Development of Parkinson Disease and Its Relationship with Incidentally Discovered White Matter Disease and Covert Brain Infarction in a Real-World Cohort.

OBJECTIVE: This study aimed to examine the relationship between covert cerebrovascular disease, comprised of covert brain infarction and white matter disease, discovered incidentally in routine care, and subsequent Parkinson disease. METHODS: Patients were ≥50 years and received neuroimaging for non-stroke indications in the Kaiser Permanente Southern California system from 2009 to 2019. Natural language processing identified incidentally discovered covert brain infarction and white matter disease and classified white matter disease severity. The Parkinson disease outcome was defined as 2 ICD diagnosis codes. RESULTS: 230,062 patients were included (median follow-up 3.72 years). A total of 1,941 Parkinson disease cases were identified (median time-to-event 2.35 years). Natural language processing identified covert cerebrovascular disease in 70,592 (30.7%) patients, 10,622 (4.6%) with covert brain infarction and 65,814 (28.6%) with white matter disease. After adjustment for known risk factors, white matter disease was associated with Parkinson disease (hazard ratio 1.67 [95%CI, 1.44, 1.93] for patients <70 years and 1.33 [1.18, 1.50] for those ≥70 years). Greater severity of white matter disease was associated with increased incidence of Parkinson disease(/1,000 person-years), from 1.52 (1.43, 1.61) in patients without white matter disease to 4.90 (3.86, 6.13) in those with severe disease. Findings were robust when more specific definitions of Parkinson disease were used. Covert brain infarction was not associated with Parkinson disease (adjusted hazard ratio = 1.05 [0.88, 1.24]). INTERPRETATION: Incidentally discovered white matter disease was associated with subsequent Parkinson disease, an association strengthened with younger age and increased white matter disease severity. Incidentally discovered covert brain infarction did not appear to be associated with subsequent Parkinson disease. ANN NEUROL 2022;92:620-630.

Stratifying Future Stroke Risk with Incidentally Discovered White Matter Disease Severity and Covert Brain Infarct Site.

BACKGROUND: Covert cerebrovascular disease (CCD) includes white matter disease (WMD) and covert brain infarction (CBI). Incidentally discovered CCD is associated with increased risk of subsequent symptomatic stroke. However, it is unknown whether the severity of WMD or the location of CBI predicts risk. OBJECTIVES: The aim of this study was to examine the association of incidentally discovered WMD severity and CBI location with risk of subsequent symptomatic stroke. METHOD: This retrospective cohort study includes patients aged ≥50 years old in the Kaiser Permanente Southern California health system who received neuroimaging for a nonstroke indication between 2009 and 2019. Incidental CBI and WMD were identified via natural language processing of the neuroimage report, and WMD severity was classified into grades. RESULTS: A total of 261,960 patients received neuroimaging; 78,555 patients (30.0%) were identified to have incidental WMD and 12,857 patients (4.9%) to have incidental CBI. Increasing WMD severity is associated with an increased incidence rate of future stroke. However, the stroke incidence rate in CT-identified WMD is higher at each level of severity compared to rates in MRI-identified WMD. Patients with mild WMD via CT have a stroke incidence rate of 24.9 per 1,000 person-years, similar to that of patients with severe WMD via MRI. Among incidentally discovered CBI patients with a determined CBI location, 97.9% are subcortical rather than cortical infarcts. CBI confers a similar risk of future stroke, whether cortical or subcortical or whether MRI- or CT-detected. CONCLUSIONS: Increasing severity of incidental WMD is associated with an increased risk of future symptomatic stroke, dependent on the imaging modality. Subcortical and cortical CBI conferred similar risks.

Stratifying future stroke risk with incidentally-discovered white matter disease severity and covert brain infarct site.

BACKGROUND: Covert cerebrovascular disease (CCD) includes white matter disease (WMD) and covert brain infarction (CBI). Incidentally-discovered CCD is associated with increased risk of subsequent symptomatic stroke. However, it is unknown whether the severity of WMD or the location of CBI predicts risk. OBJECTIVES: To examine the association of incidentally-discovered WMD severity and CBI location with risk of subsequent symptomatic stroke. METHOD: This retrospective cohort study includes patients 50 years old in the Kaiser Permanente Southern California health system who received neuroimaging for a non-stroke indication between 2009-2019. Incidental CBI and WMD were identified via natural language processing of the neuroimage report, and WMD severity was classified into grades. RESULTS: 261,960 patients received neuroimaging; 78,555 (30.0%) were identified to have incidental WMD, and 12,857 (4.9%) to have incidental CBI. Increasing WMD severity is associated with increased incidence rate of future stroke. However, the stroke incidence rate in CT-identified WMD is higher at each level of severity compared to rates in MRI-identified WMD. Patients with mild WMD via CT have a stroke incidence rate of 24.9 per 1,000 person-years, similar to that of patients with severe WMD via MRI. Among incidentally-discovered CBI patients with a determined CBI location, 97.9% are subcortical rather than cortical infarcts. CBI confers a similar risk of future stroke, whether cortical or subcortical, or whether MRI- or CT-detected. CONCLUSIONS: Increasing severity of incidental WMD is associated with an increased risk of future symptomatic stroke, dependent on the imaging modality. Subcortical and cortical CBI conferred similar risks.

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.

Benefits and Risks of Dual Versus Single Antiplatelet Therapy for Secondary Stroke Prevention: A Systematic Review for the 2021 Guideline for the Prevention of Stroke in Patients With Stroke and Transient Ischemic Attack.

BACKGROUND: Dual antiplatelet therapy (DAPT) after ischemic stroke or transient ischemic attack may reduce recurrent stroke but also increase severe bleeding compared with single antiplatelet therapy (SAPT). The American Heart Association/American Stroke Association convened an evidence review committee to perform a systematic review and meta-analysis of the benefits and risks of DAPT compared with SAPT for secondary ischemic stroke prevention. METHODS: The Medline, Embase, and Cochrane databases were searched on December 5, 2019, to identify phase III or IV randomized controlled trials (n≥100) from December 1999 to December 2019. We calculated unadjusted relative risks (RRs) and performed meta-analyses of studies based on the duration of treatment (short [≤90 days] versus long [>90 days]). RESULTS: Three short-duration randomized controlled trials were identified that enrolled mostly patients with minor stroke or high risk transient ischemic attack. In these trials, DAPT, compared with SAPT, was associated with a lower 90-day risk of recurrent ischemic stroke (pooled RR, 0.68 [95% CI, 0.55-0.83], I 2=37.1%). There was no significant increase in major bleeding with DAPT in short-duration trials (pooled RR, 1.88 [95% CI, 0.93-3.83], I 2=8.9%). In 2 long-duration treatment randomized controlled trials (mean treatment duration, 18-40 months), DAPT was not associated with a significant reduction in recurrent ischemic stroke (pooled RR, 0.89 [95% CI, 0.79-1.02], I 2=1.4%), but was associated with a higher risk of major bleeding (pooled RR, 2.42 [95% CI, 1.37-4.30], I 2=75.5%). CONCLUSIONS: DAPT was more effective than SAPT for prevention of secondary ischemic stroke when initiated early after the onset of minor stroke/high-risk transient ischemic attack and treatment duration was <90 days. However, when the treatment duration was longer and initiated later after stroke or transient ischemic attack onset, DAPT was not more effective than SAPT for ischemic stroke prevention and it increased the risk of bleeding.

Agreement between neuroimages and reports for natural language processing-based detection of silent brain infarcts and white matter disease.

BACKGROUND: There are numerous barriers to identifying patients with silent brain infarcts (SBIs) and white matter disease (WMD) in routine clinical care. A natural language processing (NLP) algorithm may identify patients from neuroimaging reports, but it is unclear if these reports contain reliable information on these findings. METHODS: Four radiology residents reviewed 1000 neuroimaging reports (RI) of patients age > 50 years without clinical histories of stroke, TIA, or dementia for the presence, acuity, and location of SBIs, and the presence and severity of WMD. Four neuroradiologists directly reviewed a subsample of 182 images (DR). An NLP algorithm was developed to identify findings in reports. We assessed interrater reliability for DR and RI, and agreement between these two and with NLP. RESULTS: For DR, interrater reliability was moderate for the presence of SBIs (k = 0.58, 95 % CI 0.46-0.69) and WMD (k = 0.49, 95 % CI 0.35-0.63), and moderate to substantial for characteristics of SBI and WMD. Agreement between DR and RI was substantial for the presence of SBIs and WMD, and fair to substantial for characteristics of SBIs and WMD. Agreement between NLP and DR was substantial for the presence of SBIs (k = 0.64, 95 % CI 0.53-0.76) and moderate (k = 0.52, 95 % CI 0.39-0.65) for the presence of WMD. CONCLUSIONS: Neuroimaging reports in routine care capture the presence of SBIs and WMD. An NLP can identify these findings (comparable to direct imaging review) and can likely be used for cohort identification.

Exploiting telerobotics for sensorimotor rehabilitation: a locomotor embodiment.

BACKGROUND: Manual treadmill training is used for rehabilitating locomotor impairments but can be physically demanding for trainers. This has been addressed by enlisting robots, but in doing so, the ability of trainers to use their experience and judgment to modulate locomotor assistance on the fly has been lost. This paper explores the feasibility of a telerobotics approach for locomotor training that allows patients to receive remote physical assistance from trainers. METHODS: In the approach, a trainer holds a small robotic manipulandum that shadows the motion of a large robotic arm magnetically attached to a locomoting patient's leg. When the trainer deflects the manipulandum, the robotic arm applies a proportional force to the patient. An initial evaluation of the telerobotic system's transparency (ability to follow the leg during unassisted locomotion) was performed with two unimpaired participants. Transparency was quantified by the magnitude of unwanted robot interaction forces. In a small six-session feasibility study, six individuals who had prior strokes telerobotically interacted with two trainers (separately), who assisted in altering a targeted gait feature: an increase in the affected leg's swing length. RESULTS: During unassisted walking, unwanted robot interaction forces averaged 3-4 N (swing-stance) for unimpaired individuals and 2-3 N for the patients who survived strokes. Transients averaging about 10 N were sometimes present at heel-strike/toe-off. For five of six patients, these forces increased with treadmill speed during stance (R2 = .99; p < 0.001) and increased with patient height during swing (R2 = .71; p = 0.073). During assisted walking, the trainers applied 3.0 ± 2.8 N (mean ± standard deviation across patients) and 14.1 ± 3.4 N of force anteriorly and upwards, respectively. The patients exhibited a 20 ± 21% increase in unassisted swing length between Days 1-6 (p = 0.058). CONCLUSIONS: The results support the feasibility of locomotor assistance with a telerobotics approach. Simultaneous measurement of trainer manipulative actions, patient motor responses, and the forces associated with these interactions may prove useful for testing sensorimotor rehabilitation hypotheses. Further research with clinicians as operators and randomized controlled trials are needed before conclusions regarding efficacy can be made.

Cholesterol Variability and Cranial Magnetic Resonance Imaging Findings in Older Adults: The Cardiovascular Health Study.

Background and Purpose- Serum cholesterol variability, independent of mean, has been associated with stroke, white matter hyperintensities on cranial magnetic resonance imaging (MRI), and other cardiovascular events. We sought to assess the relationship between total serum cholesterol (TC) variability and cranial MRI findings of subclinical or covert vascular brain injury in a longitudinal, population-based cohort study of older adults. Methods- In the Cardiovascular Health Study, we assessed associations between intraindividual TC mean, trend, and variability over ≈5 years with covert brain infarction (CBI) and white matter grade (WMG) on cranial MRI. Mean TC was calculated for each study participant from 4 annual TC measurements between 2 MRI scans. TC trend was calculated as the slope of the linear regression of the TC measurements, and TC variability was calculated as the SD of the residuals from the linear regression. We evaluated the association of intraindividual TC variability with incident CBI and worsening WMG between 2 MRI scans in primary analyses and with prevalent CBI number and WMG on the follow-up MRI scan in secondary analyses. Results- Among participants who were eligible for the study and free of clinical stroke before the follow-up MRI, 17.9% of 1098 had incident CBI, and 27.8% of 1351 had worsening WMG on the follow-up MRI. Mean, trend, and variability of TC were not associated with these outcomes. TC variability, independent of mean and trend, was significantly associated with the number of CBI (ß=0.009 [95% CI, 0.003-0.016] P=0.004; N=1604) and was associated with WMG (ß, 0.009 [95% CI, -0.0002 to 0.019] P=0.055; N=1602) on the follow-up MRI. Conclusions- Among older adults, TC variability was not associated with incident CBI or worsening WMG but was associated with the number of prevalent CBI on cranial MRI. More work is needed to validate and to clarify the mechanisms underlying such associations.

Assessment of the impact of EHR heterogeneity for clinical research through a case study of silent brain infarction.

BACKGROUND: The rapid adoption of electronic health records (EHRs) holds great promise for advancing medicine through practice-based knowledge discovery. However, the validity of EHR-based clinical research is questionable due to poor research reproducibility caused by the heterogeneity and complexity of healthcare institutions and EHR systems, the cross-disciplinary nature of the research team, and the lack of standard processes and best practices for conducting EHR-based clinical research. METHOD: We developed a data abstraction framework to standardize the process for multi-site EHR-based clinical studies aiming to enhance research reproducibility. The framework was implemented for a multi-site EHR-based research project, the ESPRESSO project, with the goal to identify individuals with silent brain infarctions (SBI) at Tufts Medical Center (TMC) and Mayo Clinic. The heterogeneity of healthcare institutions, EHR systems, documentation, and process variation in case identification was assessed quantitatively and qualitatively. RESULT: We discovered a significant variation in the patient populations, neuroimaging reporting, EHR systems, and abstraction processes across the two sites. The prevalence of SBI for patients over age 50 for TMC and Mayo is 7.4 and 12.5% respectively. There is a variation regarding neuroimaging reporting where TMC are lengthy, standardized and descriptive while Mayo's reports are short and definitive with more textual variations. Furthermore, differences in the EHR system, technology infrastructure, and data collection process were identified. CONCLUSION: The implementation of the framework identified the institutional and process variations and the heterogeneity of EHRs across the sites participating in the case study. The experiment demonstrates the necessity to have a standardized process for data abstraction when conducting EHR-based clinical studies.

Differences in presenting symptoms of acute stroke among young and older adults.

BACKGROUND: Prior studies demonstrated that young adults with stroke present later to medical attention, have lower initial NIHSS, and are frequently misdiagnosed as compared to older adults. We sought to assess potential differences in temporal and clinical characteristics of stroke symptoms between young (age 18-50 years) and older adults (age > 50). METHODS: This retrospective cohort study included patients age ≥ 18 years hospitalized at a comprehensive stroke center with acute ischemic stroke (AIS), transient ischemic attack (TIA), or intracerebral hemorrhage (ICH). Outcomes included progression of neurologic deficits over the first 24 h, fluctuation in neurologic deficits, and characterization of the triage chief complaint as typical or atypical (less specific) for stroke. Univariate analyses for baseline covariates were performed with Chi-square and Mann-Whitney U tests. Associations with the three outcomes were assessed with multivariable logistic regression. RESULTS: 432 adults (73 young adults, 359 older adults) were included in the analysis. Overall, 28% demonstrated progression of neurologic deficits, 14% had fluctuating deficits, and 26% presented with symptoms considered atypical for stroke. After adjustment for demographics, stroke subtype, diabetes, admission blood pressure, and acute revascularization treatments, increased age was inversely associated with progression of deficits (OR 0.97 per year of age, 95% CI 0.95-0.98) and fluctuation in deficits (OR 0.98 per year of age, 95% CI 0.96-0.99). Hemorrhagic stroke subtype was inversely associated with fluctuation in neurologic deficits (OR 0.050, CI 0.0028-0.24). CONCLUSION: Young adults are more likely to have progression or fluctuation of neurologic deficits in acute stroke. Patients with ischemic stroke are more likely to have fluctuation in neurologic deficits.

Intravenous tPA for Acute Ischemic Stroke in Patients with COVID-19.

BACKGROUND/PURPOSE: Coronavirus disease 2019 (COVID-19) is associated with increased risk of acute ischemic stroke (AIS), however, there is a paucity of data regarding outcomes after administration of intravenous tissue plasminogen activator (IV tPA) for stroke in patients with COVID-19. METHODS: We present a multicenter case series from 9 centers in the United States of patients with acute neurological deficits consistent with AIS and COVID-19 who were treated with IV tPA. RESULTS: We identified 13 patients (mean age 62 (±9.8) years, 9 (69.2%) male). All received IV tPA and 3 cases also underwent mechanical thrombectomy. All patients had systemic symptoms consistent with COVID-19 at the time of admission: fever (5 patients), cough (7 patients), and dyspnea (8 patients). The median admission NIH stroke scale (NIHSS) score was 14.5 (range 3-26) and most patients (61.5%) improved at follow up (median NIHSS score 7.5, range 0-25). No systemic or symptomatic intracranial hemorrhages were seen. Stroke mechanisms included cardioembolic (3 patients), large artery atherosclerosis (2 patients), small vessel disease (1 patient), embolic stroke of undetermined source (3 patients), and cryptogenic with incomplete investigation (1 patient). Three patients were determined to have transient ischemic attacks or aborted strokes. Two out of 12 (16.6%) patients had elevated fibrinogen levels on admission (mean 262.2 ± 87.5 mg/dl), and 7 out of 11 (63.6%) patients had an elevated D-dimer level (mean 4284.6 ±3368.9 ng/ml). CONCLUSIONS: IV tPA may be safe and efficacious in COVID-19, but larger studies are needed to validate these results.

Ischemic Infarction in Young Adults: A Review for Radiologists.

Ischemic strokes in young adults are devastatingly debilitating and increasingly frequent. Stroke remains the leading cause of serious disability in the United States. The consequences of this familiar disease in this atypical age group are especially detrimental and long lasting. Ischemic stroke in young adults is now emerging as a public health issue, one in which radiologists can play a key role. The incidence of ischemic infarction in young adults has risen over the past couple of decades. Increased public awareness, increased use of MRI and angiography, and more accurate diagnosis may in part explain the increased detection of stroke in young adults. The increased prevalence of stroke risk factors in young adults (especially sedentary lifestyle and hypertension) may also contribute. However, compared with older adults, young adults have fewer ischemic infarcts related to the standard cardiovascular risk factors and large- or small-vessel disease. Instead, their infarcts most commonly result from cardioembolic disease and other demonstrated causes (ie, dissection). Thus, radiologists must expand their differential diagnoses to appropriately diagnose ischemic strokes and identify their causes in the young adult population. From the more frequent cardioembolism and dissection to the less common vasculitis, drug-related, CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy), moyamoya, and hypercoagulable state-related infarcts, this article covers a wide breadth of causes and imaging findings of ischemic stroke in young adults. ©RSNA, 2019.

Effect of Dysphagia Screening Strategies on Clinical Outcomes After Stroke: A Systematic Review for the 2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke.

INTRODUCTION: Dysphagia screening protocols have been recommended to identify patients at risk for aspiration. The American Heart Association convened an evidence review committee to systematically review evidence for the effectiveness of dysphagia screening protocols to reduce the risk of pneumonia, death, or dependency after stroke. METHODS: The Medline, Embase, and Cochrane databases were searched on November 1, 2016, to identify randomized controlled trials (RCTs) comparing dysphagia screening protocols or quality interventions with increased dysphagia screening rates and reporting outcomes of pneumonia, death, or dependency. RESULTS: Three RCTs were identified. One RCT found that a combined nursing quality improvement intervention targeting fever and glucose management and dysphagia screening reduced death and dependency but without reducing the pneumonia rate. Another RCT failed to find evidence that pneumonia rates were reduced by adding the cough reflex to routine dysphagia screening. A smaller RCT randomly assigned 2 hospital wards to a stroke care pathway including dysphagia screening or regular care and found that patients on the stroke care pathway were less likely to require intubation and mechanical ventilation; however, the study was small and at risk for bias. CONCLUSIONS: There were insufficient RCT data to determine the effect of dysphagia screening protocols on reducing the rates of pneumonia, death, or dependency after stroke. Additional trials are needed to compare the validity, feasibility, and clinical effectiveness of different screening methods for dysphagia.

Accuracy of Prediction Instruments for Diagnosing Large Vessel Occlusion in Individuals With Suspected Stroke: A Systematic Review for the 2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke.

INTRODUCTION: Endovascular thrombectomy is a highly efficacious treatment for large vessel occlusion (LVO). LVO prediction instruments, based on stroke signs and symptoms, have been proposed to identify stroke patients with LVO for rapid transport to endovascular thrombectomy-capable hospitals. This evidence review committee was commissioned by the American Heart Association/American Stroke Association to systematically review evidence for the accuracy of LVO prediction instruments. METHODS: Medline, Embase, and Cochrane databases were searched on October 27, 2016. Study quality was assessed with the Quality Assessment of Diagnostic Accuracy-2 tool. RESULTS: Thirty-six relevant studies were identified. Most studies (21 of 36) recruited patients with ischemic stroke, with few studies in the prehospital setting (4 of 36) and in populations that included hemorrhagic stroke or stroke mimics (12 of 36). The most frequently studied prediction instrument was the National Institutes of Health Stroke Scale. Most studies had either some risk of bias or unclear risk of bias. Reported discrimination of LVO mostly ranged from 0.70 to 0.85, as measured by the C statistic. In meta-analysis, sensitivity was as high as 87% and specificity was as high as 90%, but no threshold on any instruments predicted LVO with both high sensitivity and specificity. With a positive LVO prediction test, the probability of LVO could be 50% to 60% (depending on the LVO prevalence in the population), but the probability of LVO with a negative test could still be ≥10%. CONCLUSIONS: No scale predicted LVO with both high sensitivity and high specificity. Systems that use LVO prediction instruments for triage will miss some patients with LVO and milder stroke. More prospective studies are needed to assess the accuracy of LVO prediction instruments in the prehospital setting in all patients with suspected stroke, including patients with hemorrhagic stroke and stroke mimics.

Blood Pressure and Heart Rate Measures Associated With Increased Risk of Covert Brain Infarction and Worsening Leukoaraiosis in Older Adults.

OBJECTIVE: In people without previous stroke, covert findings on serial magnetic resonance imaging (MRI) of incident brain infarcts and worsening leukoaraiosis are associated with increased risk for ischemic stroke and dementia. We evaluated whether various measures of blood pressure (BP) and heart rate are associated with these MRI findings. APPROACH AND RESULTS: In the CHS (Cardiovascular Health Study), a longitudinal cohort study of older adults, we used relative risk regression to assess the associations of mean, variability, and trend in systolic BP, diastolic BP, and heart rate measured at 4 annual clinic visits between 2 brain MRIs with incident covert brain infarction and worsening white matter grade (using a 10-point scale to characterize leukoaraiosis). We included participants who had both brain MRIs, no stroke before the follow-up MRI, and no change in antihypertensive medication status during follow-up. Among 878 eligible participants, incident covert brain infarction occurred in 15% and worsening white matter grade in 27%. Mean systolic BP was associated with increased risk for incident covert brain infarction (relative risk per 10 mm Hg, 1.28; 95% confidence interval, 1.12-1.47), and mean diastolic BP was associated with increased risk for worsening white matter grade (relative risk per 10 mm Hg, 1.45; 95% confidence interval, 1.24-1.69). These findings persisted in secondary and sensitivity analyses. CONCLUSIONS: Elevated mean systolic BP is associated with increased risk for covert brain infarction, and elevated mean diastolic BP is associated with increased risk for worsening leukoaraiosis. These findings reinforce the importance of hypertension in the development of silent cerebrovascular diseases, but the pathophysiologic relationships to BP for each may differ.

Factors Associated with Delay in Presentation to the Hospital for Young Adults with Ischemic Stroke.

OBJECTIVES: Young adults with ischemic stroke may present late to medical care, but the reasons for these delays are unknown. We sought to identify factors that predict delay in presentation. METHODS: We performed a retrospective cohort study of adults aged 18-50 admitted to a single academic medical center between 2007 and 2012. RESULTS: Eighty six of 141 (61%) young adults with ischemic stroke presented at the health center more than 4.5 h after stroke onset. Diabetes was associated with delays in presentation (p = 0.033, relative risk (RR) 1.4 (95% CI 1.1-1.8)), whereas systemic cancer was associated with early presentations (p = 0.033, RR 0.26 (95% CI 0.044-1.6)). Individuals who were single were more likely to present late than those who were married or living with a partner (p = 0.0045, RR 1.7 (95% CI 1.3-2.2)). Individuals who were unemployed were more likely to present late than those who were employed or in school (p = 0.020, RR 1.4 (95% CI 1.1-1.8)). Age (dichotomized as 18-35 and 36-50), race, home medications, other medical conditions (including common stroke mimics in young adults), and stroke subtype were not determinants of delay in presentation, although there was a trend toward delayed presentations in women (p = 0.076) and with low stroke severity (dichotomized as National Institutes of Health Stroke Scale (NIHSS) ≤5 and NIHSS >5, p = 0.061). CONCLUSIONS: A majority of young adults with ischemic stroke presented outside the time window for intravenous fibrinolysis. Diabetes, single status, and unemployed status were associated with delayed presentation.

Synthetic cannabis and acute ischemic stroke.

An association between marijuana use and stroke has been previously reported. However, the health risks of newer synthetic cannabinoid compounds are less well known. We describe 2 cases that introduce a previously unreported association between synthetic cannabis use and ischemic stroke in young adults. A 22-year-old woman presented with dysarthria, left hemiplegia, and left hemianesthesia within hours of first use of synthetic cannabis. She was healthy and without identified stroke risk factors other than oral contraceptive use and a patent foramen ovale without venous thromboses. A 26-year-old woman presented with nonfluent aphasia, left facial droop, and left hemianesthesia approximately 12 hours after first use of synthetic cannabis. Her other stroke risk factors included migraine with aura, oral contraceptive use, smoking, and a family history of superficial thrombophlebitis. Both women were found to have acute, large-territory infarctions of the right middle cerebral artery. Our 2 cases had risk factors for ischemic stroke but were otherwise young and healthy and the onset of their deficits occurred within hours after first-time exposure to synthetic cannabis. Synthetic cannabis use is an important consideration in the investigation of stroke in young adults.

Mortality Outcomes in a Large Population with and without Covert Cerebrovascular Disease.

Covert cerebrovascular disease (CCD) is frequently reported on neuroimaging and associates with increased dementia and stroke risk. We aimed to determine how incidentally-discovered CCD during clinical neuroimaging in a large population associates with mortality. We screened CT and MRI reports of adults aged ≥50 in the Kaiser Permanente Southern California health system who underwent neuroimaging for a non-stroke clinical indication from 2009-2019. Natural language processing identified incidental covert brain infarcts (CBI) and/or white matter hyperintensities (WMH), grading WMH as mild/moderate/severe. Models adjusted for age, sex, ethnicity, multimorbidity, vascular risks, depression, exercise, and imaging modality. Of n=241,028, the mean age was 64.9 (SD=10.4); mean follow-up 4.46 years; 178,554 (74.1%) had CT; 62,474 (25.9%) had MRI; 11,328 (4.7%) had CBI; and 69,927 (29.0%) had WMH. The mortality rate per 1,000 person-years with CBI was 59.0 (95%CI 57.0-61.1); with WMH=46.5 (45.7-47.2); with neither=17.4 (17.1-17.7). In adjusted models, mortality risk associated with CBI was modified by age, e.g. HR 1.34 [1.21-1.48] at age 56.1 years vs HR 1.22 [1.17-1.28] at age 72 years. Mortality associated with WMH was modified by both age and imaging modality e.g., WMH on MRI at age 56.1 HR = 1.26 [1.18-1.35]; WMH on MRI at age 72 HR 1.15 [1.09-1.21]; WMH on CT at age 56.1 HR 1.41 [1.33-1.50]; WMH on CT at age 72 HR 1.28 [1.24-1.32], vs. patients without CBI or without WMH, respectively. Increasing WMH severity associated with higher mortality, e.g. mild WMH on MRI had adjusted HR=1.13 [1.06-1.20] while severe WMH on CT had HR=1.45 [1.33-1.59]. Incidentally-detected CBI and WMH on population-based clinical neuroimaging can predict higher mortality rates. We need treatments and healthcare planning for individuals with CCD.