International Controlled Study of Revascularization and Outcomes Following COVID-Positive Mechanical Thrombectomy

Background and purpose

Previous studies suggest that mechanisms and outcomes in patients with COVID‐19‐associated stroke differ from those in patients with non‐COVID‐19‐associated strokes, but there is limited comparative evidence focusing on these populations. The aim of this study, therefore, was to determine if a significant association exists between COVID‐19 status with revascularization and functional outcomes following thrombectomy for large vessel occlusion (LVO), after adjustment for potential confounding factors.

Methods

A cross‐sectional, international multicenter retrospective study was conducted in consecutively admitted COVID‐19 patients with concomitant acute LVO, compared to a control group without COVID‐19. Data collected included age, gender, comorbidities, clinical characteristics, details of the involved vessels, procedural technique, and various outcomes. A multivariable‐adjusted analysis was conducted.

Results

In this cohort of 697 patients with acute LVO, 302 had COVID‐19 while 395 patients did not. There was a significant difference (p < 0.001) in the mean age (in years) and gender of patients, with younger patients and more males in the COVID‐19 group. In terms of favorable revascularization (modified Thrombolysis in Cerebral Infarction [mTICI] grade 3), COVID‐19 was associated with lower odds of complete revascularization (odds ratio 0.33, 95% confidence interval [CI] 0.23–0.48; p < 0.001), which persisted on multivariable modeling with adjustment for other predictors (adjusted odds ratio 0.30, 95% CI 0.12–0.77; p = 0.012). Moreover, endovascular complications, in‐hospital mortality, and length of hospital stay were significantly higher among COVID‐19 patients (p < 0.001).

Conclusion

COVID‐19 was an independent predictor of incomplete revascularization and poor functional outcome in patients with stroke due to LVO. Furthermore, COVID‐19 patients with LVO were more often younger and had higher morbidity/mortality rates.

Characteristics of a COVID-19 Cohort With Large Vessel Occlusion: A Multicenter International Study

BACKGROUND

The mechanisms and outcomes in coronavirus disease (COVID-19)-associated stroke are unique from those of non-COVID-19 stroke.

OBJECTIVE

To describe the efficacy and outcomes of acute revascularization of large vessel occlusion (LVO) in the setting of COVID-19 in an international cohort.

METHODS

We conducted an international multicenter retrospective study of consecutively admitted patients with COVID-19 with concomitant acute LVO across 50 comprehensive stroke centers. Our control group constituted historical controls of patients presenting with LVO and receiving a mechanical thrombectomy between January 2018 and December 2020.

RESULTS

The total cohort was 575 patients with acute LVO; 194 patients had COVID-19 while 381 patients did not. Patients in the COVID-19 group were younger (62.5 vs 71.2; P < .001) and lacked vascular risk factors (49, 25.3% vs 54, 14.2%; P = .001). Modified thrombolysis in cerebral infarction 3 revascularization was less common in the COVID-19 group (74, 39.2% vs 252, 67.2%; P < .001). Poor functional outcome at discharge (defined as modified Ranklin Scale 3-6) was more common in the COVID-19 group (150, 79.8% vs 132, 66.7%; P = .004). COVID-19 was independently associated with a lower likelihood of achieving modified thrombolysis in cerebral infarction 3 (odds ratio [OR]: 0.4, 95% CI: 0.2-0.7; P < .001) and unfavorable outcomes (OR: 2.5, 95% CI: 1.4-4.5; P = .002).

CONCLUSION

COVID-19 was an independent predictor of incomplete revascularization and poor outcomes in patients with stroke due to LVO. Patients with COVID-19 with LVO were younger, had fewer cerebrovascular risk factors, and suffered from higher morbidity/mortality rates.

Acute ischaemic stroke associated with SARS-CoV-2 infection in North America

BACKGROUND

To analyse the clinical characteristics of COVID-19 with acute ischaemic stroke (AIS) and identify factors predicting functional outcome.

METHODS

Multicentre retrospective cohort study of COVID-19 patients with AIS who presented to 30 stroke centres in the USA and Canada between 14 March and 30 August 2020. The primary endpoint was poor functional outcome, defined as a modified Rankin Scale (mRS) of 5 or 6 at discharge. Secondary endpoints include favourable outcome (mRS ≤2) and mortality at discharge, ordinal mRS (shift analysis), symptomatic intracranial haemorrhage (sICH) and occurrence of in-hospital complications.

RESULTS

A total of 216 COVID-19 patients with AIS were included. 68.1% (147/216) were older than 60 years, while 31.9% (69/216) were younger. Median [IQR] National Institutes of Health Stroke Scale (NIHSS) at presentation was 12.5 (15.8), and 44.2% (87/197) presented with large vessel occlusion (LVO). Approximately 51.3% (98/191) of the patients had poor outcomes with an observed mortality rate of 39.1% (81/207). Age >60 years (aOR: 5.11, 95% CI 2.08 to 12.56, p<0.001), diabetes mellitus (aOR: 2.66, 95% CI 1.16 to 6.09, p=0.021), higher NIHSS at admission (aOR: 1.08, 95% CI 1.02 to 1.14, p=0.006), LVO (aOR: 2.45, 95% CI 1.04 to 5.78, p=0.042), and higher NLR level (aOR: 1.06, 95% CI 1.01 to 1.11, p=0.028) were significantly associated with poor functional outcome.

CONCLUSION

There is relationship between COVID-19-associated AIS and severe disability or death. We identified several factors which predict worse outcomes, and these outcomes were more frequent compared to global averages. We found that elevated neutrophil-to-lymphocyte ratio, rather than D-Dimer, predicted both morbidity and mortality.

Stroke risk, phenotypes, and death in COVID-19: Systematic review and newly reported cases

OBJECTIVES

To investigate the hypothesis that strokes occurring in patients with coronavirus disease 2019 (COVID-19) have distinctive features, we investigated stroke risk, clinical phenotypes, and outcomes in this population.

METHODS

We performed a systematic search resulting in 10 studies reporting stroke frequency among patients with COVID-19, which were pooled with 1 unpublished series from Canada. We applied random-effects meta-analyses to estimate the proportion of stroke among COVID-19. We performed an additional systematic search for cases series of stroke in patients with COVID-19 (n = 125), and we pooled these data with 35 unpublished cases from Canada, the United States, and Iran. We analyzed clinical characteristics and in-hospital mortality stratified into age groups (<50, 50-70, >70 years). We applied cluster analyses to identify specific clinical phenotypes and their relationship with death.

RESULTS

The proportions of patients with COVID-19 with stroke (1.8%, 95% confidence interval [CI] 0.9%-3.7%) and in-hospital mortality (34.4%, 95% CI 27.2%-42.4%) were exceedingly high. Mortality was 67% lower in patients <50 years of age relative to those >70 years of age (odds ratio [OR] 0.33, 95% CI 0.12-0.94, p = 0.039). Large vessel occlusion was twice as frequent (46.9%) as previously reported and was high across all age groups, even in the absence of risk factors or comorbid conditions. A clinical phenotype characterized by older age, a higher burden of comorbid conditions, and severe COVID-19 respiratory symptoms was associated with the highest in-hospital mortality (58.6%) and a 3 times higher risk of death than the rest of the cohort (OR 3.52, 95% CI 1.53-8.09, p = 0.003).

CONCLUSIONS

Stroke is relatively frequent among patients with COVID-19 and has devastating consequences across all ages. The interplay of older age, comorbid conditions, and severity of COVID-19 respiratory symptoms is associated with an extremely elevated mortality.

Abstract TP258: Clinical and Radiographic Features of Stroke in Cryptococcal Meningoencephalitis in a US Cohort Study

Background: Cryptococcal meningitis can present with small vessel vasculitis and ischemic stroke. Acute and chronic infection carry a high mortality in both immunocompetent and immunocompromised patients. Among the survivors, multiple neurological deficit cause marked disability. Predictors of poor outcome and stroke recurrence remain unrecognized.

Methods: We aim to describe clinical and radiographic features of stroke in a prospectively collected cohort of patients with Cryptococcal meningitis. A retrospective analysis of neuroimaging studies, cerebrospinal fluid(CSF) and clinical presentation was performed at the University of Colorado Hospital between 2000-2018. A multivariable logistic regression model was constructed to explore associations between dichotomous variables and informed as risk ratios. A T-Test and Wilcoxon test were applied to means of continuous variables. Fisher's exact test and contingency tables were used.

Results: A total of 42 patients had cryptococcal meningitis, of which 31 had available imaging. Ischemic stroke was present in 8 patients (26%). Most strokes were acute (75%), lacunar (100%), multiple (88%), bilateral (63%) and localized in the basal ganglia (75%). Hyponatremia carried a RR: 5.7 (95% CI, 1.7-34.1) p=0.005. Other variables such malignancy, basal exudates, cryptococcoma, meningeal enhancement, hydrocephalus and CSF WBC did not seem to increase or reduce the risk of stroke. Anemia and hyponatremia were associated with presence of stroke, p=0.02 and p=0.03, respectively. Every unit decrease in hemoglobin is associated with 0.26 times the risk of ischemic stroke, (95% CI, 1.7-34.1) p=0.0312. Cryptococcal meningitis lead to death in 13 patients (30%) and 3 (14%) in patients with pulmonary manifestations only.

Conclusion: Cryptococcal meningitis carries a high risk of neurologic complications, including lacunar stroke, particularly in the basal ganglia. Predisposing risk factors include anemia and hyponatremia regardless of the immune status of the patients. We report a mortality comparable to developing countries in the setting of a center of reference. The most common radiographic features of cryptococcal vasculitic infection may play a role in the high mortality of the population.

Abstract WP241: 30-Day Readmission for Mechanical Thrombectomy Among Patients With Ischemic Stroke

Background: Mechanical thrombectomy (MT) is standard of care for acute ischemic stroke (AIS) due to large vessel occlusion of the anterior circulation, and is proven to improve clinical outcomes; however, little is known about short-term readmission rates and associated risk factors.

Methods: The Nationwide Readmissions Database data between January and November 2014 was used to identify patients older than 18 years who underwent MT for AIS across 22 participating states in the United States. An adjusted multivariable logistic regression model was constructed to explore associations between demographic and socioeconomic characteristics. An index hospitalization was identified with primary diagnosis of ICD-9 codes 433X1, 434.X1 and 436. A procedure code for mechanical thrombectomy was identified by 39.74.

Results: A total of 502,604 suffered AIS in 2014, 4,899 (0.97%) individuals underwent MT equally across genders, with 2385 (48.7%) women, 2514 (51.3%)[BK1] [DV2] men mostly between 65 and 84 years old. Over 60% corresponded to Medicare with 91.2% performed at large metropolitan hospitals. Males were readmitted more frequently than women within 30 days following AIS (3.35%, 2.75% respectively, p=0.0000) and only 73 (1.5%) patients were readmitted following MT. No differences in 30-day readmission were observed across median household income, admission day of the week or hospital size. Patients who underwent MT (aOR 0.62, 0.40-0.96), female sex (aOR 0.86, 0.81-0.91), hospitalization length >7 days (aOR 0.82, 0.72-0.92) were associated with lower risk of readmission at 30 days, while age 65-84 years (aOR 1.60, 1.35-1.90) represented a higher risk of readmission among adults with AIS.

Conclusions: In the United States in 2014, the readmission rate after MT for AIS of anterior circulation is 1.5% at 30 days. Older age was associated with a 60% increase in adjusted odds of readmission among adults with AIS. MT has been demonstrated to be safe and effective, however; the study dataset is limited to practices prior to recent landmark trials. We speculate that the rate of readmission will tend to decrease from 2015 onward due to better patient selection and lower complication rates.

Abstract TMP60: Trends in Neurophysiologic Intraoperative Monitoring and Occurrence of Stroke at the Time of Hospitalization for Carotid Endarterectomy

Background: intraoperative neurophysiological monitoring (IoNM) is a valuable technique for determining the need for selective intraoperative shunting and prevention of perioperative stroke in patients undergoing carotid endarterectomy (CEA).

Methods: We aimed to describe the trends of intraoperative monitoring utilization using the US-representative 2006-2015 National Inpatient Sample database. We sought to identify associations of patient’s demographics with outcomes with an adjusted multivariable logistic regression model.

Results: Between 2006-2014, there were a total of 11003 endarterectomies included in our analysis, most commonly performed in men 6764 (61.5%), and women 4239 (38.5%) mostly older than 65 years old. Intraoperative monitoring was used in 266 cases (2.45%) equally across genders, 168 (2.5%) man, 98 (2.3%) women. Nearly 80.8% undergoing CEA and IoNM were white, 8.7% black, 5.7% Hispanic with no differences of IoNM use across race. No difference between primary payer, location/teaching status or size of the hospital were observed. The use of IoNM during CEA was more frequent in the Midwest region: 32.9% (89), Northeast: 28% (74), South: 21.4% (57), and West: 17.6% (46), p=0.0000. The rate of utilization of IoNM increased across the years, 2006/08 (0.06%), 2009/11 (2.1%) and 2012/14 (4.6%). p=0.0000. Unadjusted rates of in-hospital death were not associated with IoNM. Mean length of stay(LOS) of ECA with IoNM was 8 days (95% CI, 7.36-8.76) and IoNM without ECA was 7.25 (95% CI, 7.10-7.38). Adjusted Mortality did not differ in time. During 2009-2011: aOR 0.60 (95% CI, 0.36-0.98) and 2012-2014: aOR 0.50, (95% CI, 0.29-0.86) were associated with lower odds of using Intraoperative monitoring. The Charlson Comorbidity Index aOR 1.2 (95% CI, 1.09-1.33) and Length of stay aOR 1.06 (95% CI, 1.04-1.08)

Conclusions: The percent of endarterectomies performed with IoNM has increased over the years; however, this trend does not seem to impact LOS and in-hospital mortality. This might be explained by the overall low rate of utilization, with documentation of its use in only 5.2% of CEA performed in 2014. Despite being a highly specific test in predicting neurological outcomes, the impact on perioperative stroke prevention is perhaps undervalued.

Neuroterrorism Preparedness for the Neurohospitalist

In this review article, we highlight several potential biologic and chemical agents of "neuroterrorism" of which neurohospitalists should be aware: anthrax, botulism toxin, brucella, plague, smallpox, organophosphates and nerve agents, cyanide, and carfentanil. Such agents may have direct neurologic effects, resulting in encephalopathy, paralysis, and/or respiratory failure. Neurohospitalists should be on the lookout for abnormal neurologic syndrome clustering, especially among patients presenting to the emergency department. If use of such a "neuroterrorism" agent is suspected, the neurohospitalist should immediately consult with emergency department personnel, infection control, infectious disease physicians, and/or Poison Control to make sure the scene is safe and to stabilize and isolate patients if necessary. The neurohospitalist should also immediately contact their local and/or state health department (or alternatively the US Centers for Disease Control and Prevention Emergency Operations Center) to report their suspicions and to obtain guidance and assistance.

Mobile Stroke Unit Reduces Time to Image Acquisition and Reporting

Timely administration of thrombolytic therapy is critical to maximizing the likelihood of favorable outcomes in patients with acute ischemic stroke. Although emergency medical service activation overall improves the timeliness of acute stroke treatment, the time from emergency medical service dispatch to hospital arrival unavoidably decreases the timeliness of thrombolytic administration. Our mobile stroke unit, a new-generation ambulance with on-board CT scanning capability, reduces key imaging time metrics and facilitates in-the-field delivery of IV thrombolytic therapy.

Abstract TP249: Hospital Transfer Cost Savings From Triaging Selected Stroke Patients Directly to the Comprehensive Stroke Centers (CSCs) Courtesy of the Mobile Stroke Treatment Unit (MSTU)

Introduction: The Mobile Stroke Treatment Unit (MSTU) is a novel onsite pre-hospital treatment team with all basic infra-structure to diagnose, emergently treat and hence timely triage acute ischemic and hemorrhagic stroke patients to either the primary stroke center (PSCs) or comprehensive stroke centers (CSCs). Recent evidence supports outcome benefits in favor of intra-arterial therapy (IAT) in large vessel strokes and transfers to neuro-critical care units for managing large strokes. This has resulted in a surge in transfers to CSCs summing additional transfer costs for patients not initially presenting to a CSC. This is the first ever study in the United States that utilizes a basic cost generation model to measure the economic benefits of MSTU triage directly to the CSCs by-passing PSCs, for the those patients requiring higher-level care.

Method: Mobile Stroke Treatment Unit database was used to identify patients that stroke neurologists triaged to CSCs. These included all acute ICH, IAT candidates and severe strokes with ICU needs. We calculated the average costs of a typical primary stroke center emergency room visit and the cost of a critical care transport, generating a cost savings model.

Result: Fifty two patients who were evaluated by stroke neurologists in the mobile stroke unit from July 2014 to October 2015 were adjudged candidates for comprehensive stroke centers. Twenty four (46%) of these were intra-cerebral hemorrhage (ICH) confirmed on portable head CT while the other 28 (54%) presented with major strokes with possible IA thrombectomy candidacy or anticipated Neuro ICU needs due to stroke severity. Eleven ICH and 13 ischemic stroke patients (46%) of the 52 patients by-passed PSC to be taken directly to comprehensive stroke centers with a potential of saving millions of dollars in costs and critical time.

Conclusion: Even in a city with dense presence of comprehensive stroke centers, a large cohort of patients by-passed primary stroke centers with a potential of saving millions of dollars in costs and critical time. Future goals include evaluating for difference in outcome in this group of patients that by-passed PSC courtesy MSTU. Additionally, this needs to be replicated in other counties and cities before policy changes are proposed.

Abstract 79: Pre-hospital Diagnosis in Mobile Stroke Treatment Unit

Introduction: Mobile stroke treatment unit (MSTU) has been shown to be able to provide pre-hospital thrombolysis in acute ischemic stroke (AIS). MSTU can also be used for early pre-hospital diagnosis and treatment of other neurological diseases.

Hypothesis: MSTU encounters neurological disorders other than AIS that needs emergent treatment.

Methods: We obtained pre-hospital diagnosis and treatment data from the prospectively collected dataset on 231 consecutive MSTU encounters. Based on initial clinical evaluation and neuroimaging obtained on MSTU, the stroke physician made the diagnosis of AIS (definite, probable, and possible AIS, transient ischemic attack), intracranial hemorrhage, and unlikely AIS. Non-stroke diagnosis made by MSTU physician was compared with final hospital discharge diagnosis.

Results: From July 2014 to May 2015, 231 patients were treated on MSTU of which 84 (36%) had clinical diagnosis of definite/probable AIS, 70 (31%) had possible AIS, while 14 (6%) patients had intracranial hemorrhage. Sixty-three (27%) were diagnosed as unlikely AIS including 23 (10%) metabolic encephalopathy, 19 (8%) seizures (including 1 partial status epilepticus), 16 (7%) migraines, 16 (7%) substance abuse, 6 (3%) CNS tumor, 5 (2%) infectious etiology and 3 (1%) hypoglycemia. Thirty-three (14%) patients received non-thrombolytic treatments on MSTU including anti-hypertensives (24), anti-epileptic medications (7), coagulopathy reversal (1), and mannitol (1). In patients with initial diagnosis of possible AIS, final diagnoses were 29 AIS and 25 non-strokes, while in patients initially diagnosed with unlikely AIS, 5 were AIS and 38 were non-strokes in the final discharge diagnosis.

Conclusion: About a third of MSTU encounters were deemed not AIS initially, including intra cranial hemorrhage and seizure. MSTU can also be utilized to provide early pre-hospital treatments in emergent neurological conditions other than AIS.

Abstract TP358: Prehospital Diagnosis of Intracerebral Hemorrhage in a Mobile Stroke Treatment Unit

Introduction: The mobile stroke unit (MSTU) is an on-site pre-hospital treatment team that incorporates laboratory and CT scanner and reduces times to treatment for ischemic stroke thrombolysis. The impact of MSTU on treatment and outcomes of intracerebral hemorrhage (ICH) remains unknown. We report our initial experience with ICH encountered on MSTU.

Hypothesis: ICH can be quickly identified using MSTU. Hypertension and coagulopathy are common in ICH evaluated on MSTU.

Methods: We identified ICH cases from the prospectively collected database encounters. Demographics, clinical features, MSTU imaging and repeat imaging characteristics were reviewed. Initial and follow-up hematoma volume was calculated by the ABC/2 method.

Results: Of 295 encounters on MSTU from July 2014 to July 2015, 20 (6.7%) had intracranial hemorrhage, which comprised of 17 intracerebral, 1 subarachnoid and 2 subdural hemorrhages. Median time to CT diagnosis of ICH from emergency medical dispatch was 31 minutes (interquartile range (IQR) 28-36) and that from last known well was 118 minutes (IQR 39-301). Of the 17 ICH patients, 15 (88%) were hypertensive, with a mean systolic blood pressure of 178.1 and diastolic 91.0 mm Hg. Five (29.4%) individuals were found with INR>1.4, 1 of whom received 4-factor prothrombin complex concentrate. Median NIH Stroke Scale was 11 (IQR 7.5-14.5), and median hematoma volume was 10.7 cc (IQR 4.3-30.8). One patient had significant hematoma expansion as defined by >6 cc or 33% relative volume increase.

Conclusions: Over 5% of the cases evaluated in the unit presented with ICH, most of whom were hypertensive and had small hematoma volume. MSTU enables early diagnosis of ICH after activation of emergency system, can provide early treatment, and appropriate triage.

Internal carotid artery dissection after a roller coaster ride in a 4-year-old: case report and review of the literature

BACKGROUND

Strokes associated with roller-coaster rides are unusual.

PATIENT

A previously healthy 4-year-old boy developed acute onset of left-sided weakness when flying home from a trip to an amusement park. He had frequented two roller coaster rides the day prior. Upon evaluation, he was found to have an acute right middle cerebral artery territory infarction.

RESULTS

Cerebral angiography showed dissection of the right cervical internal carotid artery and right middle cerebral artery occlusion involving the M1 segment. He was treated with aspirin. Evaluation for underlying connective tissue diseases was unremarkable.

CONCLUSION

We speculate that repetitive forces of acceleration and deceleration may have led to a cervical internal carotid artery intimal tear, followed by thromboembolism. It remains uncertain what the threshold of susceptibility to repetitive rotational changes and tolerability to G forces in an otherwise healthy child truly is.

The absence of the calcium-buffering protein calbindin is associated with faster age-related decline in hippocampal metabolism

Although reductions in the expression of the calcium-buffering proteins calbindin D-28K (CB) and parvalbumin (PV) have been observed in the aging brain, it is unknown whether these changes contribute to age-related hippocampal dysfunction. To address this issue, we measured basal hippocampal metabolism and hippocampal structure across the lifespan of C57BL/6J, calbindin D-28k knockout (CBKO) and parvalbumin knockout (PVKO) mice. Basal metabolism was estimated using steady state relative cerebral blood volume (rCBV), which is a variant of fMRI that provides the highest spatial resolution, optimal for the analysis of individual subregions of the hippocampal formation. We found that like primates, normal aging in C57BL/6J mice is characterized by an age-dependent decline in rCBV-estimated dentate gyrus (DG) metabolism. Although abnormal hippocampal fMRI signals were observed in CBKO and PVKO mice, only CBKO mice showed accelerated age-dependent decline of rCBV-estimated metabolism in the DG. We also found age-independent structural changes in CBKO mice, which included an enlarged hippocampus and neocortex as well as global brain hypertrophy. These metabolic and structural changes in CBKO mice correlated with a deficit in hippocampus-dependent learning in the active place avoidance task. Our results suggest that the decrease in CB that occurs during normal aging is involved in age-related hippocampal metabolic decline. Our findings also illustrate the value of using multiple MRI techniques in transgenic mice to investigate mechanisms involved in the functional and structural changes that occur during aging.