Hyperintense Vessels on Magnetic Resonance Imaging Correlate with Arteries in the Delayed Phase of Multiphase Computed Tomography Angiography

Collateral circulation plays an important role in protecting brain tissue from ischemic damage in acute cerebral artery occlusion, and various imaging modalities are used to evaluate collateral circulation. Angiographic imaging techniques, such as digital subtraction angiography and multiphase computed tomography (CT) angiography, directly show cerebral collateral circulation. Meanwhile, hyperintense vessels on f luid-attenuated inversion recovery and T1-weighted black-blood fast spin echo magnetic resonance imaging (MRI) are known to indirectly reflect collateral circulation in cases of cerebral artery occlusion. Herein, we compare hyperintense vessels on MRI with collateral circulation on multiphase CT angiography in a patient with acute ischemic stroke with occlusion of the middle cerebral artery.ope

Clopidogrel preventive effect based on cytochrome P450 2C19 genotype in ischaemic stroke: protocol for multicentre observational study

Introduction: Clopidogrel is an antiplatelet agent that is widely used for the secondary prevention of cardiovascular and cerebrovascular events. The genotype of cytochrome P450 2C19 (CYP2C19) differentially affects the liver's metabolism of clopidogrel, which may influence the drug's response and efficacy for cardiovascular event prevention. In contrast to prior studies of patients with coronary artery diseases, little is known about whether the CYP2C19 genotype influences the preventive efficacy of clopidogrel in patients who had a stroke. We hypothesise that, among patients who had an acute ischaemic stroke who are prescribed clopidogrel, the patients with a loss-of-function CYP2C19 genotype (poor and intermediate metabolisers) may be at a higher risk of composite cardiovascular events than those who are non-carriers (extensive metabolisers). Methods and analysis: This prospective observational multicentre study was designed to determine whether composite cardiovascular events would differ among patients who had an ischaemic stroke prescribed clopidogrel according to CYP2C19 genotype (poor or intermediate vs extensive metabolisers). Inclusion criteria were patients who had an acute ischaemic stroke who underwent CYP2C19 genotype evaluation and received clopidogrel within 72 hours of stroke onset. The primary outcome is composite cardiovascular events (stroke, myocardial infarction, or cardiovascular death) within 6 months after acute ischaemic stroke between patients categorised as poor or intermediate metabolisers and those categorised as extensive metabolisers according to their CYP2C19 genotype. Ethics and dissemination: The Institutional Review Board of Severance Hospital, Yonsei University College of Medicine approved this study (3-2019-0195). We received study approval from the institutional review board of each participating hospital. We plan to disseminate our findings at relevant conferences and meetings and through peer-reviewed journals. Trial registration number: NCT04072705.ope

False Normalization of Ankle Brachial Index: A Case of Lower Extremity Peripheral Arterial Disease with Normal Ankle-Brachial Index

Screening for lower extremity peripheral arterial disease (PAD) is essential in assessing a patient’s risk of cerebrovascular disorders. The ankle-brachial index (ABI) is widely used as a screening tool for PAD, but it can produce falsely normalized results due to factors like artery calcification and collateral vessels. We report a patient with normal ABI but confirmed lower extremity PAD through ultrasound and computed tomography (CT). This case shows the limitation of ABI for PAD diagnosis. Additional tests, such as CT or ultrasound, should be considered when PAD is suspected, even if the ABI is normal.ope

Overestimation of Carotid Artery Stenosis by Carotid Duplex Ultrasonography Due to Contralateral Occlusion

Carotid duplex ultrasonography is a noninvasive and economical method used to diagnose and monitor carotid artery diseases. However, the accuracy of carotid duplex ultrasonography is decreased in the presence of contralateral high-grade stenosis or occlusion. Among the criteria for evaluating the degree of carotid artery stenosis, the Society of Radiologists in Ultrasound consensus criteria are the most widely used owing to their high sensitivity and specificity. Here, we have presented a case in which internal carotid artery (ICA) stenosis was overestimated using the consensus criteria due to the chronic occlusion of the contralateral ICA.ope

Bleeding risk and mortality according to antithrombotic agents' exposure in cancer-related stroke patients: nationwide population-based cohort study in South Korea

Background: Ischemic stroke with active cancer is thought to have a unique mechanism compared to conventional stroke etiologies. There is no gold standard guideline for secondary prevention in patients with cancer-related stroke, hence, adequate type of antithrombotic agent for treatment is controversial. Methods: Subjects who were enrolled in National Health Insurance System Customized Research data during the period between 2010 and 2015 were observed until 2019. Subject diagnosed with ischemic stroke within six months before and 12 months after a cancer diagnosis was defined as cancer-related stroke patient. To solve immeasurable time bias, the drug exposure evaluation was divided into daily units, and each person-day was classified as four groups: antiplatelet, anticoagulant, both types, and unexposed to antithrombotic drugs. To investigate bleeding risk and mortality, Cox proportional hazards regression model with time-dependent covariates were used. Results: Two thousand two hundred eighty-five subjects with cancer-related stroke were followed and analyzed. A group with anticoagulation showed high estimated hazard ratios (HRs) of all bleeding events compared to a group with antiplatelet (major bleeding HR, 1.35; 95% confidence interval [CI], 1.20-1.52; p < 0.001). And the result was also similar in the combination group (major bleeding HR, 1.54; 95% CI, 1.13-2.09; p = 0.006). The combination group also showed increased mortality HR compared to antiplatelet group (HR, 1.72; 95% CI, 1.47-2.00; p < 0.003). Conclusions: Bleeding risk increased in the anticoagulant-exposed group compared to antiplatelet-exposed group in cancer-related stroke patients. Thus, this result should be considered when selecting a secondary prevention drug.ope

Genotype-Phenotype Correlation of the RNF213 R4810K Variant in Moyamoya Disease

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RNF213 R4810K Variant in Suspected Unilateral Moyamoya Disease Predicts Contralateral Progression

Background Early-stage unilateral moyamoya disease (MMD) is difficult to discriminate from isolated intracranial atherosclerotic stenosis, and identification of contralateral progression may aid in the diagnosis of MMD. The RNF213 (ring finger protein 213) R4810K variant is a strong genetic susceptibility factor for MMD; however, the role of contralateral progression in unilateral MMD is unknown. Methods and Results Patients who had undergone RNF213 R4810K genotyping with suspected unilateral MMD between January 2017 and August 2021 from 2 tertiary university hospitals were retrospectively reviewed. We compared the clinical features and radiographic outcomes of patients with and without this variant. The risk factors of contralateral progression in patients with suspected unilateral MMD were evaluated. The RNF213 R4810K variant was observed in 72 of 123 patients with suspected unilateral MMD, all of which were heterozygous. The allele frequency of the R4810K variant was significantly higher in the suspected unilateral MMD group compared with the historical control group (29.3% versus 1.2%; P<0.0001). Family history of MMD was significantly more common in patients with the variant than in those without (17% versus 4%; P=0.003). Eleven of 72 patients with the variant developed contralateral progression, whereas only 1 of 51 patients without the variant developed contralateral progression during a median follow-up period of 28 months (log-rank test; P=0.03). The presence of the RNF213 R4810K variant significantly correlated with contralateral progression (adjusted odds ratio, 6.39 [95% CI, 1.11-36.63]; P=0.04). Conclusions Contralateral progression is more likely to occur in patients with suspected unilateral MMD with the RNF213 R4810K variant than in those without the variant. However, because our study used a small sample size, this finding should be carefully interpreted and requires further studies with more patients and longer follow-up periods.ope

Effects of dabigatran and rivaroxaban on stroke severity according to the results of routine coagulation tests

Introduction: Prior use of direct oral anticoagulants has been associated with reduced stroke severity in patients with non-valvular atrial fibrillation (NVAF). The aim of this study was to investigate the impact of prothrombin time (PT) and activated partial thromboplastin time (aPTT) on stroke severity in patients who were receiving dabigatran or rivaroxaban at the time of stroke onset. Materials and methods: We enrolled 107 patients with NVAF who developed acute ischemic stroke while on dabigatran or rivaroxaban and presented within 24 hours to nine hospitals between January 2014 and December 2018. The results of PT and aPTT assays were obtained within 24 hours of stroke onset in all patients. We analyzed PT and aPTT in relation to stroke severity and ischemic lesion volume using correlation and multivariable regression analyses. Results: Of the 107 patients included, 46 (43.0%) were on dabigatran and 61 (57.0%) were on rivaroxaban. In patients with prior dabigatran use, while aPTT was inversely correlated with admission National Institutes of Health Stroke Scale (NIHSS) score (r = -0.369, p = 0.012) and ischemic lesion volume (r = -0.480, p = 0.005), there was no correlation between PT and either of these variables. Multivariable analysis confirmed the existence of a significant independent inverse relationship between aPTT and NIHSS score at admission (B, -0.201; 95% confidence interval [CI], -0.370 to -0.032; p = 0.005) and between aPTT and ischemic lesion volume (B, -0.076; 95% CI, -0.130 to -0.023; p = 0.007). In patients with prior rivaroxaban use, neither PT nor aPTT was associated with admission NIHSS score or ischemic lesion volume in the correlation and multivariable analyses. Conclusions: In patients with NVAF who were receiving dabigatran, prolonged aPTT was associated with reduced stroke severity.ope

Nonsustained atrial tachycardia in 24-hour Holter monitoring: a potential cardiac source of embolism in acute ischemic stroke

Background: Whether nonsustained atrial tachycardia (NSAT) has a causative role similar to paroxysmal atrial fibrillation (AF) in ischemic stroke is unclear. We investigated the clinical and imaging features of ischemic stroke patients with NSAT to demonstrate that these patients would have a higher proportion of embolic strokes. Methods: We retrospectively reviewed ischemic stroke patients who underwent Holter monitoring and selected patients with NSAT. The clinical and imaging characteristics were compared between patients with and without NSAT, and the risk factors for embolic stroke were evaluated. Moreover, the images of the selected patients were analyzed according to the Trials of Org 10172 in Acute Stroke Treatment classification. Results: From a total of 1,051 patients who had 24-hour Holter monitoring, 681 patients were selected for the study. Among the selected patients, NSAT was detected in 243 patients. The patients with NSAT had a significantly higher proportion of imaging findings suggestive of cerebral embolism compared with patients without NSAT (27% vs. 14%, P<0.001). Moreover, the presence of NSAT was a statistically significant factor associated with imaging findings suggestive of cerebral embolism in the univariate (OR, 2.22; 95% CI, 1.51-3.27; P<0.001) and multivariate (OR, 2.26; 95% CI, 1.53-3.34; P<0.001) analyses. The patients with NSAT had a significantly older age at diagnosis, higher proportion of female sex, higher proportion of hypertension, lower proportion of smokers, higher CHA2DS2-VASc score, and higher left atrium index value compared with patients without NSAT. Conclusions: The embolic pattern of acute ischemic stroke in patients with NSAT was frequently observed and shared clinical characteristics of AF rather than those of atherosclerosis. As NSAT may be a potential source of cardiac embolism, we suggest a more intensive search for modifiable risk factors such as AF in ischemic stroke in patients with NSAT.ope

Mechanism of medullary infarction based on arterial territory involvement

BACKGROUND AND PURPOSE: The blood supply to the medulla oblongata is distinct from that of other areas of the brainstem, and thus the mechanism underlying medullary infarctions may be distinct. However, few studies have investigated this. METHODS: Of 3833 stroke patients who were on the stroke registry between February 1999 and April 2008, those with medullary infarctions demonstrated on diffusion-weighted magnetic resonance imaging were enrolled. We analyzed the topography, the involved arterial territories, and the etiologic mechanisms of the lesions. RESULTS: In total, 142 patients were enrolled in the study. Bilateral medullary infarctions were rare (2.2%). Lesions involving the anteromedial or lateral territories were common in the upper medulla oblongata, whereas lateral territorial involvements were common in the middle and lower regions of the medulla oblongata. Significant stenosis (>50%) or occlusion of the vertebral artery was common (52.2%). Among stroke subtypes, large-artery atherosclerosis was most common (34.5%), while lacunae and cardioembolism were rare (3.5% and 4.2%, respectively). Vertebral artery dissection was frequent. The stroke mechanisms differed with the involved vascular territories. Large-artery atherosclerosis produced lesions in the lateral, anteromedial, and posterior territories. None of the cardioembolisms or other etiologies involved anteromedial or anterolateral territories, but all involved the lateral and/or posterior territories. Lacunar infarction was found only in the anteromedial and anterolateral territories. CONCLUSIONS: The topography and mechanisms of infarctions involving the medulla oblongata are different with the involved arterial territories. These findings may be associated with the distinct pattern of arterial supply to the medulla oblongata.ope