Secular Trends in Outcomes and Impact of Novel Oral Anticoagulants in Atrial Fibrillation-Related Acute Ischemic Stroke.

BACKGROUND: Novel oral anticoagulants (NOACs) are currently recommended for the secondary prevention of stroke in patients with acute ischemic stroke (AIS) accompanied by atrial fibrillation (AF). However, the impact of NOACs on clinical outcomes in real-world practice remains ambiguous. This study analyzes the trend of clinical events in patients with AF-related AIS and determines how much the introduction of NOACs has mediated this trend. METHODS: We identified patients with AIS and AF between January 2011 and December 2019 using a multicenter stroke registry. Annual rates of NOAC prescriptions and clinical events within 1 year were evaluated. The primary outcome was a composite of recurrent stroke, myocardial infarction, and all-cause mortality. To assess the mediation effect of NOACs on the relationship between the calendar year and these outcomes, we used natural effect models and conducted exposure-mediator, exposure-outcome, and mediator-outcome analyses using multivariable regression models or accelerated failure time models, adjusting for potential confounders. RESULTS: Among the 12 977 patients with AF-related AIS, 12 500 (average age: 74.4 years; 51.3% male) were analyzed after excluding cases of valvular AF. Between 2011 and 2019, there was a significant decrease in the 1-year incidence of the primary composite outcome from 28.3% to 21.7%, while the NOAC prescription rate increased from 0% to 75.6%. A 1-year increase in the calendar year was independently associated with delayed occurrence of the primary outcome (adjusted time ratio, 1.10 [95% CI, 1.07-1.14]) and increased NOAC prescription (adjusted odds ratio, 2.20 [95% CI, 2.14-2.27]). Increased NOAC prescription was associated with delayed occurrence of the primary outcome (adjusted time ratio, 3.82 [95% CI, 3.17 to 4.61]). Upon controlling for NOAC prescription (mediator), the calendar year no longer influenced the primary outcome (adjusted time ratio, 0.97 [95% CI, 0.94-1.00]). This suggests that NOAC prescription mediates the association between the calendar year and the primary outcome. CONCLUSIONS: Our study highlights a temporal reduction in major clinical events or death in Korean patients with AF-related AIS, mediated by increased NOAC prescription, emphasizing NOAC use in this population.

Prevalence of Mutations in Mendelian Stroke Genes in Early Onset Stroke Patients.

OBJECTIVE: Heritability of stroke is assumed not to be low, especially in the young stroke population. However, most genetic studies have been performed in highly selected patients with typical clinical or neuroimaging characteristics. We investigated the prevalence of 15 Mendelian stroke genes and explored the relationships between variants and the clinical and neuroimaging characteristics in a large, unselected, young stroke population. METHODS: We enrolled patients aged ≤55 years with stroke or transient ischemic attack from a prospective, nationwide, multicenter stroke registry. We identified clinically relevant genetic variants (CRGVs) in 15 Mendelian stroke genes (GLA, NOTCH3, HTRA1, RNF213, ACVRL1, ENG, CBS, TREX1, ABCC6, COL4A1, FBN1, NF1, COL3A1, MT-TL1, and APP) using a customized, targeted next generation sequencing panel. RESULTS: Among 1,033 patients, 131 (12.7%) had 28 CRGVs, most frequently in RNF213 (n = 59), followed by ABCC6 (n = 53) and NOTCH3 (n = 15). The frequency of CRGVs differed by ischemic stroke subtypes (p < 0.01): the highest in other determined etiology (20.1%), followed by large artery atherosclerosis (13.6%). It also differed between patients aged ≤35 years and those aged 51 to 55 years (17.1% vs 9.3%, p = 0.02). Only 27.1% and 26.7% of patients with RNF213 and NOTCH3 variants had typical neuroimaging features of the corresponding disorders, respectively. Variants of uncertain significance (VUSs) were found in 15.4% patients. INTERPRETATION: CRGVs in 15 Mendelian stroke genes may not be uncommon in the young stroke population. The majority of patients with CRGVs did not have typical features of the corresponding monogenic disorders. Clinical implications of having CRGVs or VUSs should be explored. ANN NEUROL 2023;93:768-782.

Impact of Cerebral Microbleeds in Stroke Patients with Atrial Fibrillation.

OBJECTIVES: Cerebral microbleeds are associated with the risks of ischemic stroke and intracranial hemorrhage, causing clinical dilemmas for antithrombotic treatment decisions. We aimed to evaluate the risks of intracranial hemorrhage and ischemic stroke associated with microbleeds in patients with atrial fibrillation treated with vitamin K antagonists, direct oral anticoagulants, antiplatelets, and combination therapy (i.e. concurrent oral anticoagulant and antiplatelet). METHODS: We included patients with documented atrial fibrillation from the pooled individual patient data analysis by the Microbleeds International Collaborative Network. Risks of subsequent intracranial hemorrhage and ischemic stroke were compared between patients with and without microbleeds, stratified by antithrombotic use. RESULTS: A total of 7,839 patients were included. The presence of microbleeds was associated with an increased relative risk of intracranial hemorrhage (adjusted hazard ratio [aHR] = 2.74, 95% confidence interval = 1.76-4.26) and ischemic stroke (aHR = 1.29, 95% confidence interval = 1.04-1.59). For the entire cohort, the absolute incidence of ischemic stroke was higher than intracranial hemorrhage regardless of microbleed burden. However, for the subgroup of patients taking combination of anticoagulant and antiplatelet therapy, the absolute risk of intracranial hemorrhage exceeded that of ischemic stroke in those with 2 to 4 microbleeds (25 vs 12 per 1,000 patient-years) and ≥ 11 microbleeds (94 vs 48 per 1,000 patient-years). INTERPRETATION: Patients with atrial fibrillation and high burden of microbleeds receiving combination therapy have a tendency of higher rate of intracranial hemorrhage than ischemic stroke, with potential for net harm. Further studies are needed to help optimize stroke preventive strategies in this high-risk group. ANN NEUROL 2023;94:61-74.

Causal Effect of the 25-Hydroxyvitamin D Concentration on Cerebral Small Vessel Disease: A Mendelian Randomization Study.

BACKGROUND: Previous observational studies reported that a lower serum 25-hydroxyvitamin D [25(OH)D] concentration is associated with a higher burden of cerebral small vessel disease (cSVD). The causality of this association is uncertain, but it would be clinically important, given that 25(OH)D can be a target for intervention. We tried to examine the causal effect of 25(OH)D concentration on cSVD-related phenotypes using a Mendelian randomization approach. METHODS: Genetic instruments for each serum 25(OH)D concentration and cSVD-related phenotypes (lacunar stroke, white matter hyperintensity, cerebral microbleeds, and perivascular spaces) were derived from large-scale genome-wide association studies. We performed 2-sample Mendelian randomization analyses with multiple post hoc sensitivity analyses. A bidirectional Mendelian randomization approach was also used to explore the possibility of reverse causation. RESULTS: We failed to find any significant causal effect of 25(OH)D concentration on cSVD-related phenotypes (odds ratio [95% CI], 1.00 [0.87-1.16], 1.01 [0.96-1.07], 1.06 [0.85-1.33], 1.00 [0.97-1.03], 1.02 [0.99-1.04], 1.01 [0.99-1.04] for lacunar stroke, white matter hyperintensity, cerebral microbleeds, and white matter, basal ganglia, hippocampal perivascular spaces, respectively). These results were reproduced in the sensitivity analyses accounting for genetic pleiotropy. Conversely, when we examined the effects of cSVD phenotypes on 25(OH)D concentration, cerebral microbleeds were negatively associated with 25(OH)D concentration (0.94 [0.92-0.96]). CONCLUSIONS: Given the adequate statistical power (>0.8) of the analyses, our findings suggest that the previously reported association between 25(OH)D concentration and cSVD phenotypes might not be causal and partly attributed to reverse causation.

Covert Brain Infarction as a Risk Factor for Stroke Recurrence in Patients With Atrial Fibrillation.

BACKGROUND: We aimed to evaluate covert brain infarction (CBI), frequently encountered during the diagnostic work-up of acute ischemic stroke, as a risk factor for stroke recurrence in patients with atrial fibrillation (AF). METHODS: For this prospective cohort study, from patients with acute ischemic stroke hospitalized at 14 centers between 2017 and 2019, we enrolled AF patients without history of stroke or transient ischemic attack and divided them into the CBI (+) and CBI (-) groups. The 2 groups were compared regarding the 1-year cumulative incidence of recurrent ischemic stroke and all-cause mortality using the Fine and Gray subdistribution hazard model with nonstroke death as a competing risk and the Cox frailty model, respectively. Each CBI lesion was also categorized into either embolic-appearing (EA) or non-EA pattern CBI. Adjusted hazard ratios and 95% CIs of any CBI, EA pattern CBI only, non-EA pattern CBI only, and both CBIs were estimated. RESULTS: Among 1383 first-ever stroke patients with AF, 578 patients (41.8%) had CBI. Of these 578 with CBI, EA pattern CBI only, non-EA pattern CBI only, and both CBIs were 61.8% (n=357), 21.8% (n=126), and 16.4% (n=95), respectively. The estimated 1-year cumulative incidence of recurrent ischemic stroke was 5.2% and 1.9% in the CBI (+) and CBI (-) groups, respectively (P=0.001 by Gray test). CBI increased the risk of recurrent ischemic stroke (adjusted hazard ratio [95% CI], 2.91 [1.44-5.88]) but did not the risk of all-cause mortality (1.32 [0.97-1.80]). The EA pattern CBI only and both CBIs elevated the risk of recurrent ischemic stroke (2.76 [1.32-5.77] and 5.39 [2.25-12.91], respectively), while the non-EA pattern only did not (1.44 [0.40-5.16]). CONCLUSIONS: Our study suggests that AF patients with CBI might have increased risk of recurrent stroke. CBI could be considered when estimating the stroke risk in patients with AF.

Improvement in Delivery of Ischemic Stroke Treatments but Stagnation of Clinical Outcomes in Young Adults in South Korea.

BACKGROUND: There is limited information on the delivery of acute stroke therapies and secondary preventive measures and clinical outcomes over time in young adults with acute ischemic stroke. This study investigated whether advances in these treatments improved outcomes in this population. METHODS: Using a prospective multicenter stroke registry in Korea, young adults (aged 18-50 years) with acute ischemic stroke hospitalized between 2008 and 2019 were identified. The observation period was divided into 4 epochs: 2008 to 2010, 2011 to 2013, 2014 to 2016, and 2017 to 2019. Secular trends for patient characteristics, treatments, and outcomes were analyzed. RESULTS: A total of 7050 eligible patients (mean age, 43.1; men, 71.9%) were registered. The mean age decreased from 43.6 to 42.9 years (Ptrend=0.01). Current smoking decreased, whereas obesity increased. Other risk factors remained unchanged. Intravenous thrombolysis and mechanical thrombectomy rates increased over time from 2008 to 2010 to 2017 to 2019 (9.5%-13.8% and 3.2%-9.2%, respectively; Ptrend<0.01). Door-to-needle time improved (Ptrend <.001), but onset-to-door and door-to-puncture times remained constant. Secondary prevention, including dual antiplatelets for noncardioembolic minor stroke (26.7%-47.0%), direct oral anticoagulants for atrial fibrillation (0.0%-56.2%), and statins for large artery atherosclerosis (76.1%-95.3%) increased (Ptrend<0.01). Outcome data were available from 2011. One-year mortality (2.5% in 2011-2013 and 2.3% in 2017-2019) and 3-month modified Rankin Scale scores 0 to 1 (68.3%-69.1%) and 0 to 2 (87.6%-86.2%) remained unchanged. The 1-year stroke recurrence rate increased (4.1%-5.5%; Ptrend=0.04), although the difference was not significant after adjusting for sex and age. CONCLUSIONS: Improvements in the delivery of acute stroke treatments did not necessarily lead to better outcomes in young adults with acute ischemic stroke over the past decade, indicating a need for further progress.

Disentangling poststroke cognitive deficits and their neuroanatomical correlates through combined multivariable and multioutcome lesion-symptom mapping.

Studies in patients with brain lesions play a fundamental role in unraveling the brain's functional anatomy. Lesion-symptom mapping (LSM) techniques can relate lesion location to cognitive performance. However, a limitation of current LSM approaches is that they can only evaluate one cognitive outcome at a time, without considering interdependencies between different cognitive tests. To overcome this challenge, we implemented canonical correlation analysis (CCA) as combined multivariable and multioutcome LSM approach. We performed a proof-of-concept study on 1075 patients with acute ischemic stroke to explore whether addition of CCA to a multivariable single-outcome LSM approach (support vector regression) could identify infarct locations associated with deficits in three well-defined verbal memory functions (encoding, consolidation, retrieval) based on four verbal memory subscores derived from the Seoul Verbal Learning Test (immediate recall, delayed recall, recognition, learning ability). We evaluated whether CCA could extract cognitive score patterns that matched prior knowledge of these verbal memory functions, and if these patterns could be linked to more specific infarct locations than through single-outcome LSM alone. Two of the canonical modes identified with CCA showed distinct cognitive patterns that matched prior knowledge on encoding and consolidation. In addition, CCA revealed that each canonical mode was linked to a distinct infarct pattern, while with multivariable single-outcome LSM individual verbal memory subscores were associated with largely overlapping patterns. In conclusion, our findings demonstrate that CCA can complement single-outcome LSM techniques to help disentangle cognitive functions and their neuroanatomical correlates.

Risk of future stroke in patients with a diagnosis of peripheral vertigo in the emergency department.

BACKGROUND AND PURPOSE: The temporal characteristics of stroke risks were evaluated in emergency department patients who had a diagnosis of peripheral vertigo. It was also attempted to reveal the stroke risk factor amongst those with peripheral vertigo. METHODS: This is a parallel-group cohort study in a tertiary referral hospital. After assigning each of 4367 matched patients to the comparative set of peripheral vertigo and appendicitis-ureterolithiasis groups and each of 4911 matched patients to the comparative set of peripheral vertigo and ischaemic stroke groups, the relative stroke risk was evaluated. In addition, to predict the individual stroke risk in patients with peripheral vertigo, any association between the demographic factors and stroke events was evaluated in the peripheral vertigo group. RESULTS: The peripheral vertigo group had a higher stroke risk than the appendicitis-ureterolithiasis group (hazard ratio 1.73, 95% confidence interval 1.18-2.55) but a lower risk than the ischaemic stroke group (hazard ratio 0.30, 95% confidence interval 0.24-0.37). The stroke risk of the peripheral vertigo group was just below that of small vessel stroke. The stroke risk of the peripheral vertigo group differed markedly by time: higher within 7 days, moderate between 7 days and 1 year, and diminished thereafter. Old age (>65 years), male gender and diabetes mellitus were the risk factors for stroke in the peripheral vertigo group. CONCLUSION: Patients with a diagnosis of peripheral vertigo in the emergency department showed a moderate future stroke risk and so a stroke preventive strategy tailored to the timing of symptom onset and individual risk is required.

Stroke of Other Determined Etiology: Results From the Nationwide Multicenter Stroke Registry.

BACKGROUND: Stroke of other determined etiology (OE) includes patients with an uncommon cause of stroke. We described the general characteristics, management, and outcomes of stroke in OE and its subgroups. METHODS: This study is a retrospective analysis of a prospective, multicenter, nationwide registry, the Clinical Research Center for Stroke-Korea-National Institutes of Health registry. We classified OE strokes into 10 subgroups according to the literature and their properties. Each OE subgroup was compared according to clinical characteristics, sex, age strata, lesion locations, and management. Moreover, 1-year composites of stroke and all-cause mortality were investigated according to the OE subgroups. RESULTS: In total, 2119 patients with ischemic stroke with OE types (mean age, 55.6±16.2 years; male, 58%) were analyzed. In the Clinical Research Center for Stroke-Korea-National Institutes of Health registry, patients with OE accounted for 2.8% of all patients with stroke. The most common subtypes were arterial dissection (39.1%), cancer-related coagulopathy (17.3%), and intrinsic diseases of the arterial wall (16.7%). Overall, strokes of OE were more common in men than in women (58% versus 42%). Arterial dissection, intrinsic diseases of the arterial wall and stroke associated with migraine and drugs were more likely to occur at a young age, while disorders of platelets and the hemostatic system, cancer-related coagulopathy, infectious diseases, and hypoperfusion syndromes were more frequent at an old age. The composite of stroke and all-cause mortality within 1 year most frequently occurred in cancer-related coagulopathy, with an event rate of 71.8%, but least frequently occurred in stroke associated with migraine and drugs and arterial dissection, with event rates of 0% and 7.2%, respectively. CONCLUSIONS: This study presents the different characteristics, demographic findings, lesion locations, and outcomes of OE and its subtypes. It is characterized by a high proportion of arterial dissection, high mortality risk in cancer-related coagulopathy and an increasing annual frequency of cancer-related coagulopathy in patients with stroke of OE.

Exploring the causal inference of migraine on stroke: A Mendelian randomization study.

BACKGROUND AND PURPOSE: Previous observational studies have reported that patients with migraine have an increased risk of stroke. We explored whether migraine has a causal effect on stroke using a two-sample Mendelian randomization approach. METHODS: Genetic instruments were selected from large genome-wide association studies of migraine and stroke. A two-sample Mendelian randomization analysis was performed, along with sensitivity analysis. We used migraine subtypes (any migraine, migraine with aura, migraine without aura) as risk factors and stroke, ischemic stroke, and hemorrhagic stroke as outcomes for this analysis. Ischemic stroke subtypes were also included to explore the underlying pathogenesis linking migraine to stroke. RESULTS: Migraine did not show any association with stroke (odds ratio [OR], 0.95; 95% confidence interval [CI], 0.87-1.03), ischemic stroke (OR, 0.93; 95% CI, 0.85-1.02), or hemorrhagic stroke (OR, 1.26; 95% CI, 0.84-1.91), suggesting that the observed association may not be causal. Neither migraine with aura nor without aura showed causal relationship with outcomes. The sensitivity analysis supported the results of the primary analysis. Regarding ischemic stroke subtypes, migraine seemed to have a negative association with large-artery atherosclerosis (OR, 0.81; 95% CI, 0.68-0.95), whereas associations with small-vessel occlusion or cardioembolism were not evident. CONCLUSIONS: Contrary to previous observational studies, we were unable to find any causal relationship between migraine and stroke. However, the suggested negative association of migraine in large-artery atherosclerosis warrants further research.

Fasting and Non-Fasting Triglycerides in Patients With Acute Ischemic Stroke.

BACKGROUND: Clinical implications of elevated fasting triglycerides (FTGs) and non-fasting triglycerides (NFTGs) in acute ischemic stroke (AIS) remain unknown. We aimed to elucidate the correlation and clinical significance of FTG and NFTG levels in AIS patients. METHODS: Using a multicenter prospective stroke registry, we identified AIS patients hospitalized within 24 hours of onset with available NFTG results. The primary outcome was a composite of stroke recurrence, myocardial infarction, and all-cause mortality up to one year. RESULTS: This study analyzed 2,176 patients. The prevalence of fasting and non-fasting hypertriglyceridemia was 11.5% and 24.6%, respectively. Multivariate analysis revealed that younger age, diabetes, higher body mass index and initial systolic blood pressure were independently associated with both fasting and non-fasting hypertriglyceridemia (all P < 0.05). Patients with higher quartiles of NFTG were more likely to be male, younger, ever-smokers, diabetic, and have family histories of premature coronary heart disease and stroke (all P < 0.05). Similar tendencies were observed for FTG. The composite outcome was not associated with FTG or NFTG quartiles. CONCLUSION: The fasting and non-fasting hypertriglyceridemia were prevalent in AIS patients and showed similar clinical characteristics and outcomes. High FTG and NFTG levels were not associated with occurrence of subsequent clinical events up to one year.

Annual Case Volume and One-Year Mortality for Endovascular Treatment in Acute Ischemic Stroke.

BACKGROUND: The association between endovascular treatment (EVT) case volume per hospital and clinical outcomes has been reported, but the exact volume threshold has not been determined. This study aimed to examine the case volume threshold in this context. METHODS: National audit data on the quality of acute stroke care in patients admitted via emergency department, within 7 days of onset, in hospitals that treated ≥ 10 stroke cases during the audit period were analyzed. Ischemic stroke cases treated with EVT during the last three audits (2013, 2014, and 2016) were selected for the analysis. Annual EVT case volume per hospital was estimated and analyzed as a continuous and a categorical variable (in quartiles). The primary outcome measure was 1-year mortality as a surrogate of 3-month functional outcome. As post-hoc sensitivity analysis, replication of the study results was examined using the 2018 audit data. RESULTS: We analyzed 1,746 ischemic stroke cases treated with EVT in 120 acute care hospitals. The median annual EVT case volume was 12.0 cases per hospital, and mortality rates at 1 month, 3 months, and 1 year were 12.7%, 16.6%, and 23.3%, respectively. Q3 and Q4 had 33% lower odds of 1-year mortality than Q1. Adjustments were made for predetermined confounders. Annual EVT case volume cut-off value for 1-year mortality was 15 cases per year (P < 0.02). The same cut-off value was replicated in the sensitivity analysis. CONCLUSION: Annual EVT case volume was associated with 1-year mortality. The volume threshold per hospital was 15 cases per year.

Risk of Subsequent Events in Patients With Minor Ischemic Stroke or High-Risk Transient Ischemic Attack.

This study aimed to present the prognosis after minor acute ischemic stroke (AIS) or transient ischemic attack (TIA), using a definition of subsequent stroke in accordance with recent clinical trials. In total, 9,506 patients with minor AIS (National Institutes of Health Stroke Scale ≤ 5) or high-risk TIA (acute lesions or ≥ 50% cerebral artery steno-occlusion) admitted between November 2010 and October 2013 were included. The primary outcome was the composite of stroke (progression of initial event or a subsequent event) and all-cause mortality. The cumulative incidence of stroke or death was 11.2% at 1 month, 13.3% at 3 months and 16.7% at 1 year. Incidence rate of stroke or death in the first month was 12.5 per 100 person-months: highest in patients with large artery atherosclerosis (17.0). The risk of subsequent events shortly after a minor AIS or high-risk TIA was substantial, particularly in patients with large artery atherosclerosis.

Underweight predicts poststroke cardiovascular events in patients without atrial fibrillation.

BACKGROUND AND PURPOSE: The purpose of this study was to determine whether underweight is associated with poststroke cardiovascular events and whether such association is different according to the presence of atrial fibrillation (AF). METHODS: Patients with acute stroke or transient ischemic attack who were prospectively registered in a multicenter stroke database from April 2008 to July 2020 were analyzed, excluding those aged 75 or older and those who were overweight. We prospectively captured major adverse cardiovascular events (MACE) within one year after stroke. Cox-proportional hazard regression analysis was conducted for each subgroup with or without AF after adjusting for predetermined vascular risk factors and potential confounders. RESULTS: Among 30,912 patients, 1494 (4.8%) cases were underweight and 29,418 (95.2%) cases were normal weight. The cumulative event rate of 1-year MACE was higher in the underweight group (9.0%) than in the normal weight group (5.6%). In Cox-proportional regression, underweight was associated with significantly higher MACE (adjusted hazard ratio [HR]: 1.62, 95% confidence interval [CI]: 1.26-2.09) and recurrent stroke (adjusted HR: 1.42, 95% CI: 1.02-1.98) in all study patients. In patients with AF, the risk of MACE for the underweight group was not significantly increased. In contrast, in patients without AF, the underweight group had a consistently higher risk of MACE (adjusted HR: 1.66, 95% CI: 1.25-2.22) and recurrent stroke (adjusted HR: 1.50, 95% CI: 1.05-2.14). CONCLUSIONS: Underweight increased the risk of MACE and recurrent stroke within one year after acute stroke, especially in stroke without AF.

Atrial Fibrillation-Associated Ischemic Stroke Patients With Prior Anticoagulation Have Higher Risk for Recurrent Stroke.

Background and Purpose- Ischemic stroke associated with nonvalvular atrial fibrillation (NVAF) despite prior anticoagulation may indicate underlying problems that nullify the stroke-preventing effects of oral anticoagulants. We aimed to evaluate the risk for recurrent stroke in patients with NVAF with prior anticoagulation, compared with that in patients without prior anticoagulation. Methods- This study comprised pooled individual patient data on NVAF-associated acute ischemic stroke or transient ischemic attack from 2011 to 2014 arising from the Clinical Research Collaboration for Stroke in Korea (15 South Korean stroke centers) and the Stroke Acute Management With Urgent Risk-Factor Assessment and Improvement-NVAF registry (18 Japanese stroke centers). Data on 4841 eligible patients from the Clinical Research Collaboration for Stroke in Korea registry were pooled with data on all patients (n=1192) in the Stroke Acute Management with Urgent Risk-factor Assessment and Improvement-NVAF registry. The primary outcome was recurrent ischemic stroke. The secondary outcomes were hemorrhagic stroke and all-cause death. Outcome events were captured up to 1 year after the index event. Results- Among the 6033 patients in the full cohort, 5645 patients were analyzed, of whom 1129 patients (20.0%) had received prior anticoagulation. Median age was 75 years (interquartile range, 69-81 years), and 2649 patients (46.9%) were women. Follow-up data of 4617 patient-years (median follow-up 365 days, interquartile range 335-365 days) were available. The cumulative incidence of recurrent ischemic stroke in patients with prior anticoagulation was 5.3% (60/1129), compared with the 2.9% (130/4516) incidence in patients without prior anticoagulation. The risk for recurrent ischemic stroke was higher in patients with prior anticoagulation than in those without (multivariable Cox shared-frailty model, hazard ratio 1.50 [95% CI, 1.02-2.21]). No significant differences in the risks for hemorrhagic stroke and mortality were seen between the 2 groups. Conclusions- The risk for recurrent ischemic stroke may be higher in NVAF-associated stroke patients with prior anticoagulation than in those without prior anticoagulation. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT01581502.

Association of Prediabetes and Type 2 Diabetes With Cognitive Function After Stroke: A STROKOG Collaboration Study.

Background and Purpose- Type 2 diabetes mellitus (T2D) is associated with cognitive impairment and an increased risk of dementia, but the association between prediabetes and cognitive impairment is less clear, particularly in a setting of major cerebrovascular events. This article examines the impact of impaired fasting glucose and T2D on cognitive performance in a stroke population. Methods- Seven international observational studies from the STROKOG (Stroke and Cognition) consortium (n=1601; mean age, 66.0 years; 70% Asian, 26% white, and 2.6% African American) were included. Fasting glucose level (FGL) during hospitalization was used to define 3 groups, T2D (FGL ≥7.0 mmol/L), impaired fasting glucose (FGL 6.1-6.9 mmol/L), and normal (FGL <6.1 mmol/L), and a history of diabetes mellitus and the use of a diabetes mellitus medication were also used to support a diagnosis of T2D. Domain and global cognition Z scores were derived from standardized neuropsychological test scores. The cross-sectional association between glucose status and cognitive performance at 3 to 6 months poststroke was examined using linear mixed models, adjusting for age, sex, education, stroke type, ethnicity, and vascular risk factors. Results- Patients with T2D had significantly poorer performance in global cognition (SD, -0.59 [95% CI, -0.82 to -0.36]; P<0.001) and in all domains compared with patients with normal FGL. There was no significant difference between impaired fasting glucose patients and those with normal FGL in global cognition (SD, -0.10 [95% CI, -0.45 to 0.24]; P=0.55) or in any cognitive domain. Conclusions- Diabetes mellitus, but not prediabetes, is associated with poorer cognitive performance in patients 3 to 6 months after stroke.

Effect of Heart Rate on Stroke Recurrence and Mortality in Acute Ischemic Stroke With Atrial Fibrillation.

Background and Purpose- There is a paucity of information about the role of resting heart rate in the prediction of outcome events in patients with ischemic stroke with atrial fibrillation. We aimed to investigate the relationships between the level and variability of heart rate in the acute stroke period and stroke recurrence and mortality after acute ischemic stroke in patients with atrial fibrillation. Methods- Acute patients with ischemic stroke who had atrial fibrillation and were hospitalized within 48 hours of stroke onset were identified from a multicenter prospective stroke registry database. The acute stroke period was divided into early (within 24 hours of hospitalization) and late (72 hours to 7 days from onset) stages, and data on heart rate in both stages were collected. Moreover, the level and variability of heart rate were assessed using mean values and coefficients of variation. Outcome events were prospectively monitored up to 1 year after the index stroke. Results- Among 2046 patients eligible for the early acute stage analysis, 102 (5.0%) had a stroke recurrence, and 440 (21.5%) died during the first year after stroke. A statistically significant nonlinear J-shaped association was observed between mean heart rate and mortality (P<0.04 for quadratic and overall effect) but not between mean heart rate and stroke recurrence (P>0.1 for quadratic and overall effect). The nonlinear and overall effects of the coefficients of variation of heart rate were not significant for all outcome variables. The same results were observed in the late acute stage analysis (n=1576). Conclusions- In patients with atrial fibrillation hospitalized for acute ischemic stroke, the mean heart rate during the acute stroke period was not associated with stroke recurrence but was associated with mortality (nonlinear, J-shaped association). The relationships between heart rate and outcomes were not observed with respect to heart rate variability.

Routing to Endovascular Treatment of Ischemic Stroke in Korea: Recognition of Need for Process Improvement.

BACKGROUND: To track triage, routing, and treatment status regarding access to endovascular treatment (EVT) after acute ischemic stroke (AIS) at a national level. METHODS: From national stroke audit data, potential candidates for EVT arriving within 6 hours with National Institute of Health Stroke Scale score of ≥ 7 were identified. Acute care hospitals were classified as thrombectomy-capable hospitals (TCHs, ≥ 15 EVT cases/year) or primary stroke hospital (PSH, < 15 cases/year), and patients' initial routes and subsequent inter-hospital transfer were described. Impact of initial routing to TCHs vs. PSHs on EVT and clinical outcomes were analyzed using multilevel generalized mixed effect models. RESULTS: Out of 14,902 AIS patients, 2,180 (14.6%) were EVT candidates. Eighty-one percent of EVT candidates were transported by ambulance, but only one-third were taken initially to TCHs. Initial routing to TCHs was associated with greater chances of receiving EVT compared to initial routing to PSHs (33.3% vs 12.1%, P < 0.001; adjusted odds ratio [aOR], 2.21; 95% confidence interval [CI], 1.59-2.92) and favorable outcome (38.5% vs. 28.2%, P < 0.001; aOR, 1.52; 95% CI, 1.16-2.00). Inter-hospital transfers to TCHs occurred in 17.4% of those initially routed to a PSH and was associated with the greater chance of EVT compared to remaining at PSHs (34.8% vs. 7.5%, P < 0.001), but not with better outcomes. CONCLUSION: Two-thirds of EVT candidates were initially routed to PSHs despite greater chance of receiving EVT and having favorable outcomes if routed to a TCH in Korea. Process improvement is needed to direct appropriate patients to TCHs.

Acute Stroke Care in Korea in 2013-2014: National Averages and Disparities.

BACKGROUND: This study aimed to describe the current status of acute stroke care in Korea and explore disparities among hospitals and regions. METHODS: The 2013 and 2014 national stroke audit data and the national health insurance claims data were linked and used for this study. Stroke patients hospitalized via emergency rooms within 7 days of stroke onset were selected. RESULTS: A total of 19,608 patients treated in 216 hospitals were analyzed. Among them 76% had ischemic stroke; 15%, intracerebral hemorrhage (ICH); and 9%, subarachnoid hemorrhage (SAH). Of the hospitals, 31% provided inpatient stroke unit care. Ambulances were used in 56% of cases, and the median interval from onset to arrival was 4.5 hours. One-quarter of patients were referred from other hospitals. Intravenous thrombolysis (IVT) and endovascular treatment (EVT) rates were 11% and 4%, respectively. Three-quarters of the analyzed hospitals provided IVT and/or EVT, whereas 47% of hospitals providing IVT and 67% of hospitals providing EVT had less than one case per month. Decompressive surgery was performed on 28% of ICH patients, and clipping and coiling were performed in 17.2% and 14.3% of SAH patients, respectively. There were noticeable regional disparities between the various interventions, ambulance use, arrival time, and stroke unit availability. CONCLUSION: This study describes the current status of acute stroke care in Korea. Despite quite acceptable quality of stroke care, it suggests regional and hospital disparities. Expansion of stroke units, stroke center certification or accreditation, and connections between stroke centers and emergency medical services are highly recommended.

Hospital Volume and Mortality in Acute Ischemic Stroke Patients: Effect of Adjustment for Stroke Severity.

OBJECTIVE: Stroke severity of 1 hospital is a crucial information when assessing hospital performance. We aimed to determine the effect of stroke severity in the association between hospital patient volume and outcome after acute ischemic stroke. METHODS: Data from National Acute Stroke Quality Assessment in 2013 and 2014 were analyzed. Hospital patient volume was defined as the annual number of acute ischemic stroke patients who admitted to each hospital. Comparisons among hospital patient volume quartiles before and after adjusting age, sex, onset to arrival and stroke severity were made to determine the associations between hospital patient volume and mortality at 30 days, 90 days and 1 year. Assessments for the nonlinear associations, with treating hospital patient volume as a continuous variable, and the associations between hospital patient volume and quality of care were also made. RESULTS: A total of 14,666 acute ischemic stroke patients admitted to 202 hospitals were analyzed. In the crude analysis, patients admitted to hospitals with lower patient volume showed higher mortality with a non-linear inverse association with a cut-off value of 227 patients/year. While the associations remained significant after adjusting age, sex and onset to arrival time (P's < .05), they disappeared when stroke severity was further adjusted (P's > .05). In contrary, hospital patient volume showed a nonlinear positive association with a plateau for summary measures of quality indicators even after adjustments for covariates including stroke severity (P < .001). CONCLUSIONS: Our study implicates that stroke severity should be considered when assessing hospital performance regarding outcomes of acute stroke care.