Continuous Intrathecal Medication Delivery With the IRRA flow Catheter: Pearls and Early Experience

BACKGROUND AND OBJECTIVES

Intrathecal (IT) medications are routinely introduced through catheterization of the intraventricular space or subarachnoid space. There has been sporadic use of IT medications delivered directly to the ventricle either by intermittent injection through an external ventricular drain (EVD) or by an Ommaya reservoir with a ventricular catheter. IT medication delivery through EVD has many drawbacks, including the necessary opening of a sterile system, delivery of medication in a bolus form, and requirements to clamp the EVD after medication delivery. Despite these setbacks, IT medications delivered through EVD have been used across a wide range of applications, including antibiotic delivery treatment of vasospasm with nicardipine and delivery of tissue plasminogen activator.

METHODS

We used a newly developed active fluid exchange device to treat various severe conditions involved in the cerebral ventricles. Here, we present our treatment protocols and advice on the techniques related to successful active fluid exchange therapy.

RESULTS

Seventy patients have been treated with our system with various conditions, including subarachnoid hemorrhage, intraventricular hemorrhage, ventriculitis, and cerebral abscess. Total complication rate was 14% with only 1 catheter occlusion and low rates of hemorrhage, infection, and spinal fluid leak.

CONCLUSION

Current continuous IT medication dosages and protocols are based on reports and consensus statements evaluating intermittent instillation of medication boluses. The pharmacokinetics of continuous dosing and the therapeutic and safety profiles of the medications need to be studied in a prospective manner to evaluate the true optimal dosing standards. Furthermore, the ability to deliver continuous, sterile medications directly through an IT route will open new avenues of pharmacotherapy that were previously closed. This report serves as a basic guide for the safe and effective use of the IRRA flow active fluid exchange catheter to deliver IT medications.

Characterization of length of stay after minimally invasive endoscopic intracerebral hemorrhage evacuation

BACKGROUND

Minimally invasive evacuation may help ameliorate outcomes after intracerebral hemorrhage (ICH). However, hospital length of stay (LOS) post-evacuation is often long and costly.

OBJECTIVE

To examine factors associated with LOS in a large cohort of patients who underwent minimally invasive endoscopic evacuation.

METHODS

Patients presenting to a large health system with spontaneous supratentorial ICH qualified for minimally invasive endoscopic evacuation if they met the following inclusion criteria: age ≥18, premorbid modified Rankin Scale (mRS) score ≤3, hematoma volume ≥15 mL, and presenting National Institutes of Health Stroke Scale (NIHSS) score ≥6. Demographic, clinical, radiographic, and operative characteristics were included in a multivariate logistic regression for hospital and ICU LOS dichotomized into short and prolonged stay at 14 and 7 days, respectively.

RESULTS

Among 226 patients who underwent minimally invasive endoscopic evacuation, the median intensive care unit and hospital LOS were 8 (4-15) days and 16 (9-27) days, respectively. A greater extent of functional impairment on presentation (OR per NIHSS point 1.10 (95% CI 1.04 to 1.17), P=0.007), concurrent intraventricular hemorrhage (OR=2.46 (1.25 to 4.86), P=0.02), and deep origin (OR=per point 2.42 (1.21 to 4.83), P=0.01) were associated with prolonged hospital LOS. A longer delay from ictus to evacuation (OR per hour 1.02 (1.01 to 1.04), P=0.007) and longer procedure time (OR per hour 1.91 (1.26 to 2.89), P=0.002) were associated with prolonged ICU LOS. Prolonged hospital and ICU LOS were in turn longitudinally associated with a lower rate of discharge to acute rehabilitation (40% vs 70%, P<0.0001) and worse 6-month mRS outcomes (5 (4-6) vs 3 (2-4), P<0.0001).

CONCLUSIONS

We present factors associated with prolonged LOS, which in turn was associated with poor long-term outcomes. Factors associated with LOS may help to inform patient and clinician expectations of recovery, guide protocols for clinical trials, and select suitable populations for minimally invasive endoscopic evacuation.

United States regulatory approval of medical devices used for endovascular neurosurgery: A two-decade review of FDA regulatory files

BACKGROUND

The evolution of neuroendovascular technologies has progressed substantially. Over the last two decades, the introduction of new endovascular devices has facilitated treatment for more patients, and as a result, the regulatory environment concerning neuroendovascular devices has evolved rapidly in response.

OBJECTIVE

To examine trends in the approval of neuroendovascular devices by the United States Food and Drug Administration (FDA) over the last 20 years.

METHODS

Open-access US FDA databases were queried between January 2000 and December 2022 for all devices approved by the Neurological Devices Advisory Committee. Neuroendovascular devices were manually classified and grouped by category. Device approval data, including approval times, approval pathway, and presence of predicate devices, were examined.

RESULTS

A total of 3186 neurological devices were approved via various US FDA pathways during the study period. 320 (10.0%) corresponded to neuroendovascular devices, of which 301 (94.1%) were approved via the 510(k) pathway. The percentage of 510(k) pathway neuroendovascular devices increased from 6.9% to 14.3% of all neuro devices before and after 2015, respectively. There was an increase in approval times for neuroendovascular devices cleared after 2015.

CONCLUSION

Over the last two decades, the neuroendovascular device armamentarium has rapidly expanded, especially after positive stroke trials in 2015. Regulatory approval times are significantly affected by device category, generation, company size, and company location, and a vast majority are approved by the 510(k) pathway. These results can guide further innovation in the endovascular device space and may act as a roadmap for future regulatory planning.

Transcranioplasty Ultrasonography Through a Sonolucent Prosthesis: A Review of Feasibility, Safety, and Benefits

Data on the effectiveness of transcranioplasty ultrasonography through sonolucent cranioplasty (SC) are new and heterogeneous. We performed the first systematic literature review on SC. Ovid Embase, Ovid Medline, and Web of Science Core Collection were systematically searched and published full text articles detailing new use of SC for the purpose of neuroimaging were critically appraised and extracted. Of 16 eligible studies, 6 reported preclinical research and 12 reported clinical experiences encompassing 189 total patients with SC. The cohort age ranged from teens to 80s and was 60% (113/189) female. Sonolucent materials in clinical use are clear PMMA (polymethylmethacrylate), opaque PMMA, polyetheretherketone, and polyolefin. Overall indications included hydrocephalus (20%, 37/189), tumor (15%, 29/189), posterior fossa decompression (14%, 26/189), traumatic brain injury (11%, 20/189), bypass (27%, 52/189), intracerebral hemorrhage (4%, 7/189), ischemic stroke (3%, 5/189), aneurysm and subarachnoid hemorrhage (3%, 5/189), subdural hematoma (2%, 4/189), and vasculitis and other bone revisions (2%, 4/189). Complications described in the entire cohort included revision or delayed scalp healing (3%, 6/189), wound infection (3%, 5/189), epidural hematoma (2%, 3/189), cerebrospinal fluid leaks (1%, 2/189), new seizure (1%, 2/189), and oncologic relapse with subsequent prosthesis removal (<1%, 1/189). Most studies utilized linear or phased array ultrasound transducers at 3-12 MHz. Sources of artifact on sonographic imaging included prosthesis curvature, pneumocephalus, plating system, and dural sealant. Reported findings were mainly qualitative. We, therefore, suggest that future studies should collect quantitative measurement data during transcranioplasty ultrasonography to validate imaging techniques.

Preoperative cerebral angiography nearly doubles the rate of diffusion-weighted imaging lesion detection following minimally invasive surgery for intracerebral hemorrhage

BACKGROUND

Diffusion-weighted imaging (DWI) lesions have been linked to poor outcomes after intracerebral hemorrhage (ICH). We aimed to assess the impact of cerebral digital subtraction angiography (DSA) on the presence of DWI lesions in patients who underwent minimally invasive surgery (MIS) for ICH.

METHODS

Retrospective chart review was performed on ICH patients treated with MIS in a single health system from 2015 to 2021. One hundred and seventy consecutive patients who underwent postoperative MRIs were reviewed. Univariate analyses were conducted to determine associations. Variables with p<0.05 were included in multivariate analyses.

RESULTS

DWI lesions were present in 88 (52%) patients who underwent MIS for ICH. Of the 83 patients who underwent preoperative DSA, 56 (67%) patients demonstrated DWI lesions. In this DSA cohort, older age, severe leukoaraiosis, larger preoperative hematoma volume, and increased presenting National Institutes of Health Stroke Score (NIHSS) were independently associated with DWI lesion identification (p<0.05). In contrast, of 87 patients who did not undergo DSA, 32 (37%) patients demonstrated DWI lesions on MRI. In the non-DSA cohort, presenting systolic blood pressure, intraventricular hemorrhage, and NIHSS were independently associated with DWI lesions (p<0.05). Higher DWI lesion burden was independently associated with poor modified Rankin Scale (mRS) at 6 months on a univariate (p=0.02) and multivariate level (p=0.02).

CONCLUSIONS

In this cohort of ICH patients who underwent minimally invasive evacuation, preprocedural angiography was associated with the presence of DWI lesions on post-ICH evacuation MRI. Furthermore, the burden of DWI lesions portends a worse prognosis after ICH.

Early and effective intracerebral hemorrhage evacuation is associated with a lower 1-year residual cavity volume and better functional outcomes

BACKGROUND

We explored the clinical significance of the residual hematoma cavity 1 year after minimally invasive intracerebral hemorrhage (ICH) evacuation.

METHODS

Patients presenting with spontaneous supratentorial ICH were evaluated for minimally invasive surgical evacuation. Inclusion criteria included age ≥18 years, preoperative hematoma volume (Hv) ≥15 mL, presenting National Institutes of Health Stroke Scale score ≥6, and premorbid modified Rankin Scale (mRS) score ≤3. Patients with longitudinal CT scans at least 3 months after evacuation were included in the study. Remnant cavity volumes (Cv) after evacuation were computed using semi-automatic volumetric segmentation software. Relative cavity volume (rCv) was defined as the ratio of the preoperative Hv to the remnant Cv.

RESULTS

108 patients with a total of 484 head CT scans were included in the study. The median postoperative Cv was 2.4 (IQR 0.0-11) mL, or just 6% (0-33%) of the preoperative Hv. The median residual Cv on the final head CT scan a median of 13 months (range 11-27 months) after surgery had increased to 9.4 (IQR 3.1-18) mL, or 25% (10-60%) of the preoperative Hv. rCv on the final head CT scan was negatively associated with measures of operative success including evacuation percentage, postoperative Hv ≤15 mL, and decreased time from ictus to evacuation. rCv on the final head CT scan was also associated with a worse 6-month functional outcome (β per mRS point 17.6%, P<0.0001; area under the receiver operating characteristic curve 0.91).

CONCLUSION

After minimally invasive ICH evacuation the hematoma lesion decompresses significantly, with a residual Cv just 6% of the original lesion, but then gradually increases in size over time. Early and high percentage ICH evacuation may reduce the remnant Cv over time which, in turn, is associated with improved functional outcomes.

External ventricular drain training in medical students improves procedural accuracy and attitudes towards virtual reality

OBJECTIVE

Neurosurgery residents face a learning curve at the beginning of residency. Virtual reality (VR) training may alleviate challenges through an accessible, reusable, anatomical model.

METHODS

Medical students performed external ventricular drain (EVD) placements in VR to characterize the learning curve from novice to proficient. Distance from catheter to Foramen of Monro and location with respect to ventricle were recorded. Changes in attitudes towards VR were assessed. Neurosurgery residents performed EVD placements to validate proficiency benchmarks. Resident and student impressions of the VR model were compared.

RESULTS

Twenty-one students with no neurosurgical experience and 8 neurosurgery residents participated. Student performance improved significantly from trial 1 to 3 (15 mm [12.1-20.70] vs 9.7 [5.8-15.3], p=.02). Student attitudes regarding VR utility improved significantly post-trial. The distance to Foramen of Monro was significantly shorter for residents than for students in trial 1 (9.05 [8.25-10.73] vs 15 [12.1-20.70], p=.007) and trial 2 (7.45 [6.43-8.3] vs 19.5 [10.9-27.6], p=.002). By trial 3 there was no significant difference (10.1 [8.63-10.95 vs 9.7 [5.8-15.3], p=.62). Residents and students provided similarly positive feedback for VR in resident curricula, patient consent, preoperative practice and planning. Residents provided more neutral-to-negative feedback regarding skill development, model fidelity, instrument movement, and haptic feedback.

CONCLUSIONS

Students showed significant improvement in procedural efficacy which may simulate resident experiential learning. Improvements in fidelity are needed before VR can become a preferred training technique in neurosurgery.

Abstract WP181: Trends In Ischemic Stroke Patients With Central Nervous System Infections: A Propensity Score Matched 20-year Analysis Of The National Inpatient Sample

Introduction: Infection of the central nervous system (CNS) - including meningitis, encephalitis and brain abscess - is a feared complication in hospitalized patients. Studies of CNS infection in patients with acute ischemic stroke (AIS) are scarce. We aimed to characterize AIS patients with CNS infections and assess their clinical outcomes over a 20-year period.

Methods: A query of the 2000-2019 National Inpatient Sample was performed for patients admitted with AIS (ICD9 433, 434.01, 434.11, 434.91, ICD-10 I63). Demographics, comorbidities, and outcomes were identified. Univariate analysis with t-tests or chi-square performed as appropriate. A 1:1 nearest neighbor propensity score matched cohort was generated. Variables with standardized mean differences >0.1 used in multivariate regression to generate adjusted odds ratios (AOR)/β-coefficients for the presence of CNS infections on outcomes. Significance set at an alpha level of <0.001. All analysis performed in R version 4.1.3.

Results: Total of 10,415,286 patients with AIS were included; 74,731 (0.7%) had CNS infection. Infected patients had higher Elixhauser Comorbidity Score (12.02 ± 9.24 vs. 9.75 ± 8.82; p<0.001) and NIH Stroke Score (8.78 ± 8.86 vs. 6.65 ± 7.29; p<0.001). After propensity matching, these patients had lower rates of smoking, COPD and CKD, and higher rates of systemic inflammatory disease and burr hole drainage (p<0.001). Infected patients had longer hospital stay (3.88 days; 95% CI: 3.45-4.3), higher hospital charges ($49633.46; 95% CI: $44199.59-55067.33) and were less likely to be discharged home or short-term hospital (0.78; 95% CI: 0.74-0.82)(all p<0.001).

Conclusion: In this 20 year nationally representative propensity matched analysis of patients with AIS, those with concomitant CNS infections had higher rates of comorbidities and had higher NIHSS. In addition to having longer and more expensive hospital stays, these patients were less likely to have good functional outcomes.

Abstract TMP56: Trends In Alcohol Abuse In Patients With Acute Ischemic Stroke: A 20-year Analysis Of The Nationwide Inpatient Sample

Introduction: Heavy alcohol (EtOH) consumption has been long recognized for its damaging effects to the brain and is considered a risk factor for stroke. However, the relationship between EtOH abuse and stroke on in-hospital outcomes remains unclear.

Objective: To characterize stroke patients with an EtOH abuse and examine the effects of alcohol abuse on patient outcomes over 20 years.

Methods: A query of the 2000-2019 National Inpatient Sample was performed for patients admitted with AIS (ICD9 433, 43401, 43411, 43491, ICD-10 I63). Demographics, comorbidities, and outcomes were identified. Univariate analysis with t-tests or chi-square performed as appropriate. A 1:1 nearest neighbor propensity score matched cohort was generated. Variables with standardized mean differences >0.1 used in multivariate regression to generate adjusted odds ratios (AOR)/β-coefficients for EtOH abuse on outcomes. Significance set at an alpha level of <0.001. All analysis performed in R version 4.1.3.

Results: A total of 10,415,286 patients with AIS were identified; 368,953 (3.5%) abused EtOH. EtOH abuse patients had higher Elixhauser Comorbidity Score (11.02 ± 10.38 vs. 9.72 ± 8.76; p<0.001) and NIH Stroke Score (7.19 ± 7.08 vs. 6.65 ± 7.30; p<0.001). Patients with EtOH abuse were more likely to be male, younger, smokers, covered on Medicaid, have atrial fibrillation, and be in the 0-25% percentile median income bracket (all p<0.001). After propensity matching, EtOH abuse patients had longer hospital stay (0.39 days; 95% CI: 0.28-0.5), lower hospital charges (-$3780.6; 95% CI: -$5053.16 - -$2508.04) and were less likely to be discharged home or short-term hospital (AOR 0.83; 95% CI: 0.81-0.85)(all p<0.001).

Conclusion: In this 20 year nationally representative propensity matched analysis of patients with AIS, patients that abused EtOH had higher incidences of more severe disease with worse functional outcomes, as well as lower hospital charges despite longer hospital stays.

Abstract WP206: Acute Ischemic Stroke And Vocal Fold Paralysis: A Propensity Matched 20-year Analysis Of The National Inpatient Sample

Introduction: Lower cranial nerve motor dysfunction is a well-distinguished feature in acute ischemic stroke (AIS). As a result, patients can present with vocal dysfunction, including vocal fold paralysis (VFP). Few studies have examined VFP in AIS patients.

Objective: To identify the incidence and characteristics of patients presenting with VFP after AIS.

Methods: A query of the 2000-2019 National Inpatient Sample was performed for patients admitted with AIS (ICD9 433, 43401, 43411, 43491, ICD-10 I63). Demographics, comorbidities, and outcomes were identified. Univariate analysis with t-tests or chi-square performed as appropriate. A 1:1 nearest neighbor propensity score matched cohort was generated. Variables with standardized mean differences >0.1 used in multivariate regression to generate adjusted odds ratios (AOR)/β-coefficients for VFP on outcomes. Significance set at an alpha level of <0.001. All analysis performed in R version 4.1.3.

Results: 10,415,286 patients with AIS were included; 11,328 (0.1%) had VFP. At baseline, a higher percentage of patients with VFP were younger, male, insured by Medicaid, had a higher Elixhauser Comorbidity Score, and were more likely to have a tracheostomy and ventilator use (all p<0.001). Following propensity matching, multivariate analysis revealed that patients with VFP were less likely to be discharged home (AOR 0.32; 95%CI: 0.18-0.57; p<0.001) with no effect of VFP on in-hospital mortality, length of stay, or total hospital charges (p> 0.001)

Conclusion: This is the first study to report on national trends of patients with VFP after AIS, and we found that VFP patients were more male, younger, higher overall disease burden, and required more in-hospital procedures. Though rare, VFP causes significant morbidity for patients after AIS. Patients experience significant functional deficits at discharge, as represented by the low rate of home discharge.

Abstract TP132: Racial Disparity In Outcomes Of Primary Intracerebral Hemorrhage In The United States: A 20-year Analysis Of The National Inpatient Sample

Background: Primary intracerebral hemorrhage (ICH) is a devastating disease with limited therapeutic options and poor overall outcomes. We aimed to characterize racial disparities in patients with ICH over a 20 year period and examine the prognostic impact of race on functional outcomes.

Methods: A query of the 2000-2019 National Inpatient Sample was performed for patients admitted with ICH (ICD9 431, 432.9, ICD-10 I61, I62.9). Demographics, comorbidities, and outcomes were identified. Discharge location was used as a surrogate for functional outcome. Univariate analysis with t-tests or chi-square performed as appropriate, and significant variables were entered into a multivariate regression to generate adjusted odds ratios (AOR)/β-coefficients for race on outcomes. Significance set at an alpha level of <0.001. All analysis performed in R version 4.1.3.

Results: A total of 2,000,868 patients with ICH were identified. Mean Age was 68.28 ±15.41 years. Patients were 57.2% White, 14.1 % Black, 8.3% Hispanic, and 3.9% Asian. Average Elixhauser Comorbidity Score was significantly different among the groups, with White patients having higher score on average than Asian, Black, or Hispanic Patients. There was no difference in NIH Stroke Scale among the groups. After multivariate analysis, there were no differences in odds of discharge to home or to nursing/long-term care facilities between races (p>0.001). In hospital mortality was less in Black (AOR 0.73, 95%CI: 0.64-0.84) and Hispanic (AOR 0.65, 95% CI: 0.55-0.78) patients compared to White (p<0.001).

Conclusions: This 20 year nationally representative analysis of racial disparities in ICH patients shows that despite the increasing prevalence in Black and Hispanic patients over 20 years, they have greater odds of survival during their hospital stay when compared to White patients. Further examination of healthcare systems and patient-specific factors are warranted to elucidate this phenomenon.

Abstract TP66: Trends In Alcohol Abuse In Patients With Intracerebral Hemorrhage: A 20-year Analysis Of The Nationwide Inpatient Sample

Introduction: While chronic alcohol (EtOH) abuse has long been considered a risk factor for several cardiovascular disorders including ischemic stroke, the relationship between intracerebral hemorrhage (ICH) and EtOH abuse is less known.

Objective: To characterize ICH patients with EtOH abuse and examine the effects of EtOH abuse on in-hospital outcomes over 20 years.

Methods: A query of the 2000-2019 National Inpatient Sample was performed for patients admitted with ICH (ICD9 431, 432.9, ICD-10 I61, I62.9). Demographics, comorbidities, and outcomes were identified. Univariate analysis with t-tests or chi-square performed as appropriate. A 1:1 nearest neighbor propensity score matched cohort was generated. Variables with standardized mean differences >0.1 used in multivariate regression to generate adjusted odds ratios (AOR)/β-coefficients for EtOH abuse on outcomes. Significance set at an alpha level of <0.001. All analysis performed in R version 4.1.3.

Results: In total, 2,000,868 patients with ICH were identified; 106,987 (5.3%) abused EtOH. EtOH abuse patients had higher Elixhauser Comorbidity Score (12.95 ± 10.51 vs. 10.28 ± 8.98; p<0.001) and a non-significantly lower NIH Stroke Score (11.0 ± 8.69 vs. 11.34 ± 9.53; p >0.001). Patients with EtOH abuse were more likely to be male, younger, smokers, on Medicaid, be in the 0-25% percentile median income bracket, and have atrial fibrillation, hyperlipidemia, diabetes, and seizures (all p<0.001). Patients with EtOH abuse had less in-hospital mortality, more discharge home or short term hospital, longer hospital stays and more hospital charges (all p<0.001), but after propensity matching and regression analysis these differences were no longer significant.

Conclusion: This 20 year nationally representative propensity matched analysis of patients with ICH demonstrates that concomitant EtOH does not significantly worsen in-hospital outcomes despite a higher association of other comorbidities.

Abstract WP145: Racial Disparity In Outcomes Of Acute Ischemic Stroke In The United States: A 20-year Analysis Of The National Inpatient Sample From 2000-2019

Background: Acute ischemic stroke (AIS) is associated with a high rate of morbidity and mortality. We aimed to characterize racial disparities in patients with AIS over a 20 year period and examine the prognostic impact of race on functional outcomes.

Methods: A query of the 2000-2019 National Inpatient Sample was performed for patients admitted with AIS (ICD9 433, 43401, 43411, 43491, ICD-10 I63). Demographics, comorbidities, and outcomes were identified. Discharge location was used as a surrogate for functional outcome. Univariate analysis with t-tests or chi-square performed as appropriate, and significant variables were entered into a multivariate regression to generate adjusted odds ratios (AOR)/β-coefficients for race on outcomes. Significance set at an alpha level of <0.001. All analysis performed in R version 4.1.3.

Results: A total of 10,415,286 patients with AIS were identified. Mean Age was 70.91±13.8 years. Patients were 61% White, 14.3 % Black, 6.6% Hispanic, and 2.4% Asian. Average NIH Stroke Scale differed significantly among the groups, with Asian patients having more severe disease than White, Black, or Hispanic patients (p<0.001). After multivariate analysis, Black patients had worse odds for discharge home than white patients (AOR 0.8, 95%CI: 0.77-0.83, p<0.001) with a higher likelihood of discharge to nursing/long-term care facilities (AOR 1.3, 95%CI: 1.26-1.34, p<0.001). In hospital mortality was less in Black (AOR 0.64, 95%CI: 0.58-0.7) and Hispanic (AOR 0.78, 95% CI: 0.69-0.87) patients (p<0.001).

Conclusions: This 20 year nationally representative analysis of racial disparities in patients with AIS shows that while Black patients have worse odds of discharge home, they are less likely than White patients to die in the hospital. White patients make up the majority of cases, but their percentage of total AIS cases decreased while Black patients increased over the twenty year study period.

Abstract TP87: Predictors Of Diffusion-weighted Imaging Lesion Burden In Patients After Minimally Invasive Surgery For Intracerebral Hemorrhage

Introduction: The etiology of diffusion-weighted imaging (DWI) lesions in patients after minimally invasive surgery (MIS) for acute intracerebral hemorrhage (ICH) remains unclear.

Methods: Postoperative brain MRIs of patients with spontaneous ICH from 2016-2021 who underwent imaging within one month of MIS were reviewed. DWI lesions were quantified. Lesions within 10 mm of the hematoma were excluded. Siderosis and microbleeds were identified. Leukoaraiosis was quantified using the Fazekas score. Univariate analyses were conducted to determine predictors of DWI lesion burden, and variables with P≤0.1 were included in multivariate analyses.

Results: DWI lesions were present in 84 (49%) postoperative MRIs. The average number of DWI lesions was 2.11 (range 0-74, SD 6.50). Factors associated with DWI burden in univariate analyses included increased presenting systolic blood pressure (SBP) (P=0.003), Fazekas score (P=0.004), delta SBP on day of admission (P=0.034), preoperative angiogram (P=0.062), microbleeds on MRI (P=0.065), increased presenting National Institutes of Health Stroke Score (P=0.066), presence of intraventricular hemorrhage (P=0.069), and decreased presenting Glasgow Coma Scale (P=0.076). Upon multivariate analysis, increased Fazekas score (OR 2.04, 95% CI 1.21-3.43, P=0.008), presenting SBP (OR 1.04, 95% CI 1.00-1.06, P=0.014), and preoperative angiogram (OR 10.35, 95% CI 1.44-74.36], P=0.020) were predictive of DWI burden.

Conclusions: In this unique postoperative ICH cohort, white matter changes, presenting SBP, and preoperative angiogram predicted DWI lesion burden. Larger studies are needed to understand the implications of DWI burden after MIS for ICH recovery.

Abstract 47: Outcomes In Acute Ischemic Stroke Patients Treated With Endovascular Thrombectomy Before And After 2015: An Analysis Of The National Inpatient Sample

Background: Endovascular thrombectomy (EVT) demonstrated superiority to medical management in the 2015 trials. We sought to compare outcomes in acute ischemic stroke (AIS) treated with EVT before and after 2015.

Methods: A query of the 2000-2019 National Inpatient Sample was performed for patients admitted with AIS (ICD9 433, 43401, 43411, 43491, ICD-10 I63). Demographics, comorbidities, and outcomes were identified. Univariate analysis with t-tests or chi-square performed as appropriate. A 1:1 nearest neighbor propensity score matched cohort was generated. Variables with standardized mean differences >0.1 used in multivariate regression to generate adjusted odds ratios (AOR)/β-coefficients for EVT on outcomes. Significance set at an alpha level of <0.001. All analysis performed in R version 4.1.3.

Results: A total of 10,415,286 patients with AIS were identified; 149,367 (1.4%) underwent EVT. Among the EVT cohort, 35,562 patients were treated before 2015 (23.8%) vs. 113,805 (76.2%) after. EVT patients after 2015 were more likely to be younger, on private insurance, treated at large urban nonteaching hospitals, had lower Elixhauser Comorbidity Scores (14.71 ± 9.15 vs. 16.21 ± 9.17; p<0.001) but increased markers of stroke severity such as higher rates of ventilator use, paresis, seizures, craniotomy and tracheostomy placement (all p<0.001). After propensity matching, EVT patients after 2015 were more likely to be discharged home (AOR 1.35, 95%CI:1.24-1.47), have increased hospital charges ($40828.79; 95%CI: $36391.76-45265.81), had shorter hospital stay (-0.74 days, 95%CI: -0.99 - -0.48)(all p<0.001), with no difference in In-hospital mortality.

Conclusions: This 20-year nationally representative propensity matched analysis of AIS patients shows that outcomes after EVT continue to improve following the landmark 2015 publications, with a higher chance of favorable outcome, lower hospital charge and shorter hospital stay compared to before 2015.

Abstract TP139: Characterizing Patients With Dysphagia Following Acute Ischemic Stroke: A Propensity Matched Analysis Of The 2000-2019 National Inpatient Sample

Introduction: Dysphagia is a common complication among acute ischemic stroke (AIS) patients and is associated with increased mortality and morbidity. A complete understanding of the characteristics of patients who present with dysphagia after AIS is warranted.

Objective: To identify the risk factors and outcomes of patients presenting with dysphagia after AIS over twenty years.

Methods: A query of the 2000-2019 National Inpatient Sample was performed for patients admitted with AIS (ICD9 433, 43401, 43411, 43491, ICD-10 I63). Demographics, comorbidities, and outcomes were identified. Univariate analysis with t-tests or chi-square performed as appropriate. A 1:1 nearest neighbor propensity score matched cohort was generated. Variables with standardized mean differences >0.1 used in multivariate regression to generate adjusted odds ratios (AOR)/β-coefficients for dysphagia on outcomes. Significance set at an alpha level of <0.001. All analysis performed in R version 4.1.3.

Results: 10,415,286 patients with AIS were included; 956,662 (9.2%) had in-hospital dysphagia. A higher percentage of patients with dysphagia were older, had higher Elixhauser Comorbidity Score, higher NIH Stroke Scale (NIHSS) score and a were insured by Medicare (p<0.001). After propensity matching, patients with dysphagia after AIS were less likely to experience in-hospital mortality (OR 0.61; 95%CI: 0.60-0.63) or be discharged home (AOR 0.51; 95%CI: 0.51-0.52), had decreased length of stay (0.43 days; 95%CI: 0.36-0.50), and had increased hospital charges ($14411.96; 95%CI: 13565.68-15257.44) (all p<0.001).

Conclusion: This propensity matched 20-year national analysis confirmed that dysphagia is a significant issue following AIS. These patients were more frequently male with worse neurological presentations. Despite better odds for survival and shorter hospital stay, they experience significant functional deficits at discharge and have increased hospital costs.

Abstract WP152: Trends In Stroke Patients With Associated Seizures: A 20-year Analysis Of The National Inpatient Sample From 2000-2019

Background: Seizure is a known complication following acute ischemic stroke (AIS) that can lead to severe morbidity. We sought to better characterize the risk factors for stroke following AIS and evaluate in-hospital outcomes in these patients.

Methods: A query of the 2000-2019 National Inpatient Sample was performed for patients admitted with AIS (ICD9 433, 43401, 43411, 43491, ICD-10 I63). Demographics, comorbidities, and outcomes were identified. Univariate analysis with t-tests or chi-square performed as appropriate. A 1:1 nearest neighbor propensity score matched cohort was generated. Variables with standardized mean differences >0.1 used in multivariate regression to generate adjusted odds ratios (AOR)/β-coefficients for dysphagia on outcomes. Significance set at an alpha level of <0.001. All analysis performed in R version 4.1.3.

Results: A total of 10,415,286 patients with AIS were identified; 694,495 (6.6%) had seizures. Patients with seizures had higher Elixhauser Comorbidity Score (14.81 ± 8.13 vs. 9.40 ± 8.76; p<0.001) and NIH Stroke Scale (NIHSS) Score (9.46 ± 8.68 vs. 6.50 ± 7.18; p<0.001). Patients with seizures were more likely to be female, younger, African American race, smokers, covered on Medicaid, be in the 0-25% percentile median income bracket, and be placed on a ventilator (all p<0.001). After propensity matching, seizure patients were slightly less likely to experience in-hospital mortality (AOR 0.94; 95%CI: 0.92-0.97), less likely to be discharged home (AOR 0.92, 95%CI:0.9-0.93), and had increased hospital charges ($6696.08; 95%CI: $5728.65-7663.51)(all p<0.001).

Conclusions: Approximately 7% of patients with AIS experience seizure while hospitalized, with an overall stable incidence over 20 years. Seizure is more likely to occur in women and younger patients and is associated with worse functional outcomes. The percentage of patients with seizures in AIS remained similar per year despite an increase in the absolute numbers.

Abstract TP131: Trends In Intracerebral Hemorrhage Patients With Seizures: A Propensity Score Matched 20-year Analysis Of The National Inpatient Sample

Introduction: Intracerebral hemorrhage (ICH) accounts for 15% of strokes, and an early sequelae of hemorrhagic stroke is seizure. Studies have shown up to 43% of ICH patients experience electrographic seizure within 72 hours of ictus. The clinical course of patients with seizures in ICH remains unclear.

Methods: A query of the 2000-2019 National Inpatient Sample was performed for patients admitted with ICH (ICD9 431, 432.9, ICD-10 I61, I62.9). Demographics, comorbidities, and outcomes were identified. Univariate analysis with t-tests or chi-square performed as appropriate. A 1:1 nearest neighbor propensity score matched cohort was generated. Variables with standardized mean differences >0.1 used in multivariate regression to generate adjusted odds ratios (AOR)/β-coefficients for the presence of seizures on outcomes. Significance set at an alpha level of <0.001. All analysis performed in R version 4.1.3.

Results: 2,000,868 patients with ICH were identified; 234,382 had seizures (11.7%). Patients with seizure had higher Elixhauser Comorbidity Score (15.12 ± 8.54 vs. 9.80 ± 8.98, p<0.001) and NIH Stroke Score (13.02 ± 9.85 vs. 11.17 ± 9.46, p<0.001). There were higher rates of coma, fluid/electrolyte dysfunction, CNS infections, craniotomy, and external ventricular drain placement (p<0.01). After propensity matching, patients with seizure were less likely to experience in-hospital mortality (AOR 0.85; 95% CI: 0.82-0.87), more likely to be discharged home or short-term hospital (AOR 1.31; 95% CI: 1.27-1.35), have shorter hospital stay (-0.63 days; 95% CI: -0.82 - -0.45), and lower hospital charges ($-3991.74; 95% CI: $-6196.22- -1787.27) (all p<0.001).

Conclusions: The rate of seizure among ICH patients remains unchanged over the past 2 decades. Seizure is associated with more severe presentation; however, it does not independently worsen the clinical outcome.

Abstract WP149: Racial Disparity In Intracerebral Hemorrhage Severity And Outcome: A 4-year Analysis Of The National Inpatient Sample From 2016-2019

Background: Racial disparity in ICH management and outcome is a major concern. We sought to evaluate the impact of race on ICH severity and outcome in a nationally representative database.

Methods: A query of the 2000-2019 National Inpatient Sample was performed for patients admitted with ICH (ICD9 431, 432.9, ICD-10 I61, I62.9). Demographics, comorbidities, and outcomes were identified. Discharge location was used as a surrogate for functional outcome. Univariate analysis with t-tests or chi-square performed as appropriate, and significant variables were entered into a multivariate regression to generate adjusted odds ratios (AOR)/β-coefficients for race on outcomes. Significance set at an alpha level of <0.001. All analysis performed in R version 4.1.3.

Results: A total of 390,015 patients with ICH were identified over the four years; 97,220 (24.9%) had a reported NIH Stroke Score (NIHSS). Mean Age was 69.22 ± 14.3 years. Patients were 61% White, 16.6 % Black, 9.9% Hispanic, and 4.8% Asian. Average NIHSS differed significantly among the groups, with Asian patients having more severe disease than White, Black, or Hispanic patients (p<0.001). After multivariate analysis, Hispanic patients had greater odds of discharge home compared to White patients (AOR 1.3, 95% CI 1.12-1.51, p<0.05). Black patients had greater odds of discharge to nursing care facilities (AOR 1.12, 95%CI: 1.02-1.23, p<0.001). In hospital mortality was less in Black (AOR 0.7, 95%CI: 0.6-0.81), Asian (AOR 0.66, 95% CI: 0.51-0.83) and Hispanic (AOR 0.67, 95%CI: 0.55-0.8) patients (all <0.05).

Conclusions: This nationally representative analysis demonstrates that Black patients have worse hospital outcomes after ICH while the rate of in-hospital mortality seen in Whites was higher in comparison to other races. White patients were the majority of cases and had an overall stable trend of good discharge outcome. Incidence of in-hospital mortality was highest in the Black patients over four years.

Abstract TMP44: Artificial Intelligence-driven Automated Intracerebral Hemorrhage Volume Calculation Is More Accurate Than ABC/2

Introduction: Treatment of spontaneous intracerebral hemorrhage (ICH) requires rapid, accurate estimation of hemorrhage volume to determine appropriate patient care and guide prognosis. ICH volume estimation on Computed Tomography (CT) imaging using the ABC/2 formula is the clinical gold standard, however this method can be inaccurate, suffers from observer scoring variability, and takes time to make the measurement on a workstation. Semi-Autonomous Segmentation (SAS) is the gold standard for hemorrhage volume estimation, however it is not used clinically due to the increased time for analysis. Recently, artificial intelligence (AI) driven segmentation has been developed (Viz.ai, San Francisco, California) to automatically detect ICH and calculate hematoma volume.

Objective: Our goal is to validate the accuracy of the Viz.ai ICH segmentation algorithm as a tool for determining hemorrhage volume by comparing its performance to both ABC/2 and SAS.

Methods: Seventy head CTs positive for ICH were analyzed with SAS in 3D Slicer to determine ICH volume as the standard reference volume. The same CT scans were then analyzed using the ABC/2 method. Finally, scans were uploaded to Viz.ai for ICH volume analysis.

Results: Compared against standard SAS, Viz.ai ICH volumes were more accurate than ABC/2 in 77% of cases. Average difference between Viz.ai ICH volume and SAS ICH volume was 4.9±4.2 mL (R2=0.98). Average difference between ABC/2 ICH volume and SAS ICH volume was 10.6±11.4 mL (R2=0.77).

Conclusion: This study indicates that Viz.ai more accurately estimates ICH volume than ABC/2 over a broad range of hematoma volumes when compared to standard SAS, which when coupled with significantly faster analysis compared to SAS justifies the use of AI in ICH triage workflow.

Contralesional angiotensin type 2 receptor activation contributes to recovery in experimental stroke

We and others have previously shown that angiotensin II receptor type 2 receptor (AT2R) is upregulated in the contralesional hemisphere after stroke in normoglycemic Wistar rats. In this study, we examined the expression of AT2R in type 2 diabetic Goto-Kakizaki (GK) rats and control Wistars after stroke. We also tested the contribution of the contralesional AT2R in recovery after stroke through a specific knockdown of the AT2R in this hemisphere only. Two experiments were conducted. In the first experiment, GK rats were subjected to middle cerebral artery occlusion (MCAO) and treated with the angiotensin II receptor type 1 receptor (AT1R) blocker candesartan or saline at reperfusion. Stroke outcomes, as well as AT2R expression, were examined and compared to control Wistars at 24 h. In the second experiment, localized AT2R knockdown was achieved through intrastriatal injection of short hairpin RNA (shRNA) lentiviral particles or non-targeting control into the left-brain hemisphere of Wistar rats. After 14 days, rats were subjected to right MCAO and treated with the AT2R agonist, Compound 21 (C21), or saline for 7 days. Behavioral outcomes were assessed for up to 10 days. In the first experiment, stroke reduced the expression of AT2R in GK rats. Candesartan treatment failed to improve the neurobehavioral outcomes, preserve vascular integrity or reduce oxidative/nitrative stress or apoptotic markers at 24 h post stroke in these animals. In the second experiment, contralesional AT2R knockdown reduced the C21-mediated functional recovery after stroke. In conclusion, contralesional AT2R upregulation after stroke is blunted in diabetic rats which show reduced sensitivity to post-stroke candesartan treatment. Contralesional AT2R could be involved in C21-mediated functional recovery after stroke.

Endovascular therapy versus microsurgical clipping of unruptured wide-neck aneurysms: a prospective multicenter study with propensity score analysis

OBJECTIVE

Numerous techniques have been developed to treat wide-neck aneurysms (WNAs), each with different safety and efficacy profiles. Few studies have compared endovascular therapy (EVT) with microsurgery (MS). The authors' objective was to perform a prospective multicenter study of a WNA registry using rigorous outcome assessments and to compare EVT and MS using propensity score analysis (PSA).

METHODS

Unruptured, saccular, not previously treated WNAs were included. WNA was defined as an aneurysm with a neck width ≥ 4 mm or a dome-to-neck ratio (DTNR) < 2. The primary outcome was modified Rankin Scale (mRS) score at 1 year after treatment (good outcome was defined as mRS score 0-2), as assessed by blinded research nurses and compared with PSA. Angiographic outcome was assessed using the Raymond scale with core laboratory review (adequate occlusion was defined as Raymond scale score 1-2).

RESULTS

The analysis included 224 unruptured aneurysms in the EVT cohort (n = 140) and MS cohort (n = 84). There were no differences in baseline demographic characteristics, such as proportion of patients with good baseline mRS score (94.3% of the EVT cohort vs 94.0% of the MS cohort, p = 0.941). WNA inclusion criteria were similar between cohorts, with the most common being both neck width ≥ 4 mm and DTNR < 2 (50.7% of the EVT cohort vs 50.0% of the MS cohort, p = 0.228). More paraclinoid (32.1% vs 9.5%) and basilar tip (7.1% vs 3.6%) aneurysms were treated with EVT, whereas more middle cerebral artery (13.6% vs 42.9%) and pericallosal (1.4% vs 4.8%) aneurysms were treated with MS (p < 0.001). EVT aneurysms were slightly larger (p = 0.040), and MS aneurysms had a slightly lower mean DTNR (1.4 for the EVT cohort vs 1.3 for the MS cohort, p = 0.010). Within the EVT cohort, 9.3% of patients underwent stand-alone coiling, 17.1% balloon-assisted coiling, 34.3% stent-assisted coiling, 37.1% flow diversion, and 2.1% PulseRider-assisted coiling. Neurological morbidity secondary to a procedural complication was more common in the MS cohort (10.3% vs 1.4%, p = 0.003). One-year mRS scores were assessed for 218 patients (97.3%), and no significantly increased risk of poor clinical outcome was found for the MS cohort (OR 2.17, 95% CI 0.84-5.60, p = 0.110). In an unadjusted direct comparison, more patients in the EVT cohort achieved a good clinical outcome at 1 year (93.4% vs 84.1%, p = 0.048). Final adequate angiographic outcome was superior in the MS cohort (97.6% of the MS cohort vs 86.5% of the EVT cohort, p = 0.007).

CONCLUSIONS

Although the treatments for unruptured WNA had similar clinical outcomes according to PSA, there were fewer complications and superior clinical outcome in the EVT cohort and superior angiographic outcomes in the MS cohort according to the unadjusted analysis. These results may be considered when selecting treatment modalities for patients with unruptured WNAs.

Use of emerging technologies to enhance the treatment paradigm for spontaneous intraventricular hemorrhage

The presence of intraventricular hemorrhage (IVH) portends a worse prognosis in patients presenting with spontaneous intracerebral hemorrhage (ICH). Intraventricular hemorrhage increases the rates of hydrocephalus, ventriculitis, and long-term shunt dependence. Over the past decade, novel medical devices and protocols have emerged to directly treat IVH. Presently, we review new technological adaptations to treating intraventricular hemorrhage in an effort to focus further innovation in treating this morbid neurosurgical pathology. We summarize current and historical treatments as well as innovations in IVH including novel procedural techniques, use of the Integra Surgiscope, use of the Artemis evacuator, use of BrainPath, novel catheter technology, large bore external ventricular drains, the IRRAflow, the CerebroFlo, and the future directions of the field. Technology and medical devices for both surgical and nonsurgical methods are advancing the treatment of IVH. With many promising new technologies on the horizon, prospects for improved clinical care for IVH and its etiologies remain hopeful.

Time from image acquisition to endovascular team notification: a new target for enhancing acute stroke workflow

OBJECTIVE

To quantify the time between initial image acquisition (CT angiography (CTA)) and notification of the neuroendovascular surgery (NES) team, a potentially high yield time window to target for optimization of endovascular thrombectomy (ET) treatment times.

METHODS

We reviewed our multihospital database for all patients with a stroke with emergent large vessel occlusion treated with ET between January 1, 2017 and August 5, 2020. We dichotomized patients into rapid (≤20 min) and delayed (>20 min) notification times and analyzed treatment characteristics and outcomes.

RESULTS

Of 367 patients with ELVO undergoing ET for whom notification data were available, the median time from CTA to NES team notification was 24 min (IQR 12-47). The median total treatment time was 180 min (IQR 129-252). The median times from CTA to NES team notification for rapid (n=163) and delayed (n=204) cohorts were 11 (IQR 6-15) and 43 (IQR 30-80) min, respectively (p<0.001). The median overall times to reperfusion were 134 min (IQR 103-179) and 213 min (IQR 172-291), respectively (p<0.001). The delayed patients had a significantly lower National Institutes of Health Stroke Scale (NIHSS) score on presentation (15 (IQR 9-20) vs 16 (IQR 11-22), p=0.03), were younger (70 (IQR 60-79) vs 77 (IQR 64-85), p<0.001), and more often presented with posterior circulation occlusion (16.7% vs 7.4%, p<0.01). The group with rapid notification time had a statistically larger median improvement in NIHSS score from admission to discharge (6 (IQR 0.5-14) vs 5 (IQR 0.5-10), p=0.04).

CONCLUSIONS

Time delays from initial CTA acquisition to NES team notification can prevent expedient treatment with ET. Process improvements and automated stroke detection on imaging with automated notification of the NES team may ultimately improve time to reperfusion.

Initial Stroke Thrombectomy Experience in New York City during the COVID-19 Pandemic

New York City has become the global epicenter of the coronavirus 2019 (COVID-19) pandemic. Despite a massive shift in health care resources, cerebrovascular disease continues to be a substantial burden. We review the first 10 patients undergoing thrombectomy following a series of governmental and institutional policy changes diverting resources to the care of critically ill patients with COVID-19. Ten patients with emergent large-vessel occlusion underwent thrombectomy between March 23 and April 1, 2020. Five patients tested positive for the COVID-19 virus. Successful reperfusion was achieved in 9 of 10 patients, at a median time of 37 minutes from vascular access. The postprocedural NIHSS score improved by an average of 7.7 points. Of the 5 patients positive for COVID-19, none have experienced a critical respiratory illness. We report the early incidence of COVID-19 positivity in patients with emergent large-vessel occlusion and demonstrate that thrombectomy continues to be an efficacious option, as well as safe for health care providers.

Increases in Subdural Hematoma with an Aging Population-the Future of American Cerebrovascular Disease

BACKGROUND

Subdural hematomas (SDHs) are a common and dangerous condition, with potential for a rapid rise in incidence given the aging U.S. population, but the magnitude of this increase is unknown. Our objective was to characterize the number of SDHs and practicing neurosurgeons from 2003-2016 and project these numbers to 2040.

METHODS

Using the National Inpatient Sample years 2003-2016 (nearly 500 million hospitalizations), all hospitalizations with a diagnosis of SDH were identified and grouped by age. Numerical estimates of SDHs were projected to 2040 in 10-year increments for each age group using Poisson modeling with population estimates from the U.S. Census Bureau. The number of neurosurgeons who billed the Centers for Medicare and Medicaid Services from 2012 to 2017 was noted and linearly projected to 2040.

RESULTS

From 2020-2040, SDH volume is expected to increase by 78.3%, from 135,859 to 208,212. Most of this increase will be seen in the elderly, as patients 75-84 years old will experience an increase from 37,941 to 69,914 and patients older than 85 years old will experience an increase from 31,200 to 67,181. The number of neurosurgeons is projected to increase from 4675 in 2020 to 6252 in 2040.

CONCLUSIONS

SDH is expected to increase significantly from 2020-2040, with the majority of this increase being concentrated in elderly patients. While the number of neurosurgeons will also increase, the ability of current neurosurgical resources to properly handle this expected increase in SDH will need to be addressed on a national scale.

Amino acids as signaling molecules modulating bone turnover

Except for the essential amino acids (AAs), much of the focus on adequate dietary protein intake has been on total nitrogen and caloric intake rather than AA composition. Recent data, however, demonstrate that "amino-acid sensing" can occur through either intracellular or extracellular nutrient-sensing mechanisms. In particular, members of the class 3 G-protein coupled receptor family, like the calcium-sensing receptor are known to preferentially bind specific AAs, which then modulate receptor activation by calcium ions and thus potentially impact bone turnover. In pursuing the possibility of direct nutrient effects on bone cells, we examined individual AA effects on osteoprogenitor/bone marrow stromal cells (BMSCs), a key target for bone anabolism. We demonstrate that BMSCs express both intracellular and extracellular nutrient sensing pathways and that AAs are required for BMSC survival. In addition, certain AA types, like members of the aromatic AAs, can potently stimulate increases in intracellular calcium and ERK phosphorylation/activation. Further, based on the in vitro data, we examined the effect of specific AAs on bone mass. To better evaluate the impact of specific AAs, we added these to a low-protein diet. Our data demonstrate that a low-protein diet itself is associated with a significant drop in bone mineral density (BMD) in the older mice, related, at least in part, to an increase in osteoclastic activity. This drop in BMD in mice on the low-protein diet is prevented by addition of AAs from the aromatic group. Taken together our data show that AAs function as specific and selective signaling molecules in bone cells.

Cephalad Migration of Intradural Bullet from Thoracic Spine to Cervical Spine

BACKGROUND

There are few reported instances of intraspinal migration of a bullet fragment. The majority of these migrations occur caudally, typically below the level of T10. Even fewer cases demonstrate cephalad migration from the sacral spine to the lumbar spine. We report here for the first time a case of a cephalad migration intradurally from the thoracic spine to cervical spine.

CASE DESCRIPTION

A 31-year old man presented to the emergency department with a suspected spinal cord injury following a GSW sustained to the left shoulder. A penetrating gunshot injury to the thoracic spine at the level of T2 was observed, and CT angiography revealed a cephalad migration of the bullet fragment to the level of C6. The patient had marked weakness of the bilateral upper extremities, with paraplegia of the lower extremities. There was a sensory deficit beginning at a level 1 cm below the clavicle, as well as a decrease in rectal tone. We performed a laminectomy at C6 with dural incision and removal of the main bullet fragment. Following the surgery, significant improvement in strength and sensation in the bilateral upper extremities was noted, but paraplegia and sensory loss below the level of T2 persisted.

CONCLUSIONS

In this report, we review the previously reported cases in which intraspinal migration of bullets have occurred, and discuss the unique finding in this study of cephalad migration of a bullet within the dura. In addition, we detail considerations in the management of such injuries.

TLR2 knockout protects against diabetes-mediated changes in cerebral perfusion and cognitive deficits

The risk of cognitive decline in diabetes (Type 1 and Type 2) is significantly greater compared with normoglycemic patients, and the risk of developing dementia in diabetic patients is doubled. The etiology for this is likely multifactorial, but one mechanism that has gained increasing attention is decreased cerebral perfusion as a result of cerebrovascular dysfunction. The innate immune system has been shown to play a role in diabetic vascular complications, notably through the Toll-like receptor (TLR)-stimulated release of proinflammatory cytokines and chemokines that lead to vascular damage. TLR2 has been implicated in playing a crucial role in the development of diabetic microvascular complications, such as nephropathy, and thus, we hypothesized that TLR2-mediated cerebrovascular dysfunction leads to decreased cerebral blood flow (CBF) and cognitive impairment in diabetes. Knockout of TLR2 conferred protection from impaired CBF in early-stage diabetes and from hyperperfusion in long-term diabetes, prevented the development of endothelium-dependent vascular dysfunction in diabetes, created a hyperactive and anxiolytic phenotype, and protected against diabetes-induced impairment of long-term hippocampal and prefrontal cortex-mediated fear learning. In conclusion, these findings support the involvement of TLR2 in the pathogenesis of diabetic vascular disease and cognitive impairment.

Cerebrovascular complications of diabetes: focus on cognitive dysfunction

The incidence of diabetes has more than doubled in the United States in the last 30 years and the global disease rate is projected to double by 2030. Cognitive impairment has been associated with diabetes, worsening quality of life in patients. The structural and functional interaction of neurons with the surrounding vasculature is critical for proper function of the central nervous system including domains involved in learning and memory. Thus, in this review we explore cognitive impairment in patients and experimental models, focusing on links to vascular dysfunction and structural changes. Lastly, we propose a role for the innate immunity-mediated inflammation in neurovascular changes in diabetes.

Linagliptin treatment improves cerebrovascular function and remodeling and restores reduced cerebral perfusion in Type 2 diabetes

The antihyperglycemic agent linagliptin, a dipeptidyl peptidase-4 (DPP-IV) inhibitor, has been shown to reduce inflammation and improve endothelial cell function. In this study, we hypothesized that DPP-IV inhibition with linagliptin would improve impaired cerebral perfusion in diabetic rats, as well as improve insulin-induced cerebrovascular relaxation and reverse pathological cerebrovascular remodeling. We further postulated that these changes would lead to a subsequent improvement of cognitive function. Male Type-2 diabetic and nondiabetic Goto-Kakizaki rats were treated with linagliptin for 4 wk, and blood glucose and DPP-IV plasma levels were assessed. Cerebral perfusion was assessed after treatment using laser-Doppler imaging, and dose response to insulin (10(-13) M-10(-6) M) in middle cerebral arteries was tested on a pressurized arteriograph. The impact of DPP-IV inhibition on diabetic cerebrovascular remodeling was assessed over a physiologically relevant pressure range, and changes in short-term hippocampus-dependent learning were observed using a novel object recognition test. Linagliptin lowered DPP-IV activity but did not change blood glucose or insulin levels in diabetes. Insulin-mediated vascular relaxation and cerebral perfusion were improved in the diabetic rats with linagliptin treatment. Indices of diabetic vascular remodeling, such as increased cross-sectional area, media thickness, and wall-to-lumen ratio, were also ameliorated; however, improvements in short-term hippocampal-dependent learning were not observed. The present study provides evidence that linagliptin treatment improves cerebrovascular dysfunction and remodeling in a Type 2 model of diabetes independent of glycemic control. This has important implications in diabetic patients who are predisposed to the development of cerebrovascular complications, such as stroke and cognitive impairment.

Diabetes-mediated middle cerebral artery remodeling is restored by linagliptin: Interaction with the vascular smooth muscle cell endothelin system

INTRODUCTION

Endothelin-1 (ET-1) mediates cerebrovascular remodeling in vascular smooth muscle layer of the middle cerebral arteries (MCA) in type-2 diabetic Goto-Kakizaki (GK) rats. While metformin, oral glucose lowering agent, prevent/restores vascular remodeling and reduce systemic and local ET-1 levels whether this effect was specific to metformin remained unknown. Our working hypotheses were 1) linagliptin, a DPP-IV inhibitor, can reverse diabetes-mediated cerebrovascular remodeling and this is associated with decreased ET-1, and 2) linagliptin prevents the high glucose induced increase in ET-1 and ET receptors in brain vascular smooth muscle cells (bVSMCs).

METHODS

Diabetic and non-diabetic GK rats were treated with linagliptin (4weeks). MCAs were fixed in buffered 4% paraformaldehyde and used for morphometry. Human bVSMCs incubated in normal glucose (5.5mM)/high glucose (25mM) conditions were treated with the linagliptin (100nM; 24h). ET-1 secretion and ET receptors were measured in media and cell lysate respectively. Immunostaining was performed for ET-A and ET-B receptor. ET receptors were also measured in cells treated with ET-1 (100nM) and linagliptin.

RESULTS

Linagliptin treatment regressed vascular remodeling of MCAs in diabetic animals but had no effect on blood glucose. bVSMCs in normal/high glucose condition did not show any significant difference in ET-1 secretion or ET-A and ET-B receptor expression. ET-1 treatment in high glucose condition significantly increased the ET-A receptors and this effect was inhibited by linagliptin.

CONCLUSIONS

Linagliptin is effective in reversing established pathological cerebrovascular remodeling associated with diabetes. Attenuation of the ET system could be a pleiotropic effect of linagliptin that provides vascular protection.

Abstract TP463: TLR2 Knockout Prevents Diabetes-induced Increase in Cerebral Perfusion and Decreases Fear Response

Objective: It is increasingly recognized that vascular cognitive impairment may be a new complication of the disease in both type 1 and type 2 diabetes. We have shown that diabetic Goto-Kakizaki rats present with cognitive deficits and vascular dysfunction, especially impaired relaxation that can be ameliorated by Toll-like receptor-2 (TLR2) inhibition. Since brain function heavily depends on constant perfusion, and decreased cerebral blood flow (CBF) precedes development of inflammation and cognitive deficits, we hypothesized that TLR2 knockout would confer a protection from diabetes mediated cognitive decline.

Methods and Results: Wild-type (WT) and TLR2 knockout (KO) control and diabetic mice were used. Diabetes was induced by streptozotocin (STZ) injection. 14 weeks after, cerebral perfusion was measured by MRI and cognitive function was assessed by a battery of tests including Y-maze and fear conditioning. There was no difference in cerebral perfusion in WT and TLR2 KO mice (CBF ml/100gxmin:141.1± 5.374 vs. 156.3± 6.727, p >0.05). Diabetic WT mice exhibited an increase in perfusion vs. WT control (185.3± 9.018*, p<0.05), while diabetic TLR2 KO mice did not increase significantly vs. TLR KO control (159.0± 3.038). In Y maze, % novel arm entries were not different amongst all groups. In fear conditioning, WT, WT STZ, and TLR2 KO STZ mice did not differ from each other significantly (% freezing time: WT: 25.5± 6.1, WT STZ: 31.3± 4.9, TLR2 KO STZ: 35.1±7.9). TLR2 mice had significantly decreased freezing % compared to other groups (12.2± 2.7, p<0.05).

Conclusions: Diabetes induced by STZ mediates an increase in whole brain perfusion in WT mice, an effect that is not observed in TLR2 mice. The lack of difference in percent novel arm entries is likely a result of the relative increase in exploratory behavior in the STZ groups. TLR2 KO mice were protected from the development of fear and anxiety as indicated by the low %freezing time during fear conditioning tests. This could be due to alterations in perfusion. These findings suggest that TLR2 is involved in the development of diabetic cerebrovascular disease and potentially in vascular cognitive impairment.

Abstract TP441: Linagliptin Decreases Diabetes-induced Cerebral Pathological Neovascularization in a Blood Glucose-independent Manner

Objective: Diabetes promotes dysfunctional neovascularization and cerebrovascular remodeling in diabetes. We showed that glycemic control with metformin prevents and restores diabetes-mediated pathological remodeling and neovascularization of the cerebrovasculature. Our recent data suggest that linagliptin, a dipeptidyl-peptidase-4 (DPP-4) inhibitor used for glycemic control, prevents vascular remodeling independent of glycemic control in diabetes. In this study, we test the hypothesis that linagliptin prevents dysfunctional neovascularization in a blood glucose independent manner in diabetes.

Methods: 24 week old diabetic Goto-Kakizaki (GK) (Hemoglobin A1C >6.5%) and nondiabetic Wistar rats were treated for 4 weeks with either vehicle chow or chow containing 166mg/kg linagliptin. At termination, FITC-dextran was injected to full and visualize the vasculature and brain sections were imaged by confocal microscopy for vascular density, tortuosity, vascular volume, and surface area measurements in 3 dimensional reconstruction of the cortex and striatum regions. Retinal acellular capillary formation was measured as another surrogate marker for pathological neovascularization in diabetes (n=3-4). Brain microvascular endothelial cells (BMVEC) isolated from control or diabetic rats were also treated with (100 nM) linagliptin and tested for angiogenic properties with cell migration and tube formation assays.

Results: Linagliptin reduced all indices of cerebral neovascularization compared with control rats (Table, n=3-5). In addition linagliptin significantly decreased retinal acellular capillaries and normalized the augmented angiogenic properties of diabetic BMVEC (p<0.05).

Conclusions: These results suggest that linagliptin offers therapeutic potential and effective in reversing established pathological neovascularization. Mechanisms underlying glucose independent effects of linagliptin remain to be determined.

Linagliptin attenuates diabetes-induced cerebral pathological neovascularization in a blood glucose-independent manner: Potential role of ET-1

AIMS

We have shown that glycemic control with metformin or endothelin-1 (ET-1) inhibition with bosentan prevents and restores diabetes-mediated cerebral pathological remodeling and neovascularization. Our recent data suggest that linagliptin, a member of the dipeptidyl peptidase-4 inhibitor class of glucose-lowering agents, prevents cerebrovascular remodeling and dysfunction independent of its blood glucose lowering effects. We hypothesized that linagliptin prevents pathological neovascularization via the modulation of the ET-1 system.

MATERIALS AND METHODS

24-week old diabetic Goto-Kakizaki and nondiabetic Wistar rats were treated for 4weeks with either vehicle chow or chow containing 166mg/kg linagliptin. At termination, FITC-dextran was injected to visualize the vasculature. Brain sections were imaged by confocal microscopy for vascular density, tortuosity, vascular volume, and surface in both the cortex and striatum. Retinal acellular capillary formation was measured. Brain microvascular endothelial cells (BMVEC) isolated from control or diabetic rats were treated with linagliptin with or without ET-1 dual receptor antagonist and tested for angiogenic properties with cell migration and tube formation assays.

KEY FINDING

Linagliptin reduced all indices of cerebral neovascularization compared with control rats. In vitro, linagliptin normalized the augmented angiogenic properties of BMVECs isolated from diabetic animals and bosentan reversed this response. Cells from diabetic animals had higher ET-1 and less ETB receptors than in control cells. Linagliptin significantly decreased ET-1 levels and increased ETB receptors.

SIGNIFICANCE

ET system contributes to pathological neovascularization in diabetes as evidenced by restoration of functional angiogenesis by bosentan treatment and prevention of linagliptin-mediated improvement of angiogenesis in the in vitro model.

Abstract P030: Early Cognitive Deficits Induced by Diabetes Are Masked by an Increase in Exploratory Behavior: Evidence From TLR2 Knock-out Mice

Toll-like receptor 2 (TLR2) has been shown to contribute to cardiovascular complications of diabetes such as nephropathy. However, the role of TLR2 in cerebrovascular inflammation and dysfunction leading to cognitive impairment, an emerging cerebrovascular complication of diabetes and hypertension, remains unknown. We reported that streptozotocin (STZ)-induced type-1 diabetic TLR2 knockout mice were protected from decreased cerebral blood flow (CBF) at 4 and 6 weeks post induction. Given that decreased CBF precedes cognitive impairment, we hypothesized that these TLR2-KO STZ mice would subsequently be protected from cognitive impairment. 10 week old male C57Bl:6 and TLR2-KO mice were injected with 50mg STZ/kg body weight daily for 5 days and observed alongside control mice. Fasting blood glucose was measured, with levels > 240 mg/dL considered to confirm diabetes. Cognitive function was assessed via Y-maze testing. There was no difference in total arm entries between WT and WT-STZ mice or between WT and TLR2-KO. There was a significant decrease in total entries between TLR2-KO and TLR2-KO STZ (40.33± 1.88 vs.29.67± 2.09, p≥0.05, n=12/group). However, percent novel arm entries was statistically non-significant amongst all groups. Paradoxically, both diabetic groups had a non-significant increase in percent of time spent in the novel arm vs. their respective controls (WT-STZ: 35.7±5.3 seconds vs. WT: 33.2± 4.4 seconds; TLR2-KO STZ: 41.6±5.8 seconds vs. TLR2-KO: 37.9±5.5 seconds). The lack of difference in percent novel arm entries is likely a result of the relative increase in exploratory behavior in the STZ groups. Additional experiments with open-field testing and novel object recognition test are being performed to determine if the apparent lack of change in short term hippocampal memory is due to a confounding artifact of the exploration time and whether these cognitive tests are accompanied by changes in CBF in this cohort. If indeed TLR2 KO mice are protected from early mild cognitive deficits, TLR2 antagonism may be a novel target in the prevention/treatment of cerebrovascular complications of diabetes.

Activation of Toll-like receptor 3 increases mouse aortic vascular smooth muscle cell contractility through ERK1/2 pathway

Activation of Toll-like receptor 3 (TLR3), a pattern recognition receptor of the innate immune system, is associated with vascular complications. However, whether activation of TLR3 alters vascular contractility is unknown. We, therefore, hypothesized that TLR3 activation augments vascular contractility and activates vascular smooth muscle cell (VSMC) contractile apparatus proteins. Male mice were treated with polyinosinic-polycytidylic acid (Poly I:C group, 14 days), a TLR3 agonist; control mice received saline (vehicle, 14 days). At the end of protocol, blood pressure was measured by tail cuff method. Aortas were isolated and assessed for contractility experiments using a wire myograph. Aortic protein content was used to determine phosphorylated/total interferon regulatory factor 3 (IRF3), a downstream target of TLR3 signaling, and ERK1/2 using Western blot. We investigated the TLR3/IRF3/ERK1/2 signaling pathway and contractile-related proteins such as phosphorylated/total myosin light chain (MLC) and caldesmon (CaD) in aortic VSMC primary cultures. Poly I:C-treated mice exhibited (vs. vehicle-treated mice) (1) elevated systolic blood pressure. Moreover, Poly I:C treatment (2) enhanced aortic phenylephrine-induced maximum contraction, which was suppressed by PD98059 (ERK1/2 inhibitor), and (3) increased aortic levels of phosphorylated IRF3 and ERK1/2. Stimulation of mouse aortic VSMCs with Poly I:C resulted in increased phosphorylation of IRF3, ERK1/2, MLC, and CaD. Inhibition of ERK1/2 abolished Poly I:C-mediated phosphorylation of MLC and CaD. Our data provide functional evidence for the role of TLR3 in vascular contractile events, suggesting TLR3 as a potential new therapeutic target in vascular dysfunction and regulation of blood pressure.

Abstract 260: Toll-like Receptor 3 (TLR3) Activation Causes Contraction Of Vascular Smooth Muscle Through ERK1/2 Pathway And Increases Blood Pressure In Mice

Emerging evidence has suggested that viral infection can trigger hypertension. TLR3, a pattern-recognition receptor of the innate immunity, is activated by double-stranded RNA (dsRNA) from viruses or necrotic tissue. Vascular smooth muscle cells express TLR3; thus we hypothesized that TLR3 activation causes an increase in ERK1/2 signaling-induced vascular contractility and subsequently increases blood pressure. Stimulation of mouse C57bl/6 aortic smooth muscle cells (ASMC) with polyinosine polycytidylic acid (Poly I:C) (10 μg/mL, 60 min), a synthetic analog of dsRNA, resulted in increased myosin light chain phosphorylation (pMLC) (2.2 fold vs. unstimulated cells, p<0.05), a marker of vascular contraction. This effect was accompanied by increased phosphorylation of caldesmon (pCaD) on Ser789 (3.35 vs. unstimulated cells, p<0.05) as well as activation of ERK1/2 (2.56 fold increase vs. unstimulated cells, p<0.05). Pre-treatment with PD98059 (50μM, 30 min), an ERK1/2 inhibitor, decreased Poly I:C-mediated phosphorylation of CaD and MLC. Treatment with Poly I:C for 24 hours downregulated TLR3 expression by 40% in ASMC (p<0.05). Vascular studies performed on a tension myograph showed that aortas from mice treated for 2 weeks with intraperitoneal injection of Poly I:C (20mg/Kg every 48 hours) exhibited increased contraction to norepinephrine compared to control mice (EMax as %of maximum KCl response: 126± 4.56% vs. 108± 1.61%, respectively). This effect was attenuated in aortas from Poly I:C mice pre-incubated with 10uM PD98059 (EMax as %of maximum KCl response: 110.6± 5.12%). Systolic blood pressure (mmHg) was higher in Poly IC mice compared with control (128 ± 2 vs 159 ± 2). Increased spleen and kidney weight (mg) were observed in Poly I:C mice (77.63 ± 4.67 vs. 127.06 ± 7.70 control and 141.10 ± 2.42 vs. 180.35 ± 8.85 control, respectively).Our results show that activation of TLR3 in VSMC causes ERK1/2-mediated phosphorylation of MLC and CaD, thereby contributing to augmented contraction and development of vascular dysfunction and hypertension. Our data provide the functional assessment of the role of TLR3 in vascular contractile events, suggesting TLR3 as a potential new therapeutic target in vascular dysfunction and regulation of blood pressure.

Abstract 307: Enhancement of Cerebrovascular Relaxation by Angiotensin II Type 2 Receptor Agonist, C21, is Lost in Type 2 Diabetes

Background: Angiotensin type 1 receptor (AT1R) blockers provide vascular protection and improve stroke outcomes in young otherwise healthy animals. These effects are believed to be mediated by the indirect stimulation of AT2R signaling. The AT2R agonist, compound 21 (C21), improves endothelial function in peripheral vascular beds but its effect on cerebral endothelial function remains unknown. It is important to determine the vascular effects of C21 in diabetes, a comorbid condition which is known to worsen stroke outcomes.

Methods: Endothelium-dependent relaxation was assessed in male Wistar and Type 2 diabetic Goto-Kakizaki (GK) rats (n=3-6) by measuring acetylcholine (ACh, 1 nM - 5 μm) induced dilatory response in basilar arteries. In a subset of experiments C21 dose response curves were generated (0.1 nM - 1 μM) or vessels were pre-incubated with 100 nM C21 ± 1 μM PD123319 (AT2R blocker) for 30 min prior to Ach dose response curves. Area under the curve (AUC) and half maximal effective concentration (EC50 nM) were calculated as indices of total relaxation and receptor sensitivity, respectively. Angiotensin receptors expression was measured by immunoblotting of brain homogenates.

Results: AT2R agonist C21 dose response curves showed no basilar reactivity in either control or diabetic animals. Pre-incubation with C21 enhanced relaxation to Ach in control animals (vehicle 146.7 ± 3.9 vs C21 pretreatment 229.6 ± 11.6), which was abolished by the blockade of AT2R (176.9 ± 25.5, p=0.007). Similarly, C21 improved sensitivity in control animals (vehicle 110.5 ± 32 vs C21 pretreatment 11.9 ± 2) which was abolished in the presence of PD123319 (93.8 ± 31, p=0.04). Basilar artery relaxation (AUC) was impaired in diabetic GK rats (93.9 ± 1.8%) as compared to controls (146.7 ± 3.9%) and C21 had no effect (98 ± 8.9%) indicating a disease and treatment interaction (p<0.001). Normalized AT1R expression levels were 1 ± 0.04 and 0.98 ± 0.05 in control vs diabetic rats and respective AT2R levels were 1 ± 0.1 and 0.84 ± 0.09.

Conclusion: C21 improves vascular relaxation in control but not in diabetic rats in an AT2R-dependent manner. Underlying mechanisms blunting response to C21 need to be further investigated and may impact the subsequent development of C21 as a treatment for stroke.

Abstract 064: Toll-like Receptor 2 Signaling Contributes To Cerebrovascular Dysfunction And Decreased Cerebral Blood Flow In Type-1 And Type-2 Diabetes

We have shown that type 2 diabetic Goto-Kakizaki (GK) rats develop cerebrovascular endothelial dysfunction, impaired cerebral blood flow (CBF) and mild cognitive deficits. It is increasingly recognized that vascular cognitive impairment may be a new complication of the disease in both type 1 and type 2 diabetes. Toll-like receptor-2 (TLR2) plays a role in cardiovascular complications of diabetes but its involvement in diabetic cerebrovascular disease is unknown. Since brain function heavily depends on constant perfusion, and decreased CBF precedes development of inflammation and cognitive deficits, we hypothesized that enhanced TLR2 signaling in both type 1 and 2 diabetes would contribute to cerebrovascular dysfunction and decreased CBF. Endothelium-dependent relaxation was assessed by measuring acetylcholine (ACh, 10-9 -10-4 M) induced dilatory response in basilar arteries from GK rats in the presence and absence of an anti-TLR2 (1μg) antibody. Vascular contractility to serotonin (10-9 -10-5 M) stimulation was also assessed. Area under the curve (AUC) and maximal effective concentration (Emax as % of max KCl response) were calculated as indices of total relaxation and total contraction, respectively. Basilar artery relaxation was significantly improved in the vessels preincubated (30’) with antiTLR2 (184.8± 24.0 vs. 87.7± 4, p =0.007). The EMax in response to serotonin stimulation in the anti-TLR2 treated vessels was not significantly different than the vessels from the untreated diabetic GK rats (110.6± 4.9% vs 99.4.±4.5%). To further assess the in vivo functional effects of TLR2 signaling, CBF (relative intensity) was measured using laser speckle imaging in wild type and TLR2-knockout (KO) mice using an STZ induced diabetes model. Six weeks after induction of diabetes, wild-type diabetic mice exhibited a significant decrease in CBF vs. control (210±22.5 vs. 300.3±18.4, p<0.05). This decrease in cerebral perfusion was attenuated in the TLR2-KO diabetic mice compared to TLR2 KO control (322.6±10.1 vs. 344. 5±11. 04). These findings suggest that TLR2 signaling leads to vascular dysfunction through decreased endothelium dependent relaxation, and could contribute to decreased CBF in diabetes predisposing to vascular cognitive impairment.

Abstract 189: Toll-like Receptor 2 Blockade Decreases Contractility in Angiotensin II-induced Hypertensive Rat Resistance Arteries

Toll-like receptors (TLRs) are pattern recognition receptors of the innate immune system that recognize endogenous damage-associated molecular patterns (DAMPS). TLR2 plays a role in cardiovascular diseases such as atherosclerosis and heart failure, but its role in hypertension is unknown. Angiotensin II (ANG), the effector molecule of the renin-angiotensin system, has been shown to cause an immune response leading to an inflammatory profile, in addition to its effects on vascular tone and sodium balance. We hypothesized that signaling through TLR2 in ANG-induced hypertension contributes to an increase in resistance artery contractility and vascular dysfunction. Sprague-Dawley rats were implanted with osmotic mini-pumps dispensing ANG (60 mg/day) for a 28 day period. Systolic blood pressure (measured directly via femoral canulation to confirm the ANG rats as a model of hypertension) was significantly increased in the ANG-treated rats (170 ±4.79 mmHg) vs. control (97 ±6.9 mmHg (p<0.05)). Concentration response curves to norepinephrine (NE; 10-9-10-4 M) were performed in second and third order mesenteric arteries from control and angiotensin-treated rats. Vessels were pre-incubated with and without antibody to TLR2 (1μg) for 35 minutes prior to the concentration-response curves to determine the impact of TLR2 blockade. The EMax (force of contraction as % of maximum KCl response) of the ANG vessels treated with anti-TLR2 was significantly lower than that of the ANG vessels alone (EMax: 129.2±10.69% vs 183.8±16.73%, respectively), and comparable to control-vessel levels (EMax in control vessels: 135.1±4.360%, p<0.05). Additionally, we sought to determine protein levels of TLR2 and downstream signaling protein MyD88 in the mesenteric arteries. In the arteries from the ANG treated animals, TLR2 expression was significantly increased 2.95±0.20 fold above control, and MyD88 expression was increased 1.35±0.06 fold above control (p<0.05). This suggests that TLR2 signaling leads to augmented contractility and is associated with the vascular dysfunction observed in hypertension.