Middle meningeal artery embolization reduces recurrence following surgery for septated chronic subdural hematomas

BACKGROUND

Septated chronic subdural hematomas (cSDH) have high rates of recurrence despite surgical evacuation. Middle meningeal artery embolization (MMAE) has emerged as a promising adjuvant for secondary prevention, yet its efficacy remains ill-defined.

METHODS

This is a retrospective review of septated cSDH cases treated at our institution. The surgery-only group was derived from cases performed before 2018, and the surgery+MMAE group was derived from cases performed 2018 or later. The primary outcome was reoperation rate. Secondary outcomes were recurrence, change in hematoma thickness, and midline shift.

RESULTS

A total of 34 cSDHs in 28 patients (surgery+MMAE) and 95 cSDHs in 83 patients (surgery-only) met the inclusion criteria. No significant difference in baseline characteristics between groups was identified. The reoperation rate was significantly higher in the surgery-only group (n = 16, 16.8%) compared with the surgery+MMAE cohort (n = 0, 0.0%) (p=0.006). A reduced incidence of recurrence (p=0.011) was also seen in the surgery+MMAE group.

CONCLUSIONS

MMAE for septated cSDH was found to be highly effective in preventing recurrence and reoperation. MMAE is an adjunct to surgical evacuation may be of particular benefit in this patient cohort.

Neutrophils and Neutrophil Extracellular Traps Cause Vascular Occlusion and Delayed Cerebral Ischemia After Subarachnoid Hemorrhage in Mice

BACKGROUND

After subarachnoid hemorrhage (SAH), neutrophils are deleterious and contribute to poor outcomes. Neutrophils can produce neutrophil extracellular traps (NETs) after ischemic stroke. Our hypothesis was that, after SAH, neutrophils contribute to delayed cerebral ischemia (DCI) and worse outcomes via cerebrovascular occlusion by NETs.

METHODS

SAH was induced via endovascular perforation, and SAH mice were given either a neutrophil-depleting antibody, a PAD4 (peptidylarginine deiminase 4) inhibitor (to prevent NETosis), DNAse-I (to degrade NETs), or a vehicle control. Mice underwent daily neurological assessment until day 7 and then euthanized for quantification of intravascular brain NETs (iNETs). Subsets of mice were used to quantify neutrophil infiltration, NETosis potential, iNETs, cerebral perfusion, and infarction. In addition, NET markers were assessed in the blood of aneurysmal SAH patients.

RESULTS

In mice, SAH led to brain neutrophil infiltration within 24 hours, induced a pro-NETosis phenotype selectively in skull neutrophils, and caused a significant increase in iNETs by day 1, which persisted until at least day 7. Neutrophil depletion significantly reduced iNETs, improving cerebral perfusion, leading to less neurological deficits and less incidence of DCI (16% versus 51.9%). Similarly, PAD4 inhibition reduced iNETs, improved neurological outcome, and reduced incidence of DCI (5% versus 30%), whereas degrading NETs marginally improved outcomes. Patients with aneurysmal SAH who developed DCI had elevated markers of NETs compared with non-DCI patients.

CONCLUSIONS

After SAH, skull-derived neutrophils are primed for NETosis, and there are persistent brain iNETs, which correlated with delayed deficits. The findings from this study suggest that, after SAH, neutrophils and NETosis are therapeutic targets, which can prevent vascular occlusion by NETs in the brain, thereby lessening the risk of DCI. Finally, NET markers may be biomarkers, which can predict which patients with aneurysmal SAH are at risk for developing DCI.

A Genome-Wide Association Study of Outcome After Aneurysmal Subarachnoid Haemorrhage: Discovery Analysis

Candidate gene studies have identified genetic variants associated with clinical outcomes following aneurysmal subarachnoid haemorrhage (aSAH), but no genome-wide association studies have been performed to date. Here we report the results of the discovery phase of a two-stage genome-wide meta-analysis of outcome after aSAH. We identified 157 independent loci harbouring 756 genetic variants associated with outcome after aSAH (p < 1 × 10-4), which require validation. A single variant (rs12949158), in SPNS2, achieved genome-wide significance (p = 4.29 × 10-8) implicating sphingosine-1-phosphate signalling in outcome after aSAH. A large multicentre international effort to recruit samples for validation is required and ongoing. Validation of these findings will provide significant insight into the pathophysiology of outcomes after aSAH with potential implications for treatment.

A Transcriptomic Comparative Study of Cranial Vasculature

In genetic studies of cerebrovascular diseases, the optimal vessels to use as controls remain unclear. Our goal is to compare the transcriptomic profiles among 3 different types of control vessels: superficial temporal artery (STA), middle cerebral arteries (MCA), and arteries from the circle of Willis obtained from autopsies (AU). We examined the transcriptomic profiles of STA, MCA, and AU using RNAseq. We also investigated the effects of using these control groups on the results of the comparisons between aneurysms and the control arteries. Our study showed that when comparing pathological cerebral arteries to control groups, all control groups presented similar responses in the activation of immunological processes, the regulation of intracellular signaling pathways, and extracellular matrix productions, despite their intrinsic biological differences. When compared to STA, AU exhibited upregulation of stress and apoptosis genes, whereas MCA showed upregulation of genes associated with tRNA/rRNA processing. Moreover, our results suggest that the matched case-control study design, which involves control STA samples collected from the same subjects of matched aneurysm samples in our study, can improve the identification of non-inherited disease-associated genes. Given the challenges associated with obtaining fresh intracranial arteries from healthy individuals, our study suggests that using MCA, AU, or paired STA samples as controls are feasible strategies for future large-scale studies investigating cerebral vasculopathies. However, the intrinsic differences of each type of control should be taken into consideration when interpreting the results. With the limitations of each control type, it may be most optimal to use multiple tissues as controls.

Subarachnoid Blood Clearance and Aneurysmal Subarachnoid Hemorrhage Outcomes: A Retrospective Review

BACKGROUND

Delayed cerebral ischemia (DCI) continues to be a significant contributor to morbidity and mortality following aneurysmal subarachnoid hemorrhage (aSAH). Subarachnoid blood and its degradation products have been implicated in DCI, and faster blood clearance has been hypothesized to confer better outcomes. This study evaluates the relationship between blood volume and its clearance on DCI (primary outcome) and location at 30 days (secondary outcome) after aSAH.

METHODS

This is a retrospective review of adult patients presenting with aSAH. Hijdra sum scores (HSS) were assessed independently for each computed tomography (CT) scan of patients with available scans on post-bleed days 0-1 and 2-10. This cohort was used to evaluate the course of subarachnoid blood clearance (group 1). A subset of patients in the first cohort with available CT scans on both post-bleed days 0-1 and post-bleed days 3-4 composed the second cohort (group 2). This group was used to evaluate the association between initial subarachnoid blood (measured via HSS post-bleed days 0-1) and its clearance (measured via percentage reduction [HSS %Reduction] and absolute reduction [HSS-Abs-Reduction] in HSS between days 0-1 and 3-4) on outcomes. Univariable and multivariable logistic regression models were used to identify outcome predictors.

RESULTS

One hundred fifty-six patients were in group 1, and 72 patients were in group 2. In this cohort, HSS %Reduction was associated with decreased risk of DCI in univariate (odds ratio [OR] = 0.700 [0.527-0.923], p = 0.011) and multivariable (OR = 0.700 [0.527-0.923], p = 0.012) analyses. Higher HSS %Reduction was significantly more likely to have better outcomes at 30 days in the multivariable analysis (OR = 0.703 [0.507-0.980], p = 0.036). Initial subarachnoid blood volume was associated with outcome location at 30 days (OR = 1.331 [1.040-1.701], p = 0.023) but not DCI (OR = 0.945 [0.780-1.145], p = 0.567).

CONCLUSIONS

Early blood clearance after aSAH was associated with DCI (univariable and multivariable analyses) and outcome location at 30 days (multivariable analysis). Methods facilitating subarachnoid blood clearance warrant further investigation.

Middle meningeal artery embolization of septated chronic subdural hematomas

INTRODUCTION

Middle meningeal artery embolization (MMAE) has emerged as a promising new treatment for patients with chronic subdural hematomas (cSDH). Its efficacy, however, upon the subtype with a high rate of recurrence-septated cSDH-remains undetermined.

METHODS

From our prospective registry of patients with cSDH treated with MMAE, we classified patients based on the presence or absence of septations. The primary outcome was the rate of recurrence of cSDH. Secondary outcomes included a reduction in cSDH thickness, midline shift, and rate of reoperation.

RESULTS

Among 80 patients with 99 cSDHs, the median age was 68 years (IQR 59-77) with 20% females. Twenty-eight cSDHs (35%) had septations identified on imaging. Surgical evacuation with burr holes was performed in 45% and craniotomy in 18.8%. Baseline characteristics between no-septations (no-SEP) and septations (SEP) groups were similar except for median age (SEP vs no-SEP, 72.5 vs. 65.5, p = 0.016). The recurrence rate was lower in the SEP group (SEP vs. no-SEP, 3 vs. 16.7%, p = 0.017) with higher odds of response from MMAE for septated lesions even when controlling for evacuation strategy and antithrombotic use (OR = 0.06, CI [0.006-0.536], p = 0.012). MMAE resulted in higher mean absolute thickness reduction (SEP vs. no-SEP, -8.2 vs. -4.8 mm, p = 0.016) with a similar midline shift change. The rate of reoperation did not differ (6.2 vs. 3.1%, p = 0.65).

CONCLUSION

MMAE appears to be equal to potentially more effective in preventing the recurrence of cSDH in septated lesions. These findings may aid in patient selection.

Antiplatelet and anticoagulation therapy and the risk of pituitary apoplexy in pituitary adenoma patients

PURPOSE

Pituitary apoplexy can be a life threatening and vision compromising event. Antiplatelet and anticoagulation use has been reported as a contributing factor in pituitary apoplexy (PA). Utilizing one of the largest cohorts in the literature, this study aims to determine the risk of PA in patients on antiplatelet/anticoagulation (AP/AC) therapy.

METHODS

A single center, retrospective study was conducted on 342 pituitary adenoma patients, of which 77 patients presented with PA (23%). Several potential risk factors for PA were assessed, including: patient demographics, tumor characteristics, pre-operative hormone replacement, neurologic deficits, coagulation studies, platelet count, and AP/AC therapy.

RESULTS

Comparing patients with and without apoplexy, there was no significant difference in the proportion of patients taking aspirin (45 no apoplexy vs. 10 apoplexy; p = 0.5), clopidogrel (10 no apoplexy vs. 4 apoplexy; p = 0.5), and anticoagulation (7 no apoplexy vs. 3 apoplexy; p = 0.7). However, male sex (p-value < 0.001) was a predictor for apoplexy while pre-operative hormone treatment was a protective factor from apoplexy (p-value < 0.001). A non-clinical difference in INR was also noted as a predictor for apoplexy (no apoplexy: 1.01 ± 0.09, apoplexy: 1.07 ± 0.15; p < 0.001).

CONCLUSIONS

Although pituitary tumors have a high risk for spontaneous hemorrhage, the use of aspirin is not a risk for hemorrhage. Our study did not find an increased risk of apoplexy with clopidogrel or anticoagulation, but further investigation is needed with a larger cohort. Confirming other reports, male sex is associated with an increased risk for PA.

Neurofibroma of the internal carotid artery cavernous sympathetic plexus: illustrative case

BACKGROUND

Intracranial carotid sympathetic plexus (CSP) nerve sheath tumors have rarely been reported in the literature. This study describes the first reported case of a CSP neurofibroma and the first case of a CSP nerve sheath tumor treated via an endoscopic endonasal approach followed by adjuvant radiosurgery.

OBSERVATIONS

A 53-year-old man presented with 3 days of headaches and diplopia and was found to have a complete left abducens nerve palsy. Computed tomography (CT) revealed a smoothly dilated left carotid canal, CT angiography revealed a superiorly displaced left internal carotid artery (ICA), and magnetic resonance imaging revealed a T2-hyperintense and avidly enhancing lesion in the left cavernous sinus encasing the ICA. The patient underwent subtotal resection via an endoscopic transsphenoidal transcavernous approach followed by Gamma Knife radiosurgery.

LESSONS

Nerve sheath tumors arising from the CSP are extremely rare but need to be considered when assessing unusual cavernous sinus lesions. The clinical presentation is dependent on the anatomical location of the tumor and its relationship to the ICA. The optimal treatment paradigm is unknown.

Middle Meningeal Artery Embolization for Chronic Subdural Hematomas With Concurrent Antithrombotics

BACKGROUND

Chronic subdural hematoma (CSDH) is an increasingly prevalent disease in the aging population. Patients with CSDH frequently suffer from concurrent vascular disease or develop secondary thrombotic complications requiring antithrombotic treatment.

OBJECTIVE

To determine the safety and impact of early reinitiation of antithrombotics after middle meningeal artery embolization for chronic subdural hematoma.

METHODS

This is a single-institution, retrospective study of patients who underwent middle meningeal artery (MMA) embolizations for CSDH. Patient with or without antithrombotic initiation within 5 days postembolization were compared. Primary outcome was the rate of recurrence within 60 days. Secondary outcomes included rate of reoperation, reduction in CSDH thickness, and midline shift.

RESULTS

Fifty-seven patients met inclusion criteria. The median age was 66 years (IQR 58-76) with 21.1% females. Sixty-six embolizations were performed. The median length to follow-up was 20 days (IQR 14-44). Nineteen patients (33.3%) had rapid reinitiation of antithrombotics (5 antiplatelet, 11 anticoagulation, and 3 both). Baseline characteristics between the no antithrombotic (no-AT) and the AT groups were similar. The recurrence rate was higher in the AT group (no-AT vs AT, 9.3 vs 30.4%, P = .03). Mean absolute reduction in CSDH thickness and midline shift was similar between groups. Rate of reoperation did not differ (4.7 vs 8.7%, P = .61).

CONCLUSION

Rapid reinitiation of AT after MMA embolization for CSDH leads to higher rates of recurrence with similar rates of reoperation. Care must be taken when initiating antithrombotics after treatment of CSDH with MMA embolization.

Mediation of Successful Reperfusion Effect through Infarct Growth and Cerebral Edema: A Pooled, Patient-Level Analysis of EXTEND-IA Trials and SELECT Prospective Cohort

OBJECTIVE

Reperfusion therapy is highly beneficial for ischemic stroke. Reduction in both infarct growth and edema are plausible mediators of clinical benefit with reperfusion. We aimed to quantify these mediators and their interrelationship.

METHODS

In a pooled, patient-level analysis of the EXTEND-IA trials and SELECT study, we used a mediation analysis framework to quantify infarct growth and cerebral edema (midline shift) mediation effect on successful reperfusion (modified Treatment in Cerebral Ischemia ≥ 2b) association with functional outcome (modified Rankin Scale distribution). Furthermore, we evaluated an additional pathway to the original hypothesis, where infarct growth mediated successful reperfusion effect on midline shift.

RESULTS

A total 542 of 665 (81.5%) eligible patients achieved successful reperfusion. Baseline clinical and imaging characteristics were largely similar between those achieving successful versus unsuccessful reperfusion. Median infarct growth was 12.3ml (interquartile range [IQR] = 1.8-48.4), and median midline shift was 0mm (IQR = 0-2.2). Of 249 (37%) demonstrating a midline shift of ≥1mm, median shift was 2.75mm (IQR = 1.89-4.21). Successful reperfusion was associated with reductions in both predefined mediators, infarct growth (β = -1.19, 95% confidence interval [CI] = -1.51 to -0.88, p < 0.001) and midline shift (adjusted odds ratio = 0.36, 95% CI = 0.23-0.57, p < 0.001). Successful reperfusion association with improved functional outcome (adjusted common odds ratio [acOR] = 2.68, 95% CI = 1.86-3.88, p < 0.001) became insignificant (acOR = 1.39, 95% CI = 0.95-2.04, p = 0.094) when infarct growth and midline shift were added to the regression model. Infarct growth and midline shift explained 45% and 34% of successful reperfusion effect, respectively. Analysis considering an alternative hypothesis demonstrated consistent results.

INTERPRETATION

In this mediation analysis from a pooled, patient-level cohort, a significant proportion (~80%) of successful reperfusion effect on functional outcome was mediated through reduction in infarct growth and cerebral edema. Further studies are required to confirm our findings, detect additional mediators to explain successful reperfusion residual effect, and identify novel therapeutic targets to further enhance reperfusion benefits. ANN NEUROL 2023.

Thrombectomy versus Medical Management in Mild Strokes due to Large Vessel Occlusion: Exploratory Analysis from the EXTEND-IA Trials and a Pooled International Cohort

OBJECTIVE

This study was undertaken to evaluate functional and safety outcomes for endovascular thrombectomy (EVT) versus medical management (MM) in patients with large vessel occlusion (LVO) and mild neurological deficits, stratified by perfusion imaging mismatch.

METHODS

The pooled cohort consisted of patients with National Institutes of Health Stroke Scale (NIHSS) < 6 and internal carotid artery (ICA), M1, or M2 occlusions from the Extending the Time for Thrombolysis in Emergecy Neurological Deficits - Intra-Arterial (EXTEND-IA) Trial,  Tenecteplase vs Alteplase before Endovascular Thrombectomy in Ischemic Stroke (EXTEND-IA TNK) trials Part I/II and prospective data from 15 EVT centers from October 2010 to April 2020. RAPID software estimated ischemic core and mismatch. Patients receiving primary EVT (EVT_pri ) were compared to those who received primary MM (MM_pri ), including those who deteriorated and received rescue EVT, in overall and propensity score (PS)-matched cohorts. Patients were stratified by target mismatch (mismatch ratio ≥ 1.8 and mismatch volume ≥ 15ml). Primary outcome was functional independence (90-day modified Rankin Scale = 0-2). Secondary outcomes included safety (symptomatic intracerebral hemorrhage [sICH], neurological worsening, and mortality).

RESULTS

Of 540 patients, 286 (53%) received EVT_pri and demonstrated larger critically hypoperfused tissue (Tmax > 6 seconds) volumes (median [IQR]: 64 [26-96] ml vs MM_pri : 40 [14-76] ml, p < 0.001) and higher presentation NIHSS (median [IQR]: 4 [2-5] vs MM_pri : 3 [2-4], p < 0.001). Functional independence was similar (EVT_pri : 77.4% vs MM_pri : 75.6%, adjusted odds ratio [aOR] = 1.29, 95% confidence interval [CI] = 0.82-2.03, p = 0.27). EVT had worse safety regarding sICH (EVT_pri : 16.3% vs MM_pri : 1.3%, p < 0.001) and neurological worsening (EVT_pri : 19.6% vs MM_pri : 6.7%, p < 0.001). In 414 subjects (76.7%) with target mismatch, EVT was associated with improved functional independence (EVT_pri : 77.4% vs MM_pri : 72.7%, aOR = 1.68, 95% CI = 1.01-2.81, p = 0.048), whereas there was a trend toward less favorable outcomes with primary EVT (EVT_pri : 77.4% vs MM_pri : 83.3%, aOR = 0.39, 95% CI = 0.12-1.34, p = 0.13) without target mismatch (p_interaction  = 0.06). Similar findings were observed in a propensity score-matched subpopulation.

INTERPRETATION

Overall, EVT was not associated with improved clinical outcomes in mild strokes due to LVO, and sICH was increased. However, in patients with target mismatch profile, EVT was associated with increased functional independence. Perfusion imaging may be helpful to select mild stroke patients for EVT. ANN NEUROL 2022;92:364-378.

Imaging versus Intervention in Managing Small Unruptured Intracranial Aneurysms: A Cost-Effectiveness Analysis

OBJECTIVE

Current guidelines recommend active surveillance with serial magnetic resonance angiography (MRA) for management of small, asymptomatic unruptured anterior circulation aneurysms (UIAs). We sought to determine the cost-effectiveness of active surveillance compared to immediate surgery.

METHODS

We developed a Markov cost-effectiveness model simulating patients with small (<7 mm) UIAs managed by active surveillance via MRA, immediate surgery, or watchful waiting. Inputs for the model were abstracted from the literature and used to construct a comprehensive model following persons from diagnosis to death. Outcomes were quality-adjusted life-years (QALYs), lifetime medical costs (2015 USD), and incremental cost-effectiveness ratios (ICERs). Cost-effectiveness, deterministic, and probabilistic sensitivity analyses were performed.

RESULTS

Immediate surgical treatment was the most cost-effective management strategy for small UIAs with ICER of USD 45,772 relative to active surveillance. Sensitivity analysis demonstrated immediate surgery was the preferred strategy, if rupture rate was >0.1%/year and if the diagnosis age was <70 years, while active surveillance was preferred if surgical complication risk was >11%. Probabilistic sensitivity analysis demonstrated that at a willingness-to-pay of USD 100,000/QALY, immediate surgical treatment was the most cost-effective strategy in 64% of iterations.

CONCLUSION

Immediate surgical treatment is a cost-effective strategy for initial management of small UIAs in patients <70 years of age. While more costly than MRA, surgical treatment increased QALY. The cost-effectiveness of immediate surgery is highly sensitive to diagnosis age, rupture rate, and surgical complication risk. Though there are a wide range of rupture rates and complications associated with treatment, this analysis supports the treatment of small, unruptured anterior circulation intracranial aneurysms in patients <70 years of age.

Role of platelets in the pathogenesis of delayed injury after subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) patients develop delayed cerebral ischemia and delayed deficits (DCI) within 2 weeks of aneurysm rupture at a rate of approximately 30%. DCI is a major contributor to morbidity and mortality after SAH. The cause of DCI is multi-factorial with contributions from microthrombi, blood vessel constriction, inflammation, and cortical spreading depolarizations. Platelets play central roles in hemostasis, inflammation, and vascular function. Within this review, we examine the potential roles of platelets in microthrombi formation, large artery vasospasm, microvessel constriction, inflammation, and cortical spreading depolarization. Evidence from experimental and clinical studies is provided to support the role(s) of platelets in each pathophysiology which contributes to DCI. The review concludes with a suggestion for future therapeutic targets to prevent DCI after aSAH.

Failed endovascular therapy for acute internal carotid artery occlusion from pituitary apoplexy: illustrative case

BACKGROUND

Large pituitary adenomas can rarely cause compression of the cavernous internal carotid artery (ICA) due to chronic tumor compression or invasion. Here, the authors present a case of pituitary apoplexy causing acute bilateral ICA occlusion with resultant stroke. Our middle-aged patient presented with sudden vision loss and experienced rapid deterioration requiring intubation. Computed tomography (CT) angiography revealed a large pituitary mass causing severe stenosis of the bilateral ICAs. CT perfusion revealed a significant perfusion delay in the anterior circulation. The patient was taken for cerebral angiography, and balloon angioplasty was attempted with no improvement in arterial flow. Resection of the tumor was then performed, with successful restoration of blood flow. Despite restoration of luminal patency, the patient experienced bilateral ICA infarcts.

OBSERVATIONS

Pituitary apoplexy can present as an acute stroke due to flow-limiting carotid compression. Balloon angioplasty is ineffective for the treatment of this type of compression. Surgical removal of the tumor restores the flow and luminal caliber of the ICA.

LESSONS

Pituitary apoplexy can be a rare presentation of acute stroke and should be managed with immediate surgical decompression rather than attempted angioplasty in order to restore blood flow and prevent the development of cerebral ischemia.

α7-Acetylcholine Receptor Signaling Reduces Neuroinflammation After Subarachnoid Hemorrhage in Mice

Aneurysmal subarachnoid hemorrhage (aSAH) causes a robust inflammatory response which leads worse brain injury and poor outcomes. We investigated if stimulation of nicotinic acetylcholine α7 receptors (α7-AChR) (receptors shown to have anti-inflammatory effects) would reduce inflammation and improve outcomes. To investigate the level of peripheral inflammation after aSAH, inflammatory markers were measured in plasma samples collected in a cohort of aSAH patients. To study the effect of α7-AChR stimulation, SAH was induced in adult mice which were then treated with a α7-AChR agonist, galantamine, or vehicle. A battery of motor and cognitive tests were performed 24 h after subarachnoid hemorrhage. Mice were euthanized and tissue collected for analysis of markers of inflammation or activation of α7-AChR-mediated transduction cascades. A separate cohort of mice was allowed to survive for 28 days to assess long-term neurological deficits and histological outcome. Microglia cell culture subjected to hemoglobin toxicity was used to assess the effects of α7-AChR agonism. Analysis of eighty-two patient plasma samples confirmed enhanced systemic inflammation after aSAH. α7-AChR agonism reduced neuroinflammation at 24 h after SAH in male and female mice, which was associated with improved outcomes. This coincided with JAK2/STAT3 and IRAK-M activity modulations and a robust improvement in neurological/cognitive status that was effectively reversed by interfering with various components of these signaling pathways. Pharmacologic inhibition partially reversed the α7-AChR agonist's benefits, supporting α7-AChR as a target of the agonist's therapeutic effect. The cell culture experiment showed that α7-AChR agonism is directly beneficial to microglia. Our results demonstrate that activation of α7-AChR represents an attractive target for treatment of SAH. Our findings suggest that α7-AChR agonists, and specifically galantamine, might provide therapeutic benefit to aSAH patients.

Epigenetics in blood-brain barrier disruption

The vessels of the central nervous system (CNS) have unique barrier properties. The endothelial cells (ECs) which comprise the CNS vessels contribute to the barrier via strong tight junctions, specific transporters, and limited endocytosis which combine to protect the brain from toxins and maintains brain homeostasis. Blood-brain barrier (BBB) leakage is a serious secondary injury in various CNS disorders like stroke, brain tumors, and neurodegenerative disorders. Currently, there are no drugs or therapeutics available to treat specifically BBB damage after a brain injury. Growing knowledge in the field of epigenetics can enhance the understanding of gene level of the BBB and has great potential for the development of novel therapeutic strategies or targets to repair a disrupted BBB. In this brief review, we summarize the epigenetic mechanisms or regulators that have a protective or disruptive role for components of BBB, along with the promising approaches to regain the integrity of BBB.

Haptoglobin Genotype Affects Inflammation after Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Haptoglobin (Hp) binds to and facilitates clearance of heme. Compared with HP 1-1 and 1-2 genotypes, HP 2-2 has a weaker binding affinity and has been linked with increased inflammation and vasospasm after aneurysmal subarachnoid hemorrhage (SAH).

OBJECTIVE

This study aims to assess levels of inflammatory cytokines in the context of different HP genotypes.

METHODS

Patients were enrolled among those presenting with spontaneous aneurysmal SAH. Blood was drawn at four time points; <24 hours (T1), 24-48 hours (T2), 3-5 days (T3), and 6-8 days (T4). Blood was analyzed for levels of 41 cytokines at each time point, as well as for HP genotypes. These data were analyzed using mixed-effect models to assess the association between HP genotypes and cytokine levels. The modified Rankin Scale (mRS) score was obtained at discharge, 3 months, and 6 months.

RESULTS

Fifty-seven patients were enrolled. Compared with HP 1-1 and 1-2, subjects encoding HP 2-2 had elevated levels of the following cytokines at all time points: FLT3L, IFNγ, IL-17A, TGFα, and VEGF-A. Elevations were also seen at some time points for IL-8, CSF2, FGF2, IL-7, IL-12p70, and TNFα. This study was not powered to detect differences in the functional outcome; however, there were no significant differences in dichotomized mRS scores between patients with HP 1-1/1-2 or HP 2-2.

CONCLUSION

Our findings indicate that HP 2-2 genotype leads to increased proinflammatory cytokine levels compared with HP 1-1/1-2 genotypes. These data may provide guidance for further studies seeking to identify testable markers for functional prognosis or targets for treatment.

Risk of intracranial hemorrhage associated with pregnancy in women with cerebral arteriovenous malformations

BACKGROUND

Prior studies on rupture risk of brain arteriovenous malformations (AVMs) in women undergoing pregnancy and delivery have reported conflicting findings, but also have not accounted for AVM morphology and heterogeneity. Here, we assess the association between pregnancy and the risk of intracranial hemorrhage (ICH) in women with AVMs using a cohort-crossover design in which each woman serves as her own control.

METHODS

Women who underwent pregnancy and delivery were identified using DRG codes from the Healthcare Cost and Utilization Project State Inpatient Databases for California (2005-2011), Florida (2005-2014), and New York (2005-2014). The presence of AVM and ICH was determined using ICD 9 codes. Pregnancy was defined as the 40 weeks prior to delivery, and postpartum as 12 weeks after. We defined a non-exposure control period as a 52-week period prior to pregnancy. The relative risks of ICH during pregnancy were compared against the non-exposure period using conditional Poisson regression.

RESULTS

Among 4 022 811 women identified with an eligible delivery hospitalization (median age, 28 years; 7.3% with gestational diabetes; 4.5% with preeclampsia/eclampsia), 568 (0.014%) had an AVM. The rates of ICH during pregnancy and puerperium were 6355.4 (95% CI 4279.4 to 8431.5) and 14.4 (95% CI 13.3 to 15.6) per 100 000 person-years for women with and without AVM, respectively. In cohort-crossover analysis, in women with AVMs the risk of ICH increased 3.27-fold (RR, 95% CI 1.67 to 6.43) during pregnancy and puerperium compared with a non-pregnant period.

CONCLUSIONS

Among women with AVM, pregnancy and puerperium were associated with a greater than 3-fold risk of ICH.

Sniffin' Sticks to Measure Olfactory Function and Recovery Following Bilateral Superior Turbinate Resection as Part of Endoscopic Transsphenoidal Approach

BACKGROUND

Extended endoscopic transsphenoidal (EET) approaches can include complete resection of both superior turbinate (ST) for wider exposure. Moreover, ST resection has been associated with postoperative olfactory impairment.

OBJECTIVE

We sought to determine the impact of bilateral ST resection on olfaction during a transsphenoidal approach.

METHOD

A prospective observational study was conducted on 29 patients undergoing endoscopic skull base surgery sparing the olfactory tracts at a tertiary academic center. Olfactory function was measured with Sniffin' Sticks at the preoperative visit, 2-weeks and 6 to 8 weeks postoperatively. All components: odor threshold (OT), odor discrimination (OD), odor identification (OI) and composite scores (TDI = OT+OD+OI) were evaluated.

RESULT

Study was completed in 15 patients with 14 excluded due to a variety of reasons. At 2 weeks, a significant decrease was noted in composite scores (32.3 ± 5.4 vs. 23.8 ± 5.8, P < .05) and OT (7.7 vs. 3.2, P < .05). There was a significant increase in olfactory scores between post-op weeks 2 and 6 to 8 weeks in TDI (23.8 vs. 31.4, P < .05) as well as in OT (3.2 vs. 7.6, P < .05), OD (9.4 vs. 11.1, P < .05), and OI (11.1 vs. 12.7, P < .05). No significant difference was found between TDI (32.3 ± 5.4 vs. 31.4 ± 5.1), OT (7.7 vs. 7.6), OD (11.4 vs. 11.1) and OI (13.2 vs. 12.7) from preoperative and 6-8 weeks postoperative visits.

CONCLUSION

Patients undergoing bilateral ST resection during EET procedures experience transient hyposmia postoperatively. However, the olfactory function normalizes to preoperative levels at 6 to 8 weeks. The resection of the bilateral superior turbinate does not appear to decrease olfactory function.

Full Remission of Long-Term Premenstrual Dysphoric Disorder-Like Symptoms Following Resection of a Pituitary Adenoma: Case Report

Patient: Female, 44-year-old

Final Diagnosis: Pituitary adenoma

Symptoms: Depression and anxiety

Medication:—

Clinical Procedure: —

Specialty: Neurosurgery • Psychiatry

Neurobehavioral Deficits After Subarachnoid Hemorrhage in Mice: Sensitivity Analysis and Development of a New Composite Score

Background

Because of the failure of numerous clinical trials, various recommendations have been made to improve the usefulness of preclinical studies. Specifically, the STAIR (Stroke Therapy Academic Industry Roundtable) recommendations highlighted functional outcome as a critical measure. Recent reviews of experimental subarachnoid hemorrhage (SAH) studies have brought to light the numerous neurobehavioral scoring systems that are used in preclinical SAH studies. To gain insight into the utility of these scoring systems, as well as to identify a scoring system that best captures the deficits caused by SAH in mice, we designed the current study.

Methods and Results

Adult male C57BL/6J mice were used. One cohort of mice was randomly allocated to either sham or SAH and had functional testing performed on days 1 to 3 post‐SAH using the modified Bederson Score, Katz Score, Garcia Neuroscore, and Parra Neuroscore, as well as 21 individual subtests. A new composite neuroscore was developed using the 8 most diagnostically accurate subtests. To validate the use of the developed composite neuroscore, another cohort of mice was randomly assigned to either the sham or SAH group and neurobehavior was evaluated on days 1 to 3, 5, and 7 after injury. Receiver operating characteristic curves were used to analyze the diagnostic accuracy of each scoring system, as well as the subtests. Of the 4 published scoring systems, the Parra Neuroscore was diagnostically accurate for SAH injury in mice versus the modified Bederson and Katz Scores, but not the Garcia Neuroscore. However, the newly developed composite neuroscore was found to be statistically more diagnostically accurate than even the Parra Neuroscore.

Conclusions

The findings of this study promote use of the newly developed composite neuroscore for experimental SAH studies in mice.

Microthrombi Correlates With Infarction and Delayed Neurological Deficits After Subarachnoid Hemorrhage in Mice

BACKGROUND AND PURPOSE

Delayed neurological deficits are a devastating consequence of subarachnoid hemorrhage (SAH), which affects about 30% of surviving patients. Although a very serious concern, delayed deficits are understudied in experimental SAH models; it is not known whether rodents recapitulate the delayed clinical decline seen in SAH patients. We hypothesized that mice with SAH develop delayed functional deficits and that microthrombi and infarction correlate with delayed decline.

METHODS

Adult C57BL/6J mice of both sexes were subjected to endovascular perforation to induce SAH. Mice were allowed to survive for up to 1 week post-ictus and behavioral performance was assessed daily. Postmortem microthrombi, large artery diameters (to assess vasospasm), and infarct volume were measured. These measures were analyzed for differences between SAH mice that developed delayed deficits and SAH mice that did not get delayed deficits. Correlation analyses were performed to identify which measures correlated with delayed neurological deficits, sex, and infarction.

RESULTS

Twenty-three percent of males and 47% of females developed delayed deficits 3 to 6 days post-SAH. Female mice subjected to SAH had a significantly higher incidence of delayed deficits than male mice with SAH. Mice that developed delayed deficits had significantly more microthrombi and larger infarct volumes than SAH mice that did not get delayed deficits. Microthrombi positively correlated with infarct volume, and both microthrombi and infarction correlated with delayed functional deficits. Vasospasm did not correlate with either infarction delayed functional deficits.

CONCLUSIONS

We discovered that delayed functional deficits occur in mice following SAH. Sex differences were seen in the prevalence of delayed deficits. The mechanism by which microthrombi cause delayed deficits may be via formation of infarcts.

Abstract WP308: Role of Microthrombi and Vasospasm in the Development of Delayed Neurological Deficits After Subarachnoid Hemorrhage in Mice

Rationale: Microthrombosis has been suggested as a major factor contributing to delayed neurological deterioration in patients after subarachnoid hemorrhage (SAH). However, experimental studies on the role of microthrombi in delayed deficits after SAH has not been investigated. Our hypothesis is that, following SAH, mice which develop delayed neurological deficits have a greater number of microthrombi than mice which do not develop delayed neurological deficits.

Methods: SAH was induced in adult male and female C57BL/6 mice via endovascular perforation. Mice were randomly assigned into sham (n=6/sex) or SAH groups (n=22-24/sex). Neurobehavior was performed on days 1-3, 5, and 7 post-SAH using a composite neuroscore. Animals were sacrificed on the day of delayed deficits or 7 days post-SAH. Microthrombi count and vessel diameters (for vasospasm) were measured using H&E stained brain slices. All outcomes were performed and all data were analyzed by a blinded investigator.

Results: Seventeen percent (4/24) of male mice and thirty-six percent (8/22) of female mice developed delayed deficits on days 3-5 post-SAH (Figures 1A and 1B). Those mice which developed delayed deficits had significantly more microthrombi in their brains than mice which did not develop delayed deficits; vasospasm did not correlate with delayed deficits. Additionally, female SAH mice develop delayed deficits at a higher frequency than males (Figure 1C).

Conclusions: This work shows for the first time delayed deficits in a SAH mouse model. Further, microthrombi correlated with delayed deficits, whereas no correlation was between delayed deficits and vasospasm. The data within this study suggests that preventing microthrombi may improve functional recovery and reduce the risk of delayed deficits.

Inflammation in delayed ischemia and functional outcomes after subarachnoid hemorrhage

BACKGROUND

Inflammatory mechanism has been implicated in delayed cerebral ischemia (DCI) and poor functional outcomes after subarachnoid hemorrhage (SAH). Identification of cytokine patterns associated with inflammation in acute SAH will provide insights into underlying biological processes of DCI and poor outcomes that may be amenable to interventions.

METHODS

Serum samples were collected from a prospective cohort of 60 patients with acute non-traumatic SAH at four time periods (< 24 h, 24-48 h, 3-5 days, and 6-8 days after SAH) and concentration levels of 41 cytokines were measured by multiplex immunoassay. Logistic regression analysis was used to identify cytokines associated with DCI and poor functional outcomes. Correlation networks were constructed to identify cytokine clusters.

RESULTS

Of the 60 patients enrolled in the study, 14 (23.3%) developed DCI and 16 (26.7%) had poor functional outcomes at 3 months. DCI was associated with increased levels of PDGF-ABBB and CCL5 and decreased levels of IP-10 and MIP-1α. Poor functional outcome was associated with increased levels of IL-6 and MCP-1α. Network analysis identified distinct cytokine clusters associated with DCI and functional outcomes.

CONCLUSIONS

Serum cytokine patterns in early SAH are associated with poor functional outcomes and DCI. The significant cytokines primarily modulate the inflammatory response. This supports earlier SAH studies linking inflammation and poor outcomes. In particular, this study identifies novel cytokine patterns over time that may indicate impending DCI.

Prospective Trial of Cerebrospinal Fluid Filtration After Aneurysmal Subarachnoid Hemorrhage via Lumbar Catheter (PILLAR)

Background and Purpose- The PILLAR (Extracorporeal Filtration of Subarachnoid Hemorrhage via Spinal Catheter) study is a first-in-human trial of cerebrospinal fluid (CSF) filtration in aneurysmal subarachnoid hemorrhage. The study evaluates the safety and feasibility of a novel filtration system to rapidly remove blood and blood breakdown products from CSF after securement of a ruptured aneurysm. Methods- Patients with aneurysmal subarachnoid hemorrhage had a dual-lumen lumbar, intrathecal catheter placed after aneurysm securement and received up to 24 hours of CSF filtration (neurapheresis therapy). The catheter aspirated blood-contaminated CSF from the lumbar cistern and returned filtered CSF to the thoracic subarachnoid space. Neuro checks were performed q2 hours, and CSF samples were collected for cell counts, total protein, and gram stain. Computed tomography scans were acquired at baseline and post-filtration. Clinical follow-up occurred at 2 weeks and 30 days. Results- Thirteen patients had a catheter placed (mean time 24:13 hours after ictus). The system processed 632.0 mL (180.6-1447.6 mL) CSF in 15:07 hours (5:32-24:00 hours) of filtration. The mean initial CSF red blood cell count, 2.78×10⁵ cells/µL, reduced to 1.17×10⁵ cells/µL after filtration (52.9% reduction), and total protein reduced 71%. Independent analysis of baseline and postfiltration computed tomographies found notable cisternal blood decrease, with 46.5% mean Hijdra Score reduction. Three mild, anticipated adverse events were reported. Conclusions- The initial safety and feasibility of Neurapheresis therapy in aneurysmal subarachnoid hemorrhage demonstrated the potential to safely filter CSF and remove blood and blood byproducts. Future studies are warranted. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT0287263.

Haptoglobin genotype and aneurysmal subarachnoid hemorrhage: Individual patient data analysis

OBJECTIVE

To perform an individual patient-level data (IPLD) analysis and to determine the relationship between haptoglobin (HP) genotype and outcomes after aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

The primary outcome was favorable outcome on the modified Rankin Scale or Glasgow Outcome Scale up to 12 months after ictus. The secondary outcomes were occurrence of delayed ischemic neurologic deficit, radiologic infarction, angiographic vasospasm, and transcranial Doppler evidence of vasospasm. World Federation of Neurological Surgeons (WFNS) scale, Fisher grade, age, and aneurysmal treatment modality were covariates for both primary and secondary outcomes. As preplanned, a 2-stage IPLD analysis was conducted, followed by these sensitivity analyses: (1) unadjusted; (2) exclusion of unpublished studies; (3) all permutations of HP genotypes; (4) sliding dichotomy; (5) ordinal regression; (6) 1-stage analysis; (7) exclusion of studies not in Hardy-Weinberg equilibrium (HWE); (8) inclusion of studies without the essential covariates; (9) inclusion of additional covariates; and (10) including only covariates significant in univariate analysis.

RESULTS

Eleven studies (5 published, 6 unpublished) totaling 939 patients were included. Overall, the study population was in HWE. Follow-up times were 1, 3, and 6 months for 355, 516, and 438 patients. HP genotype was not associated with any primary or secondary outcome. No trends were observed. When taken through the same analysis, higher age and WFNS scale were associated with an unfavorable outcome as expected.

CONCLUSION

This comprehensive IPLD analysis, carefully controlling for covariates, refutes previous studies showing that HP1-1 associates with better outcome after aSAH.

Abstract TP328: Platelet Hyperactivity Leads to Increased Microthrombi After Subarachnoid Hemorrhage in Mice

Rationale: Microthrombosis has been suggested as a major factor contributing to delayed neurological deterioration in patients after subarachnoid hemorrhage (SAH). Autopsy studies in humans show microthrombi throughout the brain in SAH patients. However, experimental studies on the role of platelets in microthrombosis after SAH have not investigated. Our hypothesis is that hyper active platelets will increase the microthrombi count, causing more deficits, and that preventing platelet activation will attenuate microthrombi following SAH in mice, improving outcome.

Methods: SAH was induced in 4 month old male wild-type and LIGHT-/- mice via endovascular perforation. LIGHT-/- mice have hyperactive platelets. Mice were randomly assigned into (n=8/group/strain): Sham, SAH + saline, and SAH + tirofiban (GP IIb/IIIa antagonist, 0.25 mg/kg, IV). Neurobehavior was performed on days 1-3, 5, and 7 post-SAH using a composite neuroscore. One cohort of animals was sacrificed 2 days post-SAH, and the other at 7 days post-SAH. Microthrombi count was performed using serial sections of brains stained for fibrinogen, blood vessels (DiI), and platelets. Neurobehavioral testing performed and all data was analyzed by a blinded investigator.

Results: Mice subjected to SAH have significantly more microthrombi and performed significantly worse in neurobehavior tests compared to Sham animals on days 2 and 7. Wild-type mice receiving tirofiban have fewer microthrombi and improved behavior. Platelet hyperactive (LIGHT-/-) mice are expected to have greater microthrombi count and preventing platelet aggregation is expected to reduce microthrombi count.

Conclusions: The expected conclusions are that preventing platelet aggregation after SAH attenuates the formation of microthrombi, thereby reducing functional deficits. This work is expected to highlight platelets as a therapeutic target for preventing delayed neurological deterioration in SAH patients.

Novel Dual Lumen Catheter and Filtration Device for Removal of Subarachnoid hemorrhage: First Case Report

BACKGROUND AND IMPORTANCE

The amount of subarachnoid blood and the presence of toxic blood breakdown products in the cerebrospinal fluid (CSF) have long been associated with poor outcomes in aneurysmal subarachnoid hemorrhage. The Neurapheresis™ system (Minnetronix Inc, St. Paul, Minnesota) has been developed to filter CSF and remove blood products, and is being investigated for safety and feasibility in the ExtracorPoreal FILtration of subarachnoid hemorrhage via SpinaL CAtheteR (PILLAR) study. We report the first case using this novel device.

CLINICAL PRESENTATION

A 65-yr-old female presented with a ruptured left posterior communicating artery aneurysm. Following placement of a ventriculostomy and coil embolization of her aneurysm, the patient underwent placement of a lumbar dual lumen catheter for CSF filtration as part of the PILLAR study. In this case, a total of 9 h of filtration during 31 h of catheter indwelling resulted in 309.47 mL of processed CSF without complication. Computed tomography images demonstrated an interval reduction of subarachnoid hemorrhage immediately after filtration. The patient was discharged home on postbleed day 11 and at 30 d showed good recovery.

CONCLUSION

Safety of the Neurapheresis procedure was confirmed in this first case, and we will continue to evaluate safety of the Neurapheresis system through the PILLAR trial.

Unique Contribution of Haptoglobin and Haptoglobin Genotype in Aneurysmal Subarachnoid Hemorrhage

Survivors of cerebral aneurysm rupture are at risk for significant morbidity and neurological deficits. Much of this is related to the effects of blood in the subarachnoid space which induces an inflammatory cascade with numerous downstream consequences. Recent clinical trials have not been able to reduce the toxic effects of free hemoglobin or improve clinical outcome. One reason for this may be the inability to identify patients at high risk for neurologic decline. Recently, haptoglobin genotype has been identified as a pertinent factor in diabetes, sickle cell, and cardiovascular disease, with the Hp 2-2 genotype contributing to increased complications. Haptoglobin is a protein synthesized by the liver that binds free hemoglobin following red blood cell lysis, and in doing so, prevents hemoglobin induced toxicity and facilitates clearance. Clinical studies in patients with subarachnoid hemorrhage indicate that Hp 2-2 patients may be a high-risk group for hemorrhage related complications and poor outcome. We review the relevance of haptoglobin in subarachnoid hemorrhage and discuss the effects of genotype and expression levels on the known mechanisms of early brain injury (EBI) and cerebral ischemia after aneurysm rupture. A better understanding of haptoglobin and its role in preventing hemoglobin related toxicity should lead to novel therapeutic avenues.

The Role of Thromboinflammation in Delayed Cerebral Ischemia after Subarachnoid Hemorrhage

Delayed cerebral ischemia (DCI) is a major determinant of patient outcome following aneurysmal subarachnoid hemorrhage. Although the exact mechanisms leading to DCI are not fully known, inflammation, cerebral vasospasm, and microthrombi may all function together to mediate the onset of DCI. Indeed, inflammation is tightly linked with activation of coagulation and microthrombi formation. Thromboinflammation is the intersection at which inflammation and thrombosis regulate one another in a feedforward manner, potentiating the formation of thrombi and pro-inflammatory signaling. In this review, we will explore the role(s) of inflammation and microthrombi in subarachnoid hemorrhage (SAH) pathophysiology and DCI, and discuss the potential of targeting thromboinflammation to prevent DCI after SAH.

Abstract WP82: Transcranial Doppler Detection of Microembolic Signals During the Advancement and Deployment of Pipeline Embolization Devices in Unruptured Intracranial Aneurysm Repair

Introduction: Pipeline embolization devices (PED) have become an essential tool in the endovascular treatment of complex intracranial aneurysms. A high-density stent like device, the PED functions to redirect blood flow and facilitate the growth and remodeling of the artery. Postoperative ischemic stroke proves to be the most common neurological complication associated with treatment, ranging from about 3-6% with most occurring within 30 days. Transcranial Doppler (TCD) monitoring has been used in the past to evaluate similar procedures by measuring the occurrence of microembolic signals (MES). Due to the delivery and manipulation of the PED and its thrombotic nature, microembolic events have been postulated to form during device placement and contribute to thromboembolism. Our initial study is the first to detect and measure MES during a PED procedure.

Methods: Patients undergoing endovascular PED treatment were simultaneously monitored with TCD. MES were detected, separated from artifacts, and counted for each step.

Results: Embolic signals were detected in all patients and were highest during deployment. With 3 PED deployments in the paraophthalmic ICA of 2 patients, the mean MES during PED deployment was 515 +/- 46. Average emboli per second during deployment was 1.62 +/- 0.59 verses 0.30 +/- 0.12 emboli per second observed prior to microcatheter insertion and manipulation.

Conclusion: A very high incidence of MES was observed during the procedure and PED deployment. The little success thus far in elucidating a possible mechanism to account for PED’s associated complications warrants more investigation. Determining the occurrence of MES might reveal insight into the relative safety of each step and on the formation of distal thromboembolisms.

Health disparities and stroke: the influence of insurance status on the prevalence of patient safety indicators and hospital-acquired conditions

OBJECT

The Agency for Healthcare Research and Quality patient safety indicators (PSIs) and the Centers for Medicare and Medicaid Services hospital-acquired conditions (HACs) are publicly reported quality metrics linked directly to reimbursement. The occurrence of PSIs and HACs is associated with increased mortality and hospital costs after stroke. The relationship between insurance status and PSI and HAC rates in hospitalized patients treated for acute ischemic stroke was determined using the Nationwide Inpatient Sample (NIS) database.

METHODS

The NIS was queried for all hospitalizations involving acute ischemic stroke between 2002 and 2011. The rate of each PSI and HAC was determined by searching the hospital records for ICD-9 codes. The SAS statistical software package was used to calculate rates and perform multivariable analyses to determine the effects of patient variables on the probability of developing each indicator.

RESULTS

The NIS query revealed 1,507,336 separate patient admissions that had information on both primary payer and hospital teaching status. There were 227,676 PSIs (15.1% of admissions) and 42,841 HACs reported (2.8%). Patient safety indicators occurred more frequently in Medicaid/self-pay/no-charge patients (19.1%) and Medicare patients (15.0%) than in those with private insurance (13.6%; p < 0.0001). In a multivariable analysis, Medicaid, self-pay, or nocharge patients had significantly longer hospital stays, higher mortality, and worse outcomes than those with private insurance (p < 0.0001).

CONCLUSIONS

Insurance status is an independent predictor of patient safety events after stroke. Private insurance is associated with lower mortality, shorter lengths of stay, and improved clinical outcomes.

Clinical Implications of Bilirubin-Associated Neuroprotection and Neurotoxicity

Bilirubin is a primary product of heme catabolism and exhibits both neuroprotective and neurotoxic effects. When present at physiologic concentrations, bilirubin is a potent antioxidant and serves to protect brain tissue from oxidative stress insults. The use of the anesthetic propofol attenuates ischemic injury in rats by exploiting these neuroprotective properties. At pathologic levels, bilirubin has been implicated as a neurotoxic agent, demonstrating the ability to aggregate and adhere to cellular membranes, thereby disrupting normal cellular function. Bilirubin-associated toxicities are amplified by administering drugs such as anesthetics that compete with bilirubin for albumin binding sites, resulting in increased plasma bilirubin concentrations. As such, it is crucial that bilirubin is considered in the critical care management of patients with hemorrhagic stroke, cerebral ischemic damage, and critically ill newborns.

Pipeline embolization device and subsequent vessel sacrifice for treatment of a bleeding carotid pseudoaneurysm at the skull base: a case report

An attempt at parent vessel reconstruction with Pipeline embolization devices to treat a mycotic pseudoaneurysm of the internal carotid artery at the skull base is presented. A 50-year-old woman with malignant otitis externa and bilateral temporal bone osteomyelitis presented with brisk bleeding from her left ear. She had bony dehiscence of the left carotid canal at CT and extravasation from a pseudoaneurysm of the carotid petrous segment at angiography. Carotid tortuosity proximally precluded placing a covered stent. After the lesion stopped bleeding spontaneously and given the presence of bilateral osteomyelitis putting the contralateral carotid at risk, the decision was made to attempt preservation of the parent vessel with flow diversion. However, bleeding recurred after 12 days, necessitating carotid sacrifice. This first reported experience in treating a carotid pseudoaneurysm at the skull base with the Pipeline device shows that transient cessation of bleeding is insufficient for flow diversion to be effective.

Impact of lateral mass anatomic variation on ideal polyaxial screw head mobility: technical considerations

OBJECTIVE

To assess optimal angulation characteristics of lateral mass screws for subaxial (C3 to C6) fixation of the cervical spine in the neutral position.

BACKGROUND

In the typical Magerl or Anderson placement technique, the screw trajectory is ideally parallel to the facet joint. For the rod and screw to align properly, the screw head must rotate enough to become perpendicular to the rod. If the optimal angle for the screw head is limited by the screw design, abnormal torsional forces will be generated at the rod/screw interface inducing kyphosis. In this paper, we examined the spinal anatomy in patients with normal CTs to determine the necessary range of motion between tulip head and screw to prevent forced persuasion and abnormal cervical spine alignment.

METHODS

We examined subaxial radiographs of 292 vertebrae from C3 to C6 in 73 normal subjects. Computed tomography (CT) scans of the cervical spine with multiplanar reconstructions were evaluated in the axial and sagittal planes. A planned screw entry angle of 30° based upon the midpoint of the lateral mass was used in the axial plane, and parallel to the facet joint in the sagittal plane. The screw head angle (SHA) was then calculated from this 3D measured angle.

RESULTS

The measured SHA ranged from 27 to 60°. The average SHA was 43.8°. The average SHA was not significantly different between the levels measured with consistent range and standard deviation. Seventy-six percent (223/292) of levels measured required a SHA >40°, and 12% (36/292) required a SHA >50°.

CONCLUSION

The authors recommend using cervical instrumentation systems that allow for at least 55° of freedom of the polyaxial head to prevent abnormal segmental forces. In systems with lesser angulation, technique modifications must be applied to prevent translational forces.

Pial arteriovenous fistula resulting from ventriculostomy

OBJECTIVE

Ventriculostomy complications are well documented in the literature. We report the first known example of an arteriovenous fistula created during passage of a ventriculostomy catheter for the treatment of hydrocephalus.

METHODS

A 47-year-old female patient initially presented with a subarachnoid hemorrhage and an anterior communicating artery aneurysm. The patient underwent coil embolization followed by a ventriculostomy catheter for hydrocephalus. After recovery, a follow-up angiogram demonstrated a new arteriovenous fistula at the site of the ventriculostomy. A craniotomy was performed at the site of the ventriculostomy burr-hole site. Indocyanine green videoangiography confirmed the site of the fistula.

RESULTS

The fistulous point was coagulated and divided and confirmed with both indocyanine green videoangiography and intraoperative diagnostic angiography. The patient recovered without deficit.

CONCLUSION

This is the first reported case of a pial arteriovenous fistula from a ventriculostomy catheter. The formation of a fistula can occur from trauma to cortical arteries and veins at the pial entry site. Although rare, vascular injury and subsequent fistula formation may form in patients in whom catheter tract hemorrhages occur after catheter placement.