Yo Han Jung

Long‐term efficacy and tolerability of topiramate as add‐on therapy in refractory partial epilepsy: An observational study

Purpose:  To evaluate the long‐term efficacy and tolerability of topiramate (TPM) as add‐on therapy in patients with refractory partial epilepsy.

Safety and outcome after thrombolytic treatment in ischemic stroke patients with high-risk cardioembolic sources and prior subtherapeutic warfarin use

BACKGROUND Hemorrhage is a major complication of thrombolytic treatment. Concerns have been raised about the risk of hemorrhage in patients having received warfarin. Therefore, different indications for thrombolytic treatment are in use for stroke patients on warfarin. However, it remains uncertain whether the prior warfarin use actually increases their risk of bleeding in patients treated with thrombolysis. METHODS This study included 179 consecutive patients who had high-risk cardioembolic sources and received thrombolytic treatment. Patients were treated with intravenous thrombolytic agents, or underwent intraarterial thrombolysis if their international normalized ratio (INR) was ≤1.7. We compared the frequency of bleeding complications between patients with prior warfarin use and those without. We also investigated whether there were differences in functional outcome and recanalization rates between them. RESULTS A prior warfarin use was present in 28 patients (15.6%). Although INR levels were higher in the prior warfarin group, the frequency of bleeding complications was not different between patients who received prior warfarin and those who did not. No differences were observed in patients with or without prior warfarin use, for successful recanalization rate (Thrombolysis in Myocardial Infarction grade 2 or 3), mortality, or modified Rankin score (≤2) at 3months. CONCLUSIONS Thrombolytic therapy for patients who previously received warfarin and had an INR≤1.7 did not affect bleeding risk, clinical outcome, or recanalization rate. Our data suggest that patients with a history of prior warfarin use may be safely treated with thrombolytic agents when their INR levels are low.

Classic risk factors for atherosclerosis are not major determinants for location of extracranial or intracranial cerebral atherosclerosis.

Background: The prevalence of extracranial (EC) and intracranial (IC) atherosclerosis varies among races. Although several studies have sought to identify specific vascular risk factors that are associated with EC or IC atherosclerosis, the exact relationships are uncertain. This study aimed to determine if there are any specific risk factors for EC or IC atherosclerosis. Methods: For this study, we considered 3,349 consecutive patients who had been entered into a stroke registry between January 1999 and June 2007. After the exclusion of patients who had not undergone angiography, patients with cardiac sources of embolism or other causes of stroke, and non-Koreans, we had a total of 2,169 patients of single ethnicity with an angiographic analysis. Patients with atherosclerosis in both the IC and EC arteries (856 patients) were excluded. Finally, we identified 1,313 patients who had EC atherosclerosis (EC group, n = 256), IC atherosclerosis (IC group, n = 566) or normal angiographic findings (no-lesion group, n = 488). The frequency of risk factors and the demographic parameters were compared among these groups. Results: When compared to the normal group, the IC group was associated with older age and hypertension, and the EC group was associated with older age, higher initial blood sugar and low-density lipoprotein cholesterol levels. However, in a direct comparison between the IC and EC groups, we did not observe any significant risk factors or variables except for a higher frequency of males and higher total cholesterol levels in the EC group. Conclusions: Vascular risk factors may not be major determinants of location for atherosclerosis in the EC or IC arteries.

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.

Traditional Risk Factors for Stroke in East Asia

Stroke is one of the leading causes of death and morbidity worldwide. The occurrence of stroke is strongly dependent on well-known vascular risk factors. After rapid modernization, urbanization, and mechanization, East Asian countries have experienced growth in their aged populations, as well as changes in lifestyle and diet. This phenomenon has increased the prevalence of vascular risk factors among Asian populations, which are susceptible to developing cardiovascular risk factors. However, differing patterns of stroke risk factor profiles have been noted in East Asian countries over the past decades. Even though the prevalence of vascular risk factors has changed, hypertension is still prevalent and the burden of diabetes and hypercholesterolemia will continue to increase. Asia remains a high tobacco-consuming area. Although indicators of awareness and management of vascular risk factors have increased in many East Asian countries, their rates still remain low. Here we review the burdens of traditional risk factors, such as hypertension, diabetes, hypercholesterolemia, and smoking in East Asia. We will also discuss the different associations between these vascular risk factors and stroke in Asian and non-Asian populations.

Process Improvement to Enhance Existing Stroke Team Activity Toward More Timely Thrombolytic Treatment

Background and Purpose Process improvement (PI) is an approach for enhancing the existing quality improvement process by making changes while keeping the existing process. We have shown that implementation of a stroke code program using a computerized physician order entry system is effective in reducing the in-hospital time delay to thrombolysis in acute stroke patients. We investigated whether implementation of this PI could further reduce the time delays by continuous improvement of the existing process. Methods After determining a key indicator [time interval from emergency department (ED) arrival to intravenous (IV) thrombolysis] and conducting data analysis, the target time from ED arrival to IV thrombolysis in acute stroke patients was set at 40 min. The key indicator was monitored continuously at a weekly stroke conference. The possible reasons for the delay were determined in cases for which IV thrombolysis was not administered within the target time and, where possible, the problems were corrected. The time intervals from ED arrival to the various evaluation steps and treatment before and after implementation of the PI were compared. Results The median time interval from ED arrival to IV thrombolysis in acute stroke patients was significantly reduced after implementation of the PI (from 63.5 to 45 min, p=0.001). The variation in the time interval was also reduced. A reduction in the evaluation time intervals was achieved after the PI [from 23 to 17 min for computed tomography scanning (p=0.003) and from 35 to 29 min for complete blood counts (p=0.006)]. Conclusions PI is effective for continuous improvement of the existing process by reducing the time delays between ED arrival and IV thrombolysis in acute stroke patients.

Factors Associated with Ischemic Stroke on Therapeutic Anticoagulation in Patients with Nonvalvular Atrial Fibrillation

Purpose In this study, we investigated the stroke mechanism and the factors associated with ischemic stroke in patients with nonvalvular atrial fibrillation (NVAF) who were on optimal oral anticoagulation with warfarin. Materials and Methods This was a multicenter case-control study. The cases were consecutive patients with NVAF who developed cerebral infarction or transient ischemic attack (TIA) while on warfarin therapy with an international normalized ratio (INR) ≥2 between January 2007 and December 2011. The controls were patients with NVAF without ischemic stroke who were on warfarin therapy for more than 1 year with a mean INR ≥2 during the same time period. We also determined etiologic mechanisms of stroke in cases. Results Among 3569 consecutive patients with cerebral infarction or TIA who had NVAF, 55 (1.5%) patients had INR ≥2 at admission. The most common stroke mechanism was cardioembolism (76.0%). Multivariate analysis demonstrated that smoking and history of previous ischemic stroke were independently associated with cases. High CHADS2 score (≥3) or CHA2DS2-VASc score (≥5), in particular, with previous ischemic stroke along with ≥1 point of other components of CHADS2 score or ≥3 points of other components of CHA2DS2-VASc score was a significant predictor for development of ischemic stroke. Conclusion NVAF patients with high CHADS2/CHA2DS2-VASc scores and a previous ischemic stroke or smoking history are at high risk of stroke despite optimal warfarin treatment. Some other measures to reduce the risk of stroke would be necessary in those specific groups of patients.

Cortex-sparing infarctions in patients with occlusion of the middle cerebral artery

Background In patients with a middle cerebral artery (MCA) occlusion, the involvement of the cortex may be affected by the presence of leptomeningeal anastomoses between the cerebral arteries. Methods The authors enrolled consecutive patients with acute infarctions in the MCA territory and MCA occlusion on angiographic studies. Infarct patterns were classified into three categories based on the extent of cortical surface involvement: total cortex (TC), partial cortex (PC) and no cortex (NC). The authors analysed the infarction patterns by stroke subtype, and investigated factors that resulted in cortex sparing. Results Out of 73 total patients, cortex-sparing infarctions were seen in 53 patients (72.6%, NC in 39 (53.5%) and PC in 14 (19.1%)). The extent of cortical involvement differed according to stroke subtype (p=0.036). TC was more frequent (42.9% vs 22.2%), and PC was less frequent (10.7% vs 27.9%, p=0.037) in cardioembolism than large-artery atherosclerosis. However, the proportion of patients with complete cortical sparing (NC) was similar between cardioembolism and large-artery atherosclerosis (46.4% vs 49.9%). In the upstream of leptomeningeal collateral arteries, the extent of cortical involvement was associated with significant stenosis of the ipsilateral anterior or posterior cerebral artery (p=0.011). Conclusion This study suggests that pre-existing arteriolar connections, which may cover almost entire cortical surfaces of the MCA territory, exist in many patients. The findings also suggest that the extent of cortical involvement is different between stroke subtypes, and is critically affected by the status of upstream collateral arteries.

The Ischemic Stroke Predictive Risk Score Predicts Early Neurological Deterioration

BACKGROUND Although early neurological deterioration (END) during the acute stroke period is known to be directly associated with poor short- and long-term outcomes, few studies have investigated the ability to predict END. The aim of this study was to investigate whether there are differences in the occurrence of END according to the ischemic stroke predictive risk score (iScore), which was developed to predict short- and long-term mortality. METHODS We collected data from 2150 consecutive ischemic stroke patients who were admitted to 3 study hospitals between January 2012 and June 2014. END was defined as an increase (≥4) in the National Institutes of Health Stroke Scale score within the first 72 hours of stroke onset. We calculated the 30-day iScore for each patient to determine the relationship between the iScore and occurrence of END. RESULTS Among 2150 patients, END was observed in 146 patients (6.8%). There was a positive correlation between the iScore and occurrence of END. After adjusting for potential confounders, the iScore was independently associated with END (odds ratio: 1.217 per 20-point increase in iScore, 95% confidence interval: 1.121-1.321, P < .001). There was good correlation between observed and expected outcomes predicted by the iScore (Pearson correlation coefficient: r = .950, P < .001). CONCLUSIONS The iScore can predict the risk of END development within the acute stroke stage.

Beneficial Effects of Stroke-Unit Care in Stroke Patients with Atrial Fibrillation

Purpose Continuous cardiac monitoring in a stroke unit (SU) may improve detection of atrial fibrillation (AF), and SU care may improve the rate of anticoagulation by better adherence to a standardized treatment protocol in patients with AF. We investigated the effects of the SU on the detection of AF and the rate of warfarin therapy in patients with AF. Materials and Methods Acute stroke patients who had been admitted before or after the opening of the SU were included in our study. SU patients were monitored continuously with electrocardiography. Rates of AF and warfarin therapy were compared between patients admitted to the SU (SU group) and those admitted to the general ward (GW) prior to the opening of the SU (GW group). Results Total 951 patients had been admitted to the GW prior to the opening of the SU (from January 2000 to November 2002), and 2349 patients to the SU (from January 2003 to December 2008). AF was found in 149 patients (15.7%) in the GW group and in 487 (20.7%) in the SU group. Most of AF detected during admission was paroxysmal AF (84.8%). The frequency of newly detected AF was higher in the SU group than the GW group (2.5% vs. 0.7%, p=0.001). The rate of anticoagulation consideration was also higher in the SU group. Conclusion SU care improved the detection of AF and the rate of anticoagulation consideration in acute stroke patients. Our findings support the benefits of continuous cardiac monitoring in the SU for stroke patients.