Emotional responses and psychological health among young people amid climate change, Fukushima's radioactive water release, and wars in Ukraine and the Middle East, and the mediating roles of media exposure and nature connectedness: a cross-national analysis.

BACKGROUND: New global crises are emerging, while existing global crises remain unabated. Coping with climate change, the radioactive water released into the Pacific Ocean subsequent to the Fukushima nuclear accident in Japan, and the wars in Ukraine and the Middle East (hereafter referred to as the wars) as individual crises can negatively affect the psychological health of young people, but little is known about the compounded impact of multiple crises. We aimed to examine: (1) the emotional responses of young people towards each individual crisis, (2) how aggregate levels of emotional engagement in global crises might pose different potential trajectories in psychological health, and (3) the protective or exacerbating role of media exposure and nature connectedness as mediators on psychological health outcomes of young people. METHODS: We conducted a cross-national online survey among young people (aged 18-29 years) from China, Portugal, South Africa, the USA, and the UK. We adopted stratified purposive sampling and distributed the survey using online platforms (www.wenjuan.com and www.prolific.com). Individuals were eligible for inclusion in our analysis if they were literate in Chinese or English and had no mental disorders diagnosed within the past 12 months. Participants were asked questions on their demographic characteristics and time spent on social media, including proportion of time exposed to media pertaining to global crises of interest, and they completed surveys based on validated scales that measure depression, anxiety, stress, and wellbeing, as well as emotional responses to each global crisis and nature relatedness. We assessed the survey results using descriptive statistics, ANOVA tests, cluster analysis for individual emotional responses, and structural equation modelling for the aggregate measure of emotional engagement towards individual global crises. FINDINGS: Between Oct 20 and Nov 3, 2023, 2579 individuals participated in the survey, of whom 400 participants from each country (200 male and 200 female participants) were included in our analysis (mean age 24·36 years [SD 2·86]). The mean emotional engagement varied between the global crises of interest (on a scale from 0 to 68, where 0 indicates no emotional response and 68 indicates strong emotional responses across 17 different emotions; wars: 32·42 [SD 14·57]; climate change: 28·79 [14·17]; radioactive water: 21·26 [16·08]), and emotional engagement also varied by country; for instance, for respondents from China, mean emotional engagement in radioactive water was relatively high (39·15 [10·72]) compared with the other countries, and for respondents from the USA, engagement with the wars was relatively low (29·45 [15·78]). We found significant variations in the level of emotional engagement between different crises, with distinct emotional profiles observed among individual countries. To assess the role of media exposure and nature connectedness on psychological outcomes, using structural equation modelling, we constructed a multi-country model comprising Portugal, South Africa, the USA, and the UK, and a standalone model for China. These models elucidated associations between emotional engagement and psychological distress and wellbeing, explaining substantial portions of the variance in both. Notably, while greater emotional engagement in the ecological crises (ie, climate change and radioactive water) generally predicted worse psychological health outcomes, we found the direction of effect for war crises to have positive outcomes for mental health in the standalone China model. Additionally, we found that media exposure mediated the negative effect of wars on psychological distress in the multi-country model, and positive psychological wellbeing in the standalone China model. Moreover, nature connectedness emerged as a potent mediator, effectively mitigating the adverse mental health effects of emotional engagement with some crises, such as radioactive water and climate change. INTERPRETATION: Our findings offer valuable insights into the nuanced dynamics of emotional engagement in global crises and its implications for mental health outcomes among young people across diverse global contexts. Further research is needed to understand the contribution of ongoing and new global crises towards a compounded negative future outlook on young people's mental health to identify effective communication and intervention strategies that can mitigate the effect of this global challenge. FUNDING: Research Grants Council of Hong Kong, China.

Glue embolization of ruptured pseudoaneurysm secondary to reversible cerebral vasoconstriction syndrome: An illustrative case.

BACKGROUND: Reversible cerebral vasoconstriction syndrome (RCVS) is an increasingly recognized condition characterized by thunderclap headache with or without other neurological deficits and diffuse vasoconstriction of cerebral arteries. Altered cerebrovascular tone may produce hemorrhage or stroke. METHODS: A retrospective review of patients with RCVS at our institution (2000-2023) yielded one case of pseudoaneurysm secondary to RCVS. RESULTS: Diagnostic cerebral angiogram demonstrated diffuse multifocal segmental narrowing consistent with RCVS and a left M4 pseudoaneurysm in proximity to the cortical hemorrhage. The pseudoaneurysm was treated with branch vessel sacrifice using nBCA glue in a 1 : 3 ratio with ethiodized oil. After securing the source of hemorrhage, the patient received an intra-arterial infusion of Verapamil. CONCLUSION: This unique presentation of pseudoaneurysm secondary to RCVS in this patient highlights the impact of hemodynamic alteration as a possible source of bleeding and demonstrates a potential management strategy. Endovascular management with nBCA glue embolization successfully treated this lesion.

The natural history of aneurysms incompletely occluded by placement of a flow diverter: a multiinstitutional study.

OBJECTIVE: Treatment of intracranial aneurysms by flow diversion is safe and effective and is increasingly popular. However, the correct treatment paradigm for aneurysms incompletely treated by initial placement of a flow diverter has not been established, nor have the subsequent natural history and occlusion rates of such aneurysms. The authors sought to outline the natural history of such aneurysms, which to date have been considered partially treated. METHODS: The authors retrospectively reviewed consecutive cases from 6 high-volume neurointerventional services, including all cases in which the first follow-up imaging after placement of a flow diverter showed incomplete occlusion of the aneurysm, and for which subsequent clinical and/or radiological follow-up was available. All included patients were treated with the Pipeline Flex embolization device or the Pipeline Flex embolization device with Shield Technology. Subsequent radiographic and clinical outcome data were collected and analyzed using the Kaplan-Meier survival function. RESULTS: A total of 263 patients with persistently patent aneurysms on first follow-up imaging after flow diversion were identified. Of these, 204 had clinical follow-up and 152 had additional imaging follow-up. Of this final cohort, 148 aneurysms were unruptured, and 4 were ruptured. The average aneurysm size by maximum dimension was 10.8 mm. The average recorded follow-up was 27.8 months in the cohort, with some patients followed for as long as 9 years from treatment. Over the course of 403 person-years of follow-up, no delayed aneurysm ruptures were recorded. Both with and without retreatment, aneurysms showed a trend toward progressive occlusion over time. Complications related to device placement were low. CONCLUSIONS: Aneurysms that have been incompletely treated by flow diversion have a benign natural history with progression toward occlusion over time, with or without retreatment.

Are hemodynamics responsible for inflammatory changes in venous vessel walls? A quantitative study of wall-enhancing intracranial arteriovenous malformation draining veins.

OBJECTIVE: Signal enhancement of vascular walls on vessel wall MRI might be a biomarker for inflammation. It has been theorized that contrast enhancement on vessel wall imaging (VWI) in draining veins of intracranial arteriovenous malformations (AVMs) may be associated with disease progression and development of venous stenosis. The aim of this study was to investigate the relationship between vessel wall enhancement and hemodynamic stressors along AVM draining veins. METHODS: Eight AVM patients with 15 draining veins visualized on VWI were included. Based on MR venography data, patient-specific 3D surface models of the venous anatomy distal to the nidus were segmented. The enhanced vascular wall regions were manually extracted and mapped onto the venous surface models after registration of image data. Using image-based blood flow simulations applying patient-specific boundary conditions based on phase-contrast quantitative MR angiography, hemodynamics were investigated in the enhanced vasculature. For the shear-related parameters, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT) were calculated. Velocity, oscillatory velocity index (OVI), and vorticity were extracted for the intraluminal flow-related hemodynamics. RESULTS: Visual observations demonstrated overlap of enhancement with local lower shear stresses resulting from decreased velocities. Thus, higher RRT values were measured in the enhanced areas. Furthermore, nonenhancing draining veins showed on average slightly higher flow velocities and TAWSS. Significant decreases of 55% (p = 0.03) for TAWSS and of 24% (p = 0.03) for vorticity were identified in enhanced areas compared with near distal and proximal domains. Velocity magnitude in the enhanced region showed a nonsignificant decrease of 14% (p = 0.06). Furthermore, increases were present in the OSI (32%, p = 0.3), RRT (25%, p = 0.15), and OVI (26%, p = 0.3) in enhanced vessel sections, although the differences were not significant. CONCLUSIONS: This novel multimodal investigation of hemodynamics in AVM draining veins allows for precise prediction of occurring shear- and flow-related phenomena in enhanced vessel walls. These findings may suggest low shear to be a local predisposing factor for venous stenosis in AVMs.

Refinement of nBCA embolization technique in treatment of metastatic spinal tumors: Case series and technical report.

BACKGROUND AND OBJECTIVES: Preoperative embolization of metastatic spinal tumors (MSTs) has proven advantageous in limiting intraoperative blood loss (IBL) during resection. N-butyl cyanoacrylate (nBCA) is a liquid embolic agent known for its rapid hemostatic effects. However, nBCA is associated with a higher risk of distal nontarget embolization. This study highlights the refinement of the embolization technique and assesses its efficacy in performing an initial distal segmental artery plug with concentrated nBCA followed by proximal diluted nBCA for MSTs. METHODS: A retrospective review of patients with MST (2018-2023) was performed. Patients who underwent preoperative nBCA endovascular embolization prior to tumor resection and spinal instrumentation were included. Baseline standard spinal angiography was performed. RESULTS: Sixteen patients (13 men, 3 women; 56.0 ± 12.4 years) met inclusion criteria. And 43.75% (7 of 16) had thoracic levels, 37.5% (6 of 16) lumbar, and 18.75% (3 of 16) sacral. The most common primary tumor was renal cell carcinoma (43.75%, 7 of 16). A total of 43 pedicles were embolized (median 3), resulting in complete/near complete obliteration of the tumor blush. Most pedicles (83.7%, 36 of 43) received a single dilute concentration of nBCA; however, 16.3% (7 of 43) received two separate concentrations of nBCA, a denser concentration distally into the segmental artery and a diluted concentration proximally into the tumor bed. Mean IBL was 1150 ± 1201 mL in 3 distal plug patients distal plug patients versus 1625 ± 681 mL in 12 other patients. There were no complications related to embolization. CONCLUSION: Performing a distal, concentrated nBCA plug during preoperative nBCA embolization of MSTs may increase tumor penetration and reduce IBL.

Predictors of angiographic resolution in patients with presumed reversible cerebral vasoconstriction syndrome.

INTRODUCTION: Reversible cerebral vasoconstriction syndrome is a complex neurovascular syndrome that presents with varying neurological deficits as well as segmental vasoconstriction of the small and medium cerebral arteries. There is limited literature on pathologies that mimic reversible cerebral vasoconstriction syndrome, so this study aims to understand what factors may impact the angiographic confirmation of reversible cerebral vasoconstriction syndrome on follow-up and play a role in establishing the diagnosis. METHODS: The Clinical Research Data Warehouse at this institution was employed to search the medical records for patients with diagnosis and treatment of reversible cerebral vasoconstriction syndrome between January 2010 and May 2021. After screening, 32 patients met the inclusion criteria for a presumed diagnosis of reversible cerebral vasoconstriction syndrome with both angiography on presentation and at three-month follow-up after treatment. Patients were divided into two categories: those with complete angiographic resolution, versus partial or no improvement on follow-up. Clinical and radiographic data were analyzed. RESULTS: Patients who had partial or no resolution were more likely to have a history of hypertension (p = 0.001), higher systolic blood pressure on admission (p = 0.047), and present with a recurrent thunderclap headache (p = 0.038). Binary logistic regression selected for hypertension (odds ratio [OR] 18.35 [95% CI, 1.37-245.1]) as predictive of not having reversible cerebral vasoconstriction syndrome, as can be seen by partial or no resolution on follow-up angiography (p = 0.028). CONCLUSION: Complete resolution on follow-up angiography is a distinguishing factor of reversible cerebral vasoconstriction syndrome. Our analysis revealed that a history of hypertension is the most significant predictor of confirming that a patient may not have reversible cerebral vasoconstriction syndrome. This is due, in part, to increased atherosclerotic or hypertensive cerebral arterial changes, which can mimic reversible cerebral vasoconstriction syndrome and present as partial or no resolution on angiography.

The correlation of cerebral arteriovenous malformation flow measured by quantitative MR angiography on MR-detected arteriovenous malformation microhemorrhage.

OBJECTIVE: The objective of this study was to assess the relationship of arteriovenous malformation (AVM) blood flow measured by quantitative MR angiography (QMRA) in nonruptured AVMs with MR-detected microhemorrhage. METHODS: All patients with unruptured AVMs who received baseline QMRA and gradient echo or susceptibility-weighted MRI were retrospectively reviewed (2004-2022). Imaging data, clinical history, and AVM angioarchitectural and flow features were collected and assessed. AVM flow was calculated from the difference of flow within primary arterial feeders from their contralateral counterparts. A review of the MR images determined the presence of microhemorrhages. Analysis of descriptive statistics, chi-square test, and binomial logistic regression were performed. RESULTS: Of 634 patients with cerebral AVMs at a single center, 89 patients met the inclusion criteria (54 with microhemorrhage and 35 without microhemorrhage). The calculated AVM flow was significantly higher in the group with a microhemorrhage (447.9 ± 193.1 ml/min vs 287.6 ± 235.7 ml/min, p = 0.009). In addition, the presence of venous anomaly, arterial ectasia, and diffuse nidus was significantly associated with microhemorrhage (p = 0.017, p = 0.041, and p = 0.041, respectively). Binary logistic regression found that higher flow predicted the presence of microhemorrhage (OR 1.002, 95% CI 1.000-1.004; p = 0.031). The highest AVM flow quartile significantly predicted the presence of venous anomaly (OR 3.840, 95% CI 1.037-14.213; p = 0.044), diffuse nidus (OR 6.800, 95% CI 1.766-25.181; p = 0.005), and arterial ectasia (OR 13.846, 95% CI 1.905-122.584; p = 0.018). CONCLUSIONS: This study represents the first to examine the association between flow measurements on QMRA with microhemorrhage in unruptured AVMs. Higher AVM flow, venous anomaly, arterial ectasia, and diffuse AVM nidus were related to a higher likelihood of AVM microhemorrhage. Higher AVM flow was present in AVMs with venous anomalies, a diffuse nidus, and arterial ectasia, indicating a possible interaction between these angioarchitectural findings, AVM flow, and microhemorrhage. These findings suggest a relationship between higher AVM flow and the risk of microhemorrhage.

Spiral laser scanning photoacoustic microscopy for functional brain imaging in rats.

Significance: There are many neuroscience questions that can be answered by a high-resolution functional brain imaging system. Such a system would require the capability to visualize vasculature and measure neural activity by imaging the entire brain continually and in rapid succession in order to capture hemodynamic changes. Utilizing optical excitation and acoustic detection, photoacoustic technology enables label-free quantification of changes in endogenous chromophores, such as oxyhemoglobin, deoxyhemoglobin, and total hemoglobin. Aim: Our aim was to develop a sufficiently high-resolution, fast frame-rate, and wide field-of-view (FOV) photoacoustic microscopy (PAM) system for the purpose of imaging vasculature and hemodynamics in a rat brain. Approach: Although the most PA microscopy systems use raster scanning (or less commonly Lissajous scanning), we have developed a simple-to-implement laser scanning optical resolution PAM system with spiral scanning (which we have named "spiral laser scanning photoacoustic microscopy" or sLS-PAM) to acquire an 18 mm diameter image at fast frame rate (more than 1 fps). Such a system is designed to permit continuous rat brain imaging without the introduction of photobleaching artifacts. Conclusion: We demonstrated the functional imaging capability of the sLS-PAM system by imaging cerebral hemodynamics in response to whisker and electrical stimulation and used it for vascular imaging of a modeled brain injury. We believe that we have demonstrated the development of a simple-to-implement PAM system, which could become an affordable functional neuroimaging tool for researchers.

Assessing the efficacy of VerifyNow platelet-function testing in predicting postoperative hemorrhagic complications of neuroendovascular surgery: A systematic review and meta-analysis (part 2).

BACKGROUND: Dual antiplatelet therapy is used to reduce the risk of thromboembolic complications in neuroendovascular surgery. However, the predictive utility of preoperative platelet-sensitivity testing for decreasing bleed risk in patients undergoing endovascular neurointervention remains unclear. OBJECTIVE: We conducted a systematic review and meta-analysis to illustrate the association between platelet response and risk of hemorrhagic complications from neuroendovascular surgery, examine the efficacy of the VerifyNow platelet reactivity unit (PRU) assay in predicting hemorrhagic outcomes, and assess whether a clinically useful threshold for platelet response can be defined to standardize guidelines. METHODS: PubMed, Embase, and Scopus were searched. Articles were screened for relevance by title and abstract, followed by full text. RESULTS: Of 735 resultant articles, 17 studies of 2084 patients undergoing neuroendovascular intervention were included. Diagnoses included both intracranial and extracranial pathologies, of which 37.8% were treated with flow diversion, 22.4% with stent-assisted coil embolization, 14.3% with intracranial stenting, 12.8% with simple coil embolization, 5.8% with balloon-assisted coil embolization, 2.0% with extracranial stenting, and 4.8% with an alternate method. Precisely, 52.9% (9 out of 17) of studies determined platelet hyperresponse to be an independent predictor of postoperative hemorrhagic complications, with 11.8% (2 out of 17) of studies reporting a similar but non-statistically significant trend. 35.3% (6 out of 17) of studies found no relationship between platelet response and postoperative hemorrhagic complications. The estimated clinical threshold for PRU to prevent hemorrhagic complications varied considerably across studies (range: <46-118 PRU). Meta-analysis found platelet hyperresponse to have more than a 3-fold increased risk of hemorrhagic complications compared to normoresponders (relative risk = 3.2, p = 0.001). CONCLUSION: Although this meta-analysis shows the predictive utility of the P2Y12 assay for postoperative hemorrhagic complications in neuroendovascular surgery, the optimal therapeutic threshold for minimizing bleeding risk is still uncertain. To better understand the utility of the P2Y12 assay in the perioperative period, further prospective research is needed.

Utilization of Locum Tenens in Neurosurgery.

INTRODUCTION: Despite its rising popularity, little has been described about locum tenens employment (locums) in neurosurgery. This study provides the first nationwide overview of the locums neurosurgery experience. METHODS: An anonymous online survey examined practice characteristics of respondents, extent of and satisfaction with locums, motivations for pursuing locums, case volumes, agencies used, compensation, and positive/negative aspects of experiences. Responses were collected between November 2020 and February 2021. RESULTS: Response rate for the 1852 neurosurgeons who opened the survey request was 4.9%; 36 of 91 respondents had previously worked locums and were commonly motivated by compensation or transitioning to new jobs or retirement. In our response group, 92% of locums respondents had taken more than one position and 47% had taken more than 10. Neurosurgeons performing <200 cases/year were significantly more likely to have also worked locums than those performing >200 cases/year (41.6% locums, 12.7% non-locums, P = 0.001). Responses showed that 69% of locums respondents earned $2000-$2999/day and 16% earned >$3500/day. Nearly 78% of locums respondents were satisfied with their experience(s) and 86% would take another future locums position. Being in practice for >15 years was significantly associated with satisfaction with locums (P = 0.03). Reported flaws included unfamiliarity with hospitals, limited continuity of care, credentialing burdens, and inadequate travel compensation. CONCLUSIONS: Locums is utilized by neurosurgeons across multiple practice types and may serve to complement workloads or "fill in gaps" between longer-term employment. Overall, locums neurosurgeons are well compensated, and the majority are satisfied with their experience(s). Inevitably, flaws still exist with locums employment, which may be the focus of organized efforts aiming to improve the experience.

Evaluating outcome associations with race after mechanical thrombectomy: an analysis of the NVQI-QOD acute ischemic stroke registry.

BACKGROUND: Mechanical thrombectomy has become the standard of care for acute ischemic stroke due to large vessel occlusions. Racial differences in outcomes after mechanical thrombectomy for acute ischemic stroke have not been extensively studied. We evaluate the real-world evidence for differences between races in the outcomes of thrombectomy for large vessel occlusions using the NeuroVascular Quality Initiative-Quality Outcomes Database (NVQI-QOD). METHODS: Data from the NVQI-QOD acute ischemic stroke registry were analyzed and compared for racial differences in outcomes after mechanical thrombectomy in 4507 patients from 28 US centers (17 states) between January 2014 and April 2021. Race was dichotomized into non-Hispanic White (NHW, n=3649) and non-Hispanic Black (NHB, n=858). We performed 1:1 propensity score matching resulting in a subsample of matched groups (n=761 each for NHB and NHW) to compare study endpoints using Welch's two-sided t-tests and Χ2 test for continuous and categorical outcomes, respectively. RESULTS: Prior to matching, NHW and NHB patients significantly differed in age, comorbidities, medication use, smoking status, and presenting stroke severity. No significant difference in functional outcomes or mortality, at discharge or follow-up, were revealed. NHB patients had higher average postprocedure length of stay than NHW patients, which persisted following matching (11.2 vs 9.1 days, P=0.004). CONCLUSION: Evidence from the NVQI-QOD acute ischemic stroke registry showed that outcome metrics, such as modified Rankin Scale score and mortality, did not differ significantly between racial groups; however, disparity between NHW and NHB patients in postprocedure length of stay following mechanical thrombectomy was revealed.

Assessing the efficacy of VerifyNow platelet-function testing in predicting postoperative thromboembolic complications of neuroendovascular surgery: A systematic review and meta-analysis (part 1).

BACKGROUND: Despite the heavily debated use of routine platelet-function testing, the VerifyNow Platelet Reactivity Unit (PRU) assay has been increasingly adopted as standard of care for assessing risk of postoperative thromboembolic complications of neuroendovascular surgery. OBJECTIVE: We conducted a systematic review and meta-analysis to examine the relationship between platelet response and risk of ischemic events from neuroendovascular surgery, assess the efficacy of point-of-care platelet-function testing in predicting thromboembolic outcomes, and assess whether a clinically useful threshold for platelet response can be defined in order to standardize guidelines. METHODS: PubMed, Embase, and Scopus were searched. Following deduplication, articles were first screened for relevance by title and abstract, followed by full text. RESULTS: Of 735 resultant articles, 22 studies consisting of 3266 patients undergoing neuroendovascular intervention were included. Diagnoses included both intracranial and extracranial pathologies, of which 45.8% were treated with flow diversion, 16.4% with stent-assisted coil embolization, 15.8% with intracranial stenting, 12.0% with simple coil embolization, 3.4% with balloon-assisted coil embolization, 3.6% with extracranial stenting, and 3.0% with an alternate method. 54.5% (12/22) of studies determined platelet hyporesponse to be an independent predictor of postoperative thromboembolic complications, with 27.3% (6/22) of studies reporting a similar, but non-statistically significant trend. 18.2% (4/22) of studies found no relationship between platelet response and postoperative thromboembolic complications. The estimated clinical threshold for PRU to prevent thromboembolic complications varied greatly across studies (Range: > 144-295 PRU). Meta-analysis found platelet hyporesponse to have a 2.23-fold increased risk of thromboembolic complications compared to normoresponders (RR = 2.23, P = 0.03). CONCLUSION: While PRU demonstrates a significant predictive value for postoperative thromboembolic complications of neuroendovascular surgery, the target therapeutic threshold for minimizing ischemic events remains unclear. Further studies, such as large multicenter cohorts of the existing data, are needed to standardize guidelines.

5-year stroke rates in nonvalvular atrial fibrillation after watchman compared to direct oral anticoagulants.

BACKGROUND: The WATCHMAN device (Boston Scientific; Marlborough, MA, USA) is noninferior to warfarin in preventing ischemic strokes while reducing bleeding risks associated with long term anticoagulation in nonvalvular atrial fibrillation (AFib). The device's performance compared to direct oral anticoagulants (DOAC) is less well known. OBJECTIVE: To compare 5-year major bleeding and ischemic stroke rates in patients with nonvalvular AFib who received a WATCHMAN device or DOAC therapy after a major bleeding event. METHODS: This retrospective, multicenter, 1:1 matched cohort study was derived from the PearlDiver Mariner database from 2010 to 2020. Patients with nonvalvular AFib on oral anticoagulation who had a major bleeding event were identified. Those who received either WATCHMAN or DOAC after resolution of the bleeding event were selected. The two groups were exactly matched 1:1 based on various comorbidities. Rates of ischemic stroke, transient ischemic attack (TIA), major bleeding, and hemorrhagic stroke were compared over 5 years. RESULTS: Each cohort consisted of 2248 patients after 1:1 matching. The mean CHADS2-VASC score was 4.81 ±â€¯1.25. At 5 years, the WATCHMAN cohort had significantly lower rates of major bleeding events [OR 0.24 (0.21, 0.27)], TIAs [OR 0.75 (0.58, 0.95)], and ischemic strokes [OR 0.72 (0.61, 0.86)]. There was no significant difference in hemorrhagic strokes [OR 1.14 (0.83, 1.58)]. CONCLUSION: Even in a high-risk population, the WATCHMAN is comparable to DOAC therapy in the primary prevention of hemorrhagic strokes and may provide benefit in the rates of bleeding events, TIAs, and ischemic strokes.

WITHDRAWN: A narrative review of techniques for surgical revascularization of the extracranial vertebral artery in vertebrobasilar insufficiency.

The Publisher regrets that this article is an accidental duplication of an article that has already been published in Neurochirurgie, volume 70. https://doi.org/10.1016/j.neuchi.2023.101516. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/policies/article-withdrawal.

A narrative review of techniques for surgical revascularization of the extracranial vertebral artery in vertebrobasilar insufficiency.

Vertebrobasilar insufficiency is a condition characterized by poor blood flow through the posterior circulation of the brain, which supplies the brainstem, thalamus, hippocampus, cerebellum, occipital lobes, and medial temporal lobes. Narrowing or occlusion of the vertebral arteries may be result in a range of neurological symptoms, including dizziness, imbalance, dysarthria, and even stroke. If symptomatic patients fail medical management, revascularization of the vertebral artery should be considered. Restoration of blood flow may involve transluminal balloon angioplasty or stent placement; however, certain cases may still require surgical intervention. The complexity of surgical revascularization of the vertebral artery requires careful consideration of skull base and neck anatomy. This review article will focus on bypass of the vertebral artery in the setting of ischemic pathology, describing the technique, anatomical nuances, steps involved in preoperative planning, and postoperative management.

Quantitative Blood Flow Reduction in Selective Embolization of Intranidal Fistula of Cerebral Arteriovenous Malformations: Case Series.

BACKGROUND AND OBJECTIVES: Arteriovenous malformations (AVMs) are often associated with high-flow intranidal fistulas (INFs). Although INF embolization has been suggested to provide higher reduction of total AVM flow compared with regular pedicle embolization, this effect has not previously been quantified. The aim of this study was to characterize the effect of AVM INF embolization on total AVM flow. METHODS: This study is an Institutional Review Board-approved, retrospective case series of patients from 2010 to 2022 with AVMs, both with and without INFs, who underwent quantitative magnetic resonance angiography and endovascular embolization. RESULTS: Twenty patients accounted for 35 separate embolization sessions: 13 patients with INFs underwent a total 21 embolizations and 12 patients without INFs had 14 embolizations. No significant differences were found between groups on age, sex, laterality, drainage pattern, and Spetzler-Martin grade. However, AVMs with INFs were larger than the control group (12.7 vs 8.37 cm 3 , P = .049). Baseline pre-embolization AVM flow significantly differed between AVM with INF vs control groups (522 vs 320 cc/min, P = .005). Similarly, postembolization AVM flow also differed between AVM with INF and control groups (392 vs 224 cc/min, P = .008), with a larger decrease in flow per vessel per embolization session within the AVM INF group compared with controls (101.5 vs 33.2 cc/min, P < .001). Repeated measure analysis of variance showed significant differences pre-embolization and postembolization AVM flow between those with INFs vs controls ( P < .001). CONCLUSION: This study represents the first to examine the effect of INF embolization on total AVM flow. AVMs with INFs showed higher baseline flow, and targeted embolization toward INFs significantly lowered AVM flow in comparison with controls without INFs. The results of this study emphasize the importance of recognizing the presence of INFs within AVMs and their embolization to reduce AVM flow as part of a multistep management paradigm.

Transfontanelle photoacoustic imaging of intraventricular brain hemorrhages in live sheep.

Intraventricular (IVH) and periventricular (PVH) hemorrhages in preterm neonates are common because the periventricular blood vessels are still developing up to 36 weeks and are fragile. Currently, transfontanelle ultrasound (US) imaging is utilized for screening for IVH and PVH, largely through the anterior fontanelle. However for mild hemorrhages, inconclusive diagnoses are common, leading to failure to detect IVH/PVH or, when other clinical symptoms are present, use of second stage neuroimaging modalities requiring transport of vulnerable patients. Yet even mild IVH/PVH increases the risk of moderate-severe neurodevelopmental impairment. Here, we demonstrate the capability of transfontanelle photoacoustic imaging (TFPAI) to detect IVH and PVH in-vivo in a large animal model. TFPAI was able to detect IVH/PVH as small as 0.3 mL in volume in the brain (p < 0.05). By contrast, US was able to detect hemorrhages as small as 0.5 mL. These preliminary results suggest TFPAI could be translated into a portable bedside imaging probe for improved diagnosis of clinically relevant brain hemorrhages in neonates.

Rupture-Risk Stratifying Patients with Cerebral Arteriovenous Malformations Using Quantitative Hemodynamic Flow Measurements.

Arteriovenous malformations (AVMs) are high-pressure, low-resistance arterial-venous shunts without intervening capillaries. Up to 60% of AVMs present with an intracranial hemorrhage; however, noninvasive neuroimaging has increasingly diagnosed incidental AVMs. AVM management depends on weighing the lifetime rupture risk against the risks of intervention. Although AVM rupture risk relies primarily on angioarchitectural features, measuring hemodynamic flow is gaining traction. Accurate understanding of AVM hemodynamic flow parameters will help endovascular neurosurgeons and interventional neuroradiologists stratify patients by rupture risk and select treatment plans. This review examines various neuroimaging modalities and their capabilities to quantify AVM flow, as well as the relationship between AVM flow and rupture risk. Quantitative hemodynamic studies on the relationship between AVM flow and rupture risk have not reached a clear consensus; however, the preponderance of data suggests that higher arterial inflow and lower venous outflow in the AVM nidus contribute to increased hemorrhagic risk. Future studies should consider using larger sample sizes and standardized definitions of hemodynamic parameters to reach a consensus. In the meantime, classic angioarchitectural features may be more strongly correlated with AVM rupture than the amount of blood flow.

Preoperative embolization of brain arteriovenous malformation and efficacy in intraoperative blood loss reduction: a quantitative study.

BACKGROUND: Embolization of brain arteriovenous malformations (bAVMs) is often used as adjuvant therapy to microsurgical resection to reduce the high-risk features of bAVMs such as large size and high flow. However, the effect of preoperative embolization on surgical performance and patient outcome has shown mixed results. Heterogeneity in treatment goals, selection criteria, and unpredictable changes in bAVM hemodynamics after partial embolization may account for these uncertain findings. In this study we use an objective quantitative technique to assess the impact of preoperative embolization on intraoperative blood loss (IBL). METHODS: Patients with bAVM treated with microsurgical resection only or in combination with preoperative embolization from 2012 to 2022 were retrospectively reviewed. Patients were included if quantitative magnetic resonance angiography was performed prior to any treatment. Correlation of baseline bAVM flow, volume, and IBL was evaluated between the two groups. Additionally, bAVM flow prior to and after embolization was compared. RESULTS: Forty-three patients were included, 31 of whom required preoperative embolization (20 had more than one session). Mean bAVM initial flow (362.3 mL/min vs 89.6 mL/min, p=0.001) and volume (9.6 mL vs 2.8 mL, p=0.001) were significantly higher in the preoperative embolization group; flow decreased significantly after embolization (408.0 mL/min vs 139.5 mL/min, p<0.001). IBL was comparable between the two groups (258.6 mL vs 141.3 mL, p=0.17). Linear regression continued to show a significant difference in initial bAVM flow (p=0.03) but no significant difference in IBL (p=0.53). CONCLUSION: Patients with larger bAVMs who underwent preoperative embolization had comparable IBL to those with smaller bAVMs undergoing only surgical treatment. Preoperative embolization of high-flow bAVMs facilitates surgical resection, reducing the risk of IBL.