently severe stenosis. In patients treated with medical therapy based on the findings of <50% stenosis on DSA, the rate of recurrent stroke is low.

Pivotal Trial of the Neuroform Atlas Stent for Treatment of Anterior Circulation Aneurysms: One-Year Outcomes.

BACKGROUND AND PURPOSE: Stent-assisted coil embolization using the new generation Neuroform Atlas Stent System has shown promising safety and efficacy. The primary study results of the anterior circulation aneurysm cohort of the treatment of wide-neck, saccular, intracranial, aneurysms with the Neuroform Atlas Stent System (ATLAS trial [Safety and Effectiveness of the Treatment of Wide Neck, Saccular Intracranial Aneurysms With the Neuroform Atlas Stent System]) are presented. METHODS: ATLAS IDE trial (Investigational Device Exemption) is a prospective, multicenter, single-arm, open-label study of wide-neck (neck ≥4 mm or dome-to-neck ratio <2) intracranial aneurysms in the anterior circulation treated with the Neuroform Atlas Stent and approved coils. The primary efficacy end point was complete aneurysm occlusion (Raymond-Roy class 1) on 12-month angiography, in the absence of retreatment or parent artery stenosis (>50%) at the target location. The primary safety end point was any major stroke or ipsilateral stroke or neurological death within 12 months. Adjudication of the primary end points was performed by an independent Imaging Core Laboratory and the Clinical Events Committee. RESULTS: A total of 182 patients with wide-neck anterior circulation aneurysms at 25 US centers were enrolled. The mean age was 60.3±11.4 years, 73.1% (133/182) women, and 80.8% (147/182) white. Mean aneurysm size was 6.1±2.2 mm, mean neck width was 4.1±1.2 mm, and mean dome-to-neck ratio was 1.2±0.3. The most frequent aneurysm locations were the anterior communicating artery (64/182, 35.2%), internal carotid artery ophthalmic artery segment (29/182, 15.9%), and middle cerebral artery bifurcation (27/182, 14.8%). Stents were placed in the anticipated anatomic location in all patients. The study met both primary safety and efficacy end points. The composite primary efficacy end point of complete aneurysm occlusion (Raymond-Roy 1) without parent artery stenosis or aneurysm retreatment was achieved in 84.7% (95% CI, 78.6%-90.9%) of patients. Overall, 4.4% (8/182, 95% CI, 1.9%-8.5%) of patients experienced a primary safety end point of major ipsilateral stroke or neurological death. CONCLUSIONS: In the ATLAS IDE anterior circulation aneurysm cohort premarket approval study, the Neuroform Atlas stent with adjunctive coiling met the primary end points and demonstrated high rates of long-term complete aneurysm occlusion at 12 months, with 100% technical success and <5% morbidity. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02340585.

Middle meningeal artery embolization treatment of nonacute subdural hematomas in the elderly: a multiinstitutional experience of 151 cases.

OBJECTIVE: The incidence of already common chronic subdural hematomas (CSDHs) and other nonacute subdural hematomas (NASHs) in the elderly is expected to rise as the population ages over the coming decades. Surgical management is associated with recurrence and exposes elderly patients to perioperative and operative risks. Middle meningeal artery (MMA) embolization offers the potential for a minimally invasive, less morbid treatment in this age group. The clinical and radiographic outcomes after MMA embolization treatment for NASHs have not been adequately described in elderly patients. In this paper, the authors describe the clinical and radiographic outcomes after 151 cases of MMA embolization for NASHs among 121 elderly patients. METHODS: In a retrospective review of a prospectively maintained database across 15 US academic centers, the authors identified patients aged ≥ 65 years who underwent MMA embolization for the treatment of NASHs between November 2017 and February 2020. Patient demographics, comorbidities, clinical and radiographic factors, treatment factors, and clinical outcomes were abstracted. Subgroup analysis was performed comparing elderly (age 65-79 years) and advanced elderly (age > 80 years) patients. RESULTS: MMA embolization was successfully performed in 98% of NASHs (in 148 of 151 cases) in 121 patients. Seventy elderly patients underwent 87 embolization procedures, and 51 advanced elderly patients underwent 64 embolization procedures. Elderly and advanced elderly patients had similar rates of embolization for upfront (46% vs 61%), recurrent (39% vs 33%), and prophylactic (i.e., with concomitant surgical intervention; 15% vs 6%) NASH treatment. Transfemoral access was used in most patients, and the procedure time was approximately 1 hour in both groups. Particle embolization with supplemental coils was most common, used in 51% (44/87) and 44% (28/64) of attempts for the elderly and advanced elderly groups, respectively. NASH thickness decreased significantly from initial thickness to 6 weeks, with additional decrease in thickness observed in both groups at 90 days. At longest follow-up, the treated NASHs had stabilized or improved in 91% and 98% of the elderly and advanced elderly groups, respectively, with > 50% improvement seen in > 60% of patients for each group. Surgical rescue was necessary in 4.6% and 7.8% of cases, and the overall mortality was 8.6% and 3.9% for elderly and advanced elderly patients, respectively. CONCLUSIONS: MMA embolization can be used safely and effectively as an alternative or adjunctive minimally invasive treatment for NASHs in elderly and advanced elderly patients.

Benefit of Endovascular Thrombectomy by Mode of Onset: Secondary Analysis of the DAWN Trial.

Background and Purpose- It is unknown whether the benefit of thrombectomy in late presenting acute stroke patients with imaging evidence of clinical-infarct mismatch is different in patients presenting with wake-up stroke compared with those presenting with witnessed onset or unwitnessed onset. Methods- Prespecified secondary analysis was performed from DAWN (Diffusion Weighted Imaging [DWI] or Computerized Tomography Perfusion [CTP] Assessment With Clinical Mismatch in the Triage of Wake Up and Late Presenting Strokes Undergoing Neurointervention), a multicenter, prospective, randomized clinical trial with blinded end point assessment comparing thrombectomy with the Trevo device against standard medical therapy in patients with acute stroke and clinical-infarct mismatch presenting 6 to 24 hour after the time last seen well. For the purposes of this study, the primary outcome was the proportion of modified Rankin Scale score 0 to 2 at 90 days. Univariable analysis and multivariable logistic regression was used to assess the relationship between outcome and mode of onset. Results- All 206 enrolled patients were included in the study. Mode of onset was: wake-up stroke (55.3%, n=114), witnessed onset (12.1%, n=25), and unwitnessed onset (32.5%, n=67) with median time last seen well to randomization (13.4±3.7, 10.0±3.7, 14.1±4.9 hours) respectively. Rates of 90-day modified Rankin Scale score of 0 to 2 and symptomatic intracerebral hemorrhage in the thrombectomy arm were not statistically different across patient onset subtypes (P=0.79 and P=0.40, respectively). The benefit of thrombectomy compared with best medical therapy was maintained across all 3 onset modes (rates of 90-day modified Rankin Scale score of 0 to 2 in patients allocated to thrombectomy versus control: wake-up stroke-49.3% versus 10.6%, witnessed onset-63.6% versus 21.4%, UW-41.4% versus 13.2%; P×interaction=0.79). In univariable and multivariable analyses, mode of onset was not identified as a significant predictor of modified Rankin Scale score 0 to 2 at 90 days. Conclusions- In patients with acute ischemic stroke presenting between 6 and 24 hours from time last seen well and harboring clinical-infarct mismatch, the benefit of thrombectomy was similar regardless of the wake-up, unwitnessed, or witnessed mode of onset.

Cerebral Aneurysm Wall Stress After Coiling Depends on Morphology and Coil Packing Density.

Endovascular coil embolization is now widely used to treat cerebral aneurysms (CA) as an alternative to surgical clipping. It involves filling the aneurysmal sac with metallic coils to reduce flow, induce clotting, and promote the formation of a coil/thrombus mass which protects the aneurysm wall from hemodynamic forces and prevents rupture. However, a significant number of aneurysms are incompletely coiled leading to aneurysm regrowth and/or recanalization. Computational models of aneurysm coiling may provide important new insights into the effects of intrasaccular coil and thrombus on aneurysm wall stresses. Porcine blood and platinum coils were used to construct an in vitro coil thrombus mass (CTM) for mechanical testing. A uniaxial compression test was performed with whole blood clots and CTM, with coil packing densities (CPDs) of 10%, 20%, and 30% to obtain compressive stress/strain responses. A fourth-order polynomial mechanical response function was fit to the experimentally obtained stress/strain responses for each CPD in order to represent their mechanical properties for computational simulations. Patient-specific three-dimensional (3D) geometries of three aneurysms with simple geometry and four with complex geometry were reconstructed from digital subtraction angiography (DSA) images. The CPDs were digitally inserted in the aneurysm geometries and finite element modeling was used to determine transmural peak/mean wall stress (MWS) with and without coil packing. Reproducible stress/strain curves were obtained from compression testing of CTM and the polynomial mechanical response function was found to approximate the experimental stress/strain relationship obtained from mechanical testing to a high degree. An exponential increase in the CTM stiffness was observed with increasing CPD. Elevated wall stresses were found throughout the aneurysm dome, neck, and parent artery in simulations of the CAs with no filling. Complete, 100% filling of the aneurysms with whole blood clot and CPDs of 10%, 20%, and 30% significantly reduced MWS in simple and complex geometry aneurysms. Sequential increases in CPD resulted in significantly greater increases in MWS in simple but not complex geometry aneurysms. This study utilizes finite element analysis to demonstrate the reduction of transmural wall stress following coil embolization in patient-specific computational models of CAs. Our results provide a quantitative measure of the degree to which CPD impacts wall stress and suggest that complex aneurysmal geometries may be more resistant to coil embolization treatment. The computational modeling employed in this study serves as a first step in developing a tool to evaluate the patient-specific efficacy of coil embolization in treating CAs.

A comparison of digital subtraction angiography and computed tomography angiography for the diagnosis of penetrating cerebrovascular injury.

OBJECTIVE: Penetrating cerebrovascular injury (PCVI) is a subset of traumatic brain injury (TBI) comprising a broad spectrum of cerebrovascular pathology, including traumatic pseudoaneurysms, direct arterial injury, venous sinus stenosis or occlusion, and traumatic dural arteriovenous fistulas. These can result in immediate or delayed vascular injury and consequent neurological morbidity. Current TBI guidelines recommend cerebrovascular imaging for detection, but there is no consensus on the optimum modality. The aim of this retrospective cohort study was to compare CT angiography (CTA) and digital subtraction angiography (DSA) for the diagnosis of PCVI. METHODS: The records of all patients presenting to two level I trauma centers in the United States between January 2010 and July 2016 with penetrating head or neck trauma were reviewed. Only those who had undergone both CTA and DSA were included. Clinical and neuroimaging data were collected, and PCVIs were stratified using a modified Biffl grading scheme. DSA and CTA results were then compared. RESULTS: Of 312 patients with penetrating trauma over the study period, 56 patients (91% male, mean age 32 years) with PCVI met inclusion criteria and constituted the study cohort. The mechanism of injury was a gunshot wound in 86% (48/56) of patients. Twenty-four (43%) patients had sustained an angiographically confirmed arterial or venous injury. Compared with DSA as the gold standard, CTA had a sensitivity and specificity of 72% and 63%, respectively, for identifying PCVI. CTA had a positive predictive value of 61% and negative predictive value of 70%. Seven patients (13%) required immediate endovascular treatment of PCVI; in 3 (43%) of these patients, the injury was not identified on CTA. Twenty-two patients (39%) underwent delayed DSA an average of 25 days after injury; 2 (9%) of these patients were found to harbor new pathological conditions requiring treatment. CONCLUSIONS: In this retrospective analysis of PCVI at two large trauma centers, CTA demonstrated low sensitivity, specificity, and positive and negative predictive values for the diagnosis of PCVI. These findings suggest that DSA provides better accuracy than CTA in the diagnosis of both immediate and delayed PCVI and should be considered for patients experiencing penetrating head or neck trauma.

Cerebral Intraparenchymal Hemorrhage: A Review.

IMPORTANCE: Although spontaneous intraparenchymal hemorrhage (IPH) accounts for less than 20% of cases of stroke, it continues to be associated with the highest mortality of all forms of stroke and substantial morbidity rates. OBSERVATIONS: Early identification and management of IPH is crucial. Blood pressure control, reversal of associated coagulopathy, care in a dedicated stroke unit, and identification of secondary etiologies are essential to optimizing outcomes. Surgical management of hydrocephalus and space occupying hemorrhage in the posterior fossa are accepted forms of treatment. Modern advances in minimally invasive surgical management of primary, supratentorial IPH are being explored in randomized trials. Hemorrhagic arteriovenous malformations and cavernous malformations are surgically excised if accessible, while hemorrhagic dural arteriovenous fistulas and distal/mycotic aneurysms are often managed with embolization if feasible. CONCLUSIONS AND RELEVANCE: IPH remains a considerable source of neurological morbidity and mortality. Rapid identification, medical management, and neurosurgical management, when indicated, are essential to facilitate recovery. There is ongoing evaluation of minimally invasive approaches for evacuation of primary IPH and evolution of surgical and endovascular techniques in the management of lesions leading to secondary IPH.

Eligibility for Endovascular Trial Enrollment in the 6- to 24-Hour Time Window: Analysis of a Single Comprehensive Stroke Center.

BACKGROUND AND PURPOSE: The results of the DAWN trial (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) support the benefit of endovascular therapy in patients presenting beyond the 6-hour time window with anterior circulation large vessel occlusions. The impact of these results with respect to additional number of eligible patients in clinical practice remains unknown. METHODS: A retrospective review of ischemic stroke admissions to a single DAWN trial-participating comprehensive stroke center was performed during the DAWN enrollment period (November 2014 to February 2017) to identify patients meeting criteria for DAWN and DEFUSE-3 (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke-3) eligibility. Patients presenting beyond 6 hours were further investigated to clarify reasons for trial exclusion. RESULTS: Of the 2667 patients with acute ischemic stroke admitted within the study period, 30% (n=792) presented within the 6- to 24-hour time window, and 47% (n=1242) had a National Institutes of Health Stroke Scale ≥6. Further clinical trial-specific selection criteria were applied based on the presence of large vessel occlusion, baseline modified Rankin Scale score, core infarct, and perfusion imaging (when available). There were 45 patients who met all DAWN trial criteria and 47 to 58 patients who would meet DEFUSE-3 trial criteria. Thirty-three percent of DAWN-eligible patients are DEFUSE-3 ineligible. CONCLUSIONS: Of all patients with acute ischemic stroke presenting to a single comprehensive stroke center, 1.7% of patients qualified for DAWN clinical trial enrollment with an additional 0.6% to 1% qualifying for the DEFUSE-3 trial. These data predict an increase in thrombectomy utilization with important implications for comprehensive stroke center resource optimization and stroke systems of care.

Laterality is an Independent Predictor of Endovascular Thrombectomy in Patients With Low National Institute of Health Stroke Scale.

OBJECTIVE: Endovascular thrombectomy (ET) for acute ischemic stroke (AIS) due to large-vessel occlusion (LVO) is offered to select patients meeting strict criteria. One of the criteria is stroke severity as indicated by the National Institute of Health Stroke Scale (NIHSS). Inherently, NIHSS is biased towards left hemisphere strokes (LHS) with median NIHSS score 4 points higher than right hemisphere strokes (RHS). This may potentially affect clinical decision making and thrombectomy eligibility. We sought to test this hypothesis. METHODS: Data were analyzed from consecutive AIS patients with LVO admitted to our comprehensive stroke center (June 2015-December 2016).  Following variables were studied: NIHSS score, occlusion location, time to presentation, and treatment received. RESULTS: Three hundred and fifty-one proximal-anterior circulation LVOs (ACLVO) were identified. 211 patients harboring a proximal ACLVO, were treated <24-hour from symptom onset, had a baseline mRS 0-1, ASPECTS ≥6, and NIHSS score ≥6. One hundred and twelve (53%) were LHS and 99 (47%) were RHS.  ET was performed in 87% of LHS and 78% of RHS (P = .09). In the NIHSS score >12 range, 88% of LHS and RHS received ET (P = .93). In the NIHSS score 6-12 range, 81% of LHS and 52% of RHS received ET (P = .03). CONCLUSIONS: We find comparable rates of ET between right and LHS in patients with high NIHSS but lower rates of ET of RHS than LHS in patients at lower NIHSS.  A hemisphere-laterality based adjustment to the NIHSS may better identify the full extent of patients that may benefit from ET.

Interfacility Transfer Directly to the Neuroangiography Suite in Acute Ischemic Stroke Patients Undergoing Thrombectomy.

BACKGROUND AND PURPOSE: In patients identified at referring facilities with acute ischemic stroke caused by a large vessel occlusion, bypassing the emergency department (ED) with direct transport to the neuroangiography suite may safely shorten reperfusion times. METHODS: We conducted a single-center retrospective review of consecutive patients transferred to our facility for consideration of endovascular therapy. Patients were identified as admitted directly to the neuroangiography suite (DAN), transferred to the ED before intra-arterial therapy (ED-IA), and transferred to the ED but did not receive IA therapy (ED-IV). RESULTS: A retrospective review of a prospectively maintained database of transfer patients between January 2013 and October 2016 with large vessel occlusions identified 108 ED-IV patients and 261 patients who underwent mechanical thrombectomy (DAN=111 patients and ED-IA=150 patients). There were no differences in baseline characteristics among the 3 groups. The median computed tomography ASPECTS (Alberta Stroke Program Early CT Score) was lower in the ED-IV group versus the ED-IA and DAN groups (8 versus 9; P=0.001). In the DAN versus ED-IA cohort, there were comparable rates of TICI2b/3 recanalization and access to recanalization time. There was significantly faster hospital arrival to groin access time in the DAN cohort (81 minutes versus 22 minutes; P=0.001). Functional independence at 90 days was comparable in the DAN versus ED-IA cohorts but worse in the ED-IV group (43% versus 44% versus 22%; P=0.001). CONCLUSIONS: DAN is safe, feasible, and associated with faster times of hospital arrival to recanalization. The clinical benefit of this approach should be assessed in a prospective randomized trial.

Cerebral Cavernous Malformations Patient Perception Analysis via Social Media.

BACKGROUND: The rise of social media has allowed for individuals and patients to connect with each other and influence patient behavior. This study aimed to improve our understanding of the patients' experience with cerebral cavernous malformations (CCM) via social media. METHODS: Instagram and Twitter were searched using terms of ("cavernoma," "cavernous malformations," "cavernous angioma," or "cav mal"). Public Instagram posts tagged with "#cavernoma" and "@cavernoma" identified 327 posts that directly included a patient's own experience. Twitter posts that included "#cavernoma" and "@cavernoma" were searched, yielding 75 after eliminating those that did not pertain to the patient's own experience. The posts and tweets were coded for relevant themes related to their experience with the disease. RESULTS: Overall, more patients are using Instagram (n = 327) over Twitter (n = 84) to share their personal experience with CCM with a trend for male patients to use Twitter more compared to females with a female predominance in Instagram. A total of 277 of 327 (84.7%) Instagram posts and 67 of 84 (89.3%) Twitter posts were made after the patient's surgery. The most common theme on Instagram was focused on the postoperative rehabilitation process and mobility support (52.0 and 24.5%, respectively). Other common themes present on Twitter and Instagram were recounting symptoms and complications and life satisfaction (26.0 and 24.2%, respectively). Cavernoma patients prior to surgery were more likely to discuss on Instagram their symptoms (p = 0.001), fear of bleeding (p < 0.001), and mental health (p = 0.014). Postoperatively, cavernoma patients were more likely to discuss disability than they were preoperatively (p = 0.001). CONCLUSION: Social media platforms offer a communication tool for patients with CCM patients to share their experience with other patients and the general public and portrays their personal experience with CCM. These platforms allow for physicians to better understand the patient experience following cavernoma surgery.