Network analysis of stroke systems of care in Korea

Background

The landscape of stroke care has shifted from stand-alone hospitals to cooperative networks among hospitals. Despite the importance of these networks, limited information exists on their characteristics and functional attributes.

Methods

We extracted patient-level data on acute stroke care and hospital connectivity by integrating national stroke audit data with reimbursement claims data. We then used this information to transform interhospital transfers into a network framework, where hospitals were designated as nodes and transfers as edges. Using the Louvain algorithm, we grouped densely connected hospitals into distinct stroke care communities. The quality and characteristics in given stroke communities were analysed, and their distinct types were derived using network parameters. The clinical implications of this network model were also explored.

Results

Over 6 months, 19 113 patients with acute ischaemic stroke initially presented to 1009 hospitals, with 3114 (16.3%) transferred to 246 stroke care hospitals. These connected hospitals formed 93 communities, with a median of 9 hospitals treating a median of 201 patients. Derived communities demonstrated a modularity of 0.904 , indicating a strong community structure, highly centralised around one or two hubs. Three distinct types of structures were identified: single-hub (n=60), double-hub (n=22) and hubless systems (n=11). The endovascular treatment rate was highest in double-hub systems, followed by single-hub systems, and was almost zero in hubless systems. The hubless communities were characterised by lower patient volumes, fewer hospitals, no hub hospital and no stroke unit.

Conclusions

This network analysis could quantify the national stroke care system and point out areas where the organisation and functionality of acute stroke care could be improved.

Digital coincidence counting with 4πβ(PPC)-γ for the standardization of 60Co

A 4πβ(PPC)-γ coincidence system has been made at KRISS based on a digital DAQ. 60Co sources were measured to verify the system. The maximum detection efficiency for beta particles was estimated to be 96.7 %. Massic activities for sample sources had 0.005 % of the sample variability error, which was well within the expanded standard uncertainty of 0.54 % (k = 2).

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.

A simplified cranial cavity model to understand the relationship between intracranial pressure and dural sinus pressure

Although accurate intracranial pressure (ICP) monitoring is essential for the diagnosis and treatment of severe brain diseases, current methods are performed invasively. Therefore, a safe and less invasive ICP measurement is required. The purpose of our study was to develop a simplified cranial cavity model for a better understanding of the relationship between the ICP and the pressure measurement within the dural venous sinus (DVS) to support the validity of using sinus pressure as the surrogate of the ICP. The in-house cranial cavity model had three components: the brain part, the DVS part, and the subarachnoid space (SAS) part. Pressure in other parts was measured when the pressure in the SAS part and, separately, brain part was increased from 0 (baseline) to 50 mmHg at intervals of 10 mmHg. When the pressure in the SAS part was increased from 10 to 50 mmHg at 10 mmHg interval, pressures of both the brain and DVS parts increased without significant difference (all P > 0.05). However, pressures in both the SAS and DVS parts differed while the pressure in the brain part was increased. The pressures in both parts showed about 70% of the increase in the brain part. Nevertheless, the pressures in the SAS and DVS parts were not significantly different (P > 0.05). A simplified in-house cranial cavity model was developed consisting of three compartments to represent the actual intracranial spaces. The pressure measurement within the DVS was feasible to use as a surrogate for the ICP measurement.

Body mass index and waist circumference as predictors of recurrent vascular events after a recent ischemic stroke

OBJECTIVES

Although elevated body mass index (BMI) is a risk factor for stroke, it appears to protect against recurrent vascular events. We tried to evaluate BMI and waist circumference (WC) as predictors of recurrent stroke and vascular events in a cohort of stroke survivors who were followed for 12 months.

MATERIALS AND METHODS

We analyzed the stroke registry database of 6 hospitals and recruited patients with a first-ever stroke who were admitted from January 2011 to November 2019 and had their BMI and WC measured. Cox proportional hazards models were used to compare risks of recurrent stroke and major vascular events (a composite of stroke, myocardial infarction, or vascular death) between different BMI and WC quintiles. Reference categories were patients in the lowest quintiles.

RESULTS

A total of 14 781 patients were analyzed. Patients in the second quintile of BMI had the lowest risk of recurrent stroke (adjusted hazard ratio (HR) 0.72; 95% confidence interval (CI) 0.58-0.91); patients in the highest quintile had the lowest risk or a major vascular event (adjusted HR 0.71; 95% CI 0.58-0.86). Patients in the fourth quintile of WC had the lowest risk of recurrent stroke (adjusted HR 0.73; 95% CI 0.59-0.91) and a major vascular event (adjusted HR 0.72; 95 % CI 0.60-0.86).

CONCLUSIONS

Our results show favorable effects of excess body weight and intra-abdominal fat on avoidance of vascular events after stroke and a favorable effect of intra-abdominal fat on avoidance of recurrent stroke.

Comparison of Hospital Performance in Acute Ischemic Stroke Based on Mortality and Functional Outcome in South Korea

BACKGROUND

Recent evidence suggests a correlation between modified Rankin Scale-based measures, an outcome measure commonly used in acute stroke trials, and mortality-based measures used by health agencies in the evaluation of hospital performance. We aimed to examine whether the 2 types of measures are interchangeable in relation to evaluation of hospital performance in acute ischemic stroke.

METHODS

Five outcome measures, unfavorable functional outcome (3-month modified Rankin Scale score ≥2), death or dependency (3-month modified Rankin Scale score ≥3), 1-month mortality, 3-month mortality, and 1-year mortality, were collected for 8292 individuals who were hospitalized for acute ischemic stroke between January 2014 and May 2015 in 14 hospitals participating in the Clinical Research Collaboration for Stroke in Korea - National Institute of Health registry. Hierarchical regression models were used to calculate per-hospital risk-adjusted outcome rates for each measure. Hospitals were ranked and grouped based on the risk-adjusted outcome rates, and the correlations between the modified Rankin Scale-based and mortality-based ranking and their intermeasure reliability in categorizing hospital performance were analyzed.

RESULTS

The comparison between the ranking based on the unfavorable functional outcome and that based on 1-year mortality resulted in a Spearman correlation coefficient of -0.29 and Kendall rank coefficient of -0.23, and the comparison of grouping based on these 2 types of ranks resulted in a weighted kappa of 0.123 for the grouping in the top 33%/middle 33%/bottom 33% and 0.25 for the grouping in the top 20%/middle 60%/bottom 20%, respectively. No significant correlation or similarity in grouping capacities were found between the rankings based on the functional outcome measures and those based on the mortality measures.

CONCLUSIONS

This study shows that regardless of clinical correlation at an individual patient level, functional outcome-based measures and mortality-based measures are not interchangeable in the evaluation of hospital performance in acute ischemic stroke.

Measurement of Direct-Photon Cross Section and Double-Helicity Asymmetry at sqrt[s]=510 GeV in p[over →]+p[over →] Collisions

We present measurements of the cross section and double-helicity asymmetry A_{LL} of direct-photon production in p[over →]+p[over →] collisions at sqrt[s]=510  GeV. The measurements have been performed at midrapidity (|η|<0.25) with the PHENIX detector at the Relativistic Heavy Ion Collider. At relativistic energies, direct photons are dominantly produced from the initial quark-gluon hard scattering and do not interact via the strong force at leading order. Therefore, at sqrt[s]=510  GeV, where leading-order-effects dominate, these measurements provide clean and direct access to the gluon helicity in the polarized proton in the gluon-momentum-fraction range 0.02<x<0.08, with direct sensitivity to the sign of the gluon contribution.

Biological mechanism of sex difference in stroke manifestation and outcomes

BACKGROUND AND OBJECTIVES

Female 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.

METHODS

This MRI-based multicenter study included 6,464 consecutive patients with acute ischemic stroke (<7-days) from 11-centers in South-Korea (May-2011∼January-2013). Multivariable statistical and brain mapping methods were used to analyze clinical and imaging data collected prospectively: admission National Institutes of Health Stroke Scale (NIHSS)-score, early neurological deterioration within 3-weeks, modified Rankin Scale (mRS)-score at 3-months, and culprit cerebrovascular lesion (symptomatic large artery steno-occlusion and cerebral infarction) locations.

RESULTS

Mean (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, P<0.001) and had more frequent early neurological deterioration (adjusted-difference 3.5%; P=0.002) than male patients. Female patients had more frequent striatocapsular lesions (43.6% vs. 39.8%, P=0.001) and less frequent cerebrocortical and cerebellar lesions than male patients, which aligned with angiographic findings: female patients had more prevalent symptomatic steno-occlusion of the middle cerebral artery (31.1% vs. 25.3%; P<0.001) compared to male patients, who had more frequent symptomatic steno-occlusion of the extracranial internal carotid artery (14.2% vs. 9.3%; P<0.001) and vertebral artery (6.5% vs. 4.7%; P=0.001). Cortical infarcts in female patients, specifically left-sided parieto-occipital regions, were associated with higher NIHSS-scores than expected for similar infarct volumes in male patients. Consequently, female patients had a higher likelihood of unfavorable functional outcome (mRS-score>2) than male patients (adjusted-absolute-difference 4.5%; 95%-CI 2.0-7.0; P<0.001).

DISCUSSION

Female 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.

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.

Efficacy and safety of oxiracetam in patients with vascular cognitive impairment: A multicenter, randomized, double-blinded, placebo-controlled, phase IV clinical trial

BACKGROUND

Oxiracetam may have a modest effect on preventing cognitive decline. Exercise can also enhance cognitive function. This trial aims to investigate the effect of oxiracetam on post-stroke cognitive impairment and explore whether this effect is modified by exercise. Furthermore, the mechanisms that mediate this effect will be investigated through a neural network analysis.

METHODS

This is a multicenter, randomized, double-blind, placebo-controlled phase IV trial. Patients who complained of cognitive decline 3 months after stroke and had a high risk of cognitive decline were eligible. Patients were randomly assigned to receive either 800 mg of oxiracetam or placebo twice daily for 36 weeks. After randomization, a predetermined exercise protocol was provided to each participant, and the degree of physical activity was assessed using wrist actigraphy at 4, 12, 24, and 36 weeks. Resting-state functional MRI was obtained in baseline and 36-week follow-up. Co-primary endpoints are changes in the Mini-Mental State Examination and Clinical Dementia Rating-Sum of Boxes. Secondary endpoints include changes in the NINDS-CSN VCIHS-Neuropsychology Protocol, Euro QoL, patient's global assessment, and functional network connectivity. If there is a significant difference in physical activity between the two groups, the interaction effect between physical activity and the treatment group will be examined. A total of 500 patients were enrolled from February 2018, and the last patient's final follow-up was completed in September 2022.

CONCLUSION

This trial is meaningful not only to prove the efficacy of oxiracetam, but also evaluate whether exercise can modify the effects of medication and how cognitive function can be restored. Trial registrationhttp://cris.nih.go.kr (KCT0005137).

Optimal use of antithrombotic agents in ischemic stroke with atrial fibrillation and large artery atherosclerosis

BACKGROUND

Optimal antithrombotic regimens to prevent recurrent stroke in patients with ischemic stroke due to atrial fibrillation (AF) and atherosclerotic large-vessel stenosis remain unknown.

AIMS

This study aimed to evaluate the effect of multiple antithrombotic therapies on outcomes at 1 year after ischemic stroke due to two or more causes.

METHODS

We identified 862 patients with ischemic stroke due to AF and large artery atherosclerosis from the linked data. These patients were categorized into three groups according to antithrombotic therapies at discharge: (1) antiplatelets, (2) oral anticoagulants (OAC), and (3) antiplatelets plus OAC. The study outcomes were recurrent ischemic stroke, composite outcomes for cardiovascular events, and major bleeding after 1 year. Inverse probability of treatment weighting (IPTW) was used to balance the three groups using propensity scores.

RESULTS

Among 862 patients, 169 (19.6%) were treated with antiplatelets, 405 (47.0%) were treated with OAC, and 288 (33.4%) were treated with antiplatelets and OAC. After applying IPTW, only OAC had a significant beneficial effect on the 1-year composite outcome (hazard ratio (HR): 0.37, 95% confidence interval (CI): 0.23-0.60, p < 0.001) and death (HR: 0.35, 95% CI: (0.19-0.63), p < 0.001). The combination of antiplatelet agents and OAC group had an increased risk of major bleeding complications (HR: 5.27, 95% CI: (1.31-21.16), p = 0.019). However, there was no significant difference in 1-year recurrent stroke events among the three groups.

CONCLUSION

This study demonstrated that OAC monotherapy was associated with lower risks of composite outcome and death in patients at 1 year after ischemic stroke due to AF and atherosclerotic stenosis. In addition, the combination of an antiplatelet and OAC had a high risk of major bleeding.

Abstract WMP43: Health Care Disparities In Reperfusion Therapy For Patients With Acute Ischemic Stroke Across Hospitals

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.

Abstract WMP97: Symptomatic Steno-occlusion Of Major Cerebral Arteries And Stroke Recurrence In Acute Ischemic Stroke Patients With Atrial Fibrillation

Introduction: There is lack of knowledge on whether symptomatic steno-occlusion (SYSO), common in acute ischemic stroke (AIS) patients with atrial fibrillation (AF), could increase the long-term risk of stroke recurrence in these patients.

Methods: From a prospective cohort of patients with AIS and AF enrolled in 14 centers between Oct 2017 and Dec 2018, we identified patients who underwent MR angiography during hospitalization and completed 3-year follow-up including death during follow-up. SYSO was defined as (1) ≥ 50% stenosis or occlusion of cerebral arteries relevant to acute infarction or (2) any residual stenosis after endovascular treatment. Using cause-specific hazard models with non-stroke death as a competing risk, the risk of any recurrent stroke and recurrent ischemic stroke was estimated according to SYSO, respectively.

Results: A total of 889 patients (mean age, 74.4 years; men, 54.6 %; median NIHSS, 6) were analyzed for this study. During the median 1096 days of follow-up, 152 any recurrent strokes, 142 recurrent ischemic strokes, and 208 deaths were observed. Patients with SYSO, compared to those without, were more likely to be older, be female, have hypertension, diabetes and history of stroke/TIA, and be on antiplatelets at discharge and were less likely to be on anticoagulants at discharge ( p <.05). The cumulative incidence of recurrent stroke in patients with and without SYSO was 25.2% and 8.3% at 1 month, 33.1% and 9.9% at 1 year, and 41.8% and 13.1% at 3 years, respectively ( p <.001). With adjusting age, sex, hypertension, diabetes, history of stroke/TIA, discharge antiplatelets, and discharge anticoagulants, SYSO increased the risk of any stroke recurrence (adjusted hazard ratio [95% confidence interval]; 3.02 [2.18-4.20]; p <.001) and ischemic stroke recurrence (3.20 [2.28-4.51]; p <.001).

Conclusions: SYSO in AIS patients with AF substantially increased the risk of recurrent stroke by a 3-fold or more. Accordingly, SYSO should be considered in stratifying the risk of recurrence in AIS patients with AF.

Abstract WP207: Treatments Advanced, But Outcomes Stagnated In Young Adults With Acute Ischemic Stroke In Korea Between 2008 And 2019

Background: Outcome improvement in young stroke patients is of great interest given their long life expectancy and substantial societal burden. We aimed to investigate whether the treatment advancement has been made and translated into outcome improvement in young patients with acute ischemic stroke (AIS).

Methods: From a prospective multicenter stroke registry in South Korea, young AIS patients (aged 18-50) hospitalized between 2008 and 2019 were identified. The study period was divided into 4 epochs. The secular trends of patient characteristics, treatments, and outcomes adjusted for potential confounders were analyzed.

Results: This study included 7,050 young AIS patients (mean age 43.1; men 71.9%) from 70,567 enrolled during the period. The mean age decreased from 43.6 years in 2008-2010 to 42.9 years in 2017-19 (P trend =.009). Obesity increased (40.1% to 49.0%), but current smoking decreased (53.1% to 42.8%). Other vascular risk factors and sex proportions did not change (P trend ’s > 0.5). Onset-to-arrival time and door-to-puncture time for mechanical thrombectomy did not change (P trend ’s > 0.5), but door-to-needle time for intravenous thrombolysis improved (P trend <.001). Acute and secondary stroke prevention treatments including intravenous thrombolysis (9.5% to 13.8%), mechanical thrombectomy (3.2% to 9.2%), dual antiplatelet therapy for minor stroke (26.6% to 48.0%), direct oral anticoagulant for atrial fibrillation (0.0% to 56.2%) and statins (71.5% to 91.2%) improved significantly (P trend ’s <.01). For stroke outcomes, for which data were available since 2011, the proportions of 3-month modified Rankin Scale 0-1 (68.3% to 69.1%) and 0-2 (87.6% to 86.2%), one-year mortality (2.5% to 2.4%), and one-year stroke recurrence (4.4% to 5.3%) did not improve (adjusted P trend ’s > 0.2).

Conclusions: This study shows that the treatment improvements did not lead to outcome improvements in young AIS patients. The findings indicate that we should not be complacent with the current advances.

Admission hyperglycemia, stroke subtypes, outcomes in acute ischemic stroke

AIMS

Whether admission hyperglycemia is differentially associated with early vascular outcomes in acute ischemic stroke (AIS) depending on stroke subtype has been incompletely delineated.

METHODS

In a multicenter, prospective stroke registry, patients with AIS were categorized based on admission glucose levels into normoglycemia, moderate hyperglycemia, and severe hyperglycemia (<140mg/dl, 140-179mg/dl, and ≥180mg/dl, respectively) groups. Multivariate analysis assessed the interaction between the hyperglycemia and ischemic stroke subtypes of large artery atherothrombosis (LAA), cardioembolism (CE), and small vessel occlusion (SVO) and early vascular outcomes (3-month stroke, all-cause mortality, and composite of stroke, MI, and all-cause mortality).

RESULTS

Among the 32,772 patients (age:69.0±12.6yrs, male:58.4%) meeting eligibility criteria, 61.9% were in the normoglycemia group, 19.5% were in the moderate hyperglycemia group, and 18.7% were in the severe hyperglycemia group. Substantial interactions between hyperglycemia groups and stroke subtypes were observed for 3-month stroke (P_interaction = 0.003) and composite of stroke, MI, and all-cause mortality (P_interaction = 0.001), with differential recurrence strongest among CE, intermediate among LAA, and least among SVO.

CONCLUSIONS

Hyperglycemia was differently associated with the risk of 3-month stroke by ischemic stroke subtype. The associations of hyperglycemia with 3-month stroke were greatest in CE subtype but not in SVO subtype. These results suggest that the effect of glucose-lowering treatment after AIS may differ according to stroke subtype.

Abstract WP98: Utilization Of Perfusion Imaging For Acute Ischemic Stroke: Secular Trends And Effects On Outcomes Of Endovascular Treatment

Introduction: Perfusion imaging (PI) could guide decision-making for endovascular treatment (EVT) of acute ischemic stroke (AIS). However, PI was underused even in the US before the pivotal EVT trials proved its usefulness in 2018. This study aimed to describe the secular trends of PI utilization and investigate the effectiveness of PI-based EVT in real-world practice.

Methods: Using a prospective multicenter (n=17) stroke registry in South Korea, we identified patients with AIS who presented within 24 hours from onset between 2011 and 2021. The study period was divided into 3 epochs: 2011-2014, 2015-2017, and 2018-2021. The study population was divided into the early (arrival within 6 hours) and late window (6-24 hours) groups.

Results: A total of 51,650 patients (15,654 patients in 2011-2014, 14,432 patients in 2015-2017, and 21,564 patients in 2018-2021) were analyzed. Utilization of PI decreased in the overall population and early window group ( P trend <0.001); 43.3% and 54.1% in 2011-2014, 40.1% and 44.1% in 2015-2017, and 38.4% and 40.2% in 2018-2021, respectively; but increased in the late window group ( P trend <0.001); 31.3% in 2011-2014, 35.7% in 2015-2017, and 36.5% in 2018-2021. Of 10,872 patients with anterior large-vessel occlusion (aLVO), the EVT rate was not different between patients with and without PI (48.7% vs. 46.6%, P =0.08) in the early window but higher in those with PI than without PI in the late window (29.8% vs. 18.7%, P <0.001). The EVT outcome (3-month mRS 0-2) was not different between patients with and without PI in the early window (44.1% vs. 41.8%, P =0.21) and late window (38.4% vs. 39.2%, P =0.81). Propensity score analysis and instrumental variable analysis with PI rate per center as an instrument will be performed to adjust imbalances between patients with and without PI.

Conclusion: Between 2011 and 2021 in South Korea, PI utilization has decreased in patients arriving within 6 hours from onset but has increased in those arriving between 6 and 24 hours. Among patients with aLVO, PI likely increased the EVT rate in the late window but did not in the early window. PI utilization did not seem to affect the EVT outcomes, but in-depth analysis is required.

Frequency, management, and outcomes of early neurologic deterioration due to stroke progression or recurrence

OBJECTIVE

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

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.

Abstract 44: Impact Of Novel Oral Anticoagulant Use On Secular Trend Of Vascular Events Or Death After Atrial Fibrillation-related Acute Ischemic Stroke

Introduction: Now novel oral anticoagulants (NOAC) are strongly recommended for secondary stroke prevention in patients with atrial fibrillation (AF). However, it remains unclear to what extent the introduction of NOACs improved clinical outcomes in real-world practice.

Methods: Using a nationwide prospective multi-center stroke registry database, we identified consecutive AIS patients with AF enrolled between Jan 2011 and Dec 2019, and analyzed one-year clinical events and NOAC prescription at discharge. The primary outcome was the composite of stroke, myocardial infarction, and all-cause death. To assess the mediation effect of NOAC on the outcomes, we performed natural effect models according to the calendar year. The exposure-mediator analysis, exposure-outcome analysis, and mediator-outcome analysis were performed using multivariate regression analysis according to the characteristics of the variables.

Results: We analyzed 12,500 patients (mean age, 74.4 years; 51.3% male; median NIHSS at presentation, 8). From 2011 to 2019, the cumulative one-year incidence of the primary composite outcome (28.3% to 22.1%), all-cause mortality (23.8% to 17.9%), and stroke recurrence (8.3% to 5.1%) significantly decreased, while the NOAC prescription rate at discharge increased (0% to 75.6%). One-year increase in the calendar year was independently associated with a delayed occurrence of primary composite outcomes (Step 1: adjusted Time Ratio (aTR), 1.10; 95% confidence interval, 1.07-1.14) and with an increased NOAC prescription rate (Step 2: adjusted odds ratio, 2.20; 2.14-2.27). Increase in the NOAC prescription rate was significantly associated with the delayed occurrence of primary composite outcome (Step 3: aTR, 3.80; 3.15-4.58). However, after controlling for the NOAC prescription rate (mediator), the calendar year was no longer associated with the primary composite outcomes. (Step 4: aTR, 0.78; 95% CI 0.60-1.03). Thus, our results indicate full mediation of NOAC prescription in the association between the calendar year and primary composite outcomes.

Conclusion: The reduced risk of major vascular events or death over time in AIS patients with AF was fully mediated by the increase in NOAC use.

Frequency of serous tubal intraepithelial carcinoma (STIC) in patients with high grade serous ovarian cancer

OBJECTIVE

Serous tubal intraepithelial carcinoma (STIC) is a known precursor of high-grade serous ovarian cancer (HGSOC). This study aimed to evaluate the proportion of STIC in patients with HGSOC and analyze the STIC-related prognosis in patients with HGSOC.

MATERIALS AND METHODS

All pathology reports at our institution that included bilateral salpingectomies of patients with HGSOC from January 2013 to December 2018 were reviewed by two experienced pathologists. The specimens from the ovaries and the salpinx including fimbria were examined. We analyzed the correlation between STIC and HGSOC and compared the clinical characteristics and STIC-related prognostic outcomes in patients with HGSOC.

RESULTS

Eleven of the 76 cases were STIC. BRCA mutations were found in 16.9% of patients with HGSOC. STIC was observed in 30.0% of patients with BRCA mutations and in 14.3% of patients without BRCA mutations. The incidence of STIC in patients with BRCA mutations was approximately twice that in patients without BRCA mutations; however, the difference was not statistically significant (P = 0.231). Further, the 5-year survival rate of patients without STIC appeared to be high; nevertheless, the difference was not statistically significant (59.7% vs. 47.4%, P = 0.633). Moreover, there was no significant difference in disease-free survival rate according to STIC (36.4% vs. 33.1%, P = 0.956).

CONCLUSION

STIC was identified in patients with HGSOC, and STIC incidence was prominent in HGSOC related to BRCA mutation. Although low frequency, STIC was detected in patients without BRCA mutation. Therefore, prophylactic salpingectomy may be useful for prevention of HGSOC.

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.

Three-dimensional navigation-guided percutaneous trans-symphyseal screw for mechanically unstable pubic symphysis diastasis

Minimally invasive trans-symphyseal screw (TSS) for pubic symphysis diastasis was recently advocated, and its feasibility and reproducibility under 3D-navigation guidance are explored. Fifteen cases between 2016 and 2021 with a background of pubic symphysis diastasis are reviewed in this case series. Twenty-two TSS were inserted with an average Injury Severity Score of 35.3. Sixty percent received a one-stage procedure including fracture reduction, intra-operative 3D imaging, and planning followed by execution. The mean operative time and blood loss were 132 minutes and 160 ml, respectively. Average fracture healing was 5.8 months with two delayed unions at 9 months. The pubic symphysis distance was maintained in all cases at 6 months post-op. The average Marjeed score, Multicenter Study Group Pelvic Outcome Score, and Numeric pain rating scale were 60.2, 6.5, and 2.7, respectively. We conclude that 3D-navigation-guided percutaneous TSS restores pelvic stability and provides satisfactory pain control, and thus a safe and effective alternative to open reduction internal fixation.

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.

Differential influences of LDL cholesterol on functional outcomes after intravenous thrombolysis according to prestroke statin use

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 (< 100/100–130/ > 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.

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.

Effectiveness and safety of EVT in patients with acute LVO and low NIHSS

Background and purpose

There is much uncertainty in endovascular treatment (EVT) decisions in patients with acute large vessel occlusion (LVO) and mild neurological deficits.

Methods

From a prospective, nationwide stroke registry, all patients with LVO and baseline NIHSS &lt;6 presenting within 24 h from the time last known well (LKW) were included. Early neurological deterioration (END) developed before EVT was prospectively collected as an increasing total NIHSS score ≥2 or any worsening of the NIHSS consciousness or motor subscores during hospitalization not related to EVT. Significant hemorrhage was defined as PH2 hemorrhagic transformation or hemorrhage at a remote site. The modified Rankin Scale (mRS) was prospectively collected at 3 months.

Results

Among 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]).

Conclusions

The 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.

Effect of Heart Rate on 1-Year Outcome for Patients With Acute Ischemic Stroke

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<0.001). Maximum heart rate had the highest predictive power. The estimated cutoff point for the primary outcome was 81 beats per minute for mean heart rate and 100 beats per minute for maximum heart rate. Patients with heart rates above these cutoff points had a higher risk of the primary outcome (adjusted hazard ratio, 1.80 [95% CI, 1.57-2.06] for maximum heart rate and 1.65 [95% CI, 1.45-1.89] for mean heart rate). The associations were replicated in a separate validation dataset (N=10 000). 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.

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.

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.

One-Year Blood Pressure Trajectory After Acute Ischemic Stroke

Background Although the effect of blood pressure on poststroke outcome is well recognized, the long-term trajectory of blood pressure after acute ischemic stroke and its influence on outcomes have not been studied well. Methods and Results We analyzed systolic blood pressure (SBP) measurements in 5514 patients with acute ischemic stroke at ≥2 of 7 prespecified time points during the first year after stroke among those enrolled in a multicenter prospective registry. Longitudinal SBPs were categorized using a group-based trajectory model. The primary outcome was a composite of stroke recurrence, myocardial infarction, and all-cause mortality up to 1 year after stroke. The study subjects were categorized into 4 SBP trajectory groups: low (27.0%), moderate (59.5%), persistently high (1.2%), and slowly dropping (12.4%). In the first 3 groups, SBP decreased during the first 3 to 7 days and remained steady thereafter. In the slowly dropping SBP group, SBPs decreased from 182 to 135 mm Hg during the first 30 days, then paralleled the trajectory of the moderate SBP group. Compared with the reference, the moderate SBP group, the slowly dropping SBP group was at higher risk for the primary outcome (adjusted hazard ratio [HR], 1.32; 95% CI, 1.05‒1.65) and mortality (adjusted HR, 1.35; 95% CI, 1.03‒1.78). Primary outcome rates were similarly high in the persistently high SBP group. Conclusions Four 1-year longitudinal SBP trajectories were identified in patients with acute ischemic stroke. Patients in the slowly dropping SBP and persistently high SBP trajectory groups were prone to adverse cardiovascular outcomes after stroke.

Abstract WMP102: Prevalence Of Genetic Mutations In 15 Mendelian Stroke Genes In Young Stroke Patients

Introduction: Although the heritability of stroke might be higher in young-age stroke population, it is even uncertain how many of them has monogenic causes of stroke. We aimed to estimate the prevalence and clinical characteristics of 15 monogenic disorders associated with stroke in a large, unselected young-age stroke population

Methods: From a prospective, nationwide, multicenter, acute stroke registry of consecutive patients admitted to 15 academic or regional stroke centers in Korea, we enrolled all patients aged 55 years or younger except those who refuse to participate in this study. We performed genetic analysis using a customized targeted next-generation sequencing panel ( GLA, NOTCH3, HTRA1, RNF213, ACVRL1, ENG, CBS, TREX1, ABCC6, COL4A1, FBN1, NF1, COL3A1, MT-TL1, and APP ) to find clinically relevant genetic variants, and reviewed clinical information of the patients.

Results: Genetic analysis was performed in 1,033 patients (male 70.7%, mean age 45.8±7.9). Twenty-eight clinically relevant genetic variants were identified in 131 (12.7%) patients, and were found most frequently in RNF213 (59, 5.7%) followed by ABCC6 (53, 5.1%) and NOTCH3 (15, 1.5%). Genetic variants were more commonly observed in younger group than older group (17.1% vs. 9.3%, p=0.021), but were not different according to vascular risk factor burden. Patients with premature (<60y) family history of stroke had genetic variants more frequently than those with family history at ≥60y (23.7% vs. 11.4%, p=0.047). Typical neuroimaging abnormalities were observed in only 25% of patients with RNF213 variants and 27% of those with NOTCH3 variants. Variants of uncertain significance were found in 15.4%.

Conclusion: Clinically relevant genetic variants were not uncommon than expected. We might have opportunities to improve our daily practice by genetic counseling patients and their families to reduce the future stroke.

Abstract TP180: Secular Trends For Demographics, Characteristics, Management, And Clinical Outcome Of Young Adults With Acute Ischemic Stroke

Background: The incidence of stroke in young adults is increasing with the growing prevalence of stroke risk factors among young adults over the last decades. However, studies on secular trends in the young-age stroke population are scarce.

Methods: We extracted data of acute ischemic stroke (AIS) patients aged 18-50 (n=7053; age, 43±6; male, 72%) from the multicenter stroke registry in South Korea. Demographics, risk factors, stroke characteristics, management, and clinical outcomes in young adults with AIS were summarized according to calendar year (2008-2019). Trends analysis was conducted using a linear regression model for continuous variables and the Mann-Kendall trend test for categorical variables.

Results: There was no significant change between 2008 and 2019 in the proportions of young adults among female patients (7.1% to 7.0%, p=0.44). However, the proportions of young adults within male patients tended to decrease (12.4% to 10.7%; p=0.001) The prevalence, and awareness of risk factors were unchanged during the study period. Regarding stroke subtypes, there was a significant increase in other determined etiology (8% to 20%; p<0.001) and a tendency to decrease in large artery atherosclerosis (26% in 2008; 34% in 2009 to 26% in 2019; p=0.28). The endovascular thrombectomy (EVT) rate increased (2% to 8%; p<0.001), but the intravenous thrombolysis rate (8.8% to 10.6%) and door-to-needle time (38 to 36 min) did not change. Use of dual antiplatelet (DAPT; 29% to 55%; p=<0.001) increased and direct oral anticoagulants (DOACs) in patients with atrial fibrillation tended to increase (11.7% in 2013 to 44.8% in 2019; p=0.07; DOAC began to be used in 2013 in Korea). However, the use of anticoagulants among young adult patients having atrial fibrillation tended to decrease (80% to 66%; p=0.054). Clinical outcomes, including a 3-month modified ranking scale 0-2 (84.6% to 85.2%), 1-year mortality (2.8% to 2.4%), and stroke recurrence rate (4.5 to 5.6%), did not improve during the study period.

Conclusions: Among young adults with ischemic stroke, the EVT rate and use of DAPT or DOACs increased. Still, awareness of risk factors, door-to-needle time, and anticoagulation for atrial fibrillation required more attention to improve clinical outcomes.

Association of ischemic stroke onset time with presenting severity, acute progression, and long-term outcome: A cohort study

BACKGROUND

Preclinical data suggest circadian variation in ischemic stroke progression, with more active cell death and infarct growth in rodent models with inactive phase (daytime) than active phase (nighttime) stroke onset. We aimed to examine the association of stroke onset time with presenting severity, early neurological deterioration (END), and long-term functional outcome in human ischemic stroke.

METHODS AND FINDINGS

In a Korean nationwide multicenter observational cohort study from May 2011 to July 2020, we assessed circadian effects on initial stroke severity (National Institutes of Health Stroke Scale [NIHSS] score at admission), END, and favorable functional outcome (3-month modified Rankin Scale [mRS] score 0 to 2 versus 3 to 6). We included 17,461 consecutive patients with witnessed ischemic stroke within 6 hours of onset. Stroke onset time was divided into 2 groups (day-onset [06:00 to 18:00] versus night-onset [18:00 to 06:00]) and into 6 groups by 4-hour intervals. We used mixed-effects ordered or logistic regression models while accounting for clustering by hospitals. Mean age was 66.9 (SD 13.4) years, and 6,900 (39.5%) were women. END occurred in 2,219 (12.7%) patients. After adjusting for covariates including age, sex, previous stroke, prestroke mRS score, admission NIHSS score, hypertension, diabetes, hyperlipidemia, smoking, atrial fibrillation, prestroke antiplatelet use, prestroke statin use, revascularization, season of stroke onset, and time from onset to hospital arrival, night-onset stroke was more prone to END (adjusted incidence 14.4% versus 12.8%, p = 0.006) and had a lower likelihood of favorable outcome (adjusted odds ratio, 0.88 [95% CI, 0.79 to 0.98]; p = 0.03) compared with day-onset stroke. When stroke onset times were grouped by 4-hour intervals, a monotonic gradient in presenting NIHSS score was noted, rising from a nadir in 06:00 to 10:00 to a peak in 02:00 to 06:00. The 18:00 to 22:00 and 22:00 to 02:00 onset stroke patients were more likely to experience END than the 06:00 to 10:00 onset stroke patients. At 3 months, there was a monotonic gradient in the rate of favorable functional outcome, falling from a peak at 06:00 to 10:00 to a nadir at 22:00 to 02:00. Study limitations include the lack of information on sleep disorders and patient work/activity schedules.

CONCLUSIONS

Night-onset strokes, compared with day-onset strokes, are associated with higher presenting neurologic severity, more frequent END, and worse 3-month functional outcome. These findings suggest that circadian time of onset is an important additional variable for inclusion in epidemiologic natural history studies and in treatment trials of neuroprotective and reperfusion agents for acute ischemic stroke.

Abstract WP184: The Risk Of Stroke Recurrence According To Neuroimaging Parameters In Patients With Acute Ischemic Stroke And Atrial Fibrillation

Purpose: The usefulness of the existing risk stratification tools for atrial fibrillation (AF) is limited in predicting stroke recurrence in patients with acute ischemic stroke (AIS). Neuroimaging parameters obtained from diagnostic work-up of AIS could offer more elaborate prediction.

Methods: A multicenter prospective cohort of AIS patients with AF recruited from 14 university hospitals or regional stroke centers were followed up for recurrent ischemic stroke (RIS) and a composite of all stroke and TIA. Neuroimaging features were derived from acute and chronic infarction patterns, and SVD markers such as lacunes, CMBs, and WMH. Cumulative incidences according to each neuroimaging parameter were estimated and compared using the Kaplan-Meier method with log-rank test and multivariable cause-specific hazard models with death as a competing risk.

Results: A total of 2,270 patients were followed up for 431 days (IQR, 365-735), during which 111 RISs and 130 composite outcomes occurred. In unadjusted analysis, lesion multiplicity among acute infarction patterns, the presence of chronic non-lacunar infarction, and the presence of lacunes among SVD markers increased the risk of RIS significantly (Table). Other neuroimaging features such as territory multiplicity and location, confluency, topography, and size of acute lesions, lesion multiplicity, territory multiplicity, confluency, topography, and size of chronic infarction, number of lacunes, presence of CMBs, and WMH did not affect the incidence of RIS. The adjusted hazard ratios of lesion multiplicity of acute infarction, chronic infarction and lacunes were 1.45 (95% CI, 0.99-2.11), 1.57 (1.06-2.34) and 1.97 (1.30-2.98) for RIS, respectively. Similar findings were obtained for the composite outcome.

Conclusions: Several neuroimaging markers were associated with recurrent ischemic stroke in AIS with AF. This could pave the way to a new stratification scheme for AF including neuroimaging parameters.

Abstract WP186: Long-term Incidence Of Gastrointestinal Bleeding After Ischemic Stroke

Background: Incidence of gastrointestinal (GI) bleeding after acute ischemic stroke (AIS) was reported as 1.5% during hospitalization, one-thirds of which required blood transfusion. However, it is not known about the long-term incidence and the incidence rates by period after AIS.

Methods: AIS patients who were admitted to the 14 participating hospitals between 2011 and 2013 were identified using a nationwide multicenter prospective stroke registry database. GI bleeding was captured with related diagnosis codes by International Classification of Diseases-10th Revision through the linkage between the registry database and the claims data. Bleeding requiring at least 2 packs of blood transfusion was defined as major GI bleeding. Incidence rates were calculated for each period as follow; 0-30 days, 31-90 days, 91-180 days, 181-365 days, 1-2 years, 2-3years, after 3 years.

Results: Of 10,818 AIS patients, 59.0% were male and mean age was 67.5 ± 12.9 years. The median follow-up duration was 3.1 (interquartile range 2.3 to 4.0) years. During 31,208 person-years, 947 patients (8.8%) had 1,224 episodes of major GI bleeding. Annual incidence rate was 3.92 per 100 person-years. The incidence rates by periods were the highest at 19.21 per 100 person-years in the first month of AIS, gradually decreased to 9.02 in one to three months, 6.18 in three to six months, and 3.48 in six to twelve months. After three years, it remained at about 2.62 events per 100 person-years. During the observation period, only one major GI bleeding occurred without recurrence in about 80% of patients, about 13% recurred twice, and about 6% of patients had three or more recurrences. In the multivariable recurrent event analysis, anemia at admission, lower eGFR below 60, and mRS at 3 months ≥4 were independently associated with higher risk of major GI bleeding during the most of the observation period above 3 years.

Conclusions: Major GI bleeding, requiring transfusion, seems to occur frequently after AIS, and the risk was gradually decreased after stroke. The efforts are needed to prevent it, especially in stroke patients with anemia and decreased renal function.

Risk Factors of Unfavorable Outcomes, Major Bleeding, and All-Cause Mortality in Patients with Venous Thromboembolism

Purpose

This study aimed to analyze the clinical outcomes of venous thromboembolism (VTE) patients and identify the risk factors for VTE-related unfavorable outcomes, major bleeding, and 30-day all-cause mortality.

Materials and Methods

From January 2016 to December 2020, 198 patients with confirmed VTE were enrolled. Potential risk factors for unfavorable outcomes, major bleeding, and all-cause mortality were analyzed.

Results

VTE-related unfavorable outcomes developed in 13.1%, while 30-day all-cause mortality was 8.6%. In the multivariate analysis, a pulse ≥110/min and respiratory rate ≥30/min were statistically significant predictors for VTE-related unfavorable outcomes. Diabetes was a significant risk factor for major bleeding. In addition, a history of malignancy, no anticoagulation treatment, and need for mechanical ventilation were significant predictors of all-cause mortality.

Conclusion

VTE-related mortality and morbidity rates remained high. In cases of tachycardia and tachypnea, early aggressive treatment is needed to prevent unfavorable outcomes. Patients with risk factors should be closely monitored.

Standardization of 129I using the movable 4πβ(LS)-X(NaI(Tl)) system

The ¹²⁹I standardization, using the movable 4πβ(LS)-X(NaI(Tl)) coincidence system, was performed for two ¹²⁹I radioactive sources - one was dissolved in 0.1M NaOH solution and the other in 0.1M HNO₃ solution. The system incorporates three movable PM tubes for a β-counter placed on a plane and a X-ray detector that can be moved up to the bottom of the vial. The β-efficiency depending on the amount of radioactive solution was investigated with 14 liquid scintillation samples prepared by gravimetrically dispensing 4.4-145 mg of ¹²⁹I radioactive solution. The β-efficiencies above 90% were observed at less than 56 mg, but it was at most 70% at 145 mg. This occurred regardless of the activity of the sample or the type of chemical solution used to dissolve ¹²⁹I source. The activity concentration of each ¹²⁹I source was determined by efficiency-extrapolation method for samples with an activity range of 0.28-4.5 kBq. The β-efficiency points were derived over 10 intervals by moving 3-PM tubes in fine steps of about 1 mm from the sample. The highest value for β-efficiency was 95%. The combined uncertainty were 0.25% and 0.26%, respectively. The stated precision obtained using the system is better than that previously reported in the literature obtained by the triple to double coincidence ratio (TDCR) or the CIEMAT/NIST efficiency tracing method.

Association of Prestroke Glycemic Control With Vascular Events During 1-Year Follow-up

Background and Objectives

We 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.

Methods

Patients 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.

Results

Of 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]).

Dicussion

In 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.

Placental Pathologic Changes Associated with Fetal Growth Restriction and Consequent Neonatal Outcomes

To evaluate the pathological changes of the placenta to determine the mechanism underlying placenta-derived fetal growth restriction (FGR) and investigate its influence on neonatal outcomes. Study design: This retrospective case-control study included 120 singleton pregnancies with FGR as well as 120 gestational age-matched controls. We compared the placental pathological findings and neonatal outcomes according to the presence of placental malperfusion. Results: The FGR group demonstrated lower placental weight (350.8 ± 118.8 vs. 436.1 ± 109.7g, P < .0001), smaller chorionic plate area (157.7 ± 48.0 vs. 201.5 ± 53.4 cm², P < .0001), and higher rate of villous change lesions (84.2% vs. 52.5%, P < .0001) than the control group. FGR neonates with placental malperfusion had a higher rate of adverse neonatal outcomes (87.1% vs. 63.2%, P = .0175). Conclusion: Small placentas and placental malperfusion reflected in villous changes are associated with FGR. FGR neonates with placental malperfusion are more susceptible to adverse neonatal outcomes.

Relation of Pre-Stroke Aspirin Use With Cerebral Infarct Volume and Functional Outcomes

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 < 3), particularly in large artery atherosclerosis stroke and cardioembolic stroke (adjusted difference = 7.2%, 95% CI = 1.8 to 12.5 and adjusted difference = 6.4%, 95% CI = 1.7 to 11.1, respectively). Pre‐stroke aspirin use (vs nonuse) was associated with 85% less frequent cerebral thrombus‐related susceptibility vessel sign (SVS) in large artery atherosclerosis stroke (adjusted difference = −1.4%, 95% CI = −2.1 to −0.8, p < 0.001) and was associated with ~40% lower SVS volumes, particularly in cardioembolic stroke (adjusted difference = −0.16 cm³, 95% CI = −0.29 to −0.02, p = 0.03). Moreover, pre‐stroke aspirin use was not significantly associated with hemorrhagic transformation (adjusted difference = −1.1%, p = 0.09).

Interpretation

Pre‐stroke aspirin use associates with improved functional independence in patients with first‐ever ischemic large arterial stroke by reducing infarct volume and/or END, likely by decreasing thrombus burden, without increased risk of hemorrhagic transformation. ANN NEUROL 2021;90:763–776

Prestroke Glucose Control and Functional Outcome in Patients With Acute Large Vessel Occlusive Stroke and Diabetes After Thrombectomy

OBJECTIVE

To evaluate whether prestroke glucose control is associated with functional outcomes in patients with acute large vessel occlusive stroke and diabetes who underwent intra-arterial thrombectomy (IAT).

RESEARCH DESIGN AND METHODS

From the Clinical Research Center for Stroke-Korea registry, we included patients with emergent large vessel occlusive stroke with diabetes who underwent IAT between January 2009 and March 2020. The association between the HbA_1c level at admission and functional outcomes (modified Rankin Scale at 3 months after the index stroke) was assessed.

RESULTS

A total of 1,351 patients were analyzed. Early neurological deterioration was more common in patients with higher levels of HbA_1c at admission (P = 0.02 according to HbA_1c quintiles, P = 0.003 according to an HbA_1c cutoff value of 7.0%) than in those with lower HbA_1c levels. Higher HbA_1c levels at admission were significantly associated with decreased odds of favorable functional outcomes at a threshold of 7.0-7.1%. The association was consistently observed in subgroups divided according to age, sex, stroke subtype, occlusion site, degree of recanalization, thrombolysis modalities, time from symptom onset to groin puncture, and treatment period.

CONCLUSIONS

Prestroke glucose control with a target HbA_1c of ≤7.0% may be beneficial for neurological recovery in patients with diabetes undergoing IAT for large vessel occlusive stroke, regardless of stroke subtype, bridging intravenous thrombolysis, occlusion site, degree of recanalization, and treatment period.

Comparative effectiveness of combined antiplatelet treatments in acute minor ischaemic stroke

Background

No 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.

Methods

We 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.

Results

Among 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.

Conclusion

Other 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.

Classification of cardioembolic stroke based on a deep neural network using chest radiographs

BACKGROUND

Although chest radiographs have not been utilised well for classifying stroke subtypes, they could provide a plethora of information on cardioembolic stroke. This study aimed to develop a deep convolutional neural network that could diagnose cardioembolic stroke based on chest radiographs.

METHODS

Overall, 4,064 chest radiographs of consecutive patients with acute ischaemic stroke were collected from a prospectively maintained stroke registry. Chest radiographs were randomly partitioned into training/validation (n = 3,255) and internal test (n = 809) datasets in an 8:2 ratio. A densely connected convolutional network (ASTRO-X) was trained to diagnose cardioembolic stroke based on chest radiographs. The performance of ASTRO-X was evaluated using the area under the receiver operating characteristic curve. Gradient-weighted class activation mapping was used to evaluate the region of focus of ASTRO-X. External testing was performed with 750 chest radiographs of patients with acute ischaemic stroke from 7 hospitals.

FINDINGS

The areas under the receiver operating characteristic curve of ASTRO-X were 0.86 (95% confidence interval [CI], 0.83-0.89) and 0.82 (95% CI, 0.79-0.85) during the internal and multicentre external testing, respectively. The gradient-weighted class activation map demonstrated that ASTRO-X was focused on the area where the left atrium was located. Compared with cases predicted as non-cardioembolism by ASTRO-X, cases predicted as cardioembolism by ASTRO-X had higher left atrial volume index and lower left ventricular ejection fraction in echocardiography.

INTERPRETATION

ASTRO-X, a deep neural network developed to diagnose cardioembolic stroke based on chest radiographs, demonstrated good classification performance and biological plausibility.

FUNDING

Grant No. 14-2020-046 and 08-2016-051 from the Seoul National University Bundang Research Fund and NRF-2020M3E5D9079768 from the National Research Foundation of Korea.

Longitudinal proteomic profiling provides insights into host response and proteome dynamics in COVID-19 progression

In managing patients with coronavirus disease 2019 (COVID‐19), early identification of those at high risk and real‐time monitoring of disease progression to severe COVID‐19 is a major challenge. We aimed to identify potential early prognostic protein markers and to expand understanding of proteome dynamics during clinical progression of the disease. We performed in‐depth proteome profiling on 137 sera, longitudinally collected from 25 patients with COVID‐19 (non‐severe patients, n = 13; patients who progressed to severe COVID‐19, n = 12). We identified 11 potential biomarkers, including the novel markers IGLV3‐19 and BNC2, as early potential prognostic indicators of severe COVID‐19. These potential biomarkers are mainly involved in biological processes associated with humoral immune response, interferon signalling, acute phase response, lipid metabolism, and platelet degranulation. We further revealed that the longitudinal changes of 40 proteins persistently increased or decreased as the disease progressed to severe COVID‐19. These 40 potential biomarkers could effectively reflect the clinical progression of the disease. Our findings provide some new insights into host response to SARS‐CoV‐2 infection, which are valuable for understanding of COVID‐19 disease progression. This study also identified potential biomarkers that could be further validated, which may support better predicting and monitoring progression to severe COVID‐19.

Development of a movable 4πβ(LS)-γ coincidence counting system for activity standardization of β-γ emitters

A new movable 3PM-γ coincidence system, based on 4πβ(LS)-γ coincidence counting, for activity measurement of β-γ emitters has been designed at the Korea Research Institute of Standards and Science (KRISS). The system incorporates 3 PM tubes on the plane and two detectors placed above and below the center of the plane. The 3 PM tubes for β-counters in the plane are movable up to 100 mm from a liquid scintillation vial, thus enabling the variation of β-detection efficiencies by a geometrical technique. A NaI(Tl) γ-counter was set above for the present work. The β-event is determined by counting the logical sum of three double coincidences. All the necessary electronics, i.e., logical sum, adjusting the duration of dead-time of each counting channel and coincidence resolving times, and analyzing coincidence relation, were specially designed to be fabricated in an integrated circuit. Details of the detectors, the electronics, the overall movable 3PM-γ coincidence system are presented, as well as the results of investigations to assess its operating characteristics. Validation measurements have been performed with ⁶⁰Co and ⁵⁷Co sources. The highest β-detection efficiency achieved with ⁶⁰Co and ⁵⁷Co was 97% and 95%, respectively. The activity concentration determined with a new system agreed with calibrated values within the uncertainty range. Further results from validation measurements and the corresponding uncertainty budgets are presented.

Diagnostic Performance of F-18 FDG PET/CT Compared with CA125, HE4, and ROMA for Epithelial Ovarian Cancer

OBJECTIVE

This study aimed to examine the diagnostic performance of F-18 fluorodeoxyglucose positron emission tomography with computed tomography (F-18 FDG PET/CT) compared with cancer antigen 125 (CA125), human epididymis protein 4 (HE4), and risk of ovarian malignancy algorithm (ROMA) score to distinguish epithelial ovarian cancer from benign tumors.

METHODS

A total of 46 patients with pelvic masses, who underwent F-18 FDG PET/CT, CA125, and HE4 before surgery between January 2015 and December 2018, were included in this retrospective study. The diagnostic performance of CA125, HE4, ROMA score, and maximum standardized uptake value (SUVmax) to differentiate epithelial ovarian cancer from benign pelvic tumors was examined by receiver operating characteristic curve analysis.

RESULTS

Among the 46 patients, 28 were cases of ovarian cancers and 18 were of benign. The mean values of CA125, HE4, ROMA score, and SUVmax were significantly higher in the ovarian cancer group than the benign group. In early cancer stages (stages I and II), Area under the curve for SUVmax was significantly higher than CA125 and ROMA score (0.778 for CA125, 0.753 for HE4, 0.682 for ROMA score, and 0.922 for SUVmax).

CONCLUSION

SUVmax using F-18 FDG PET/CT showed a high diagnostic accuracy for differentiating epithelial ovarian cancer from benign pelvic tumors, including early stage ovarian cancer. F-18 FDG PET/CT can be a useful modality for the assessment of pelvic mass.<br />.

Effect of Transport Time on the Use of Reperfusion Therapy for Patients with Acute Ischemic Stroke in Korea

BACKGROUND

We investigated the association between geographic proximity to hospitals and the administration rate of reperfusion therapy for acute ischemic stroke.

METHODS

We identified patients with acute ischemic stroke who visited the hospital within 12 hours of symptom onset from a prospective nationwide multicenter stroke registry. Reperfusion therapy was classified as intravenous thrombolysis (IVT), endovascular therapy (EVT), or combined therapy. The association between the proportion of patients who were treated with reperfusion therapy and the ground transport time was evaluated using a spline regression analysis adjusted for patient-level characteristics. We also estimated the proportion of Korean population that lived within each 30-minute incremental service area from 67 stroke centers accredited by the Korean Stroke Society.

RESULTS

Of 12,172 patients (mean age, 68 ± 13 years; men, 59.7%) who met the eligibility criteria, 96.5% lived within 90 minutes of ground transport time from the admitting hospital. The proportion of patients treated with IVT decreased significantly when stroke patients lived beyond 90 minutes of the transport time (P = 0.006). The proportion treated with EVT also showed a similar trend with the transport time. Based on the residential area, 98.4% of Korean population was accessible to 67 stroke centers within 90 minutes.

CONCLUSION

The use of reperfusion therapy for acute stroke decreased when patients lived beyond 90 minutes of the ground transport time from the hospital. More than 95% of the South Korean population was accessible to 67 stroke centers within 90 minutes of the ground transport time.

Abstract P470: Annual Endovascular Treatment Procedural Volume and One Year Mortality in Acute Ischemic Stroke

Background: In-hospital and 30-day mortality, 3-month functional outcome were reported as associated with endovascular treatment (EVT) case volume per hospital, but one-year mortality was unknown. Furthermore, the hospital EVT volume threshold based on one-year mortality was not reported. We aimed to investigate whether there was a correlation between annual EVT case volume per hospital and one-year mortality and suggest volume threshold.

Methods: Data from Korean national survey for assessing quality of acute stroke care were used. The survey was conducted since 2005 and the subject was patients with acute stroke who were admitted via emergency rooms within 7 days of onset at hospitals treating 10 or more stroke cases during the three (2013, 2014) or six (2016) month survey period. Ischemic stroke cases treated with EVT during the last available three assessments (2013, 2014, and 2016) were selected for the analysis.

Results: A total of 1,746 ischemic stroke cases (age, 69.2 ± 12.4years; male, 56.6%) treated in 120 hospitals with EVT were analyzed. The median annual EVT case volume was 12.0 cases per hospital (interquartile range, 6.0-22.9) and the mortality at one-month, three-month, and one-year were 12.7%, 16.6%, and 23.3%, respectively. When divided into quartiles according to the annual EVT case volume, the lowest quartile group was found to have the highest one-year mortality (odds ratio [95% confidence intervals], 1.49 [1.04-2.13]), adjusted for age, sex, NIHSS, onset to arrival time. Restricted cubic splines performed on the annual EVT case volume per hospital revealed that cut-off value for the probability of one-year mortality was 15 cases per year ( p <0.02) (Figure).

Conclusions: There was an association between annual EVT case volume and one-year mortality, and the volume threshold per hospital based on the one-year mortality was found to be 15 EVT cases per year.

Abstract P648: The Presence and the Features of Silent Brain Infarction Are Associated With Stroke Recurrence in Acute Ischemic Stroke Patients With Atrial Fibrillation

Background: The significance of silent brain infarction (SBI) for stroke recurrence in acute ischemic stroke (AIS) patients with atrial fibrillation (AF) has yet to be elucidated. This study aims to evaluate SBI as an independent predictor and which characteristics of SBI are associated with stroke recurrence in AIS patients with AF.

Methods: A multicenter prospective cohort recruited AIS patients with non-valvular AF from 14 centers from Oct 2017 to Dec 2018, and followed for ischemic stroke recurrence, all types of stroke and TIA, and all-cause mortality. Three patient groups; stroke patients with prior stroke history (PS), first-ever stroke with SBI [F-SBI(+)] and first-ever stroke without SBI [F-SBI(-)] were compared with Cox frailty model according to predetermined covariates. SBI subtypes; embolic-appearing pattern (EAP) and non-EAP, and SBI characteristics; size, numbers, and vascular territory involvements were assessed.

Results: A total of 978 AF-AIS patients [27.5% PS, 29.1% F-SBI(+), 43.4% F-SBI(-)] were followed for 365 [348-374] days (median). Incidence of ischemic stroke recurrence in F-SBI(+) was higher than F-SBI(-), however, there was no significant difference compared to PS (p=0.860). Adjusted hazards for ischemic stroke recurrence and all kinds of stroke and TIA in F-SBI(+) were shown to be elevated [HR 3.87 (95% CI 1.53-9.16) and 2.60 (1.21-5.56)], and similar to PS [4.20 (1.73-10.24) and 2.90 (1.36-6.18)] when compared to F-SBI(-), respectively. Despite irrelevance in non-EAP SBI, a 4-fold increase of hazards in EAP SBI was observed [4.07 (1.63-10.13)]. Other SBI characteristics were not associated with outcomes. SBI and SBI features did not increase all-cause mortality.

Conclusions: SBI and specifically, EAP SBI elevated stroke recurrence in AF-AIS patients as much prior stroke has increased the risk. Considering SBI to predict recurrence is suggested likewise prior stroke history is scored in AF thromboembolic risk estimation tools.

CHA2DS2-VASc score in acute ischemic stroke with atrial fibrillation: results from the Clinical Research Collaboration for Stroke in Korea

We investigated a multicenter registry to identify estimated event rates according to CHA2DS2-VASc scores in patients with acute ischemic stroke (AIS) and atrial fibrillation (AF). The additional effectiveness of antiplatelets (APs) plus oral anticoagulants (OACs) compared with OACs alone considering the CHA2DS2-VASc scores was also explored. This study retrospectively analyzed a multicenter stroke registry between Jan 2011 and Nov 2017, identifying patients with acute ischemic stroke with AF. The primary outcome event was a composite of recurrent stroke, myocardial infarction, and all-cause mortality within 1 year. A total of 7395 patients (age, 73 ± 10 years; men, 54.2%) were analyzed. The primary outcome events at one year ranged from 5.99% (95% CI 3.21–8.77) for a CHA2DS2-VASc score of 0 points to 30.45% (95% CI 24.93–35.97) for 7 or more points. After adjustments for covariates, 1-point increases in the CHA2DS2-VASc score consistently increased the risk of primary outcome events (aHR 1.10 [1.06–1.15]) at 1-year. Among OAC-treated patients at discharge (n = 5500), those treated with OAC + AP (vs. OAC alone) were more likely to experience vascular events, though among patients with a CHA2DS2-VASc score of 5 or higher, the risk of primary outcome in the OAC + AP group was comparable to that in the OAC alone group (P_int = 0.01). Our study found that there were significant associations of increasing CHA2DS2-VASc scores with the increasing risk of vascular events at 1-year in AIS with AF. Further study would be warranted.