Contemporary Statistics of Acute Ischemic Stroke and Transient Ischemic Attack in 2021: Insights From the CRCS-K-NIH Registry.

This report presents the latest statistics on the stroke population in South Korea, sourced from the Clinical Research Collaborations for Stroke in Korea-National Institute for Health (CRCS-K-NIH), a comprehensive, nationwide, multicenter stroke registry. The Korean cohort, unlike western populations, shows a male-to-female ratio of 1.5, attributed to lower risk factors in Korean women. The average ages for men and women are 67 and 73 years, respectively. Hypertension is the most common risk factor (67%), consistent with global trends, but there is a higher prevalence of diabetes (35%) and smoking (21%). The prevalence of atrial fibrillation (19%) is lower than in western populations, suggesting effective prevention strategies in the general population. A high incidence of large artery atherosclerosis (38%) is observed, likely due to prevalent intracranial arterial disease in East Asians and advanced imaging techniques. There has been a decrease in intravenous thrombolysis rates, from 12% in 2017-2019 to 10% in 2021, with no improvements in door-to-needle and door-to-puncture times, worsened by the coronavirus disease 2019 pandemic. While the use of aspirin plus clopidogrel for non-cardioembolic stroke and direct oral anticoagulants for atrial fibrillation is well-established, the application of direct oral anticoagulants for non-atrial fibrillation cardioembolic strokes in the acute phase requires further research. The incidence of early neurological deterioration (13%) and the cumulative incidence of recurrent stroke at 3 months (3%) align with global figures. Favorable outcomes at 3 months (63%) are comparable internationally, yet the lack of improvement in dependency at 3 months highlights the need for advancements in acute stroke care.

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

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

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.

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.

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

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

Executive Summary of Stroke Statistics in Korea 2018: A Report from the Epidemiology Research Council of the Korean Stroke Society.

Despite the great socioeconomic burden of stroke, there have been few reports of stroke statistics in Korea. In this scenario, the Epidemiologic Research Council of the Korean Stroke Society launched the "Stroke Statistics in Korea" project, aimed at writing a contemporary, comprehensive, and representative report on stroke epidemiology in Korea. This report contains general statistics of stroke, prevalence of behavioral and vascular risk factors, stroke characteristics, pre-hospital system of care, hospital management, quality of stroke care, and outcomes. In this report, we analyzed the most up-to-date and nationally representative databases, rather than performing a systematic review of existing evidence. In summary, one in 40 adults are patients with stroke and 232 subjects per 100,000 experience a stroke event every year. Among the 100 patients with stroke in 2014, 76 had ischemic stroke, 15 had intracerebral hemorrhage, and nine had subarachnoid hemorrhage. Stroke mortality is gradually declining, but it remains as high as 30 deaths per 100,000 individuals, with regional disparities. As for stroke risk factors, the prevalence of smoking is decreasing in men but not in women, and the prevalence of alcohol drinking is increasing in women but not in men. Population-attributable risk factors vary with age. Smoking plays a role in young-aged individuals, hypertension and diabetes in middle-aged individuals, and atrial fibrillation in the elderly. About four out of 10 hospitalized patients with stroke are visiting an emergency room within 3 hours of symptom onset, and only half use an ambulance. Regarding acute management, the proportion of patients with ischemic stroke receiving intravenous thrombolysis and endovascular treatment was 10.7% and 3.6%, respectively. Decompressive surgery was performed in 1.4% of patients with ischemic stroke and in 28.1% of those with intracerebral hemorrhage. The cumulative incidence of bleeding and fracture at 1 year after stroke was 8.9% and 4.7%, respectively. The direct costs of stroke were about ₩1.68 trillion (KRW), of which ₩1.11 trillion were for ischemic stroke and ₩540 billion for hemorrhagic stroke. The great burden of stroke in Korea can be reduced through more concentrated efforts to control major attributable risk factors for age and sex, reorganize emergency medical service systems to give patients with stroke more opportunities for reperfusion therapy, disseminate stroke unit care, and reduce regional disparities. We hope that this report can contribute to achieving these tasks.

Distinct intrathecal interleukin-17/interleukin-6 activation in anti-N-methyl-d-aspartate receptor encephalitis.

The aim of this study was to compare serum and cerebrospinal fluid (CSF) cytokine/chemokine levels between anti-NMDAR and anti-LGI1 encephalitis patients. Samples from fourteen anti-NMDAR encephalitis patients, ten anti-LGI1 encephalitis patients, and ten controls were analyzed for the following cytokines/chemokines: IL-1b, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IL-13, IL-17A, IL-23, GM-CSF, IFN-gamma, TNF-alpha, and CXCL13. Compared with controls, CSF IL-17A, IL-6 and CXCL13 were elevated in anti-NMDAR encephalitis patients (post-hoc p-values 0.002, 0.011, and 0.011, respectively) but not in anti-LGI1 encephalitis patients. In the serum, only IL-2 was increased in anti-NMDAR encephalitis. Intrathecal IL-17/IL-6 activation is a characteristic of anti-NMDAR encephalitis.

Rituximab treatment for autoimmune limbic encephalitis in an institutional cohort.

OBJECTIVE: To determine efficacy and safety of rituximab treatment as a second-line immunotherapy treatment for autoimmune limbic encephalitis (ALE) and to determine factors associated with functional improvement and favorable outcome following rituximab treatment. METHODS: We recruited 80 patients with ALE who were treated with rituximab as a second-line immunotherapy from the Korea Autoimmune Synaptic and Paraneoplastic Encephalitis Registry and reviewed 81 patients without rituximab as a control. We grouped patients according to the detection or type of antibodies; in addition, we evaluated clinical, laboratory, first-line immunotherapy, and rituximab treatment profiles and defined main outcomes as improvements on the modified Rankin Scale (mRS) score and a favorable mRS score (0-2) at the last follow-up. RESULTS: Functional improvement occurred more frequently in the rituximab group compared to the control group. In the rituximab group, 30 (37.5%) patients had synaptic autoantibodies, 15 (18.8%) in the paraneoplastic autoantibodies, and 35 (43.8%) were antibody-negative. The effect of rituximab was the same regardless of autoantibody status. Additional monthly rituximab therapy and partial response to first-line immunotherapies were associated with mRS score improvements, as well as favorable mRS scores. mRS scores of 4-6 as the worst neurologic status predicted an unfavorable mRS score. There were no reported serious infusion-related or infectious adverse effects of rituximab. CONCLUSIONS: Rituximab is effective and safe as a second-line immunotherapy for ALE, regardless of autoantibody status. Additional monthly rituximab therapy might potentiate the efficacy of rituximab. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that rituximab improves mRS scores for patients with autoimmune limbic encephalitis who fail first-line therapy.

Cardiac sympathetic dysfunction in anti-NMDA receptor encephalitis.

Patients with anti-NMDA receptor (anti-NMDAR) encephalitis frequently suffer from autonomic dysfunctions, which can cause substantial morbidity. This study assessed cardiac autonomic functions in patients with anti-NMDAR encephalitis using heart rate variability (HRV) analysis. This was a retrospective single-center case-control study. Eleven patients with anti-NMDAR encephalitis and 15 age- and sex-matched controls were included in this study. To ensure that autonomic dysfunction does not occur in any encephalitis, we additionally analyzed HRV of 9 patients with herpes encephalitis (HSE) and compared with that of NMDAR encephalitis patients and controls. Five minute resting stationary electrocardiogram was collected from each subject, and HRV was analyzed. Total power and low frequency (LF) power were lower in anti-NMDAR encephalitis patients than those in controls (p=0.005, 0.001 respectively), indicating cardiac autonomic dysfunction especially in sympathetic system. Patients with HSE showed no significant difference in HRV parameters compared with that of controls. Cardiac autonomic dysfunction was associated with 3 month functional outcome in anti-NMDAR encephalitis patients.

Non-stiff anti-amphiphysin syndrome: clinical manifestations and outcome after immunotherapy.

Amphiphysin antibody causes paraneoplastic stiff-person syndrome and can also result in a variety of neurological manifestations. Here, we investigated the clinical spectrum of 20 patients with non-stiff anti-amphiphysin syndrome and their responses to immunotherapy. The most common neurological manifestation was limbic encephalitis (n=10), followed by dysautonomia (n=9), and cerebellar dysfunction (n=6). Cancer was detected in only seven patients. Intravenous immunoglobulin or steroid treatment was effective in most patients, but three improved only after rituximab treatment. Our study suggests that anti-amphiphysin syndrome can manifest as non-stiff encephalomyelitis and is only partially associated with cancer. Active immunotherapy, including rituximab, would be beneficial.

Anti-N-methyl-d-aspartate receptor encephalitis in Korea: clinical features, treatment, and outcome.

BACKGROUND AND PURPOSE: Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is the most common type of autoimmune synaptic encephalitis and it often responds to treatment. We analyzed the clinical characteristics of anti-NMDAR encephalitis in Korea. METHODS: Serum and/or cerebrospinal fluid (CSF) of adult patients (aged ≥18 years) with encephalitis of undetermined cause were screened for anti-NMDAR antibodies using a cell-based indirect immunofluorescence assay. The patients came from 41 university hospitals. RESULTS: Of the 721 patients screened, 40 were identified with anti-NMDAR antibodies and clinical details of 32 patients were obtained (median age, 41.5 years; 15 females). Twenty-two patients (68.8%) presented with psychiatric symptoms, 16 (50%) with seizures, 13 (40.6%) with movement disorders, 15 (46.9%) with dysautonomia, 11 (34.4%) with memory disturbance, and 11 (34.4%) with speech disturbance. Magnetic resonance imaging, electroencephalography, and CSF examinations yielded nonspecific findings. Tumor information was only available for 22 patients: 5 patients had tumors, and 2 of these patients had ovarian teratomas. Twenty-two patients received immunotherapy and/or surgery, and therapeutic responses were analyzed in 21 patients, of which 14 (66.7%) achieved favorable functional outcomes (score on the modified Rankin Scale of 0-2). CONCLUSIONS: This study investigated the clinical characteristics of adult anti-NMDAR encephalitis in Korea. Currently, elderly patients who do not have tumors are commonly diagnosed with this condition. Understanding the detailed clinical characteristics of this disease will improve the early detection of anti-NMDAR encephalitis in patients both young and old.

Clinical manifestations and outcomes of the treatment of patients with GABAB encephalitis.

Encephalitis associated with anti-γ-aminobutyric acid-B (GABAB) receptor antibodies has been identified recently. However, only a few cases have been reported to date and its clinical manifestations and prognosis have not been investigated systematically. We identified five cases of GABAB encephalitis in Korea. Here we present the clinical features, treatment responses, and brain positron emission tomography findings of the cases. The patients had a clinical triad of memory changes, seizure, and association with small-cell lung cancer. Early diagnosis and comprehensive immune modulation may provide a good outcome.

VGKC-complex/LGI1-antibody encephalitis: clinical manifestations and response to immunotherapy.

Leucine-rich glioma inactivated 1 (LGI1) was recently identified as a target protein in autoimmune synaptic encephalitis, a rare condition associated with autoantibodies against structures in the neuronal synapse. Studies dealing with LGI1 are small in number and the various outcomes of different therapeutic regimens are not well studied. Here, we analyzed clinical characteristics of 14 patients with LGI1 antibodies, and outcomes according to therapeutic strategies. Most patients exhibited abnormal brain positron emission tomography and that patients treated with steroids alone were more likely to relapse and had less favorable outcomes than those treated with steroids and intravenous immunoglobulins.