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.

Patient Selection and Clinical Efficacy of Urgent Superficial Temporal Artery-Middle Cerebral Artery Bypass in Acute Ischemic Stroke Using Advanced Magnetic Resonance Imaging Techniques.

BACKGROUND: Selected patients with acute ischemic stroke might benefit from superficial temporal artery-middle cerebral artery (STA-MCA) bypass, but the indications for urgent STA-MCA bypass are unknown. OBJECTIVE: To report our experiences of urgent STA-MCA bypass in patients requiring urgent reperfusion who were ineligible for other reperfusion therapies, using advanced magnetic resonance imaging (MRI) techniques. METHODS: The inclusion criteria for urgent STA-MCA bypass were as follows: acute infarct volume <70 mL with a ratio of perfusion/diffusion lesion volume ≥1.2, and a regional cerebral blood volume ratio >0.85. From January 2013 to October 2015, 21 urgent STA-MCA bypass surgeries were performed. The control group included 19 patients who did not undergo bypass surgery mainly due to refusal of surgery or the decision of the neurologist. Clinical and radiological data were compared between the surgery and control group. RESULTS: The median age of the control group (70 years, interquartile range [IQR] 58-76) was higher than that of the surgery group (62 years, IQR 49-66), but the median preoperative diffusion and perfusion lesion volumes of the surgery group (13.8 mL, IQR 7.5-26.0 and 120.9 mL, IQR 84.9-176.0, respectively) were higher than those of the control group (5.6 mL, IQR 2.1-9.1 and 69.7 mL, IQR 23.9-125.3, respectively). Sixteen (76.2%) patients in the surgery group and 2 (10.5%) patients in the control group had favorable outcomes ( P < .001). Logistic regression analysis identified bypass surgery as the strongest predictive factor. CONCLUSION: STA-MCA bypass can be used as a therapeutic tool for acute ischemic stroke. Advanced MRI techniques are helpful for selecting patients and for decision making.

High residual platelet reactivity (HRPR) for adenosine diphosphate (ADP) stimuli is a determinant factor for long-term outcomes in acute ischemic stroke with anti-platelet agents: The meaning of HRPR after ADP might be more prominent in large atherosclerotic infarction than other subtypes of AIS.

High residual platelet activation (HRPA) after ADP stimuli has associated with recurrent vascular events in acute atherothrombosis with the use of antiplatelet agents (APAs). However, there has been little evidence supporting this association in acute ischemic stroke (AIS). In this study, we evaluated the influences of HRPR after ADP stimuli on the 1-year incidence of recurrent cardiovascular events and mortality in AIS with APAs. We conducted an observational, referral center cohort study on 968 AIS patients with APAs from January 2010 to December 2013 who were evaluated using optical platelet aggregometry (OPA). All patients received the dual APA combination of aspirin and clopidogrel or aspirin alone. We evaluated their platelet function 5 days after hospital admission using OPA. HRPR after ADP stimuli was defined as platelet aggregation of 70 % or greater according to OPA after 10 µM ADP stimuli. The primary endpoint was a composite of all causes of death, myocardial infarction, and stroke at the 1-year follow-up. The secondary endpoints were each component of the primary endpoint. The event rate of primary endpoint was 11.3 % (109/968). Its rate was significantly higher in the patients with HRPR (16.7 %) than in those without (9.7 %). HPRP was independently associated with the primary endpoint (OR = 1.97, CI 1.22-3.18, p < 0.01). According to the AIS subtype, the presence of HRPR was independently significant for the occurrence of the primary endpoint in the large artery atherosclerosis (LAA) subtype only (OR = 2.26, CI 1.15-4.45, p = 0.02). In this study, the presence of HRPR after ADP stimuli is associated with a poor long-term outcome after acute ischemic stroke. In particular, the influence of this factor might be more prominent in LAA compared with other types of AIS.

Relative CBV ratio on perfusion-weighted MRI indicates the probability of early recanalization after IV t-PA administration for acute ischemic stroke.

BACKGROUND: We hypothesized that the relative cerebral blood volume (rCBV) ratio on perfusion-weighted imaging (PWI) using MRI might serve as a predictor of early recanalization (ER) after intravenous tissue plasminogen activator (IV t-PA) administration for acute ischemic stroke. METHODS: Patients with acute middle cerebral artery (MCA) ischemic stroke (IS) were enrolled in the study. They were evaluated by MRI, including PWI and diffusion-weighted imaging, before administration of IV t-PA and underwent digital subtraction angiography (DSA) of the brain within 2 h after t-PA administration. We compared the rCBV ratio on PWI between patients with and without ER on DSA and investigated the proportion of patients with an excellent outcome at 90 days after t-PA administration (modified Rankin Scale score 0-1) among those with and without ER. RESULTS: 85 patients with acute MCA IS were included; 16 patients (18.8%) experienced ER on DSA after IV t-PA administration. Patients with ER more frequently had an excellent outcome at 90 days than those without ER. The rCBV ratio on PWI was higher in the ER group (1.01±0.21, p<0.01) than in the non-ER group (0.82±0.18). After adjusting for the presence of atrial fibrillation and the serum glucose level, the rCBV ratio on PWI (OR 1.07; 95% CI 1.02 to 1.12; p<0.01) was a significant independent indicator of ER. CONCLUSIONS: The results of this study suggest that the rCBV ratio on PWI might serve as a useful indicator of ER after IV t-PA administration.

Vasospastic Amaurosis Fugax Diagnosed by Cerebral Angiography.

UNLABELLED: We report a case of recurrent monocular blindness presumed to be caused by vasospasm, demonstrated by digital subtraction angiography. CASE REPORT: A 65-year-old man presented with recurrent visual loss in the left eye for 2 years. He had histories of hypertension, cigarette smoking, and May-Thurner syndrome. The symptom occurred variably from twice a day to once a week and usually lasted for 5 minutes. Brain magnetic resonance imaging, magnetic resonance angiography, and ophthalmologic evaluation did not reveal any abnormality. Cerebral digital subtraction angiography was performed. On the left internal carotid angiogram, vasospasm occurred in the cervical portion of the left internal carotid artery and, subsequently, the blood flow to the left ophthalmic artery diminished. This phenomenon was reproducible and, in the absence of vasospasm, the ophthalmic artery was well visualized with no steno-occlusive lesion. Examination of the carotid duplex showed diffuse luminal narrowing and increased flow velocities in the left cervical internal carotid artery without atherosclerotic plaque. Treatment was started with nimodipine, which markedly reduced the attacks. CONCLUSION: We assumed that vasomotor instability, which made the vessels vulnerable to spasm, may have caused a recurrent ocular symptom in our patient.

New brain infarcts on magnetic resonance imaging after coronary artery bypass graft surgery: lesion patterns, mechanism, and predictors.

OBJECTIVE: New brain infarcts after coronary artery bypass graft (CABG) are markedly more frequent than clinically evident stroke and have been proposed as a surrogate marker of postprocedural stroke. We sought to investigate the lesion patterns, mechanisms, and predictors of new brain infarction after CABG surgery. METHODS: This was a prospective pre- and postoperative brain magnetic resonance imaging (MRI) study in consecutive patients who underwent isolated CABG. Preoperative MRI included diffusion-weighted imaging (DWI) and magnetic resonance angiography. DWI was repeated on postoperative day 3. Clinical variables, intraoperative findings, and laboratory findings were compared between patients with and without new brain infarcts on DWI. RESULTS: Of a total of 127 included patients, 35 (27.6%) showed new brain infarcts on DWI. Most lesions were clinically silent, located in the cortical territory (80%), small (<1.5cm) in diameter (89%), and not related to the underlying cerebral arterial abnormality (80%). Old age (odds ratio [OR] = 1.09, 95% confidence interval [CI] = 1.03-1.15), use of cardiopulmonary bypass (OR = 3.12, 95% CI = 1.13-8.57), a moderate to severe aortic plaque (OR = 21.17, 95% CI = 2.01-222.58), and high levels of high-sensitivity C-reactive protein (OR = 1.35, 95% CI = 1.08-1.70) were independent predictors of new brain infarction. INTERPRETATION: Post-CABG new brain infarcts are mostly silent and cortically located. Old age, aortic arch atherosclerosis, use of cardiopulmonary bypass, and systemic inflammatory response may contribute to the pathogenesis of post-CABG new brain infarcts.

Ischemic stroke in patients with cancer: is it different from usual strokes?

BACKGROUND: It remains unclear whether the characteristics of ischemic stroke in patients with cancer (ISC) differ from usual ischemic strokes (non-ISC). Although a small number of studies have been conducted to characterize ISC, the status of cancer has rarely been considered seriously. AIMS: We aimed to investigate the features of ISC according to the status of cancer, and compare their characteristics with those of non-ISC. METHODS: We assessed and classified 204 ISC patients into two groups: 104 with active (ISC-active) and 100 with inactive (ISC-inactive) cancer. For each ISC patient, two age- and gender-matched ischemic stroke patients without history of cancer were selected as non-ISC control subjects. We compared the clinical/laboratory data, stroke mechanisms, and diffusion weighted imaging (DWI) lesion patterns between ISC-active and non-ISC patients, and between ISC-inactive and non-ISC patients. RESULTS: ISC-active patients demonstrated higher C-reactive protein (CRP) and D-dimer, more frequent cryptogenic stroke and patterns of multiple DWI lesions (in bilateral anterior or in anterior and posterior circulations), and less prevalent conventional risk factors than non-ISC patients, while ISC-inactive patients revealed no such marked differences. Among ISC-active patients, both elevated CRP and D-dimer levels were associated with cryptogenic mechanism and multiple lesion patterns. Furthermore, ISC-active patients with cryptogenic strokes tended to have multiple lesion patterns and metastasis. CONCLUSIONS: ISC-active, but not ISC-inactive, is distinct in terms of risk factors, stroke mechanisms, and lesion patterns. Chronic inflammation and an activated coagulation system may contribute to the pathogenic mechanism of strokes, the extent of each depending on the activity and severity of cancer.

Biomarkers and location of atherosclerosis: matrix metalloproteinase-2 may be related to intracranial atherosclerosis.

BACKGROUND: Various biomarkers are linked with the pathophysiology of atherosclerosis. We hypothesized that these factors may be associated with the location and burden of cerebral atherosclerosis. METHODS: We evaluated 177 consecutive patients with chronic (>6 months) ischemic stroke: 68 with small vessel occlusion (SVO) and 109 with large-artery atherosclerosis (LAA), with the latter further sub-classified into 80 patients with intracranial atherosclerosis (ICAS) and 29 with extracranial atherosclerosis (ECAS). The number of ≥50% steno-occlusions on magnetic resonance angiography was used to assess the burden of atherosclerosis. Serum concentrations of the biomarkers (matrix metalloproteinases (MMP)-2 and -9, homocysteine, interleukin (IL)-6, tumor necrosis factor-α, C-reactive protein, adiponectin, leptin, resistin, free fatty acid, and lipoprotein(a)) and the metabolic syndrome were measured in each study subject. RESULTS: Decreased plasma concentrations of MMP-2 (p = 0.020) and homocysteine (p = 0.038) were more closely associated with ICAS than with ECAS, whereas increased IL-6 concentrations were related to severe (≥4 steno-occlusions) atherosclerosis (p = 0.031). Multiple logistic regression analysis showed that the lowest tertile of MMP-2 was independently associated with ICAS (OR 4.84, 95% CI 1.29-18.19, p = 0.022). CONCLUSION: Low MMP-2 plasma levels are associated with intracranial location of cerebral atherosclerosis, suggesting that MMP-2 may play a role in the development of ICAS.

New cerebral lesions on T2*-weighted gradient-echo imaging after cardiac valve surgery.

BACKGROUND: It is well known that silent ischemic brain lesions on diffusion-weighted imaging (DWI) commonly occur after various interventional procedures or surgeries. However, to our knowledge, postoperative new lesions on T2*-weighted gradient-echo imaging (GRE) have never been explored. METHODS: This prospective observational study enrolled 19 consecutive patients undergoing cardiac valve surgery. Preoperative and postoperative (within 7 days) GRE and DWI were performed. New GRE lesions were defined as signal loss lesions on postoperative GRE which were not observed on preoperative GRE. Long-term follow-up GRE was performed in a limited number of cases. RESULTS: Twelve patients developed 26 small (<10 mm) new GRE lesions. Of these patients, 1 had a generalized seizure accompanied by confusion and facial weakness with DWI lesions, and 1 showed confusion of short duration without DWI lesions. Long-term follow-up GRE was performed 3 years after surgery in 4 patients. Of the 12 new GRE lesions in these 4 patients, 11 lesions were still observable on long-term follow-up GRE. CONCLUSIONS: New cerebral lesions on GRE after cardiac valve surgery are common and are presumed to be rapidly developed microbleeds and mostly asymptomatic. Further studies are needed to investigate the precise nature and clinical implications of new GRE lesions.