Risk of Early Versus Later Rebleeding From Dural Arteriovenous Fistulas With Cortical Venous Drainage.

BACKGROUND: Cranial dural arteriovenous fistulas with cortical venous drainage are rare lesions that can present with hemorrhage. A high rate of rebleeding in the early period following hemorrhage has been reported, but published long-term rates are much lower. No study has examined how risk of rebleeding changes over time. Our objective was to quantify the relative incidence of rebleeding in the early and later periods following hemorrhage. METHODS: Patients with dural arteriovenous fistula and cortical venous drainage presenting with hemorrhage were identified from the multinational CONDOR (Consortium for Dural Fistula Outcomes Research) database. Natural history follow-up was defined as time from hemorrhage to first treatment, rebleed, or last follow-up. Rebleeding in the first 2 weeks and first year were compared using incidence rate ratio and difference. RESULTS: Of 1077 patients, 250 met the inclusion criteria and had 95 cumulative person-years natural history follow-up. The overall annualized rebleed rate was 7.3% (95% CI, 3.2-14.5). The incidence rate of rebleeding in the first 2 weeks was 0.0011 per person-day; an early rebleed risk of 1.6% in the first 14 days (95% CI, 0.3-5.1). For the remainder of the first year, the incidence rate was 0.00015 per person-day; a rebleed rate of 5.3% (CI, 1.7-12.4) over 1 year. The incidence rate ratio was 7.3 (95% CI, 1.4-37.7; P, 0.026). CONCLUSIONS: The risk of rebleeding of a dural arteriovenous fistula with cortical venous drainage presenting with hemorrhage is increased in the first 2 weeks justifying early treatment. However, the magnitude of this increase may be considerably lower than previously thought. Treatment within 5 days was associated with a low rate of rebleeding and appears an appropriate timeframe.

Performance of Automated RAPID Intracranial Hemorrhage Detection in Real-World Practice: A Single-Institution Experience.

BACKGROUND AND PURPOSE: Intracranial hemorrhage (ICH) is a common finding in patients presenting to the emergency department with acute neurological symptoms. Noncontrast head computed tomography (NCCT) is the primary modality for assessment and detection of ICH in the acute setting. RAPID ICH software aims to automatically detect ICH on NCCT and was previously shown to have high accuracy when applied to a curated test data set. Here, we measured the test performance characteristics of RAPID ICH software in detecting ICH on NCCT performed in patients undergoing emergency stroke evaluation at a tertiary academic comprehensive stroke center. MATERIALS AND METHODS: This retrospective study assessed consecutive patients over a 6-month period who presented with acute neurological symptoms suspicious for stroke and underwent NCCT with RAPID ICH postprocessing. RAPID ICH detection was compared with the interpretation of a reference standard comprising a board-certified or board-eligible neuroradiologist, or in cases of discrepancy, adjudicated by a consensus panel of 3 neuroradiologists. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of RAPID ICH for ICH detection were determined. RESULTS: Three hundred seven NCCT scans were included in the study. RAPID ICH correctly identified 34 of 37 cases with ICH and 228 of 270 without ICH. RAPID ICH had a sensitivity of 91.9% (78.1%-98.3%), specificity of 84.4% (79.6%-88.6%), NPV of 98.7% (96.3%-99.6%), PPV of 44.7% (37.6%-52.1%), and overall accuracy of 85.3% (80.9%-89.1%). CONCLUSIONS: In a real-world scenario, RAPID ICH software demonstrated high NPV but low PPV for the presence of ICH when evaluating possible stroke patients.

Changes in Patient Volumes and Outcomes After Adding Thrombectomy Capability.

BACKGROUND AND PURPOSE: With the rising demand for endovascular thrombectomy (EVT) and introduction of thrombectomy-capable stroke centers (TSC), there is interest among existing stroke hospitals to add EVT capability to attract and retain stroke patient referrals. In this work, we quantify changes in patient volumes and outcomes when adding EVT capability to an existing stroke center. METHODS: In MATLAB 2017a Simulink, we simulate a 3-center system comprising an EVT-capable comprehensive stroke center, an EVT-incapable primary stroke center, and an EVT-incapable primary stroke center that gains EVT capability (TSC). We model these changes in 2 geographic settings (urban and rural) using 2 routing paradigms (Nearest Center and Bypass). In Nearest Center, patients are sent to the nearest center regardless of EVT capability. In Bypass, patients with severe strokes are sent to the nearest EVT-capable center, and all others are sent to the nearest center. Probability of good clinical outcome is determined by type and timing of treatment using outcomes reported in clinical trials. RESULTS: Adding EVT capability in the Bypass model produced an absolute increase of 40.1% in total volume of patients with stroke and 31.2% to 31.9% in total volume of acute stroke treatments at the TSC. In the Nearest Center model, the total volume of patients with stroke did not change, but total volume of acute stroke treatment at the TSC had an absolute increase of 9.3% to 9.5%. Good clinical outcomes saw an absolute increase of 0.2% to 0.6% in the whole population and 0.3% to 1.8% in the TSC population. CONCLUSIONS: Adding EVT capability shifts patient and treatment volume to the TSC. However, these changes produce modest improvement in overall population health. Health systems should weigh relative hospital and patient benefits when considering adding EVT capability.

Demographic Disparities in Proximity to Certified Stroke Care in the United States.

Background and Purpose: Demographic disparities in proximity to stroke care influence time to treatment and clinical outcome but remain understudied at the national level. This study quantifies the relationship between distance to the nearest certified stroke hospital and census-derived demographics. Methods: This cross-sectional study included population data by census tract from the United States Census Bureau's 2014­2018 American Community Survey, stroke hospitals certified by a state or national body and providing intravenous thrombolysis, and geographic data from a public mapping service. Data were retrieved from March to November 2020. Quantile regression analysis was used to compare relationships between road distance to the nearest stroke center for each census tract and tract-level demographics of age, race, ethnicity, medical insurance status, median annual income, and population density. Results: Two thousand three hundred eighty-eight stroke centers and 71 929 census tracts including 316 995 649 individuals were included. Forty-nine thousand nine hundred eighteen (69%) tracts were urban. Demographic disparities in proximity to certified stroke care were greater in nonurban areas than urban areas. Higher representation of individuals with age ≥65 years was associated with increased median distance to a certified stroke center in nonurban areas (0.51 km per 1% increase [99.9% CI, 0.42­0.59]) but not in urban areas (0.00 km [−0.01 to 0.01]). In urban and nonurban tracts, median distance was greater with higher representation of American Indian (urban: 0.10 km per 1% increase [0.06­0.14]; nonurban: 1.06 km [0.98­1.13]) or uninsured populations (0.02 km [0.00­0.03]; 0.27 km [0.15­0.38]). Each $10 000 increase in median income was associated with a decrease in median distance of 5.04 km [4.31­5.78] in nonurban tracts, and an increase of 0.17 km [0.10­0.23] in urban tracts. Conclusions: Disparities were greater in nonurban areas than in urban areas. Nonurban census tracts with greater representation of elderly, American Indian, or uninsured people, or low median income were substantially more distant from certified stroke care.

Higher-Quality Data Collection Is Critical to Establish the Safety and Efficacy of Pediatric Mechanical Thrombectomy.

BACKGROUND AND PURPOSE: Because children often have lifelong morbidity after stroke, there is considerable enthusiasm to pursue mechanical thrombectomy in childhood stroke based on literature reports. However, current published data may reflect inconsistent reporting and publication bias, which limit the ability to assess safety and efficacy of mechanical thrombectomy in childhood stroke. METHODS: This retrospective cohort study compared reporting quality and clinical outcomes for mechanical thrombectomy between a trial-derived cohort of 42 children treated with mechanical thrombectomy for acute stroke at study sites and 133 patients reported in the literature. National Institutes of Health Stroke Scale at baseline, 24 hours after mechanical thrombectomy, and at discharge were compared between study site patients and literature patients. Odds ratios (ORs) were used to compare reporting frequencies. Proportional odds logistic regression was used to compare outcomes. RESULTS: Premechanical thrombectomy National Institutes of Health Stroke Scale was available in 93% of study patients compared with 74% of patients in the literature (OR, 4.42 [95% CI, 1.47-19.89]). Postmechanical thrombectomy National Institutes of Health Stroke Scale was available in 69% of study patients compared with 29% of literature cases at 24 hours (OR, 5.48 [95% CI, 2.62-12.06]), and 64% of study patients compared with 32% of cases at discharge (OR, 3.85 [95% CI, 1.87-8.19]). For study sites, median scores were 12 at baseline, 9 at 24 hours, and 5 at discharge. Median scores in case reports were 15 at baseline, 4 at 24 hours, and 3 at discharge. ORs for differences in outcomes between groups were 5.97 (95% CI, 2.28-15.59) at 24 hours and 3.68 (95% CI, 1.45-9.34) at discharge. CONCLUSIONS: Study site patients had higher rates of National Institutes of Health Stroke Scale reporting and worse short-term outcomes compared with literature reports. Rigorous data collection is needed before treatment guidelines for pediatric mechanical thrombectomy can be developed.

Pediatric Thrombectomy: Design and Workflow Lessons From Two Experienced Centers.

Endovascular thrombectomy has played a major role in advancing adult stroke care and may serve a similar role in pediatric stroke care. However, there is a need to develop better evidence and infrastructure for pediatric stroke care. In this work, we review 2 experienced pediatric endovascular thrombectomy programs and examine key design features in both care environments, including a formalized protocol and workflow, integration with an adult endovascular thrombectomy workflow, simplification and automation of workflow steps, pediatric adaptations of stroke imaging, advocacy of pediatric stroke care, and collaboration between providers, among others. These essential features transcend any single hospital environment and may provide an important foundation for other pediatric centers that aim to enhance the care of children with stroke.

Blood Pressure Goals and Clinical Outcomes after Successful Endovascular Therapy: A Multicenter Study.

OBJECTIVE: Elevated systolic blood pressure (SBP) after successful revascularization (SR) via endovascular therapy (EVT) is a known predictor of poor outcome. However, the optimal SBP goal following EVT is still unknown. Our objective was to compare functional and safety outcomes between different SBP goals after EVT with SR. METHODS: This international multicenter study included 8 comprehensive stroke centers and patients with anterior circulation large vessel occlusion who were treated with EVT and achieved SR. SR was defined as modified thrombolysis in cerebral ischemia 2b to 3. Patients were divided into 3 groups based on SBP goal in the first 24 hours after EVT. Inverse probability of treatment weighting (IPTW) propensity analysis was used to assess the effect of different SBP goals on clinical outcomes. RESULTS: A total of 1,019 patients were included. On IPTW analysis, the SBP goal of <140mmHg was associated with a higher likelihood of good functional outcome and lower odds of hemicraniectomy compared to SBP goal of <180mmHg. Similarly, SBP goal of <160mmHg was associated with lower odds of mortality compared to SBP goal of <180mmHg. In subgroup analysis including only patients with pre-EVT SBP of ≥140mmHg, an SBP of <140mmHg was associated with a higher likelihood of good functional outcome, lower odds of symptomatic intracranial hemorrhage, and lower odds of requirement for hemicraniectomy compared to SBP goal of <180mmHg. INTERPRETATION: SBP goals of <140 and < 160mmHg following SR with EVT appear to be associated with better clinical outcomes than SBP of <180mmHg. ANN NEUROL 2020;87:830-839.

Large-Scale Assessment of Scan-Time Variability and Multiple-Procedure Efficiency for Cross-Sectional Neuroradiological Exams in Clinical Practice.

Scheduling of CT and MR exams requires reasonable estimates for expected scan duration. However, scan-time variability and efficiency gains from combining multiple exams are not quantitatively well characterized. In this work, we developed an informatics approach to quantify typical duration, duration variability, and multiple-procedure efficiency on a large scale, and used the approach to analyze 48,766 CT- and MR-based neuroradiological exams performed over one year. We found MR exam durations demonstrated higher absolute variability, but lower relative variability and lower multiple-procedure efficiency, compared to CT exams (p < 0.001). Our approach enables quantification of real-world operational performance and variability to inform optimal patient scheduling, efficient resource utilization, and sustainable service planning.

Blood Pressure and Outcome After Mechanical Thrombectomy With Successful Revascularization.

Background and Purpose- Successful reperfusion can be achieved in more than two-thirds of patients treated with mechanical thrombectomy. Therefore, it is important to understand the effect of blood pressure (BP) on clinical outcomes after successful reperfusion. In this study, we investigated the relationship between BP on admission and during the first 24 hours after successful reperfusion with clinical outcomes. Methods- This was a multicenter study from 10 comprehensive stroke centers. To ensure homogeneity of the studied cohort, we included only patients with anterior circulation who achieved successful recanalization at the end of procedure. Clinical outcomes included 90-day modified Rankin Scale, symptomatic intracerebral hemorrhage (sICH), mortality, and hemicraniectomy. Results- A total of 1245 patients were included in the study. Mean age was 69±14 years, and 51% of patients were female. Forty-nine percent of patients had good functional outcome at 90-days, and 4.7% suffered sICH. Admission systolic BP (SBP), mean SBP, maximum SBP, SBP SD, and SBP range were associated with higher risk of sICH. In addition, patients in the higher mean SBP groups had higher rates of sICH. Similar results were found for hemicraniectomy. With respect to functional outcome, mean SBP, maximum SBP, and SBP range were inversely associated with the good outcome (modified Rankin Scale score, 0-2). However, the difference in SBP parameters between the poor and good outcome groups was modest. Conclusions- Higher BP within the first 24 hours after successful mechanical thrombectomy was associated with a higher likelihood of sICH, mortality, and requiring hemicraniectomy.

Isolated Internal Carotid Artery Thrombus and Cerebral Infarction in a Patient with Necrotizing Pancreatitis: Case Report.

Isolated internal carotid artery (ICA) thrombus in the absence of underlying atherosclerotic disease is a rare entity. We report a case of a patient presenting with right arm weakness, slurred speech, and altered mental status in the setting of acute on chronic pancreatitis. The patient was found to have scattered left cerebral hemisphere cortical infarctions, and catheter angiography confirmed the presence of intraluminal left ICA thrombus, with no evidence of atherosclerotic disease in the cervical or intracranial vasculature. Further workup also demonstrated the presence of anemia of chronic disease. The patient was initiated on anticoagulation, and follow-up imaging demonstrated a complete resolution of the left ICA thrombus. In the reported case, coagulopathy in the setting of acute on chronic pancreatitis was presumably the primary etiology. Anemia of chronic disease, related to a proinflammatory state, may also play a contributory role.

Space: The Final Frontier for IR.

A manned mission to Mars requires advanced on-board medical capabilities to address medical incidents that may arise during long-duration interplanetary spaceflight. As this role does not exactly match that of any single specialty, the ideal choice of physician is not immediately obvious. In this work, we review the considerable challenges of providing medical care in the austere conditions of interplanetary space travel and explain why an interventional radiologist may be well-equipped to deliver diagnostic and therapeutic care within these severely constrained conditions.

Transient cortical weakness following cerebral angiography: A new syndrome.

Transient cortical blindness is a known complication of iodinated contrast administration and is believed to reflect osmotic injury or autoregulatory dysfunction of the posterior circulation. Here, we report 2 cases of postangiography transient cortical weakness, a rare clinical analog to transient cortical blindness that affects the anterior circulation. The symptoms, timeline, and imaging findings of transient cortical weakness are distinct from more common post-procedural complications such as acute ischemic stroke or transient ischemic attack.

In-hospital imaging utilization after elective endovascular brain aneurysm treatment: a surrogate metric for the value of hospitalization.

OBJECTIVE: Despite the adoption of same-day outpatient surgical procedures in some specialties, it remains common practice to admit patients for monitoring after elective endovascular treatment of brain aneurysms to monitor for complications. The necessity of such monitoring has not been fully characterized. Here, the authors reviewed the utilization of imaging during posttreatment hospitalization, a surrogate measure for workup of suspected complications requiring hospital resources, to infer the value of inpatient monitoring after endovascular aneurysm treatment. METHODS: Clinical and angiographic data from eligible patients were retrospectively assessed for demographic characteristics, imaging indications, timing of imaging, and imaging findings. Patients were included if they underwent elective endovascular brain aneurysm treatment, and patients were excluded if significant intraprocedural complications occurred. The recorded imaging modalities included CT, MRI, catheter-based imaging, and ultrasound; plain radiographs were excluded. Multivariable logistic regression analysis was performed to identify predictors of the need for posttreatment imaging. RESULTS: In total, 1229 elective endovascular procedures for brain aneurysm treatment were included. Patients underwent imaging before discharge in 13.4% (165/1229) of cases, with significant findings in 5.0% (61/1229) of cases. The median (interquartile range) time to first posttreatment imaging was 13.2 (4.2-22.8) hours. The need for imaging during posttreatment hospitalization was positively associated with larger aneurysm size (p < 0.05) and negatively associated with underlying cardiovascular disease (p < 0.05). CONCLUSIONS: More than 1 in 8 patients who underwent elective endovascular brain aneurysm treatment required imaging during posttreatment hospitalization, most within the first 24 hours, and 1 in 20 had significant findings. These results suggest the importance of short-term hospitalization after elective endovascular aneurysm treatment.

The VEBAS score: a practical scoring system for intracranial dural arteriovenous fistula obliteration.

BACKGROUND: Tools predicting intracranial dural arteriovenous fistulas (dAVFs) treatment outcomes remain scarce. This study aimed to use a multicenter database comprising more than 1000 dAVFs to develop a practical scoring system that predicts treatment outcomes. METHODS: Patients with angiographically confirmed dAVFs who underwent treatment within the Consortium for Dural Arteriovenous Fistula Outcomes Research-participating institutions were retrospectively reviewed. A subset comprising 80% of patients was randomly selected as training dataset, and the remaining 20% was used for validation. Univariable predictors of complete dAVF obliteration were entered into a stepwise multivariable regression model. The components of the proposed score (VEBAS) were weighted based on their ORs. Model performance was assessed using receiver operating curves (ROC) and areas under the ROC. RESULTS: A total of 880 dAVF patients were included. Venous stenosis (presence vs absence), elderly age (<75 vs ≥75 years), Borden classification (I vs II-III), arterial feeders (single vs multiple), and past cranial surgery (presence vs absence) were independent predictors of obliteration and used to derive the VEBAS score. A significant increase in the likelihood of complete obliteration (OR=1.37 (1.27-1.48)) with each additional point in the overall patient score (range 0-12) was demonstrated. Within the validation dataset, the predicted probability of complete dAVF obliteration increased from 0% with a 0-3 score to 72-89% for patients scoring ≥8. CONCLUSION: The VEBAS score is a practical grading system that can guide patient counseling when considering dAVF intervention by predicting the likelihood of treatment success, with higher scores portending a greater likelihood of complete obliteration.

Travel time and distance for bypass and non-bypass routing of stroke patients in the USA.

BACKGROUND: Endovascular thrombectomy is not available at all hospitals that offer intravenous thrombolysis, prompting debate regarding the preferred transport destination for acute ischemic stroke. This study aimed to quantify real-world travel time and distance of bypass and non-bypass transport models for large-vessel occlusion (LVO) and non-LVO stroke. METHODS: This cross-sectional study included population data of census tracts in the contiguous USA from the 2014-2018 United States Census Bureau's American Community Survey, stroke (thrombolysis-capable) and thrombectomy-capable centers certified by a state or national body, and road network data from a mapping service. Census tracts were categorized by urbanization level. Data were retrieved from March to November 2020. Travel times and distances were calculated for each census tract to each of the following: nearest stroke center (nearest), nearest thrombectomy-capable center (bypass), and nearest stroke center then to the nearest thrombectomy-capable center (transfer). Population-weighted median and IQR were calculated nationally and by urbanization. RESULTS: 72 538 census tracts, 2388 stroke hospitals, and 371 thrombectomy-capable centers were included. Nationally, population-weighted median travel time for nearest and bypass routing was 11.7 min (IQR 7.7-19.3) and 26.4 min (14.8-55.1), respectively. For transfer routing, the population-weighted median travel times with 60 min, 90 min, and 120 min door-in-door-out times were 94.1 min (78.5-127.7), 124.1 min (108.5-157.7), and 154.1 min (138.4-187.6), respectively. CONCLUSIONS: Bypass routing offers modest travel time benefits for LVO patients and incurs modest penalties for non-LVO patients. Differences are greatest in rural areas. A majority of Americans live in areas for which current guidelines recommend bypass.

Retreatment of previously flow diverted intracranial aneurysms with the pipeline embolization device.

BACKGROUND AND PURPOSE: Flow diversion of intracranial aneurysms with the Pipeline Embolization Device (PED) is frequently performed, but the outcomes of retreatment for aneurysms that failed to occlude after prior treatment with PED have not been well studied. Here, we report the safety and efficacy of PED retreatment after initial failure to occlude. MATERIALS AND METHODS: Clinical and angiographic data from eligible patients were retrospectively assessed for demographics, aneurysm occlusion status, and clinical outcomes. Patients were included in this study if they underwent PED retreatment to treat an aneurysm that had previously been treated with PED. RESULTS: Retreatment of previously flow-diverted aneurysms with PED was performed in 42 cases. At final angiographic follow-up, angiographic improvement was observed after 45% (19/42) of retreatments and complete aneurysm occlusion was observed following 26% (11/42). Significant clinical complications occurred in 10% (4/42) of PED retreatments. CONCLUSIONS: Retreatment of intracranial aneurysms with PED following initial failure to achieve aneurysm occlusion has a low rate of subsequent complete aneurysm occlusion.