Hyo Suk Nam

Yonsei Stroke Registry

Background and Purpose: The hospital-based stroke registry is a well-established method useful for understanding diverse clinical characteristics of stroke related to geographical, racial or environmental differences. We analyzed the data from 1,000 patients with acute cerebral infarctions registered with the Yonsei Stroke Registry (YSR) which is the first prospective hospital-based observational study in Korea. Methods: All patients had cerebral infarctions and presented within 7 days of onset. CT or MRI was performed in all patients and a vascular imaging study (digital subtraction or magnetic resonance angiography) was conducted in 53.9% of the patients. Subtype classification was made through a consensus approach based on the strict application of TOAST criteria. Results: The mean age of patients was 62 ± 12 years, and 60.8% were males. Undetermined cause (UD) was the most frequent subtype (40.6%), which was followed by lacunar stroke (LS 21.5%), cardiac embolism (CE 18.3%), large-artery atherosclerosis (LAA 16.5%) and other determined causes (3.1%). Hypertension was found in 64.3%, smoking in 35.2%, diabetes mellitus in 26.9%, hypercholesterolemia in 24.1%, high hematocrit (≧50%) in 21.8%, clinically identified potential cardiac sources of embolism in 18.3%, a history of previous stroke in 22.0% and a history of previous transient ischemic attack in 4.7%. Recurrent stroke was associated with a higher number of risk factors (p < 0.001) and a higher incidence of LAA (p = 0.003) than the first stroke. Vertebrobasilar artery territorial infarction was found in 39.8%, which was associated with higher incidences of LAA and LS and a lower incidence of CE than carotid artery territorial lesions (p = 0.001). The 30-day mortality rate was 5.3% and cerebral herniation caused early death in 52%. Conclusion: The distribution of stroke subtypes in the YSR was largely comparable with that of western registries. The highest incidence of UD might be related to the strict application of TOAST criteria.

A randomized trial of mesenchymal stem cells in multiple system atrophy

Neuroprotective or regenerative strategies are invaluable in multiple system atrophy (MSA) due to its rapid progression with fatal prognosis. We evaluated the efficacy of autologous mesenchymal stem cells (MSC) in patients with MSA‐cerebellar type (MSA‐C).

A new subtype classification of ischemic stroke based on treatment and etiologic mechanism.

A new subtype classification of ischemic stroke was developed to reflect recent therapeutic strategies as well as evolving concepts of stroke definitions and mechanisms. In 200 consecutive patients with acute ischemic stroke, the inter-rater reliability and proportion of subtypes of the new classification system were assessed and compared with those of the Trial of ORG 10172 in the Acute Stroke Treatment (TOAST) classification. The most frequent subtype of the new classification was atherothrombosis (n = 80, 40%), followed by stroke of undetermined etiology (n = 54, 27%), small artery disease (n = 33, 16.5%), cardioembolism (n = 26, 13%), and stroke of other determined etiology (n = 7, 3.5%). Three raters agreed to the stroke subtype diagnosis in 165 out of 200 cases and the overall ĸ value was excellent (ĸ = 0.82). The new classification system for brain infarction was easy to use and had high inter-rater reliability.

Stroke awareness decreases prehospital delay after acute ischemic stroke in korea

BackgroundDelayed arrival at hospital is one of the major obstacles in enhancing the rate of thrombolysis therapy in patients with acute ischemic stroke. Our study aimed to investigate factors associated with prehospital delay after acute ischemic stroke in Korea.MethodsA prospective, multicenter study was conducted at 14 tertiary hospitals in Korea from March 2009 to July 2009. We interviewed 500 consecutive patients with acute ischemic stroke who arrived within 48 hours. Univariate and multivariate analyses were performed to evaluate factors influencing prehospital delay.ResultsAmong the 500 patients (median 67 years, 62% men), the median time interval from symptom onset to arrival was 474 minutes (interquartile range, 170-1313). Early arrival within 3 hours of symptom onset was significantly associated with the following factors: high National Institutes of Health Stroke Scale (NIHSS) score, previous stroke, atrial fibrillation, use of ambulance, knowledge about thrombolysis and awareness of the patient/bystander that the initial symptom was a stroke. Multivariable logistic regression analysis indicated that awareness of the patient/bystander that the initial symptom was a stroke (OR 4.438, 95% CI 2.669-7.381), knowledge about thrombolysis (OR 2.002, 95% CI 1.104-3.633) and use of ambulance (OR 1.961, 95% CI 1.176-3.270) were significantly associated with early arrival.ConclusionsIn Korea, stroke awareness not only on the part of patients, but also of bystanders, had a great impact on early arrival at hospital. To increase the rate of thrombolysis therapy and the incidence of favorable outcomes, extensive general public education including how to recognize stroke symptoms would be important.

Improved Time Intervals by Implementation of Computerized Physician Order Entry-Based Stroke Team Approach

Background: The need for rapid evaluation and treatment of acute stroke patients has been well documented. A computerized physician order entry (CPOE) system can improve communication and provide immediate access to information, which may be useful for an effective team approach program targeted to reduce in-hospital time delays. Methods: To reduce the time from a patient’s arrival at the emergency department to thrombolysis, a team approach program using CPOE was developed, and its efficacy was investigated by comparing time intervals from arrival to evaluation and intravenous tissue-type plasminogen activator (tPA) treatment before and after the implementation of the program. Results: Among 379 consecutive patients who were screened as potential candidates for thrombolysis, 25 patients (6.6%) received tPA during a 1-year period after initiation of the program. Fourteen patients were treated with tPA in the previous year. After program implementation, time from arrival to computed tomography scan was reduced from 34 to 19 min (p = 0.01). Time to report of complete blood count was also shortened from 52 to 33 min (p < 0.01). Finally, time from arrival to tPA treatment was reduced by 23 min (from 79 to 56 min; p < 0.01). Onset-to-door time tended to be longer after the program implementation (from 41 to 60 min; p = 0.14). Conclusions: Implementation of the CPOE-based team approach program significantly reduced time from emergency department arrival to evaluations and treatment.

Frequency and Significance of Cardiac Sources of Embolism in the TOAST Classification

Background: This study was aimed at determining the frequency and coexistent patterns of high- and medium-risk cardiac sources of embolism (CSE) as defined by the Trial of ORG 10172 in the Acute Stroke Treatment (TOAST) classification system and at investigating how identified CSE contributed to this classification. Methods: We analyzed data from 2,482 patients with acute cerebral infarctions who registered in the Yonsei Stroke Registry over a 10-year period. Cardiac sources were divided into high- and medium-risk groups based on the TOAST classification. Results: Of the 2,482 patients, 1,130 (46%) underwent echocardiographic studies. At least one CSE was detected in 629 patients (25%). Atrial fibrillation was the most common high-risk CSE. Patent foramen ovale, spontaneous echo contrast and congestive heart failure comprised most of the medium-risk CSE. Atrial fibrillation frequently accompanied coexistent CSE (69%) such as spontaneous echo contrast, congestive heart failure, and left atrial/appendage thrombus, while patent foramen ovale was detected in isolation in more than 90% of the patients. Patients with a high-risk CSE were more likely to be diagnosed with cardioembolism (83%) than patients with only a medium-risk CSE (58%). Conclusions: Our study elucidated the frequency and various coexistent patterns of CSE in Korean stroke patients as defined by the TOAST classification system. In addition, we have demonstrated a higher correlation between high-risk CSE and cardioembolism than with medium-risk CSE and cardioembolism.

Red blood cell distribution width is associated with poor clinical outcome in acute cerebral infarction

Increased red blood cell distribution width (RDW), which is a marker of anisocytosis, is associated with mortality and cardiovascular events in the general population and in patients with heart failure or coronary heart disease. We investigated whether RDW in acute cerebral infarction is predictive of functional outcome and mortality. A total of 847 consecutive patients with first-ever acute cerebral infarction who presented to the emergency department within seven days of symptom onset were enrolled in this study. We investigated the association of RDW with poor functional outcome (modified Rankin Scale >2) and all-cause mortality at three months, as well as survival time for one year after stroke onset. Multivariate logistic regression revealed that higher RDW was independently associated with poor functional outcome (adjusted odds ratio [OR], 1.222 per 1% increment in RDW, 95% confidence interval [CI] 1.059-1.409, p=0.006) and all-cause death (adjusted OR, 1.395 per 1% increment in RDW, 95% CI 1.168-1.665, p<0.001) at three months after stroke onset. RDW was an independent predictor of survival in multivariate Cox-proportional regression model (adjusted hazard ratio, 1.328 per 1% increment in RDW, 95%CI 1.178-1.498, p<0.001). The addition of RDW to a survival model significantly increased predictability for survival across the entire follow-up period (weighted average of the area-under the curves, 0.858 vs. 0.841, p<0.05). In conclusion, higher RDW measured in cases of acute stage cerebral infarction was associated with poor functional outcome and mortality. RDW may be used as a biomarker for the prediction of long-term outcomes in patients with acute cerebral infarction.

Different prognostic value of white blood cell subtypes in patients with acute cerebral infarction

OBJECTIVE We aimed to investigate the relationship of each white blood cells (WBC) subtype with neurologic severity and outcome in acute stroke. METHODS We included 779 patients with first-ever acute cerebral infarction within 72 h after symptom onset. We investigated the association between counts for WBC subtypes in peripheral blood at admission and (1) initial stroke severity; (2) early change in stroke severity within one week; and (3) functional outcome at three months. RESULTS Higher total WBC and neutrophil counts were associated with more severe stroke at admission (p<0.001). In contrast, lower lymphocyte counts were associated with a lesser improvement during the first week after admission (p<0.05) and with poor functional outcome at three months (OR=0.706 per 1000 lymphocyte counts/mm(3), p=0.020). CONCLUSIONS Our study merits further investigation on the role of each WBC subtype in ischemic injury and different prognostic value of WBC subtypes measured at admission in acute stroke.

A Computerized In-Hospital Alert System for Thrombolysis in Acute Stroke

Background and Purpose— An effective stroke code system that can expedite rapid thrombolytic treatment requires effective notification/communication and an organized team approach. We developed a stroke code program based on the computerized physician order entry (CPOE) system and investigated whether implementation of this CPOE-based program is useful for reducing the time from arrival at emergency departments (ED) to evaluation steps and the initiation of thrombolytic treatment in various hospital settings. Methods— The CPOE-based program was implemented by 10 hospitals. Time intervals from arrival at the ED to blood tests, computed tomography scanning, and thrombolytic treatment during the 1-year period before and the 1-year period after the program implementation were compared. Results— Time intervals from ED arrival to evaluation steps were significantly reduced after implementation of the CPOE-based program. Times from ED arrival to CT scan, complete blood counts, and prothrombin time testing were reduced by 7.7 minutes, 5.6 minutes, and 26.8 minutes, respectively (P<0.001). The time from ED arrival to intravenous thrombolysis was reduced from 71.7±33.6 minutes to 56.6±26.9 minutes (P<0.001). The number of patients who were treated with thrombolysis increased from 3.4% (199/5798 patients) before the CPOE-based program to 5.8% (312/5405 patients) afterward (P<0.001). The CPOE implementation also improved the inverse relationship between onset-to-door time and door-to-needle time. Conclusions— The CPOE-based stroke code could be successfully implemented to reduce in-hospital time delay in thrombolytic therapy in various hospital settings. CPOE may be used as an efficient tool to facilitate in-hospital notification/communication and an organized team approach.

Increases in Cerebral Atherosclerosis According to CHADS2 Scores in Patients With Stroke With Nonvalvular Atrial Fibrillation

Background and Purpose— The CHADS2 score is used for risk stratification of ischemic stroke in patients with nonvalvular atrial fibrillation and high CHADS2 scores are associated with increased risk of stroke. Most components of the CHADS2 score are also risk factors for atherosclerosis. Therefore, high CHADS2 scores can be associated with concomitant cerebral atherosclerosis and subsequently atherothrombotic stroke. The aim of this study was to determine whether there are differences in the presence and burden of concomitant cerebral atherosclerosis according to CHADS2 scores in patients with stroke with nonvalvular atrial fibrillation. Methods— We included 780 consecutive patients with nonvalvular atrial fibrillation who had undergone angiographic studies at index stroke between August 1994 and March 2010 in the present study. We investigated the relationships between the CHADS2 score and the presence, severity, and pattern of cerebral atherosclerosis and stroke mechanism. Results— Of the 780 patients, concomitant arterial stenosis (≥50%) was found in 231 patients (29.6%). The number of arteries with atherosclerosis increased as the CHADS2 score increased (P<0.001) as did the proportion of combined extracranial and intracranial atherosclerosis (P<0.001). Multivariate analyses showed that high risk based on the CHADS2 score was an independent predictor of concomitant cerebral atherosclerosis (OR, 3.121; 95% CI, 1.770 to 5.504) and the presence of proximal stenosis at the symptomatic artery (OR, 3.043; 95% CI, 1.458 to 6.350). Conclusions— The CHADS2 score can predict the presence of concomitant cerebral artery atherosclerosis. Increased risk of stroke in patients with high CHADS2 scores may be partly explained by increased frequency and burden of cerebral atherosclerosis.