Moo-Young Ahn

Gender differences in the functional recovery after acute stroke.

Background and Purpose PurposezzInterest in gender differences in the effects of acute stroke is growing worldwide. However, gender differences in functional recovery after acute stroke in the Korean population have yet to be evaluated. The aim of this investigation was to compare long-term functional outcomes between male and female after acute stroke. Methods Patients with acute stroke were enrolled prospectively between January 2005 and January 2009. Baseline characteristics, risk factors, stroke subtypes, time delay from onset to arrival at a hospital, active treatment, and stroke severity were compared between male and female. Differences in mortality and disability at discharge, and at 3 months and 1 year after stroke onset were also investigated. Functional disabilities were categorized into two groups: good outcome (score on modified Rankin scale ≤2) and poor outcome (score on modified Rankin scale >2). Results Among 1,055 patients with acute stroke, 575 were male (aged 64.83±11.98 years, mean±SD) and 480 were female (aged 70.09±13.02 years). There were no gender differences in mortality at 3 months and 1 year after stroke. The frequency of poor outcomes was higher in female patients than in male patients at discharge (39.8% versus 30.9%, respectively; p=0.003), the 3 months follow-up (32.3% versus 20.8%, respectively; p<0.001), and the 1 year follow-up (31.1% versus 18.7%, respectively; p=0.001). After adjusting for multiple confounding factors including age and stroke severity, the female gender persisted as a predictor of poor functional outcome at 3 months and 1 year after stroke. Conclusions Female patients have greater difficulty than male patients in recovering from a disabled state after acute stroke. Future studies should investigate the causes of this gender difference.

Low Glomerular Filtration Rate Increases Hemorrhagic Transformation in Acute Ischemic Stroke

Background: Decreased glomerular filtration rate (GFR) can increase the risk of bleeding tendency and hemorrhagic stroke. However, the relationship between the levels of GFR and hemorrhagic transformation (HT) after acute ischemic stroke is largely unknown. The aim of this study was to assess whether GFR level is associated with HT in acute ischemic stroke. Methods: We reviewed 770 consecutive patients with acute ischemic stroke within 7 days from September 2007 to February 2012 in a prospective stroke registry database. We calculated the patient’s GFR using the Cockcroft-Gault equation, and divided them into 3 groups: ≥60, 30–59 and <30 ml/min/1.73 m2. HTs were identified by follow-up computed tomography (CT) or magnetic resonance imaging, and were defined as (1) any degree of high density within the area of low attenuation of vascular territory on noncontrast brain CT, or (2) low-signal intensity area in gradient echo within high-signal intensity meaning acute infarct on diffusion-weighted imaging. Multivariable logistic regression analyses were used to estimate the risk of GFR for HT. Stratification analyses were done according to the presence of HT high risk factors: atrial fibrillation (AF), thrombolysis and large size infarction. Additional logistic regression model for symptomatic HTs was established with the same variables. Results: HTs were noted in 131 patients (17.0%) and symptomatic HTs in 63 patients (8.2%). In univariate analysis, HTs were more frequent in patients with AF (51.9 vs. 16.7%, p < 0.001) and large-size infarction (42.0 vs. 5.3%, p < 0.001). The risk of HT was associated with decreased GFR among 3 subgroups classified according to the value of estimated GFR: 49/394 (12.4%) in the GFR ≥60 group, 66/312 (21.2%) in the 30≤ GFR <59 group and 16/64 (25.0%) in the GFR <30 group (p = 0.002). We found a significant association between the GFR <30 group and HTs in acute ischemic stroke (OR 2.90; 95% CI 1.26–6.68, p = 0.012) after adjusting for other risk factors. Moreover, the incidence of HTs was higher in the subgroups without thrombolysis (OR 3.49; 95% CI 1.44–8.46) and without AF (OR 3.44; 95% CI 1.10–10.76). Decreased GFR also had a tendency of increasing symptomatic HTs (OR 2.39; 95% CI 0.72–7.94, p = 0.154). Conclusions: Low levels of GFR are associated with a high risk of HT after acute ischemic stroke. Further studies are needed to elucidate whether HT in the patients with renal insufficiency are related to a worse outcome after acute ischemic stroke.

Associations of cigarette smoking with intracranial atherosclerosis in the patients with acute ischemic stroke

BACKGROUND Although cigarette smoking has been established as an important risk factor for stroke, the effect on the atherosclerotic stenosis, which are based on observational studies, have been controversial. We set out to examine the differences in the risk factors between smokers and nonsmokers and to investigate the association of cigarette smoking with cerebral arterial stenosis. METHODS A total of 989 consecutive patients with acute noncardioembolic ischemic stroke were prospectively enrolled from June 2004 to January 2010. The risk factor profiles were compared between smokers and nonsmokers. We analyzed the degree of stenosis in all MRA, and evaluated influencing factors in the patients with intracranial atherosclerosis (ICAS) and extracranial atherosclerosis (ECAS) who were randomly matched by age and sex. RESULTS There were differences in the distribution of risk factors between the 467 (70.0%) nonsmokers and the 215 (30.0%) smokers. Nonsmokers were older (71.7±11.0 versus 61.7±12.0, p<0.001) and had a higher frequency of hypertension than smokers had (75.4% versus 64.0%, p=0.002). When smokers and nonsmokers were age- and sex-matched, smoking was more prevalent in patients with ICAS than with ECAS (32.9% versus 28.2%). Conditional regression analysis revealed that smoking and hypertension increased the odds of ICAS [smoking, odds ratio (OR): 1.83, p=0.026; hypertension, OR: 1.84, p=0.01], whereas hyperlipidemia increased the odds of ECAS (OR: 1.87, p=0.034). CONCLUSION The distributions of the major risk factors for ischemic stroke were different between smokers and nonsmokers. Cigarette smoking may be more associated with ICAS than with ECAS after adjusting for potential risk factors.

Implication of Left Ventricular Diastolic Dysfunction in Cryptogenic Ischemic Stroke

Background and Purpose— Left ventricular diastolic dysfunction (LVDD) is a predictor for atrial fibrillation (AF). This study was aimed to investigate whether LVDD in cryptogenic ischemic stroke (CS) could be a clue to stroke mechanism. Methods— The clinical and echocardiographic findings of 1589 consecutive patients with acute ischemic stroke or transient ischemic attack between 2004 and 2013 were reviewed. LVDDs among stroke subtypes were graded by transthoracic echocardiography into 4 groups by severity: normal, abnormal relaxation (grade I), pseudonormal (grade II), and restrictive diastolic filling (grade III), whereas severe LVDD was defined as grade III. We classified the lesion pattern of CS into cardioembolism-mimic or non–cardioembolism-mimic and determined whether cardioembolism-mimic lesions were associated with severe LVDD. Results— The fraction of severe LVDD in CS was not different from that of stroke with AF (27.3% versus 37.1%; P=0.173) but was significantly higher than that of stroke without AF (27.3% versus 13.4%; P=0.008). Cardioembolism-mimic CS had more severe LVDD than non–cardioembolism-mimic CS (41.4% versus 11.5%; P=0.013). LVDD of grade II (odds ratio, 4.37; 95% confidence interval, 2.99–6.41) and grade III (odds ratio, 5.60; 95% confidence interval, 3.42–9.17) were independently related to stroke with AF after adjusting covariates. Conclusions— The severe LVDD could be a predictor of stroke with AF, and its frequency was similar between CS and stroke with AF. Cardioembolism-mimic CS had significantly more severe LVDD than non–cardioembolism-mimic CS. LVDD could be helpful to discriminate the stroke mechanism in the patients with acute CS.

Association between Hypertriglyceridemia and Lacunar Infarction in Type 2 Diabetes Mellitus

BACKGROUND Although recent studies have shown that the elevation of serum triglyceride (TG) is related to the increased incidence of ischemic stroke, the relationship between hypertriglyceridemia and subtypes of ischemic stroke is largely unknown. This study attempted to evaluate whether hypertriglyceridemia is associated with lacunar stroke in diabetes mellitus (DM). METHODS A total of 2141 consecutive patients with acute ischemic stroke were enrolled from March 2005 to April 2014, excluding the subjects with undetermined/other determined etiology or no lipid data. We compared the lipid profiles among stroke subtypes. The estimated serum TG levels and the interaction between DM and stroke subtypes were determined by analysis of covariance (ANCOVA) and Tukeys multiple comparison. RESULTS In ANCOVA test, the difference of estimated TG between DM and non-DM patients was largest in small-vessel occlusion (SVO; 159.7 [95% confidence interval {CI}, 143.2-176.2] versus 122.4 [95% CI, 106.1-138.7]), and a significant interaction was observed between DM and stroke subtypes for TG levels (P = .013) but not for total cholesterol (P = .363), low-density lipoprotein cholesterol (P = .171), or high-density lipoprotein cholesterol (P = .231). By Tukeys multiple comparison, SVO was consistently associated with DM for serum TG levels (P < .001). CONCLUSIONS In acute ischemic stroke with DM, serum TG level was significantly associated with lacunar infarction adjusting for other lipid profiles and vascular risk factors. Further studies are warranted to reveal the pathophysiologic implication of hypertriglyceridemia for lacunar infarction in type 2 DM.

Association of Internal Border Zone Infarction with Middle Cerebral Artery Steno-Occlusion

Background: Demonstrating the precise anatomical area of the internal border zone (IB) by brain imaging has been unclear, and it is not well known which relevant arteries are associated with IB infarction. Methods: Patients with IB infarctions were selected from 748 consecutive patients with acute ischemic stroke. The IB infarctions were identified by coronal diffusion-weighted imaging, excluding lesions over the upper pole of the lateral ventricle. The angiographic findings of the internal carotid artery (ICA) and middle cerebral artery (MCA), on contrast-enhanced MRA, were evaluated in the patients with and without IB infarction. Results: Thirty patients met the criteria for an IB infarction: 7 had MCA steno-occlusion without ICA disease, and 23 had ICA steno-occlusion. Sixty-one patients had ICA steno-occlusion without IB infarction. The multiple logistic regression analysis showed that a more than moderate degree of steno-occlusion of the MCA was a significant factor (OR, 11.32; p = 0.006) associated with IB infarction; whereas that of the ICA was not significant (OR, 2.19; p = 0.298). Conclusion: The results of this study suggest that IB infarctions were associated with MCA steno-occlusion. ICA disease resulting in IB infarctions would be expected to have significant MCA steno-occlusion causing hemodynamic compromise.

Uremic parkinsonism with atypical phenotypes and radiologic features.

Uremic encephalopathy with bilateral basal ganglia lesions has been reported as an acute neurometabolic disease which shows reversible clinical course and brain imaging features. The exact nature and pathophysiology have not been well established. We encountered two patients who showed a relapsing and aggravating course and an atypical phenotype including parkinsonism with paroxysmal dystonic head tremor and acute onset monoparesis of the lower extremity. They also showed unusual radiological findings which revealed combined lesions in the basal ganglia and cortex, persistent hemorrhagic transformation, and focal ischemic lesion in the internal capsule. Herein, we present the unusual phenomenology with atypical radiologic findings and suggest the possible multifactorial pathogenesis of uremic encephalopathy.

Recently Uncontrolled Glycemia in Diabetic Patients Is Associated with the Severity of Intracranial Atherosclerosis

BACKGROUND AND PURPOSE Diabetes mellitus is a specific risk factor for intracranial atherosclerosis (ICAS) regardless of race. However, it is largely unknown whether poor glycemic control is associated with the severity of ICAS in diabetic patients. METHODS We selected diabetic patients with acute ischemic stroke who were prospectively registered between March 2005 and December 2015. The patients who had a high-risk source of cardiogenic embolism were excluded. ICAS was graded from 0 to 3 by the number of significant (≥50%) stenoses on intracranial magnetic resonance angiography, and was divided into 4 types: unilateral anterior, bilateral anterior, posterior, and anterior plus posterior. Ordinal and multinomial regression tests were applied for the factors influencing the number and types of ICAS. RESULTS A total of 774 patients with noncardioembolic acute ischemic stroke with diabetes were enrolled. The multiplicity of ICAS was independently associated with age (odds ratio [OR], 1.035 per 1 year, 1.018-1.052; P < .001), hypertension (OR, 1.992, 1.336-2.965; P = .001), and glycated hemoglobin (HbA1c; OR, 1.207 per 1%, 1.089-1.338; P < .001) in the ordinal regression model. In multinomial regression, bilateral anterior stenosis tended to be correlated with age (OR, 1.042, 1.008-1.077; P = .016) and HbA1c (OR, 1.201 per 1%, .991-1.520; P = .057). Both anterior and posterior stenoses were significantly associated with age (OR, 1.056, 1.029-1.084; P < .001), hypertension (OR, 2.584, 1.404-4.762; P = .002), and HbA1c (OR, 1.272, 1.070-1.511; P = .006). CONCLUSIONS Age, concomitant hypertension, and HbA1c were factors associated with multiple intracranial stenoses. Further study is warranted to elucidate whether poor glycemic control facilitates ICAS in diabetic patients.

Left Ventricular Ejection Fraction Predicts Poststroke Cardiovascular Events and Mortality in Patients without Atrial Fibrillation and Coronary Heart Disease

Background and Objectives It is controversial that decreased left ventricular function could predict poststroke outcomes. The purpose of this study is to elucidate whether left ventricular ejection fraction (LVEF) can predict cardiovascular events and mortality in acute ischemic stroke (AIS) without atrial fibrillation (AF) and coronary heart disease (CHD). Methods Transthoracic echocardiography was conducted consecutively in patients with AIS or transient ischemic attack at Soonchunhyang University Hospital between January 2008 and July 2016. The clinical data and echocardiographic LVEF of 1,465 patients were reviewed after excluding AF and CHD. Poststroke disability, major adverse cardiac events (MACE; nonfatal stroke, nonfatal myocardial infarction, and cardiovascular death) and all-cause mortality during 1 year after index stroke were prospectively captured. Cox proportional hazards regressions analysis were applied adjusting traditional risk factors and potential determinants. Results The mean follow-up time was 259.9±148.8 days with a total of 29 non-fatal strokes, 3 myocardial infarctions, 33 cardiovascular deaths, and 53 all-cause mortality. The cumulative incidence of MACE and all-cause mortality were significantly higher in the lowest LVEF (<55) group compared with the others (p=0.022 and 0.009). In prediction models, LVEF (per 10%) had hazards ratios of 0.54 (95% confidence interval [CI], 0.36–0.80, p=0.002) for MACE and 0.61 (95% CI, 0.39–0.97, p=0.037) for all-cause mortality. Conclusions LVEF could be an independent predictor of cardiovascular events and mortality after AIS in the absence of AF and CHD.

Numbers of Stroke Patients and Stroke Subtypes According to Highest and Lowest Daily Temperatures in Seoul

Background and Purpose There is conflicting evidence for whether or not the incidence of stroke is influenced by the daily temperature. The association between daily temperature and incidence of stroke is largely unknown in Korea. This study attempted to evaluate whether the maximum or minimum daily temperature is associated with increased numbers of strokes and stroke subtypes among Seoul residents. Methods We obtained the maximum and minimum daily temperatures in Seoul from the Korean Meteorological Administration between January 2005 and December 2014. Consecutive patients with acute stroke were registered who visited the emergency room or outpatient clinic in Soonchunhyang University Hospital, Seoul. The residential addresses of cases were restricted to within a 2-kilometer radius of this hospital. The stroke events were prospectively recorded with onset time, and were classified by subtypes. The categories of daily temperature were divided by 10℃ from the mean temperature. The mean daily number of strokes was calculated during the study period. One-way analysis of variance and Duncans post-hoc test were applied to compare the number of strokes among the temperature groups. Results In total, 2,313 acute strokes were identified during the period: 1,643 ischemic strokes and 670 hemorrhagic strokes. The number of cases was significantly higher when the maximum daily temperature was >32℃ or ≤3℃ (p=0.048) or the minimum daily temperature was ≤-11.0℃ (p=0.020). The lowest maximum daily temperature was associated with increased instances of intracerebral hemorrhage (p=0.029) and small-vessel occlusion (p=0.013), while the highest maximum daily temperature was associated with an increased instance of large-artery atherosclerosis (p=0.045). Conclusions The daily temperature had measurable and different associations with the number of strokes and strokes subtypes in Seoul, Korea.