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Background: Korea recently established 70 emergency medical service areas. However, there are many concerns that medical resources for stroke could not be evenly distributed through the country. We aimed to compare the treatment quality and outcomes of acute stroke among the emergency medical service areas.Methods: This study analyzed the data of 28,800 patients admitted in 248 hospitals which participated in the 8th acute stroke quality assessment by Health Insurance Review and Assessment Service. Individual hospitals were regrouped into emergency service areas according to the address of the location. Assessment indicators and fatality were compared by the service areas. We defined the appropriate hospital by the performance of intravenous thrombolysis.Results: In seven service areas, there were no hospitals which received more than 10 stroke patients for 6 months. In nine service areas, there were no patients who underwent intravenous thrombolysis (IVT). Among 167 designated emergency medical centers, 50 hospitals (29.9%) responded that IVT was impossible 24 hours a day. There are 97 (39.1%) hospitals that meet the definitions of appropriate hospital. In 23 service areas (32.9%) had no appropriate or feasible hospitals. The fatality of service areas with stroke centers were 6.9% within 30 days and 15.6% within 1 year from stroke onset than those without stroke centers (7.7%, 16.9%, respectively).Conclusions: There was a wide regional gap in the medical resource and the quality of treatments for acute stroke among emergency medical service areas in Korea. The poststroke fatality rate of the service areas which have stroke centers or appropriate hospitals were significantly low.

Heritability of stroke is assumed not to be low, especially in the young-age 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.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 (CRGV) 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.Among 1,033 patients, 131 (12.7%) had 28 CRGV, most frequently in RNF213 (n=59), followed by ABCC6 (n=53) and NOTCH3 (n=15). The frequency of CRGV differed by ischemic stroke subtypes (p0.01)-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 51-55 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 (VUS) were found in 15.4% patients.CRGV in 15 Mendelian stroke genes may not be uncommon in the young stroke population. The majority of patients with CRGV did not have typical features of the corresponding monogenic disorders. Clinical implications of having CRGV or VUS should be explored. This article is protected by copyright. All rights reserved.

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.

Background and ObjectivesFemale patients tend to have greater disability and worse long-term outcomes after stroke than male patients. To date, the biological basis of sex difference in ischemic stroke remains unclear. We aimed to 1) assess sex differences in clinical manifestation and outcomes of acute ischemic stroke and 2) investigate whether the sex disparity is due to different infarct locations or different impacts of infarct in the same location.MethodsThis MRI-based multicenter study included 6,464 consecutive patients with acute ischemic stroke (ResultsMean (SD) age was 67.5 (12.6) years, and 2,641 (40.9%) were female patients. Percentage infarct volumes on diffusion-weighted MRI did not differ between female patients and male patients (median 0.14% vs. 0.14%, P=0.35). However, female patients showed higher stroke severity (NIHSS-score, median 4 vs. 3, P2) than male patients (adjusted-absolute-difference 4.5%; 95%-CI 2.0–7.0; PDiscussionFemale patients have more frequent middle cerebral artery disease and striatocapsular motor-pathway involvement with acute ischemic stroke, along with left parieto-occipital cortical infarcts showing greater severity for equivalent infarct volumes than in male patients. This leads to more severe initial neurological symptoms, higher susceptibility to neurological worsening, and less 3-month functional independence, when compared with male patients.

BackgroundThere 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 (AIS). This study investigated whether advances in these treatments improved outcomes in this population.MethodsUsing a prospective multicenter stroke registry in Korea, young adults (aged 18–50 years) with AIS hospitalized between 2008 and 2019 were identified. The observation period was divided into four epochs: 2008–2010, 2011–2013, 2014–2016, and 2017–2019. Secular trends for patient characteristics, treatments, and outcomes were analyzed.ResultsA total of 7,050 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 2008–2010 to 2017–2019 (9.5% to 13.8% and 3.2% to 9.2%, respectively; Ptrend’strendtrend’strend=0.04), but was not significant after adjusting for warfarin use.ConclusionImprovements in the delivery of acute stroke treatments did not necessarily lead to better outcomes in young adults with AIS over the past decade, indicating a need for further improvement.

Background: Medical care disparities are wide, and stroke in no exception. Reperfusion therapy is the standard treatment for acute ischemic stroke, but its use may vary across hospitals. Methods: Data from 75,870 patients admitted to 247 acute stroke hospitals nationwide were obtained through the 2013-2018 acute stroke quality evaluation program conducted by the Health Insurance Review and Assessment Service. The primary outcome was the hospital reperfusion therapy rate (RTR), defined as the proportion of intravenous tissue plasminogen activator (IVT) and/or endovascular thrombectomy (EVT) cases in patients potentially eligible for reperfusion therapy (onset-to-arrival time ≤ 6 hours and initial NIHSS score ≥ 4). Hospital RTRs, adjusted for age, sex, onset-to-arrival time, and initial stroke severity, were analyzed with hospital characteristics. Results: During the study period, 10,513 stroke patients were potentially eligible for reperfusion treatment and were admitted to 247 acute care hospitals. The RTR of the study population was 52.9%. The mean hospital RTR was 34.8% [median (IQR) 37.5% (9.8 - 56.2)]. A higher number of beds and average monthly stroke admissions were associated with a higher hospital RTR. Multivariable analysis revealed the average stroke admission per month, presence of stroke unit, the average IVT per month, and the average EVT per month were the independent determinants for hospital RTR. Hospital RTR was inversely correlated with 1-year mortality regardless of hospital stroke volume. Conclusions: RTRs vary widely across hospitals. The higher the hospital stroke volume, the higher the hospital RTRs. High hospital RTRs correlates with low 1-year mortality regardless of hospital stroke volume.

Objective: Prostate-specific antigen (PSA) is widely used as a screening tool of prostate cancer, although there has been a controversy about efficacy. In Korea, rapid growth of obesity prevalence in adult men is a one of the biggest health problems. The objective of this study was to evaluate the potential association between body mass index (BMI), waist circumference (WC) and PSA.Methods: We calculated BMI and WC of a total of 25,603 males who visited the Soonchunhyang University Cheonan Hospital Health Promotion Center from January 2016 to December 2020. This was categorized as follows: BMI < 23 kg/m2 (normal), 23 kg/m2 ≤ BMI < 25 kg/m2 (overweight), BMI ≥ 25 kg/m2 (obesity) and WC < 90 cm (normal), WC ≥ 90 cm (abdominal obesity). We analyzed the association between BMI, WC and PSA.Results: The mean PSA value was 1.08 ng/mL, 1.03 ng/mL, and 0.97 ng/mL at normal, overweight, and obesity group, respectively. The mean PSA value was 1.04 ng/mL and 0.96 ng/mL at normal and abdominal obesity group. Thus, the mean PSA value decreased with an increase in BMI and WC category (P < 0.001). The correlation coefficient between BMI, WC and PSA was -0.055, -0.044 and they were statistically significant (P < 0.001).Conclusion: We observed a significant negative correlation between BMI, WC and PSA value. Therefore, PSA value should be considered in relation to BMI and WC.

OBJECTIVE We investigated (1) the associations of pre-stroke aspirin use with thrombus burden, infarct volume, hemorrhagic transformation, early neurological deterioration (END), and functional outcome, and (2) whether stroke subtypes modify these associations in first-ever ischemic stroke. METHODS This multicenter magnetic resonance imaging (MRI)-based study included 5,700 consecutive patients with acute first-ever ischemic stroke, who did not undergo intravenous thrombolysis or endovascular thrombectomy, from May 2011 through February 2014. Propensity score-based augmented inverse probability weighting was performed to estimate adjusted effects of pre-stroke aspirin use. RESULTS The mean age was 67 years (41% women), and 15.9% (n = 907) were taking aspirin before stroke. Pre-stroke aspirin use (vs nonuse) was significantly related to a reduced infarct volume (by 30%), particularly in large artery atherosclerosis stroke (by 45%). In cardioembolic stroke, pre-stroke aspirin use was associated with a ~50% lower incidence of END (adjusted difference = -5.4%, 95% confidence interval [CI] = -8.9 to -1.9). Thus, pre-stroke aspirin use was associated with ~30% higher likelihood of favorable outcome (3-month modified Rankin Scale score

Background and ObjectivesWe evaluated the association between admission glycated hemoglobin (HbA1c) and subsequent risk of composite vascular events, including stroke, myocardial infarction (MI), and vascular death, in patients with acute ischemic stroke and diabetes.MethodsPatients who had a TIA or an acute ischemic stroke within 7 days of symptom onset and diabetes were included in a retrospective cohort design using the stroke registry of the Clinical Research Center for Stroke in Korea. The association between admission HbA1c and composite vascular events, including stroke, MI, and vascular death, during 1-year follow-up was estimated using the Fine-Gray model. The risk of composite vascular events according to the ischemic stroke subtype was explored using fractional polynomial and linear-quadratic models.ResultsOf the 18,567 patients, 1,437 developed composite vascular events during follow-up. In multivariable analysis using HbA1c as a categorical variable, the risk significantly increased at a threshold of 6.8%–7.0%. The influence of admission HbA1c level on the risk of composite vascular events was pronounced particularly among those in whom fasting glucose at admission was ≤130 mg/dL. The optimal ranges of HbA1c associated with minimal risks for composite vascular events were lowest for the small vessel occlusion subtype (6.6 [95% confidence internal [CI], 6.3–6.9]) compared to the large artery atherosclerosis (7.3 [95% CI, 6.8–7.9]) or the cardioembolic subtype (7.4 [95% CI, 6.3–8.5]).DicussionIn patients with ischemic stroke and diabetes, the risks of composite vascular events were significantly associated with admission HbA1c. The optimal range of admission HbA1c was below 6.8%–7.0% and differed according to the ischemic stroke subtype.

This study aimed to elucidate whether low-density lipoprotein cholesterol (LDL-C) levels differentially affect functional outcomes after intravenous thrombolysis (IVT) depending on prestroke statin use. Patients with acute ischemic stroke treated with IVT were categorized into low, intermediate, and high LDL-C groups based on LDL-C levels at admission ( 130 mg/dl, respectively). Multivariable logistic regression analyses were performed to explore the relationships between LDL-C and clinical outcomes (good outcomes at 3 months, modified Rankin Scale scores 0–2). The interaction between LDL-C levels and prestroke statin use regarding functional outcomes was investigated. Among the 4711 patients (age, 67 ± 12 years; males, 62.1%) who met the eligibility criteria, compared with the high LDL-C group, the low and intermediate LDL-C groups were not associated with good outcomes at 3 months according to the multivariable analysis. A potential interaction between the LDL-C group and prestroke statin use on good outcomes at 3 months was observed (Pinteraction = 0.07). Among patients with prestroke statin use, low (aOR 1.84 [1.04–3.26]) and intermediate (aOR 2.31 [1.20–4.47]) LDL-C groups were independently associated with a greater likelihood of having a 3-month good outcome. Our study showed that LDL-C was not associated with a 3-month good outcome, but prestroke statin use could modify the influence of LDL-C levels on functional outcomes after IVT.

Hydrolyzed proteins have an advantage over intact proteins in terms of their rate of digestion and absorption. The high-pressure enzymatic extraction (HPE) method has been shown to improve the quality characteristics of hydrolysates from Protaetia brevitarsis seulensis (Kolbe) larvae (PBSL). This study investigated the effects of the HPE treatment period, a key candidate factor, on the quality characteristics of PBSL HPE hydrolysates. The hydrolysates were prepared by HPE for 0, 12, 18, 24, 30, and 36 h under optimized conditions—solid:solvent ratio (1:14 [w/v]), using complex proteases (Alcalase:Flavorzyme:Bromelain = 1:1:1, 4%), treatment temperature (50oC), and pressure level (100 MPa). All quality characteristics tended to be superior with longer HPE treatment periods, most of which had the highest values at 30 h, with no significant difference or a slight decrease after that. The quality characteristics of the PBSL HPE hydrolysates were improved by 1.3-1.7 times under conditions of optimal HPE treatment period.

BackgroundNo study has thoroughly compared the effectiveness of combined antiplatelet treatments (other than clopidogrel–aspirin) versus clopidogrel–aspirin or aspirin alone for early secondary prevention in acute ischaemic stroke.MethodsWe identified patients with acute, minor, non-cardiogenic ischaemic stroke treated with aspirin alone, clopidogrel–aspirin or other combination treatment. Propensity scores considering the inverse probability of treatment weighting were used to adjust for baseline imbalances. The primary outcome was the composite of all strokes (ischaemic or haemorrhagic), myocardial infarction and all-cause mortality at 3 months.ResultsAmong 12 234 patients (male: 61.9%; age: 65.5±13 years) who met the eligibility criteria, aspirin, clopidogrel–aspirin and other combination treatments were administered in 52.2%, 42.9% and 4.9% of patients, respectively. In the crude analysis, the primary outcome event at 3 months occurred in 14.5% of the other combination group, 14.4% of the aspirin group and 13.0% of the clopidogrel–aspirin group. In the weighted Cox proportional hazards analysis, the 3-month primary outcome event occurred less frequently in the clopidogrel–aspirin group than in the other combination group (weighted HR: 0.82 (0.59–1.13)), while no association was found between the aspirin group (weighted HR: 1.04 (0.76–1.44)) or other combination group and the 3-month primary outcome.ConclusionOther combined antiplatelet treatment, compared with aspirin alone or clopidogrel–aspirin, was not associated with reduced risks of primary composite vascular events or recurrent stroke during the first 3 months after stroke. Therefore, the results suggest that other combination treatments, particularly the cilostazol-based combination, may not be effective alternatives for clopidogrel–aspirin to prevent early vascular events in patients with acute minor stroke. Further exploration in clinical trials will be needed.

Objective: Several studies suggested that heart rate variability (HRV) is a risk factor for metabolic syndrome. The objective of this study was to evaluate the association between HRV and metabolic syndrome among Korean adults.Methods: We included 6,945 people who visited the Soonchunhyang University Cheonan Hospital Health Examination Center and tested HRV, from March 2016 to November 2019. Among them, 6,827 subjects were included. We excluded those who had a history of hypertension, diabetes, stroke, or other disease and excluded them from the omission of questionnaires. We examined HRV with machine WISE-8000 (MooYoo Instruments, Seongnam, Korea) and divided three groups of HRV results. The diagnosis of metabolic syndrome was made using criteria modified National Cholesterol Education Program Adult Treatment Panel III. Logistic regression analysis was used to calculate odds ratios between HRV results and metabolic syndrome.Results: The odds ratio for metabolic syndrome in low HRV result was 2.87 (95% confidence interval [CI], 1.87–3.34) compared with high HRV result. After adjustment for age, smoking, alcohol consumption, and physical activity, the odds ratio for metabolic syndrome in low HRV result was also 3.37 (95% CI, 2.44–4.65) compared with high HRV result.Conclusion: Low HRV result using WISE-8000 (MooYoo Instruments) showed an increased risk for metabolic syndrome. HRV was associated with an increased risk of metabolic syndrome in Korean adults.

Prostate cancer (PCa) morbidity in the majority of patients is due to metastatic events, which are a clinical obstacle. Therefore, a better understanding of the mechanism underlying metastasis is imperative if we are to develop novel therapeutic strategies. Receptor activator of nuclear factor kappa-B (NF-κB) ligand (RANKL) regulates bone remodelling. Thus, agents that suppress RANKL signalling may be useful pharmacological treatments. Here, we used preclinical experimental models to investigate whether an inactive form of RANKL affects bone metastasis in RANKL-induced PCa. RANKL was associated with epithelial–mesenchymal transition (EMT) and expression of metastasis-related genes in PC3 cells. Therefore, we proposed a strategy to induce anti-cytokine antibodies using mutant RANKL as an immunogen. RANKL promoted migration and invasion of PC3 cells through EMT, and induced a significant increase in binding of β-catenin to TCF-4, an EMT-induced transcription factor in PCa cells, via mitogen-activated protein kinase and β-catenin/TCF-4 signalling. Thus, RANKL increased EMT and the metastatic properties of PC3 cells, suggesting a role as a therapeutic target to prevent PCa metastasis. Treatment with mutant RANKL reduced EMT and metastasis of PC3 PCa cells in an experimental metastasis model. Thus, mutant RANKL could serve as a potential vaccine to prevent and treat metastatic PCa.

Background and Purpose: Although statins are effective in secondary prevention of ischemic stroke, they are also associated with an increase risk of intracranial hemorrhage (ICH) in certain conditions. In the TST trial (Treat Stroke to Target), we prespecified an exploration of the predictors of incident ICH. Methods: Patients with ischemic stroke in the previous 3 months or transient ischemic attack within the previous 15 days and evidence of cerebrovascular or coronary artery atherosclerosis were randomly assigned in a 1:1 ratio to a target LDL (low-density lipoprotein) cholesterol of Results: Among 2860 patients enrolled, 31 incident ICH occurred over a median follow-up of 3 years (18 and 13 in the lower and higher target group, 3.21/1000 patient-years [95% CI, 2.38–4.04] and 2.32/1000 patient-years [95% CI, 1.61–3.03], respectively). While there were no baseline predictors of ICH, uncontrolled hypertension (HR, 2.51 [95% CI, 1.01–6.31], P =0.041) and being on anticoagulant (HR, 2.36 [95% CI, 1.00–5.62], P =0.047)] during the trial were significant predictors. On-treatment low LDL cholesterol was not a predictor of ICH. Conclusions: Targeting an LDL cholesterol of Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01252875; EUDRACT identifier: 2009-A01280-57.

The frequency, management, and outcomes of early neurologic deterioration (END) after ischemic stroke specifically due to stroke progression or stroke recurrence have not been well delineated.In a multicenter, nationwide registry, data on END due to stroke progression or recurrence confirmed by imaging were collected prospectively between January 2019 and July 2020. Patient characteristics, management strategies, and clinical outcomes were analyzed.Among 14,828 consecutive ischemic stroke patients, 1717 (11.6%) experienced END, including 1221 (8.2%) with END due to stroke progression (SP) or stroke recurrence (SR). Active management after END was implemented in 64.2% of patients. Active management strategies included volume expansion (29.2%), change in antithrombotic regimen (26.1%), induced hypertension (8.6%), rescue reperfusion therapy (6.8%), intracranial pressure lowering with hyperosmolar agents (1.5%), bypass surgery (0.6%), and hypothermia (0.1%). Active management strategies that varied with patient features included volume expansion and induced hypertension, used more often in large artery atherosclerosis and small vessel occlusion, and rescue endovascular thrombectomy, more common in other (dissection), cardioembolism, and large artery atherosclerosis. Active management was associated with higher rates of freedom from disability (modified Rankin Scale, mRS, 0-1; 24.3% vs. 16.6%) and functional independence (mRS, 0-2; 41.6% vs. 27.7%) at 3 months.END specifically due to stroke progression or recurrence occurs in 1 in 12 acute ischemic stroke patients. In this observational study, active management, undertaken in two-thirds of patients, was most often hemodynamic or antithrombotic and was associated with improved functional outcomes.

The expected growth of stroke burden in Korea in early 2000s led to the initiation of a government-funded clinical research project with the goal of development and implementation of national stroke guidelines. The CRCS-K (Clinical Research Collaboration for Stroke in Korea) began as a part of this project. For stroke epidemiology and quality of care research, the CRCS-K developed a multicenter, prospective, stroke registry and began collection of data in 2008. Now, about 100 000 cases have been registered at 17 university hospitals or regional stroke centers and about 200 articles have been published based on the registry experience. The analysis of the 10-year secular trends showed overall improvement of stroke care and outcomes and areas for improvement. This large-scale, high-quality dataset provides opportunities to explore and compare treatment disparities using the comparative effectiveness research methods, design and conduct a registry-based randomized clinical trial, connect the registry data with other data sources including the national claims data and neuroimaging or genetic data, and collaborate with other international researchers. An international stroke registry consortium may be a viable future direction.

Rationale: The optimal duration of dual antiplatelet therapy (DAPT) with clopidogrel-aspirin for the large artery atherosclerotic (LAA) stroke subtype has been debated. Aims: To determine whether the 1-year risk of recurrent vascular events could be reduced by a longer duration of DAPT in patients with the LAA stroke subtype. Methods and study design: A total of 4806 participants will be recruited to detect a statistically significant relative risk reduction of 22% with 80% power and a two-sided alpha error of 0.05, including a 10% loss to follow-up. This is a registry-based, multicenter, prospective, randomized, open-label, blinded end point study designed to evaluate the efficacy and safety of a 12-month duration of DAPT compared with a 3-month duration of DAPT in the LAA stroke subtype. Patients will be randomized (1:1) to either DAPT for 12 months or DAPT for 3 months, followed by monotherapy (either aspirin or clopidogrel) for the remaining 9 months. Study outcomes: The primary efficacy outcome of the study is a composite of stroke (ischemic or hemorrhagic), myocardial infarction, and all-cause mortality for 1 year after the index stroke. The secondary efficacy outcomes are (1) stroke, (2) ischemic stroke or transient ischemic attack, (3) hemorrhagic stroke, and (4) all-cause mortality. The primary safety outcome is major bleeding. Discussion: This study will help stroke physicians determine the appropriate duration of dual therapy with clopidogrel-aspirin for patients with the LAA stroke subtype. Trial registration: URL: https://cris.nih.go.kr/cris . CRIS Registration Number: KCT0004407

Electrode degradation during the resistance spot welding (RSW) of coated steels has been a major challenge in automobile manufacturing as it affects the weld quality in terms of nugget size, defects, and mechanical properties. In this work, we investigate the effect of electrode degradation on such a defect, Zn-assisted liquid metal embrittlement (LME) cracking, in RSW by producing 400 consecutive welds of galvannealed TRIP steel. Infrared thermography, carbon imprinting, dynamic resistance, optical imaging, SEM, and EDS were used to characterize various phenomena during consecutive welding. LME crack severity was found to be unaffected in the first 80 consecutive welds. However, the severity declined sharply between 80–200 welds, and further, it remained low in 200–400 welds. The electrode experienced geometrical degradation (increase in the radius of curvature and face diameter) and metallurgical degradation (Cu-Zn-Fe alloy layer formation) during consecutive welding. The geometrical degradation, specifically the radius of curvature, was confirmed as the main factor affecting LME cracking. On the other hand, metallurgical degradation did not affect the LME cracking in the first 200 welds as its influence was overcome by the geometrical degradation. However, a small impact of metallurgical degradation was detected in 200–400 welds in the form of local rise and fall in the temperature and LME crack length.

Background and purposeThere is much uncertainty in endovascular treatment (EVT) decisions in patients with acute large vessel occlusion (LVO) and mild neurological deficits.MethodsFrom a prospective, nationwide stroke registry, all patients with LVO and baseline NIHSS ResultsAmong 1,083 patients, 149 (14%) patients received EVT after a median of 5.9 [3.6–12.3] h after LKW. In propensity score-matched analyses, EVT was not associated with mRS 0-1 (matched OR 0.99 [0.63–1.54]) but increased the risk of a significant hemorrhage (matched OR, 4.51 [1.59–12.80]). Extraneous END occurred in 207 (19%) patients after a median of 24.5 h [IQR, 13.5–41.9 h] after LKW (incidence rate, 1.41 [95% CI, 1.23–1.62] per 100 person-hours). END unrelated to EVT showed a tendency to modify the effectiveness of EVT (P-for-interaction, 0.08), which decreased the odds of having mRS 0–1 in mild LVO patients without END (adjusted OR, 0.63 [0.40–0.99]).ConclusionsThe use of EVT in patients with acute LVO and low NIHSS scores may require the assessment of individual risks of early deterioration, hemorrhagic complications and expected benefit.

Background Previous literature about the effect of heart rate on poststroke outcomes is limited. We attempted to elucidate (1) whether heart rate during the acute period of ischemic stroke predicts subsequent major clinical events, (2) which heart rate parameter is best for prediction, and (3) what is the estimated heart rate cutoff point for the primary outcome. Methods and Results Eight thousand thirty‐one patients with acute ischemic stroke who were hospitalized within 48 hours of onset were analyzed retrospectively. Heart rates between the 4th and 7th day after onset were collected and heart rate parameters including mean, time‐weighted average, maximum, and minimum heart rate were evaluated. The primary outcome was the composite of recurrent stroke, myocardial infarction, and mortality up to 1 year after stroke onset. All heart rate parameters were associated with the primary outcome ( P ’s Conclusions These findings suggest that heart rate during the acute period of ischemic stroke is a predictor of major clinical events, and optimal heart rate control might be a target for preventing subsequent cardiovascular events.

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.

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.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.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 (Annual EVT case volume was associated with 1-year mortality. The volume threshold per hospital was 15 cases per year.

ObjectiveTo improve epidemiologic knowledge of neurologic deterioration (ND) in patients with acute ischemic stroke (AIS).MethodsIn this prospective observational study, we captured ND prospectively in 29,446 patients with AIS admitted to 15 hospitals in Korea within 7 days of stroke onset. ND was defined as an increase in NIH Stroke Scale (NIHSS) score ≥2 (total), or ≥1 (motor or consciousness), or any new neurologic symptoms. Change in incidence rate after stroke onset, causes, factors associated with ND, modified Rankin Scale (mRS) score at 3 months and 1 year, and a composite of stroke, myocardial infarction, and all-cause death at 1 year were assessed.ResultsND occurred in 4,299 (14.6%) patients. The highest rate, 6.95 per 1,000 person-hours incidence, was within the first 6 hours, which decreased to 2.09 within 24–48 hours, and 0.66 within 72–96 hours after stroke onset. Old age, female sex, diabetes, early arrival, large artery atherosclerosis as a stroke subtype, high NIHSS scores, glucose level, systolic blood pressure, leukocytosis at admission, recanalization therapy, TIA without a relevant lesion, and steno-occlusion of relevant arteries were associated with ND. The causes were stroke progression (71.8%) followed by recurrence (8.5%). Adjusted relative risks (95% CI) for poor outcome (mRS 3–6) at 3 months and 1 year were 1.75 (1.70–1.80) and 1.70 (1.65–1.75), respectively. The adjusted hazard ratio (95% CI) for the composite event was 1.59 (1.45–1.74).ConclusionsND should be taken into consideration as a factor that may influence the outcome in acute ischemic stroke.

ObjectiveStroke is a devastating and costly disease; however, there is a paucity of information on long-term costs and on how they differ according to 3-month modified Rankin scale (mRS) score, which is a primary outcome variable in acute stroke intervention trials.MethodsWe analyzed a prospective multicenter stroke registry (Clinical Research Collaboration for Stroke in Korea) database through linkage with claims data from the National Health Insurance Service with follow-up to December 2016. Healthcare expenditures were converted into daily cost individually, and annual and cumulative costs up to 5 years were estimated and compared according to the 3-month mRS score.ResultsBetween January 2011 and November 2013, 11,136 patients were enrolled in the study. The mean age was 68 years, and 58% were men. The median follow-up period was 3.9 years (range 0–5 years). Mean cumulative cost over 5 years was $117,576 (US dollars [USD]); the cost in the first year after stroke was the highest ($38,152 USD), which increased markedly from the cost a year before stroke ($8,718 USD). The mean 5-year cumulative costs differed significantly according to the 3-month mRS score (p < 0.001); the costs for a 3-month mRS score of 0 or 5 were $53,578 and $257,486 USD, respectively. Three-month mRS score was an independent determinant of long-term costs after stroke.ConclusionsWe show that 3-month mRS score plays an important role in the prediction of long-term costs after stroke. Such estimates relating to 3-month mRS categories may be valuable when undertaking health economic evaluations related to stroke care.