Bivalirudin as a substitute for heparin in neurointervention for patients with heparin-induced thrombocytopenia

OBJECTIVES

Heparin-induced thrombocytopenia is a known complication of heparin exposure with potentially life-threatening sequelae. Direct thrombin inhibitors can be substituted for heparin in patients with heparin-induced thrombocytopenia that require anticoagulation. However, the use of direct thrombin inhibitors as a substitute for heparin has not been widely reported in the neuroendovascular literature.

MATERIALS AND METHODS

Here we report the first use of the direct thrombin inhibitor bivalirudin in a neuroendovascular procedure as a substitute for heparin in a patient with a ruptured pseudoaneurysm and heparin-induced thrombocytopenia, and review the literature on the use of bivalirudin and argatroban for such patients.

RESULTS

Bivalirudin was safely and effectively used in the case reported, with no thrombotic or hemorrhagic complications. Our literature review revealed a paucity of studies on the use of heparin alternatives, including bivalirudin, in neuroendovascular procedures in patients with heparin-induced thrombocytopenia.

CONCLUSIONS

Heparin-induced thrombocytopenia is an important iatrogenic disease process in patients undergoing neuroendovascular procedures, and developing protocols to diagnose and manage heparin-induced thrombocytopenia is important for healthcare systems. While further research needs to be done to establish the full range of anticoagulation options to substitute for heparin, our case indicates bivalirudin as a potential candidate.

Fixed- Versus Variable-Dose Prothrombin Complex Concentrate for the Emergent Reversal of Vitamin K Antagonists: A Systematic Review and Meta-Analysis

OBJECTIVES

Four-factor prothrombin complex concentrate (4-PCC) is recommended for rapid reversal of vitamin K antagonists (VKAs) such as warfarin, yet optimal dosing remains uncertain.

DATA SOURCES

A systematic review was conducted of PubMed, Embase, and Ovid MEDLINE (Wolters Kluwer) databases from January 2000 to August 2023 for clinical studies comparing fixed- vs. variable-dose 4-PCC for emergent VKA reversal with at least one reported clinical outcome.

STUDY SELECTION

Abstracts and full texts were assessed independently and in duplicate by two reviewers.

DATA EXTRACTION

Data were extracted independently and in duplicate by two reviewers using predefined extraction forms.

DATA SYNTHESIS

The analysis comprised three randomized trials and 16 cohort studies comprising a total of 323 participants in randomized trials (161 in fixed dosage and 162 in variable dosage) and 1912 patients in cohort studies (858 in fixed-dose and 1054 in variable dose). Extracranial bleeding was the predominant indication, while intracranial hemorrhage varied. Overall, a fixed-dose regimen may be associated with a lower dose of 4-PCC and results in a reduction in 4-PCC administration time compared with a variable-dose regimen. A fixed-dose regimen also likely results in increased clinical hemostasis. While there is no clear difference between the two regimens in terms of achieving a goal international normalized ratio (INR) less than 2, a fixed-dose regimen is less likely to achieve a goal INR less than 1.5. High certainty evidence indicates that the fixed-dose regimen reduces both mortality and the occurrence of thromboembolic events. Additional subgroup analyses provides exploratory data to guide future studies.

CONCLUSIONS

A fixed-dose regimen for 4-PCC administration provides benefits over a variable-dose regimen in terms of dose reduction, faster administration time, improved clinical hemostasis, and reduced mortality and thromboembolic events. Further studies are warranted to better refine the optimal fixed-dose regimen.

P2Y12 inhibitor use predicts hematoma expansion in patients with intracerebral hemorrhage

OBJECTIVE

Hematoma expansion (HE) predicts disability and death after acute intracerebral hemorrhage (ICH). Aspirin and anticoagulants have been associated with HE. We tested the hypothesis that P2Y12 inhibitors predict subsequent HE in patients. We explored laboratory measures of P2Y12 inhibition and dual antiplatelet therapy with aspirin (DAPT).

METHODS

We prospectively identified patients with ICH. Platelet activity was measured with the VerifyNow-P2Y12 assay. Hematoma volumes for initial and follow-up CTs were calculated using a validated semi-automated technique. HE was defined as the difference between hematoma volumes on the initial and follow-up CT scans. Nonparametric statistics were performed with Kruskal-Wallis H, and correction for multiple comparisons performed with Dunn's test.

RESULTS

In 194 patients, 15 (7.7%) were known to take a P2Y12 inhibitor (clopidogrel in all but one). Patients taking a P2Y12 inhibitor had more HE compared to patients not taking a P2Y12 inhibitor (3.5 [1.2-11.9] vs. 0.1 [-0.8-1.4] mL, p = 0.004). Patients taking DAPT experienced the most HE (7.2 [2.6-13.8] vs. 0.0 [-1.0-1.1] mL, p = 0.04). The use of P2Y12 inhibitors was associated with less P2Y12 activity (178 [149-203] vs. 288 [246-319] P2Y12 reaction units, p = 0.005).

INTERPRETATION

Patients taking a P2Y12 inhibitor had more HE and less P2Y12 activity. The effect was most pronounced in patients on DAPT, suggesting a synergistic effect of P2Y12 inhibitors and aspirin with respect to HE. Acute reversal of P2Y12 inhibitors in acute ICH requires further study.

Clot composition and recanalization outcomes in mechanical thrombectomy

BACKGROUND

Mechanical thrombectomy (MT) has become standard for large vessel occlusions, but rates of complete recanalization are suboptimal. Previous reports correlated radiographic signs with clot composition and a better response to specific techniques. Therefore, understanding clot composition may allow improved outcomes.

METHODS

Clinical, imaging, and clot data from patients enrolled in the STRIP Registry from September 2016 to September 2020 were analyzed. Samples were fixed in 10% phosphate-buffered formalin and stained with hematoxylin-eosin and Martius Scarlett Blue. Percent composition, richness, and gross appearance were evaluated. Outcome measures included the rate of first-pass effect (FPE, modified Thrombolysis in Cerebral Infarction 2c/3) and the number of passes.

RESULTS

A total of 1430 patients of mean±SD age 68.4±13.5 years (median (IQR) baseline National Institutes of Health Stroke Scale score 17.2 (10.5-23), IV-tPA use 36%, stent-retrievers (SR) 27%, contact aspiration (CA) 27%, combined SR+CA 43%) were included. The median (IQR) number of passes was 1 (1-2). FPE was achieved in 39.3% of the cases. There was no association between percent histological composition or clot richness and FPE in the overall population. However, the combined technique resulted in lower FPE rates for red blood cell (RBC)-rich (P<0.0001), platelet-rich (P=0.003), and mixed (P<0.0001) clots. Fibrin-rich and platelet-rich clots required a higher number of passes than RBC-rich and mixed clots (median 2 and 1.5 vs 1, respectively; P=0.02). CA showed a trend towards a higher number of passes with fibrin-rich clots (2 vs 1; P=0.12). By gross appearance, mixed/heterogeneous clots had lower FPE rates than red and white clots.

CONCLUSIONS

Despite the lack of correlation between clot histology and FPE, our study adds to the growing evidence supporting the notion that clot composition influences recanalization treatment strategy outcomes.

Charlson Comorbidity Index and Frailty as Predictors of Resolution Following Middle Meningeal Artery Embolization for Chronic Subdural Hematoma

BACKGROUND

Research on variables associated with chronic subdural hematoma (cSDH) resolution following middle meningeal artery embolization (MMAE) is limited. This study investigated the clinical utility of age-adjusted Charlson Comorbidity Index (ACCI) and modified 5-item Frailty Index (mFI - 5) for predicting cSDH resolution following MMAE.

METHODS

We identified patients who underwent MMAE at our institution between January 2018 and December 2022, with at least 20 days of follow-up and one radiographic follow-up study. Patient demographics, characteristics, and outcomes were collected. Complete resolution was defined as absence of subdural collections on CT-scan at last follow-up. Nonage adjusted CCI (CCI), ACCI, and mFI - 5 scores were calculated. Univariate and multivariable logistic regression analyzed the relationship between cSDH resolution and variables. A receiver operating characteristic (ROC) curve established the utility of ACCI and mFI - 5 in predicting hematoma resolution.

RESULTS

The study included 85 MMAE procedures. In univariate analysis, patients without resolution were older, had higher CCI, higher ACCI, higher mFI - 5, and were more likely to have diabetes mellitus. In multivarible analysis, CCI (OR: 0.66, 95% CI: 0.48, 0.91) was independently associated with resolution controlling for age and antithrombotic resumption. The area under the ROC (AUROC) curve was 0.75 (95% CI: 0.65-0.85) for ACCI and 0.64 (95% CI: 0.52-0.76) for mFI - 5. The optimal cutoffs for predicting resolution were ACCI ≥5 (sensitivity = 0.63, specificity = 0.77), and mFI - 5 > 0 (sensitivity = 0.84, specificity = 0.43).

CONCLUSIONS

ACCI and mFI - 5 moderately predict MMAE resolution and may aid in medical decision-making.

Background Subtraction Angiography with Deep Learning Using Multi-frame Spatiotemporal Angiographic Input

Catheter Digital Subtraction Angiography (DSA) is markedly degraded by all voluntary, respiratory, or cardiac motion artifact that occurs during the exam acquisition. Prior efforts directed toward improving DSA images with machine learning have focused on extracting vessels from individual, isolated 2D angiographic frames. In this work, we introduce improved 2D + t deep learning models that leverage the rich temporal information in angiographic timeseries. A total of 516 cerebral angiograms were collected with 8784 individual series. We utilized feature-based computer vision algorithms to separate the database into "motionless" and "motion-degraded" subsets. Motion measured from the "motion degraded" category was then used to create a realistic, but synthetic, motion-augmented dataset suitable for training 2D U-Net, 3D U-Net, SegResNet, and UNETR models. Quantitative results on a hold-out test set demonstrate that the 3D U-Net outperforms competing 2D U-Net architectures, with substantially reduced motion artifacts when compared to DSA. In comparison to single-frame 2D U-Net, the 3D U-Net utilizing 16 input frames achieves a reduced RMSE (35.77 ± 15.02 vs 23.14 ± 9.56, p < 0.0001; mean ± std dev) and an improved Multi-Scale SSIM (0.86 ± 0.08 vs 0.93 ± 0.05, p < 0.0001). The 3D U-Net also performs favorably in comparison to alternative convolutional and transformer-based architectures (U-Net RMSE 23.20 ± 7.55 vs SegResNet 23.99 ± 7.81, p < 0.0001, and UNETR 25.42 ± 7.79, p < 0.0001, mean ± std dev). These results demonstrate that multi-frame temporal information can boost performance of motion-resistant Background Subtraction Deep Learning algorithms, and we have presented a neuroangiography domain-specific synthetic affine motion augmentation pipeline that can be utilized to generate suitable datasets for supervised training of 3D (2d + t) architectures.

Outpatient telemedicine in neurosurgery: 15,677 consecutive encounters in a comparative analysis of its effectiveness and impact on the surgical conversion rate

OBJECTIVE

The coronavirus disease 2019 (COVID-19) pandemic has necessitated the use of telehealth visits (THVs). The effects on neurosurgical practice have not been well characterized, especially concerning new-patient THVs. Therefore, the authors of this study reviewed their institution's experience with outpatient clinic visits and THVs from before the COVID-19 pandemic to the present to focus on clinical metrics, rates of surgery, and the effects of implementing THVs in order to better understand their implications for clinical practice as more data emerge over time.

METHODS

The authors reviewed 15,677 consecutive new outpatient in-person visits (IPVs), THVs, and neurosurgical procedures/cases proceeding from their institution between 2018 and 2022 for trends and associations related to THVs.

RESULTS

Among spine patients, there was no difference in the proportion of encounters that led to surgery (surgical conversion rate) between THVs and IPVs (p = 0.49). Among cranial patients, THVs were negatively associated with conversion (OR 0.73, p = 0.03). On average, patients using THVs lived further from the hospital (p < 0.001); however, the patient catchment area appeared unchanged. The median distance to the hospital among THV patients was counterbalanced by a decreased distance for spine patients pursing IPVs (p < 0.001), with no significant change to case volume. There was no change in distance to the hospital among cranial patients. For both cranial and spine patients, surgical conversion was more likely among those who lived a great distance from the hospital if their initial encounter was an IPV (p = 0.007 and < 0.001, respectively). However, there was no relationship between distance from the hospital and surgical conversion among THV patients (p = 0.565). The availability of THVs did not significantly affect follow-up time (p = 0.837). For new patients at IPVs, there was no difference in time to the operating room between cranial and spine cases; for new patients at THVs, however, time to the operating room was significantly faster for cranial cases than for spine cases (p = 0.0018).

CONCLUSIONS

Compared to IPVs, THVs lead to decreased surgical conversion for cranial patients but not spine patients. THVs do not appear to increase the catchment area. For patients who live far from the hospital, an IPV is associated with surgical conversion. Surgical conversion is faster following cranial THVs than after spine THVs. THVs did not increase the duration of follow-up.

Unplanned readmission after carotid stenting versus endarterectomy: analysis of the United States Nationwide Readmissions Database

BACKGROUND

Hospital readmissions are costly and reflect negatively on care delivered.

OBJECTIVE

To have a better understanding of unplanned readmissions after carotid revascularization, which might help to prevent them.

METHODS

The Nationwide Readmissions Database was used to determine rates and reasons for unplanned readmission following carotid endarterectomy (CEA) and carotid artery stenting (CAS). Trends were assessed by annual percent change, modified Poisson regression was used to estimate risk ratios (RR) for readmission, and propensity scores were used to match cohorts.

RESULTS

Analysis yielded 522 040 asymptomatic and 55 485 symptomatic admissions for carotid revascularization between 2010 and 2015. Higher 30-day readmission rates were noted after CAS versus CEA in both symptomatic (9.1% vs 7.7%, p<0.001) and asymptomatic (6.8% vs 5.7%, p<0.001) patients. Readmission rates trended lower over time, significantly so for 90-day readmissions in symptomatic patients undergoing CEA. The most common cause for 30-day readmission was stroke in both symptomatic (5.5%) and asymptomatic (3.9%) patients. Factors associated with a higher risk of readmission included age over 80; male gender; Medicaid health insurance; and increases in severity of illness, mortality risk, and comorbidity indices. Analysis of matched cohorts showed that CAS had higher readmission than CEA (RR=1.14 (95% CI 1.06 to 1.22); p<0.001) only in asymptomatic patients. Adverse events during initial admission which predicted 30-day readmission included acute renal failure and acute respiratory failure in asymptomatic patients; hematoma and cardiac events were additional predictive adverse events in symptomatic patients.

CONCLUSIONS

Readmission is not uncommon after carotid revascularization, occurs more often after CAS, and is predicted by baseline factors and by preventable adverse events at initial admission.

Abstract WP94: Prediction Of Stroke Thrombectomy Outcomes From The Neurovascular Quality Initiative-quality Outcomes Database (NVQI-QOD) Registry Using Probabilistic Learning Models

Introduction: Mechanical Thrombectomy (MT) is standard-of-care interventional management of Acute Ischemic Stroke (AIS) due to large vessel occlusions. However, patient outcomes remain variable after intervention, with unclear optimization strategies for patient selection. The NVQI-QOD registry documents detailed patient characteristics, pre-operative imaging, procedure metrics, and post-operative outcomes of neurointerventional procedures. Data are highly informative, but there is inherent uncertainty in all medical interventions. We introduce a probabilistic learning model that predicts the expected distribution of MT outcomes.

Methods: We identified two groups of variables from the NVQI-QOD AIS Thrombectomy registry: 1) data available at the time of MT (Group-preop), and 2) data available 24 h after MT, which can be valuable for prognostication (Group-24h). After filtering missing values, there were 1174 and 1405 examples in the two groups, respectively. In each group, training and test datasets were split using a ratio of 8:2. A probabilistic Neural Network (NN) ( Fig. 1a ) was developed to predict the distribution of changes in pre- and post-MT NIH Stroke Scale (NIHSS) ( y ), and it was trained using both groups of variables as inputs.

Results: After training, the probabilistic network accurately described the distributions of changes in the NIHSS (represented by predicted means and SDs) based on input variables ( Fig. 1b - upper ). Notably, in Group-preop, even patients with the worst predicted outcomes had an approximately 50% chance of improvement. Fig. 1b - lower demonstrates the relative importance of variables to the NN.

Conclusions: This NN model demonstrates the utility of probabilistic learning in clinical decision-making and prognosis. Our results reinforce the substantial benefits of MT, that can still improve outcomes in nearly half of patients with the worst predicted change in NIHSS on pre-operative analysis.

Abstract 99: Clot Composition And Reperfusion Outcomes In 1430 Mechanical Thrombectomy Patients: Analysis Of The Stroke Thromboembolism Registry Of Imaging And Pathology

Background: Understanding clot composition may allow for better technical planning and improved outcomes in mechanical thrombectomy (MT). We sought to correlate clot composition with reperfusion outcomes in MT.

Methods: Clinical, imaging, and clot data from patients enrolled in the STRIP Registry from September 2016 to September 2020 were analyzed. Samples were fixed in 10% phosphate-buffered formalin and stained with hematoxylin and eosin and Martius Scarlett Blue. Percent composition, richness, and gross appearance were evaluated. Outcome measures included the rate of First-Pass Effect (mTICI2c/3, FPE) and the number of device passes.

Results: A total of 1430 patients (mean age, 68.4±13.5years; median [IQR] baseline NIHSS,17.2 [10.5-23]; IV-tPA use, 36%; Stent-Retrievers [SR], 27%; Contact Aspiration [CA], 27%; Combined SR + CA, 43%) were included. The median [IQR] number of passes was 1 [1-2]. FPE was achieved in 39.3% of the cases. There was no association between percent histological composition or clot richness and FPE in the overall population. However, the combined technique resulted in lower FPE rates for RBC-rich (P<0.0001), platelet-rich (P=0.003), and mixed (P<0.0001) clots. Fibrin-rich and platelet-rich clots required a higher number of passes compared to RBC-rich and mixed clots (median, 2 and 1.5 vs.1, respectively, P=0.02). CA displayed a trend towards a higher number of passes with fibrin-rich clots (2 vs.1, P=0.12). By gross appearance, mixed/heterogeneous clots had lower FPE rates than red and white clots.

Conclusion: Despite the lack of correlation between clot histology and FPE in the overall population, our study adds to the growing body of evidence supporting the notion that clot composition influences reperfusion treatment strategy outcomes. Additional studies are needed.

Quantification of clot spatial heterogeneity and its impact on thrombectomy

BACKGROUND

Compositional and structural features of retrieved clots by thrombectomy can provide insight into improving the endovascular treatment of ischemic stroke. Currently, histological analysis is limited to quantification of compositions and qualitative description of the clot structure. We hypothesized that heterogeneous clots would be prone to poorer recanalization rates and performed a quantitative analysis to test this hypothesis.

METHODS

We collected and did histology on clots retrieved by mechanical thrombectomy from 157 stroke cases (107 achieved first-pass effect (FPE) and 50 did not). Using an in-house algorithm, the scanned images were divided into grids (with sizes of 0.2, 0.3, 0.4, 0.5, and 0.6 mm) and the extent of non-uniformity of RBC distribution was computed using the proposed spatial heterogeneity index (SHI). Finally, we validated the clinical significance of clot heterogeneity using the Mann-Whitney test and an artificial neural network (ANN) model.

RESULTS

For cases with FPE, SHI values were smaller (0.033 vs 0.039 for grid size of 0.4 mm, P=0.028) compared with those without. In comparison, the clot composition was not statistically different between those two groups. From the ANN model, clot heterogeneity was the most important factor, followed by fibrin content, thrombectomy techniques, red blood cell content, clot area, platelet content, etiology, and admission of intravenous tissue plasminogen activator (IV-tPA). No statistical difference of clot heterogeneity was found for different etiologies, thrombectomy techniques, and IV-tPA administration.

CONCLUSIONS

Clot heterogeneity can affect the clot response to thrombectomy devices and is associated with lower FPE. SHI can be a useful metric to quantify clot heterogeneity.

Concomitant cervical spine fractures are the primary driver of disability after traumatic vertebral artery dissection: A Case series of 123 patients

Background

Traumatic vertebral artery dissections (tVADs) occur in up to 20% of patients with head trauma, yet data on their presentation and associated sequelae are limited.

Aims and Objectives

To characterize the tVAD population and identify factors associated with clinical outcomes.

Materials and Methods

We retrospectively analyzed all cases of tVAD at our institution from January 2004 to December 2018 with respect to mechanism of injury, clinical presentation, anatomic factors, associated pathologies, and relevant outcomes.

Results

Of the 123 patients with tVAD, the most common presenting symptoms were neck pain (n=76, 67.3%), headache (57.5%), and visual changes (29.6%). 101 cases (82.1%) were unilateral, and 22 cases (17.9%) were bilateral. V2 was the most involved anatomic segment (83 cases, 70.3). 30 cases (25.4%) led to stroke, and 39 cases (31.7%) had a concomitant cervical fracture. The anatomic segment and number of segments involved, and baseline clinical and demographic characteristics were not associated with risk of stroke. Patients with associated fractures were older (50.3 years v. 36.4 years, p=0.0233), had a higher comorbid disease burden (CCI 1 vs. CCI 1, p<0.0007), were more likely to smoke (OR 3.0 [1.2178, 7.4028], p=0.0202), be male (OR 7.125 [3.0181, 16.8236], p<0.0001), and have mRS≥3 at discharge (OR 3.0545 [1.0937, 8.5752], p=0.0449). On multivariable regression, only fracture independently predicted mRS≥3 at discharge (OR 5.6898 [1.5067, 21.4876], p=0.010).

Conclusion

tVADs may be associated with stroke and/or cervical fracture. Presenting symptoms predict stroke, but baseline demographic and clinical characteristics do not. Comorbid cervical fractures, not stroke, drive negative outcomes.

Ethical Considerations in Surgical Decompression for Stroke

Stroke is a major cause of morbidity and mortality. Neurosurgical decompression is often considered for the treatment of malignant infarcts and intraparenchymal hemorrhages, but this treatment can be frought with ethical dilemmas. In this article, the authors outline the primary principles of bioethics and their application to stroke care, provide an overview of key ethical issues and special situations in the neurosurgical management of stroke, and highlight methods to improve ethical decision-making for patients with stroke. Understanding these ethical principles is essential for stroke care teams to deliver appropriate, timely, and ethical care to patients with stroke.

Correlation of von Willebrand factor and platelets with acute ischemic stroke etiology and revascularization outcome: an immunohistochemical study

BACKGROUND

Platelets and von Willebrand factor (vWF) are key components of acute ischemic stroke (AIS) emboli. We aimed to investigate the CD42b (platelets)/vWF expression, its association with stroke etiology and the impact these components may have on the clinical/procedural parameters.

METHODS

CD42b/vWF immunostaining was performed on 288 emboli collected as part of the multicenter STRIP Registry. CD42b/VWF expression and distribution were evaluated. Student's t-test and χ² test were performed as appropriate.

RESULTS

The mean CD42b and VWF content in clots was 44.3% and 21.9%, respectively. There was a positive correlation between platelets and vWF (r=0.64, p<0.001**). We found a significantly higher vWF level in the other determined etiology (p=0.016*) and cryptogenic (p=0.049*) groups compared with cardioembolic etiology. No significant difference in CD42b content was found across the etiology subtypes. CD42b/vWF patterns were significantly associated with stroke etiology (p=0.006*). The peripheral pattern was predominant in atherosclerotic clots (36.4%) while the clustering (patchy) pattern was significantly associated with cardioembolic and cryptogenic origin (66.7% and 49.8%, respectively). The clots corresponding to other determined etiology showed mainly a diffuse pattern (28.1%). Two types of platelets were distinguished within the CD42b-positive clusters in all emboli: vWF-positive platelets were observed at the center, surrounded by vWF-negative platelets. Thrombolysis correlated with a high platelet content (p=0.03*). vWF-poor and peripheral CD42b/vWF pattern correlated with first pass effect (p=0.03* and p=0.04*, respectively).

CONCLUSIONS

The vWF level and CD42b/vWF distribution pattern in emboli were correlated with AIS etiology and revascularization outcome. Platelet content was associated with response to thrombolysis.

Mass Deployment of Deep Neural Network: Real-Time Proof of Concept With Screening of Intracranial Hemorrhage Using an Open Data Set

BACKGROUND

Intracranial hemorrhage (ICH) is considered an emergency that requires rapid medical or surgical management. Previous studies have used artificial intelligence to attempt to expedite the diagnosis of this pathology on neuroimaging. However, these studies have used local, institution-specific data for training of networks that limit deployment of across broader hospital networks or regions because of data biases.

OBJECTIVE

To demonstrate the creation of a neural network based on an openly available imaging data tested on data from our institution demonstrating a high-efficacy, institution-agnostic network.

METHODS

A data set was created from publicly available noncontrast computed tomography images of known ICH. These data were used to train a neural network using distinct windowing and augmentation. This network was then validated in 2 phases using cohort-based (phase 1) and longitudinal (phase 2) approaches.

RESULTS

Our convolutional neural network was trained on 752 807 openly available slices, which included 112 762 slices containing intracranial hemorrhage. In phase 1, the final network performance for intracranial hemorrhage showed a receiver operating characteristic curve (AUC) of 0.99. At the inflection point, our model showed a sensitivity of 98% at a threshold specificity of 99%. In phase 2, we obtained an AUC of 0.98 after analysis of 726 scans with a negative predictive value of 99.70% (n = 726).

CONCLUSION

We demonstrate an effective neural network trained on completely open data for screening ICH at an unrelated institution. This study demonstrates a proof of concept for screening networks for multiple sites while maintaining high efficacy.

Histological composition of retrieved emboli in acute ischemic stroke is independent of pre-thrombectomy alteplase use

BACKGROUND AND PURPOSE

Given recent evidence suggesting the clot composition may be associated with revascularization outcomes and stroke etiology, clot composition research has been a topic of growing interest. It is currently unclear what effect, if any, pre-thrombectomy thrombolysis has on clot composition. Understanding this association is important as it is a potential confounding variable in clot composition research. We retrospectively evaluated the composition of retrieved clots from ischemic stroke patients who did and did not receive pre-treatment tPA to study the effect of tPA on clot composition.

MATERIALS AND METHODS

Consecutive patients enrolled in the Stroke Thromboembolism Registry of Imaging and Pathology (STRIP) were included in this study. All patients underwent mechanical thrombectomy and retrieved clots were sent to a central core lab for processing. Histological analysis was performed using Martius Scarlett Blue (MSB) staining and area of the clot was also measured on the gross photos. Student's t test was used for continuous variables and chi-squared test for categorical variables.

RESULTS

A total of 1430 patients were included in this study. Mean age was 68.4±13.5 years. Overall rate of TICI 2c/3 was 67%. A total of 517 patients received tPA (36%) and 913 patients did not (64%). Mean RBC density for the tPA group was 42.97±22.62% compared to 42.80±23.18% for the non-tPA group (P=0.89). Mean WBC density for the tPA group was 3.74±2.60% compared to 3.42±2.21% for the non-tPA group (P=0.012). Mean fibrin density for the tPA group was 26.52±15.81% compared to 26.53±15.34% for the non-tPA group (P=0.98). Mean platelet density for the tPA group was 26.22±18.60% compared to 26.55±19.47% for the non-tPA group (P=0.75). tPA group also had significantly smaller clot area compared to non-tPA group.

CONCLUSIONS

Our study 1430 retrieved emboli and ischemic stroke patients shows no interaction between tPA administration and clot composition. These findings suggest that tPA does not result in any histological changes in clot composition.

Continued dominance of carotid endarterectomy over stenting in the United States: Volumes, outcomes, and complications from the National Inpatient Sample (1997-2015)

BACKGROUND

The introduction of carotid stenting (CAS) has led to numerous comparative trials with carotid endarterectomy (CEA).

OBJECTIVE

To review real-world volumes, outcomes and complications following CEA versus CAS over an extended period to identify durable changes in practice.

METHODS

Data were extracted from the National Inpatient Sample. Trends were assessed by annual percent change (APC) and adjusted risk ratios (aRR)s were calculated across the last 5 years of the study period.

RESULTS

During 1997-2015, 199,330 symptomatic and 1,995,637 asymptomatic patients underwent carotid revascularization. In symptomatic patients, CEA declined (1997-2004; APC -7.68%, p<0.001) and CAS rose (1997-2008; APC 15.48%, p<0.001) during the first decade, subsequently becoming more muted. In asymptomatic patients, CEA decreased whereas CAS initially increased (1997-2006; APC 20.27%, p<0.001) and then decreased (2007-2015; APC -4.52%, p<0.001). Routine discharge after symptomatic revascularization declined in CEA after 2003 and in CAS after 2006 (APC -1.72% and -3.11% respectively, p<0.001 for both), corresponding to increasing patient comorbidity; similar trends were seen in asymptomatic patients. Death decreased after CEA (symptomatic and asymptomatic; APC -4.85% and -3.53% respectively, p<0.001 for both) and CAS (asymptomatic only, APC -2.53%, p=0.04). CAS remained associated with higher aRR for death, venous thromboembolism and seizures in all patients, and stroke and non-routine discharge in symptomatic patients, during the last 5 years of the study period.

CONCLUSIONS

Mortality has improved but routine discharge has decreased following both CEA and CAS, congruent with increasing patient comorbidity. Trends in volumes, outcomes and complication rates continue to favor CEA in real-world practice.

Holohemispheric Prostate Carcinoma Dural Metastasis Mimicking Subdural Hematoma: Case Report and Review of the Literature

Prostate carcinomas are the most common malignancy to metastasize to the dura. These metastases can commonly mimic subdural hematomas and may similarly present with brain compression. The optimal management and outcomes after surgical management are not well characterized. We present a case of prostate carcinoma metastatic to the dura that was initially thought to be a large isodense subdural hematoma and was treated with surgical decompression. We also review the literature regarding prostate dural metastases mimicking subdural hematomas and discuss the relevant imaging findings, treatments, and outcomes. Dural metastasis should be considered when a patient with known metastatic prostate cancer presents with imaging evidence of a subdural mass.

Abstract WMP94: Frequency And Outcome Of Endovascular Rescue After Carotid Endarterectomy: Analysis Of The National Inpatient Sample

Introduction: Secondary thrombosis or embolism in the immediate period after carotid endarterectomy (CEA) may require urgent/emergent endovascular rescue (i.e., carotid artery stenting [CAS] and/or thrombectomy). We aimed to estimate the proportion such rescue procedures after CEA in a national setting, and to compare their outcomes to CEA patients not undergoing endovascular rescue.

Methods: Using the 2018 National Inpatient Sample database and ICD-10 codes, all adult patients undergoing CEA were selected. Endovascular rescue was defined as CAS or thrombectomy performed on the same side as CEA, on the same day as or the days after CEA, and in the same hospitalization.

Results: A total of 68005 patients undergoing CEA were studied (mean age±SD: 71.24±8.97, 39735 [58.4%] male). Of these, 310 (0.5%) patients underwent endovascular rescue (220 [71%] CAS, 60 [19.4%] thrombectomy, and 30 [9.7%] both). In 240 (77.4%) of these patients, rescue was performed the same day as CEA. Patients undergoing endovascular rescue were not different in age (p=0.21) or sex (p=0.06) but were different in race (p=0.02), income (p=0.002), and insurance (p<0.001) compared to patients without rescue (Table). Patients undergoing rescue had a longer length of hospital stay (5.6±5.1 vs 2.9±4.4 days, p<0.001), lower frequency of routine discharge (58.1% vs 82.4%, p<0.001), and higher mortality (4.8% vs 0.5%, p<0.001).

Conclusions: Endovascular rescue is rarely needed in the immediate postoperative period after CEA but is associated with worse outcomes and higher mortality. A better understanding of factors associated with endovascular rescue may help better predict and prevent the need for such procedures.

Flow Diversion of Posterior Circulation Aneurysms: Systematic Review of Disaggregated Individual Patient Data

BACKGROUND

Experience with endoluminal flow diversion for the treatment of posterior circulation aneurysms is limited.

PURPOSE

We sought to investigate factors associated with the safety and efficacy of this treatment by collecting disaggregated patient-level data from the literature.

DATA SOURCES

PubMed, EMBASE, and Ovid were searched up through 2019 for articles reporting flow diversion of posterior circulation aneurysms.

STUDY SELECTION

Eighty-four studies reported disaggregated data for 301 separate posterior circulation aneurysms.

DATA ANALYSIS

Patient, aneurysm, and treatment factors were collected for each patient. Outcomes included the occurrence of major complications, angiographic occlusion, and functional outcomes based on the mRS.

DATA SYNTHESIS

Significant differences in aneurysm and treatment characteristics were seen among different locations. Major complications occurred in 22%, angiographic occlusion was reported in 65% (11.3 months of mean follow-up), and good functional outcomes (mRS 0-2) were achieved in 67% (13.3 months of mean follow-up). Multivariate analysis identified age, number of flow diverters used, size, and prior treatment to be associated with outcome measures. Meta-analysis combining the current study with prior large nondisaggregated series of posterior circulation aneurysms treated with flow diversion found a pooled incidence of 20% (n = 712 patients) major complications and 75% (n = 581 patients) angiographic occlusions.

LIMITATIONS

This study design is susceptible to publication bias. Use of antiplatelet therapy was not uniformly reported.

CONCLUSIONS

Endoluminal flow diversion is an important tool in the treatment of posterior circulation aneurysms. Patient age, aneurysm size, prior treatment, and the number of flow diverters used are important factors associated with complications and outcomes.

Traumatic and Spontaneous Vertebral Artery Dissections: An Analysis of Tertiary-Center 310 Patient Cohort

BACKGROUND

Vertebral artery dissections (VADs) are rare yet potentially devastating events. While the etiology of these events is either traumatic or spontaneous, there is a paucity of quantitative literature comparing the two.

OBJECTIVE

To identify differences in predisposing factors, event characteristics, and clinical outcomes between traumatic VADs (tVADs) and spontaneous VADs (sVADs).

METHODS

We retrospectively identified patients with VADs presenting to our institution at VAD onset with at least a 3-mo follow-up. Demographics, event characteristics, treatment details, and neurological outcomes as modified Rankin scale (mRS) scores were collected.

RESULTS

Of the 310 patients sustaining 366 VADs total, 187 (60.3%) patients experienced a total of 221 (60.4%) sVADs and 123 (39.7%) patients experienced a total of 145 (39.6%) tVADs. sVADs were more likely to occur in the intracranial course of the artery (P = .042) and have a lower mRS at discharge, 3-month, and last clinical follow-up (P = 003, .002, and .001, respectively). tVADs were more likely associated with concomitant fractures (P < .001).

CONCLUSION

Despite similar patient populations, tVADs are associated with higher mRS scores at all time points. Although further study is needed, this may suggest other concomitant trauma rather than the VAD itself is contributing to worse neurological status in patients with tVADs.

Clinical Characteristics, Course, and Outcomes of Vertebral Artery Dissections in the Postpartum Period

BACKGROUND

Postpartum vertebral artery dissections (ppVADs) are rare but potentially morbid conditions that occur in otherwise healthy patients.

OBJECTIVE

To evaluate clinical characteristics of ppVADs.

METHODS

Demographic, clinical, treatment, and outcome data were collected on ppVADs and are presented in a case series of 12 patients and compared to the general cohort.

RESULTS

In total, 12 patients had ppVADs in our cohort of 310 patients with vertebral artery dissections (VADs). They occurred 11.27 days (95% CI, -0.85 to 23.39) postdelivery. Of these, there were 5 (42%) with a hypertensive disorder of pregnancy, and 4 (33%) who had migraines. A total of 3 (25%) had ischemic strokes and 1 (8%) had a subarachnoid hemorrhage. In total, 2 patients (17%) had unfavorable modified Rankin Scale (mRS, 2-6) at discharge from hospital. Patients with ppVADs more often had bilateral VADs (42% vs 17%, P = .03), had pseudoaneurysms (50% vs 18%, P = .0068), were younger (33.83 years vs 44.32 years, P = .018), and had lower Charlson Comorbidity Index (CCI = 0 vs 0.99, P = .0038). Anticoagulant treatment was used in a similar percentage of patients. Multivariate analysis revealed 3 factors were predictive of change in mRS: CCI (OR = 1.09, 95% CI, 1.02-1.15), stroke (OR = 0.78, 95% CI, 0.65-0.95), and mRS at hospital discharge (OR = 0.80, 95% CI, 0.74-0.87).

CONCLUSION

There are only 15 isolated ppVADs reported in the literature; this study adds 12 patients with 17 ppVADs. Postpartum VADs occur in younger, healthier patients than in the general cohort, raising questions about mechanism of injury. The majority of ppVADs have good neurological outcomes.

Characteristics and Predictors of Outcome of Pseudoaneurysms Associated With Vertebral Artery Dissections: A 310-Patient Case Series

BACKGROUND

Vertebral artery dissections (VADs) are a common cause of stroke in young patients and can result in various secondary effects, including pseudoaneurysm formation.

OBJECTIVE

To identify differences in predisposing factors and outcomes for VADs with and without concomitant pseudoaneurysms.

METHODS

We retrospective chart reviewed patients who presented to our institution at the time of VAD with at least a 3-mo clinical follow-up. Demographics, VAD characteristics, treatment, and outcomes represented as modified Rankin scale (mRS) scores were collected.

RESULTS

Of 310 patients with a VAD included in this study, 301 patients had an identified pseudoaneurysm status, with 54 pseudoaneurysm-associated VADs and 247 VADs not associated with pseudoaneurysm. VAD patients with associated pseudoaneurysms were more likely to be female (P < .004), have bilateral VADs (P < .001), and have fewer vertebral artery segments affected (P = .018), and less likely to have stroke (P < .008) or occlusion of the vertebral artery (P < .001). There was no difference in the proportion of patients treated with antiplatelet agents (P = .12) or anticoagulants (P = .27) between the groups. VAD patients with associated pseudoaneurysms were more likely to have a higher mRS at 3-mo follow-up (P = .044) but not discharge (P = .18) or last follow-up (P = .05). VAD patients with pseudoaneurysms were equally likely to have resolution of occlusion (P = .40) and stenosis (P = .19).

CONCLUSION

Demographics and clinical and radiological characteristics of VADs associated with pseudoaneurysms are different from those without associated pseudoaneurysms. Vertebral artery dissections with concomitant pseudoaneurysms are neither associated with worse functional nor radiographic outcomes.

Histological evaluation of acute ischemic stroke thrombi may indicate the occurrence of vessel wall injury during mechanical thrombectomy

Background

Several animal studies have demonstrated that mechanical thrombectomy (MT) for acute ischemic stroke (AIS) may cause vessel wall injury (VWI). However, the histological changes in human cerebral arteries following MT are difficult to determine.

Objective

To investigate the occurrence of VWI during MT by histological and immunohistochemical evaluation of AIS clots.

Methods

As part of the multicenter STRIP registry, 277 clots from 237 patients were analyzed using Martius Scarlett Blue stain and immunohistochemistry for CD34 (endothelial cells) and smooth muscle actin (smooth muscle cells).

Results

MT devices used were aspiration catheters (100 cases), stentriever (101 cases), and both (36 cases). VWI was found in 33/277 clots (12%). There was no significant correlation between VWI and MT device. The degree of damage varied from grade I (mild intimal damage, 24 clots), to grade II (relevant intimal and subintimal damage, 3 clots), and III (severe injury, 6 clots). VWI clots contained significantly more erythrocytes (p=0.006*) and less platelets/other (p=0.005*) than non-VWI clots suggesting soft thrombus material.

Thrombolysis correlated with a lower rate of VWI (p=0.04*). VWI cases showed a significantly higher number of passes (2 [1–4] vs 1 [1–3], p=0.028*) and poorer recanalization outcome (p=0.01*) than cases without VWI.

Conclusions

Histological markers of VWI were present in 12% of AIS thrombi, suggesting that VWI might be related to MT. VWI was associated with soft thrombus consistency, higher number of passes and poorer revascularization outcome. There was no significant correlation between VWI and MT device.

Chiropractic associated vertebral artery dissection: An analysis of 34 patients amongst a cohort of 310

BACKGROUND

Vertebral artery dissections (VAD) are a rare but important cause of ischemic stroke, especially in younger patients. Many etiologies have been identified, including MVAs, cervical fractures, falls, physical exercise, and cervical chiropractic manipulation. The goal of this study was to investigate the subgroup of patients who suffered a chiropractor-associated injury and determine how their prognosis compared to other-cause VAD.

METHODS

We conducted a retrospective chart review of 310 patients with vertebral artery dissections who presented at our institution between January 2004 and December 2018. Variables included demographic data, event characteristics, treatment, radiographic outcomes, and clinical outcomes measured using the modified Rankin Scale.

FINDINGS

Overall, 34 out of our 310 patients suffered a chiropractor-associated injury. These patients tended to be younger (p = 0.01), female (p = 0.003), and have fewer comorbidities (p = 0.005) compared to patients with other-cause VADs. The characteristics of the injuries were similar, but chiropractor-associated injuries appeared to be milder at discharge and at follow-up. A higher proportion of the chiropractor-associated group had injuries in the 0-2 mRS range at discharge and at 3 months (p = 0.05, p = 0.04) and no patients suffered severe long-term neurologic consequences or death (0% vs. 9.8%, p = 0.05). However, when a multivariate binomial regression was performed, these effects dissipated and the only independent predictor of a worse injury at discharge was the presence of a cervical spine fracture (p < 0.001).

INTERPRETATION

Chiropractor-associated injuries are similar to VADs of other causes, and apparent differences in the severity of the injury are likely due to demographic differences between the two populations.

Pipeline embolization of cerebral aneurysms in pediatric patients: combined systematic review of patient-level data and multicenter retrospective review

OBJECTIVE

Cerebral aneurysms in the pediatric population are rare and optimal treatment strategies are not as well characterized as in adults. The Pipeline embolization device (PED) is an endoluminal flow diverter that is commonly used to treat aneurysms in adults, but experience with this device in children is limited. The authors sought to further characterize PED use and outcomes in this specific population by performing both a systematic review of patient-level data from studies reporting the use of the PED to treat pediatric aneurysms and a retrospective review of their experience.

METHODS

A systematic review of the PubMed, Embase, and Scopus databases was performed to identify studies reporting the use of the PED in pediatric patients (age ≤ 18 years). Disaggregated data regarding demographics, aneurysm characteristics, treatment, and outcomes were collected. Retrospective data from the authors' two institutions were also included.

RESULTS

Thirty studies comprising patient-level data on 43 pediatric patients with 47 aneurysms were identified. An additional 9 patients with 9 aneurysms were included from the authors' institutions for a total of 52 patients with 56 aneurysms. The mean patient age was 11.1 years. Presentations included aneurysm rupture (17.3%) and symptomatic mass effect (23.1%). Aneurysms were located in the anterior circulation in 55.4% of cases, and 73.2% were described as nonsaccular. Imaging follow-up was available for 89.3% with a mean follow-up of 13.3 months. Aneurysm occlusion was reported in 75%, with 1 case each (1.8%) demonstrating significant in-stent stenosis and parent vessel occlusion. Clinical follow-up was reported in 90.4% with a mean follow-up of 14.7 months. Good functional outcomes (modified Rankin Scale score of 0-1 or Glasgow Outcome Scale score of 5) were reported in 65.4% of the total population. Two major complications were reported, including 1 death.

CONCLUSIONS

Despite substantial differences in aneurysm location and type between published pediatric and adult patient populations treated with the PED, the use of the PED in the pediatric population appears to be safe. While the short-term effectiveness is also similar to that of adults, additional studies are needed to further characterize the long-term outcomes and better define the use of this device in pediatric patients.

Refractory Stroke Thrombectomy: Prevalence, Etiology, and Adjunctive Treatment in a North American Cohort

BACKGROUND AND PURPOSE

Acute stroke intervention refractory to mechanical thrombectomy may be due to underlying vessel wall pathology including intracranial atherosclerotic disease and intracranial arterial dissection or recalcitrant emboli. We studied the prevalence and etiology of refractory thrombectomy, the safety and efficacy of adjunctive interventions in a North American-based cohort.

MATERIALS AND METHODS

We performed a multicenter, retrospective study of refractory thrombectomy, defined as unsuccessful recanalization, vessel reocclusion in <72 hours, or required adjunctive antiplatelet glycoprotein IIb/IIIa inhibitors, intracranial angioplasty and/or stenting to achieve and maintain reperfusion. Clinical and imaging criteria differentiated etiologies for refractory thrombectomy. Baseline demographics, cerebrovascular risk factors, technical/clinical outcomes, and procedural safety/complications were compared between refractory and standard thrombectomy groups. Multivariable logistic regression analysis was performed to determine independent predictors of refractory thrombectomy.

RESULTS

Refractory thrombectomy was identified in 25/302 cases (8.3%), correlated with diabetes (44% versus 22%, P = .02) as an independent predictor with OR = 2.72 (95% CI, 1.05-7.09; P = .04) and inversely correlated with atrial fibrillation (16% versus 45.7%, P = .005). Refractory etiologies were secondary to recalcitrant emboli (20%), intracranial atherosclerotic disease (60%), and/or intracranial arterial dissection (44%). Four (16%) patients were diagnosed with early vessel reocclusion, and 21 patients underwent adjunctive salvage interventions with glycoprotein IIb/IIIa inhibitor infusion alone (32%) or intracranial angioplasty and/or stenting (52%). There were no significant differences in TICI 2b/3 reperfusion efficacy (85.7% versus 90.9%, P = .48), symptomatic intracranial hemorrhage rates (0% versus 9%, P = .24), favorable clinical outcomes (39.1% versus 48.3%, P = .51), or mortality (13% versus 28.3%, P = .14) versus standard thrombectomy.

CONCLUSIONS

Refractory stroke thrombectomy is encountered in <10% of cases, independently associated with diabetes, and related to underlying vessel wall pathology (intracranial atherosclerotic disease and/or intracranial arterial dissection) or, less commonly, recalcitrant emboli. Emergent salvage interventions with glycoprotein IIb/IIIa inhibitors or intracranial angioplasty and/or stenting are safe and effective adjunctive treatments.

Per pass analysis of thrombus composition retrieved by mechanical thrombectomy

BACKGROUND AND AIM

Mechanical thrombectomy (MT) for large vessel occlusion often requires multiple passes to retrieve the entire thrombus load. In this multi-institutional study we sought to examine the composition of thrombus fragments retrieved with each pass during MT.

METHODS

Patients who required multiple passes during thrombectomy were included. Histopathological evaluation of thrombus fragments retrieved from each pass was performed using Martius Scarlet Blue staining and the composition of each thrombus component including RBC, fibrin and platelet was determined using image analysis software.

RESULTS

154 patients underwent MT and 868 passes was performed which resulted in 263 thrombus fragments retrieval. The analysis of thrombus components per pass showed higher RBC, lower fibrin and platelet composition in the pass 1 and 2 when compared to pass 3 and passes 4 or more combined (P values <0.05). There were no significant differences between thrombus fragments retrieved in pass 1 and pass 2 in terms of RBC, WBC, fibrin, and platelet composition (P values >0.05). Similarly, when each composition of thrombus fragments retrieved in pass 3 and passes 4 or more combined were compared with each other, no significant difference was noted (P values >0.05).

CONCLUSION

Our findings confirm that thrombus fragments retrieved with each pass differed significantly in histological content. Fragments in the first passes were associated with lower fibrin and platelet composition compared to fragments retrieved in passes three and four or higher. Also, thrombus fragments retrieved after failed pass were associated with higher fibrin and platelet components.

Prothrombin Complex Concentrate for Emergent Reversal of Intracranial Hemorrhage in Patients with Ventricular Assist Devices

BACKGROUND

Intracranial hemorrhage (ICH) is a devastating complication for patients with ventricular assist devices (VADs). The safety of emergent anticoagulation reversal with four-factor prothrombin complex concentrate (PCC) and optimal timing of anticoagulation resumption are not clear. In addition, lactate dehydrogenase (LDH) is used as a biomarker for thromboembolic risk, but its utility in guiding anticoagulation management after reversal with PCC has not be described.

METHODS

We retrospectively reviewed a consecutive series of patients with VADs presenting with ICH between 2014 and 2020 who received four-factor PCC for rapid anticoagulation reversal. We collected the timing of PCC administration, timing of resumption of anticoagulation, survival, occurrence of thromboembolic events, and LDH levels throughout hospitalization.

RESULTS

We identified 16 ICH events in 14 patients with VADs treated with rapid anticoagulation reversal using four-factor PCC (11 intraparenchymal, 4 subdural, 1 subarachnoid hemorrhage). PCC was administered at a mean of 3.3 ± 0.3 h after imaging diagnosis of ICH. Overall mortality was 63%. Survivors had higher presenting Glasgow Coma Scale (median 15, interquartile range [IQR] 15-15 versus 14, IQR 8-14.7, P = 0.041). In all six instances where the patient survived, anticoagulation was resumed on average 9.16 ± 1.62 days after reversal. There were no thromboembolic events prior to resumption of anticoagulation. Three events occurred after anticoagulation resumption and within 3 months of reversal: VAD thrombosis in a patient with thrombosis at the time of reversal, ischemic stroke, and readmission for elevated LDH in the setting of subtherapeutic international normalized ratio.

CONCLUSIONS

Our limited series found no thromboembolic complications immediately following anticoagulation reversal with PCC prior to resumption of anticoagulation. LDH trends may be useful to monitor thromboembolic risk after reversal.

Carotid Stenting without Embolic Protection Increases Major Adverse Events: Analysis of the National Surgical Quality Improvement Program

BACKGROUND AND PURPOSE

Published data regarding embolic protection device efficacy is mixed, and its use during carotid artery stent placement remains variable. We, therefore, examined the frequency of embolic protection device use and its association with outcomes after carotid artery stent placement using a national quality improvement data base.

MATERIALS AND METHODS

Patients undergoing carotid artery stent placement with or without embolic protection devices were identified in the American College of Surgeons National Surgical Quality Improvement Program data base. The primary outcome was the incidence of major adverse cardiovascular events (defined as death, stroke, or myocardial infarction/arrhythmia) within 30 days. Propensity scoring was used to create 2 matching cohorts of patients using demographic and baseline variables.

RESULTS

Between 2011 and 2018, among 1200 adult patients undergoing carotid artery stent placement, 23.8% did not have embolic protection devices. There was no trend toward increased embolic protection device use with time. Patients without embolic protection device use received preoperative antiplatelets less frequently (90.6% versus 94.6%, P = .02), underwent more emergent carotid artery stent placement (7.2% versus 3.6%, P = .01), and had a higher incidence of major adverse cardiovascular events (OR = 1.81; 95% CI, 1.11-2.94) and stroke (OR = 3.31; 95% CI, 1.71-6.39). After compensating for baseline imbalances using propensity-matched cohorts (n = 261 for both), carotid artery stent placement without an embolic protection device remained associated with increased major adverse cardiovascular events (9.2% versus 4.2%; OR = 2.30; 95% CI, 1.10-4.80) and stroke (6.5% versus 1.5%; OR = 4.48; 95% CI, 1.49-13.49).

CONCLUSIONS

Lack of embolic protection device use during carotid artery stent placement is associated with a 4-fold increase in the likelihood of perioperative stroke. Nevertheless, nearly one-quarter of patients in the American College of Surgeons National Surgical Quality Improvement Program underwent unprotected carotid artery stent placement. Efforts targeting improved embolic protection device use during carotid artery stent placement are warranted.

Association between clot composition and stroke origin in mechanical thrombectomy patients: analysis of the Stroke Thromboembolism Registry of Imaging and Pathology

BACKGROUND

We retrospectively evaluated the composition of retrieved clots from ischemic stroke patients to study the association between histological composition and stroke etiology METHODS: Consecutive patients enrolled in the Stroke Thromboembolism Registry of Imaging and Pathology (STRIP) were included in this study. All patients underwent mechanical thrombectomy and retrieved clots were sent to a central core lab for processing. Histological analysis was performed using martius scarlet blue (MSB) staining, and quantification for red blood cells (RBCs), white blood cells (WBCs), fibrin and platelets was performed using Orbit Image Software. A Wilcoxon test was used for continuous variables and χ² test for categorical variables.

RESULTS

1350 patients were included in this study. The overall rate of Thrombolysis In Cerebral Infarction (TICI) 2c/3 was 68%. 501 patients received tissue plasminogen activator (tPA) (37%). 267 patients (20%) had a large artery atherosclerosis (LAA) source, 662 (49%) a cardioembolic (CE) source, 301 (22%) were cryptogenic, and the remainder had other identifiable sources including hypercoagulable state or dissection. LAA thrombi had a higher mean RBC density (46±23% vs 42±22%, p=0.01) and a lower platelet density (24±18% vs 27±18%, p=0.03) than CE thrombi. Clots from dissection patients had the highest mean RBC density (50±24%) while clots from patients with a hypercoagulable state had the lowest mean RBC density (26±21%).

CONCLUSIONS

Our study found statistically significant but clinically insignificant differences between clots of CE and LAA etiologies. Future studies should emphasize molecular, proteomic and immunohistochemical characteristics to determine links between clot composition and etiology.

Volumes, outcomes, and complications after surgical versus endovascular treatment of aneurysms in the United States (1993–2015): continued evolution versus steady-state after more than 2 decades of practice

OBJECTIVE

Adoption of endovascular treatment (EVT) and other advances in aneurysm care have shifted practice patterns of cerebral aneurysm treatment over the past 2 decades in the US. The objective of this study was to determine whether resulting trends in volumes, outcomes, and complications have matured in general practice or continue to evolve.

METHODS

Data were obtained from the National Inpatient Sample from 1993 to 2015. ICD-9 codes were used to estimate annual volumes, outcomes, and complications following treatment of ruptured and unruptured aneurysms. Univariate and multivariate analyses were used to estimate risk ratios for complications and outcomes. Trends in time were assessed utilizing annual percentage change (APC).

RESULTS

The authors found a nearly 5-fold increase in annual admissions with diagnoses of unruptured aneurysms, whereas SAH volume increased less than 50%. Clipping ruptured aneurysms steadily declined (APC −0.86%, p = 0.69 until 1999, then −6.22%, p < 0.001 thereafter), whereas clipping unruptured aneurysms slightly increased (APC 2.02%, p < 0.001). EVT tripled in 2002–2004 and steadily increased thereafter (APC 7.22%, p < 0.001 and 5.85%, p = 0.01 for unruptured and ruptured aneurysms, respectively). Despite a 3-fold increase in both diagnosis and treatment of unruptured aneurysms, the incidence of SAH remained steady at 12 per 100,000 persons per year (APC 0.04%, p = 0.83). In contrast, SAH severity increased over time, as did patient age and comorbidities (all p < 0.001). SAH led to nonroutine discharge more frequently over time after both EVT and clipping (APC 1.24% and 1.10%, respectively), although mortality decreased during the same time (APC −2.48% and −1.44%, respectively). Complications were more frequent after clipping than EVT, but this differential risk diminished during the study period and was less perceptible in ruptured aneurysms. The proportion of patients discharged home after treatment of unruptured aneurysms was significantly lower (p < 0.001) after clipping (69.3%–79.5%) than EVT (88.3%–93.3%); both proportions changed minimally since 1998 (APC −0.39%, p = 0.02, and APC −0.11%, p = 0.14, respectively).

CONCLUSIONS

EVT volume markedly increased for ruptured and unruptured aneurysms from 1993 to 2015, whereas clipping decreased for ruptured and slightly increased for unruptured aneurysms. The incidence of SAH remained unchanged despite increased diagnosis and treatment of unruptured aneurysms. In ruptured aneurysms, SAH severity has increased over time, as have age, comorbidities, and nonroutine discharges. In contrast, routine discharge after treatment of unruptured aneurysms remains largely unchanged since 1998 and remains lower with clipping.

Endovascular Thrombectomy after Large-Vessel Ischemic Stroke: Utilization, Outcomes, and Readmissions across the United States

Background Following publication of trials demonstrating the efficacy of thrombectomy, societal guidelines were revised in 2015 to recommend this procedure for large-vessel stroke. Purpose To evaluate real-world thrombectomy rates, adverse events, outcomes, and readmissions across the United States in the 2 years after large-scale adoption of thrombectomy for acute stroke. Materials and Methods In this retrospective study, the authors queried the National Inpatient Sample and Nationwide Readmissions Database for patients undergoing thrombectomy between 2016 and 2017. Thrombectomy rates were compared by using the χ² test. Adjusted risk ratios (aRRs) were obtained for factors affecting routine discharge, mortality, and readmission by using multivariable Poisson regression with clustering at the hospital level. Results There were 290 460 admissions (mean age, 70.5 years ± 14.2 [standard deviation]; 148 620 women) for internal carotid or middle cerebral artery stroke; 30 835 (10.6%) of these patients underwent thrombectomy. Thrombectomy rates were lower in patients aged 90 years or older (1815 of 24 090 patients, 7.5%), Black patients (4280 of 43 365 patients, 9.9%), patients with the lowest income (8520 of 85 905 patients, 9.9%), and those treated in West South Central division hospitals (2695 of 34 355 patients, 7.8%) (P < .001 for all). The inpatient mortality rate was 12.1% (3740 of 30 835 patients), and 19.1% of patients (5900 of 30 835) were discharged to home. In adjusted analyses, routine discharge was less likely in patients aged 90 years or older (aRR: 0.12; 95% CI: 0.09, 0.16; P < .001) and octogenarians (aRR: 0.37; 95% CI: 0.33, 0.41; P < .001). Patients aged 90 years or older (aRR: 1.78; 95% CI: 1.48, 2.14; P < .001), octogenarians (aRR: 1.76; 95% CI: 1.51, 2.06; P < .001), Asians and/or Pacific Islanders (aRR: 1.21; 95% CI: 1.06, 1.39; P = .005), and those treated in teaching (aRR: 1.20; 95% CI: 1.07, 1.34; P = .001) or West South Central division (aRR: 1.35; 95% CI: 1.14, 1.60; P < .001) hospitals had a higher risk of death. Following discharge, 18.9% of patients (3449 of 18 274) were readmitted within 90 days. Conclusion Rates and outcomes of thrombectomy are affected by demographic, socioeconomic, and hospital-related factors. Fewer than one-fifth of patients are discharged to home, nearly one-fifth are readmitted within 90 days, and mortality and outcomes may be less favorable than in published trials. © RSNA, 2021 Online supplemental material is available for this article.

Analysis of Mechanical Thrombectomy for Acute Ischemic Stroke on Nights and Weekends Versus Weekdays at Comprehensive Stroke Centers

OBJECTIVE

The "weekend effect" has been shown to affect outcomes in acute ischemic stroke. We sought to compare metrics and outcomes of emergent stroke thrombectomy at three affiliated comprehensive stroke centers on weekdays versus nights/weekends for a three-year period beginning in 2015, when thrombectomy became common practice for large vessel occlusion acute ischemic stroke.

METHODS

We performed a retrospective analysis of all stroke thrombectomy patients treated from 2015 to 2018 to compare standard thrombectomy metrics and outcomes in patients presenting during weekdays or nights/weekends.

RESULTS

Two hundred-sixteen mechanical thrombectomy cases were evaluated, with 50.9% of patients presenting on weekdays and 49.1% presenting on nights/weekends. There were no statistical differences in baseline characteristics in demographics, stroke risk factors, or stroke severity, but patients presenting on nights/weekends had longer times from last known normal to presentation (130 versus 72.5 minutes, p=0.03). Door-to-groin times were delayed in patients presenting on nights/weekends compared to weekdays (median 104.5 versus 86 minutes, respectively; p=0.007) but groin-to-reperfusion times were similar (51.5 versus 48 minutes, respectively; p=0.4). Successful reperfusion was similar in both groups (90.6% nights/weekends versus 90% weekdays; p=1.0) as were the incidence of symptomatic intracerebral hemorrhage (10.4% nights/weekend versus 7.3% weekdays; p=0.48) and 90-day good functional outcomes based on the modified Rankin Scale did not differ between the two groups in a shift analysis (p=0.545).

CONCLUSIONS

Despite delays in door-to-groin puncture times in acute ischemic stroke patients presenting on nights/weekends compared to weekdays, we did not identify significant differences in successful reperfusion or functional outcomes in this cohort. Further studies are warranted to continue to evaluate differences in stroke care on nights/weekends versus weekdays.

Feasibility of intraoperative computed tomography for endoscopic-assisted intraparenchymal hemorrhage evacuation

BACKGROUND

Minimally-invasive intraparenchymal hemorrhage (IPH) evacuation may provide a functional and mortality benefit, especially if there is minimal residual hematoma. Several methods have been used to confirm extent of IPH evacuation, including intraoperative computed tomography (CT). We sought to evaluate the feasibility of intraoperative CT in endoscopic-assisted IPH evacuation, with a focus on the operative workflow and imaging quality.

METHODS

We retrospectively reviewed all endoscopic-assisted IPH evacuation procedures utilizing intraoperative CT performed at our institution over a 9-month period. We describe the operative room setup and workflow for using intraoperative CT and compare the intra- and postoperative imaging findings.

RESULTS

Eight consecutive procedures were included in this study. Intraoperative CT provided useful information that informed intraoperative decision-making in each case. There were no clinically significant differences in residual hematoma volume or midline shift between intra- and postoperative CT scans. Streak artifact was present in all cases due to the head holder, but did not significantly inhibit image evaluation.

CONCLUSION

Intraoperative CT is an effective method of evaluating the extent of IPH evacuation in endoscopic-assisted procedures.

Metachronous spinal pial arteriovenous fistulas: case report

Spinal pial arteriovenous fistulas (spAVFs) are believed to be congenital lesions, and the development of a de novo spAVF has not been previously described. A 49-year-old female with a childhood history of vascular malformation-induced right lower-extremity hypertrophy presented in 2004 with progressive pain in her right posterior thigh and outer foot. Workup revealed 3 separate type IV spAVFs, which were treated by combined embolization and resection, with final conventional angiography showing no residual spinal vascular lesion in 2005. Ten years later, the patient returned with new right lower-extremity weakness, perineal pain, and left plantar foot numbness. Repeat spinal angiography demonstrated 2 de novo intertwined conus medullaris spAVFs.

Spinal neurovascular complications with anterior thoracolumbar spine surgery: a systematic review and review of thoracolumbar vascular anatomy

OBJECTIVE

Spinal cord infarction due to interruption of the spinal vascular supply during anterior thoracolumbar surgery is a rare but devastating complication. Here, the authors sought to summarize the data on this complication in terms of its incidence, risk factors, and operative considerations. They also sought to summarize the relevant spinal vascular anatomy.

METHODS

They performed a systematic literature review of the PubMed, Scopus, and Embase databases to identify reports of spinal cord vascular injury related to anterior thoracolumbar spine procedures as well as operative adjuncts and considerations related to management of the segmental artery ligation during such anterior procedures. Titles and abstracts were screened, and studies meeting inclusion criteria were reviewed in full.

RESULTS

Of 1200 articles identified on the initial screening, 16 met the inclusion criteria and consisted of 2 prospective cohort studies, 10 retrospective cohort studies, and 4 case reports. Four studies reported on the incidence of spinal cord ischemia with anterior thoracolumbar surgery, which ranged from 0% to 0.75%. Eight studies presented patient-level data for 13 cases of spinal cord ischemia after anterior thoracolumbar spine surgery. Proposed risk factors for vasculogenic spinal injury with anterior thoracolumbar surgery included hyperkyphosis, prior spinal deformity surgery, combined anterior-posterior procedures, left-sided approaches, operating on the concavity side of a scoliotic curve, and intra- or postoperative hypotension. In addition, eight studies analyzed operative considerations to reduce spinal cord ischemic complications in anterior thoracolumbar surgery, including intraoperative neuromonitoring and preoperative spinal angiography.

CONCLUSIONS

While spinal cord infarction related to anterior thoracolumbar surgery is rare, it warrants proper consideration in the pre-, intra-, and postoperative periods. The spine surgeon must be aware of the relevant risk factors as well as the pre- and intraoperative adjuncts that can minimize these risks. Most importantly, an understanding of the relevant spinal vascular anatomy is critical to minimizing the risks associated with anterior thoracolumbar spine surgery.

Magnesium and Risk of Bleeding Complications From Ventriculostomy Insertion

BACKGROUND AND PURPOSE

Hemorrhages are a serious complication of brain surgery, and magnesium has shown hemostatic properties in hemorrhagic stroke and non-neurological surgeries. External ventricular drain (EVD) insertion is an advantageous model of emergency neurosurgical hemorrhage risk because it is common, standardized, and the operator is blinded to the outcome during the procedure. We tested the hypothesis that low magnesium is associated with risk of hemorrhagic complications from EVD insertion.

METHODS

Patients with spontaneous intracerebral hemorrhage and aneurysmal subarachnoid hemorrhage were enrolled in a prospective, observational study. Demographic and clinical variables were prospectively recorded, including serum magnesium measurements. Catheter tract hemorrhage (CTH) was measured on postoperative head computed tomography within 48 hours of EVD insertion.

RESULTS

We observed 50 CTH among 327 EVD procedures (15.3%) distributed similarly among intracerebral hemorrhage (21/116 [18.1%]) and subarachnoid hemorrhage (29/211 [13.7%]). Magnesium was lower in patients with CTH compared with those without (median 1.8 versus 2.0 mg/dL, P<0.0001). Higher magnesium was associated with lower odds of CTH (odds ratio 0.67 per 0.1 mg/dL magnesium [95% CI, 0.56-0.78], P<0.0001) after adjustment for other risk factors, with similar effect in the intracerebral hemorrhage and subarachnoid hemorrhage subgroups. Preprocedural increase in magnesium (odds ratio 0.68 [0.52-0.85]) and dose of preprocedural magnesium sulfate (odds ratio 0.67 [0.40-0.97]) were associated with reduced CTH risk after adjustment for initial magnesium and other risk factors.

CONCLUSIONS

Lower magnesium at the time of EVD insertion was an independent predictor of hemorrhagic complications. Baseline risk was attenuated by preprocedural increases in magnesium, suggesting a therapeutic opportunity.

Follow-up neutrophil-lymphocyte ratio after stroke thrombectomy is an independent biomarker of clinical outcome

BACKGROUND

Admission neutrophil-lymphocyte ratio (NLR) is significantly correlated to clinical outcomes in acute ischemic stroke (AIS). We investigated follow-up NLR and temporal changes in NLR after endovascular thrombectomy (EVT) with respect to successful revascularization, clinical outcomes, symptomatic intracranial hemorrhage (sICH) and mortality.

METHODS

Retrospective analysis of EVT for anterior circulation emergent LVO was performed with both admission (NLR1) and 3-7 day follow-up NLR (NLR2) laboratory data. Patient demographics, National Institutes of Health Stroke Scale (NIHSS) presentations, reperfusion efficacy (modified Thrombolysis in Cerebral Infarction (mTICI) score), sICH, and clinical outcomes (modified Rankin Scale (mRS)) at 90 days were studied. Univariate analyses correlated NLR1, NLR2, and temporal change in NLR (NLR2-NLR1) with successful reperfusion (mTICI ≥2b), favorable outcomes (mRS ≤2), sICH, and mortality. Multivariable logistic regression model evaluated the independent effects of NLR2 on favorable outcomes.

RESULTS

142 AIS patients with median NIHSS 17 underwent EVT within 24 hours, and met NLR laboratory inclusion criteria. Lower follow-up NLR2 and less temporal change in NLR over 3-7 days, but not admission NLR1, inversely correlated with successful reperfusion (p<0.05) and favorable clinical outcomes (p<0.001). Higher follow-up NLR2 and greater temporal change in NLR was significantly associated with sICH and mortality (p≤0.05). In multivariable logistic regression, lower follow-up NLR2 remained a predictor of favorable outcomes (OR 0.785, p=0.001), independent of age or successful reperfusion.

CONCLUSIONS

Follow-up NLR is a readily available and modifiable biomarker that correlates with the degree of reperfusion after mechanical stroke thrombectomy. Lower follow-up NLR2 at 3-7 days is associated with successful reperfusion and an independent predictor of favorable clinical outcomes, with reduced risk for sICH and mortality.

Spontaneous Thrombosis of a Middle Meningeal Arteriovenous Fistula With Subsequent Pseudoaneurysm Formation: Case Report and Review of Literature

BACKGROUND AND IMPORTANCE

Middle meningeal artery (MMA) pseudoaneurysms and middle meningeal arteriovenous fistulas (MMAVFs) are rarely reported after head injury. We report an unusual case of delayed MMA pseudoaneurysm formation after spontaneous thrombosis of an MMAVF, and review existing literature on MMAVF treatment and results.

CLINICAL PRESENTATION

A 59-yr-old male presented with a 5-d history of worsening left-sided headaches, followed by nausea, lethargy, and difficulty with speech. Non-contrast computed tomography demonstrated a left temporal intraparenchymal hemorrhage (IPH) and an acute left-sided subdural hematoma (SDH). Cerebral angiography found abnormal shunting between the right MMA and the right sphenoparietal sinus, consistent with an MMAVF. During the course of admission, the patient's neurological condition deteriorated requiring craniotomy for evacuation of SDH and IPH. Given the presumed incidental nature of the contralateral MMAVF, conservative management was recommended. Follow-up imaging 2 mo after surgery revealed spontaneous thrombosis of the right MMAV. Repeat imaging 5 mo later revealed an MMA pseudoaneurysm at the prior fistulous site, which was subsequently embolized with Onyx, occluding the pseudoaneurysm and the MMA both proximal and distal to the pseudoaneurysm.

CONCLUSION

Spontaneous thrombosis of an MMAVF is rare and only seen in 13.1% of cases. However, subsequent delayed formation of an MMA pseudoaneurysm has not been described. Our case therefore demonstrates that MMAVF thrombosis may not indicate complete healing of the underlying injury to the MMA, and suggests the need for continued follow-up of such lesions despite initial apparent resolution.

Mechanical Thrombectomy for Delayed Thrombosis of Pipeline Embolization Device

BACKGROUND

In-stent thrombosis is a potentially dangerous complication of flow diversion for cerebral aneurysms. The optimal management strategy for such thrombosis is not known. Here we present a case of acute ischemic stroke caused by occlusion of a Pipeline Embolization Device (PED) construct placed 18 months earlier for treatment of a fusiform middle cerebral artery aneurysm. This was successfully treated with mechanical thrombectomy with good neurologic outcome.

CASE DESCRIPTION

A 40-year-old woman presented with acute onset of left-sided weakness and occlusion of the right middle cerebral artery harboring a PED construct. Intraarterial glycoprotein IIb/IIIa inhibitor was administered without success. Mechanical thrombectomy was then performed using a stent retriever and aspiration, and the patient was loaded with dual antiplatelet therapy. The patient showed initial neurologic improvement but several hours later demonstrated recurrent symptoms due to reocclusion of the PED construct. This was again treated with mechanical thrombectomy followed by an intravenous P2Y12 inhibitor infusion. She ultimately made an excellent neurologic recovery with persistent patency of the PED construct.

CONCLUSIONS

Mechanical thrombectomy with a stent retriever and aspiration is a therapeutic option for treatment of delayed thrombosis of a flow-diverting stent.

Management and outcome of intracranial hemorrhage in patients with left ventricular assist devices

OBJECTIVE

As the use of left ventricular assist devices (LVADs) has expanded, cerebrovascular complications have become an increasing source of morbidity and mortality in this population. Intracranial hemorrhage (ICH) in particular remains a devastating complication in patients who undergo LVAD placement with no defined management guidelines. The authors therefore reviewed surgical and anticoagulation management and outcomes of patients with LVADs who presented to their institution with ICH.

METHODS

This retrospective cohort study assessed outcomes of patients who underwent LVAD placement at a single institution between 2007 and 2016 and in whom imaging demonstrated ICH.

RESULTS

During the study period, 281 patients had a HeartMate II or HeartWare LVAD placed. There were 37 episodes of ICH (recurrent in 3 cases). ICHs were categorized as intraparenchymal hemorrhage (IPH; n = 22, 59%), subdural hemorrhage (SDH; n = 6, 16%), and subarachnoid hemorrhage (SAH; n = 9, 24%). Neurosurgical intervention was deemed necessary in 27.3%, 66.7%, and 0% of patients with IPH, SDH, and SAH, respectively; overall survival > 30 days for each type of hemorrhage was 41%, 83%, and 89%, respectively. No patients had LVAD thrombus as a result of reversal of anticoagulation. Combined with prior reports, good outcomes are seen more often following surgery for SDH than for IPH (57% vs 7%, p = 0.004) in patients who underwent VAD placement.

CONCLUSIONS

Patients with IPH who undergo LVAD placement have poor outcomes regardless of anticoagulation reversal or neurosurgical intervention, whereas those with SDH may have good outcomes with medical and surgical intervention, and those with SAH appear to do well without anticoagulation reversal or surgery. When needed, anticoagulation reversal was not associated with an increase in LVAD thrombosis in this series.

Conservative Management and Natural History of Ruptured Basilar Perforator Artery Aneurysms: Two Cases and Literature Review

BACKGROUND

Basilar perforator aneurysms are rare causes of subarachnoid hemorrhage and their natural history is poorly characterized. Although various treatment strategies have been reported, conservative management is an option that has been associated with a high likelihood of spontaneous resolution.

CASE DESCRIPTION

Here we present 2 cases of subarachnoid hemorrhage, 1 diffuse and the other perimesencephalic, due to small ruptured basilar perforator artery aneurysms. These aneurysms were only identified after repeat angiography. Conservative management with serial imaging was pursued. Both patients did well clinically and repeat imaging demonstrated spontaneous resolution of the ruptured aneurysms. We also provide a literature review of ruptured basilar perforator aneurysms, showing a ~10% re-rupture rate within the early post-rupture period but otherwise a high rate of spontaneous resolution.

CONCLUSIONS

Although basilar perforator aneurysms can re-rupture, there is also a high likelihood of spontaneous resolution. Given the challenges of treatment, conservative management is an option that can be considered.