Shuhei Okazaki

Osaka City University, Ōsaka, Ōsaka, Japan

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Publications (37)164.19 Total impact

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    ABSTRACT: Infective endocarditis is often associated with cerebral complications, the most serious of which is intraoperative hemorrhagic stroke owing to anticoagulation for cardiopulmonary bypass. However, its prevalence and risk factors are unknown. We evaluated the prevalence and risk factors of intraoperative hemorrhagic stroke in patients with infective endocarditis. In 246 patients who underwent valve surgery for active endocarditis between 2005 and 2012, 127 patients had both preoperative and postoperative intracranial neuroimaging. The prevalence and risk factors of intraoperative stroke were analyzed in those 127 patients. Valve surgery was performed in 127 patients 19.6 ± 27.1 days after infective endocarditis diagnosis. Fourteen experienced intraoperative hemorrhagic stroke, and 1 died. None of 29 patients with preoperative hemorrhagic stroke showed exacerbation of hemorrhagic lesions, whereas 1 of 57 patients with preoperative cerebral infarction showed hemorrhagic transformation of infarct lesions. Thirteen of 14 hemorrhagic complications were new ectopic intracranial hemorrhage. Multivariate analysis showed not preoperative cerebral lesions but preoperative low hemoglobin level as the only risk factor for intraoperative hemorrhagic stroke (odds ratio, 0.51; 95% confidence interval, 0.26 to 0.87; p = 0.03). A preoperative hemoglobin cutoff value of 9.2 g/dL was determined by receiver operating curve analysis. Of 41 patients with preoperative hemoglobin level less than 9.2 g/dL, 9 (22%) had intraoperative new hemorrhage, whereas 4 (5%) of 86 patients with hemoglobin level of at least 9.2 g/dL had ectopic new hemorrhage. Intraoperative hemorrhagic stroke was not rare, and ectopic hemorrhagic stroke, associated with preoperative anemia, was more prevalent than hemorrhagic transformation of existing cerebral lesions. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
    The Annals of thoracic surgery 05/2015; DOI:10.1016/j.athoracsur.2015.02.056 · 3.65 Impact Factor
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    ABSTRACT: Stroke is one of the major complications observed in patients with an implanted left ventricular assist device (LVAD). The purpose of this study was to clarify the types and characteristics of acute stroke in patients after LVAD implantation by using brain computed tomography (CT) findings. Between 2005 and 2012, 110 consecutive patients who underwent LVAD implantation were reviewed. The most commonly used device was the pulsatile extracorporeal LVAD. Amongst them, 49 patients suffered from acute stroke at least once with a total of 115 stroke events. The clinical categories, lesion sites, laboratory data and CT findings of each acute stroke event were analyzed. Cerebral infarction (35 patients, 72 events), cerebral hemorrhage (25 patients, 31 events) and subarachnoid hemorrhage (SAH) (23 patients, 33 events) were identified. A mean of 2.3 stroke events occurred per person. Of the 72 infarction events, multiple infarctions were observed in 29 events. Of the cerebral hemorrhage events (n = 31), almost all were subcortical lesions (n = 27) and none were observed in the basal ganglia. Of the 23 patients with SAH events (n = 33), SAH localized within a single sulcus, sulcus SAH, was observed in 25 events. Computed tomography findings of acute stroke after implantation of an LVAD are characteristically multifocal cortical lesions, regardless of brain infarction and hemorrhage. Unexpectedly, sulcus SAH was a common stroke subtype in patients with implanted LVADs. Sulcus SAH should be carefully examined in patients after LVAD implantation, when they complain of non-specific neurological complaints. © 2015 EAN.
    European Journal of Neurology 04/2015; DOI:10.1111/ene.12712 · 3.85 Impact Factor
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    ABSTRACT: The relationship between transient ischemic attack (TIA) clinical etiology, positive diffusion-weighted imaging (DWI) findings, and stroke recurrence is controversial. This study aimed to clarify the prevalence of positive DWI findings and TIA recurrence in relation to TIA patient characteristics. The subjects were patients admitted to our stroke unit within 7 days after symptom onset between January 2006 and July 2013. We examined DWI findings and TIA recurrence according to etiologic subtypes. We enrolled 139 patients with lacunar TIA (n = 17), atherothrombotic TIA (n = 35), cardioembolic TIA (n = 25), TIA due to other causes (n = 32), or TIA with undetermined etiology (n = 30). The prevalence of positive DWI findings was highest among the cardioembolic TIA patients (56.0%). No association was found between the prevalence of positive DWI findings and symptom duration, motor presence, or ABCD(2) score. Plasma d-dimer level was significantly higher in the DWI-positive group than that in the DWI-negative group (P = .01). The prevalence of TIA recurrence was highest (5 of 35, 14.3%) among the atherothrombotic TIA patients, regardless of positive DWI findings. None of the patients treated with the anticoagulant and antiplatelet combination therapy experienced a recurrence. In contrast, almost all patients with cardioembolic TIA received anticoagulant treatment and none experienced recurrence. The prevalence of positive DWI findings was high among the cardiogenic TIA patients. TIA recurrence was often observed among the atherothrombotic TIA patients treated with antiplatelets. Management of patients with atherothrombotic TIA requires further aggressive antithrombotic strategy. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.
    Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 03/2015; 24(5). DOI:10.1016/j.jstrokecerebrovasdis.2014.12.023 · 1.99 Impact Factor
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    ABSTRACT: Although atherosclerosis starts in early life, evidence on risk factors and atherosclerosis in individuals aged <45 years is scarce. Therefore, we studied the relationship between risk factors, common carotid intima-media thickness (CIMT), and first-time cardiovascular events in adults aged <45 years. Our study population consisted of 3067 adults aged <45 years free from symptomatic cardiovascular disease at baseline, derived from 6 cohorts that are part of the USE-IMT initiative, an individual participant data meta-analysis of general-population-based cohort studies evaluating CIMT measurements. Information on risk factors, CIMT measurements, and follow-up of the combined end point (first-time myocardial infarction or stroke) was obtained. We assessed the relationship between risk factors and CIMT and the relationship between CIMT and first-time myocardial infarction or stroke using a multivariable linear mixed-effects model and a Cox proportional-hazards model, respectively. During a follow-up of 16.3 years, 55 first-time myocardial infarctions or strokes occurred. Median CIMT was 0.63 mm. Of the risk factors under study, age, sex, diastolic blood pressure, body mass index, total cholesterol, and high-density lipoprotein cholesterol related to CIMT. Furthermore, CIMT related to first-time myocardial infarction or stroke with a hazard ratio of 1.40 per SD increase in CIMT, independent of risk factors (95% confidence interval, 1.11-1.76). CIMT may be a valuable marker for cardiovascular risk in adults aged <45 years who are not yet eligible for standard cardiovascular risk screening. This is especially relevant in those with an increased, unfavor-able risk factor burden. © 2015 American Heart Association, Inc.
    Hypertension 01/2015; DOI:10.1161/HYPERTENSIONAHA.114.04658 · 7.63 Impact Factor
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    ABSTRACT: Background Clinical manifestations and outcomes of atherosclerotic disease differ between ethnic groups. In addition, the prevalence of risk factors is substantially different. Primary prevention programs are based on data derived from almost exclusively White people. We investigated how race/ethnic differences modify the associations of established risk factors with atherosclerosis and cardiovascular events. Methods We used data from an ongoing individual participant meta-analysis involving 17 population-based cohorts worldwide. We selected 60,211 participants without cardiovascular disease at baseline with available data on ethnicity (White, Black, Asian or Hispanic). We generated a multivariable linear regression model containing risk factors and ethnicity predicting mean common carotid intima-media thickness (CIMT) and a multivariable Cox regression model predicting myocardial infarction or stroke. For each risk factor we assessed how the association with the preclinical and clinical measures of cardiovascular atherosclerotic disease was affected by ethnicity. Results Ethnicity appeared to significantly modify the associations between risk factors and CIMT and cardiovascular events. The association between age and CIMT was weaker in Blacks and Hispanics. Systolic blood pressure associated more strongly with CIMT in Asians. HDL cholesterol and smoking associated less with CIMT in Blacks. Furthermore, the association of age and total cholesterol levels with the occurrence of cardiovascular events differed between Blacks and Whites. Conclusion The magnitude of associations between risk factors and the presence of atherosclerotic disease differs between race/ethnic groups. These subtle, yet significant differences provide insight in the etiology of cardiovascular disease among race/ethnic groups. These insights aid the race/ethnic-specific implementation of primary prevention.
    PLoS ONE 01/2015; DOI:10.1371/journal.pone.0132321 · 3.53 Impact Factor
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    ABSTRACT: Background: Although the echolucent plaque in carotid stenosis is associated with future ischemic stroke, the predictive value of echogenicity in small and medium size carotid plaques on vascular events has not been thoroughly examined. Thus, we prospectively tested the hypothesis that plaque echogenicity of carotid atheroma can predict the future total cardiovascular events in patients with vascular risk factors. Methods: Ultrasound assessment of carotid intima-media complex thickness (IMT) and plaque echogenicity using integrated backscatter (IBS) analysis was performed in 596 patients aged 40 or more, with any history of vascular events or with at least 1 risk factor, who were enrolled between 2001 and 2006 in the Osaka Follow-up Study for Carotid Atherosclerosis, part 2 (OSACA2). We followed the incidence of total cardiovascular events including cerebrovascular events, coronary heart disease (CHD), and peripheral artery disease (PAD) for 6.4 years. We divided the patients into two groups according to the IBS index above (echorich plaques) and under (echolucent plaque) the median value, and calculated the hazard ratios (HR) of the echolucent group compared with the echogenic group in the risk of cardiovascular events. Results: Among 596 patients, carotid stenosis was found only in 87 patients. During the follow-up period, we observed 121 cardiovascular events including 63 cerebrovascular events, 45 CHD cases, and 13 PAD cases. The patients with incident cardiovascular events had larger plaque thickness and lower IBS index than those without incident vascular events. The relative risk of vascular events for echolucent versus echorich plaques was 1.45 (95% confidence interval [CI] 0.99-2.13, p = 0.058) after adjustment for risk factors and plaque thickness. In patients with plaque size above the median value (>2.1 mm), the relative risk of vascular events for echolucent plaques was 1.72 (95% CI 1.06-2.85, p = 0.029), but this association was not observed in patients with plaque size <2.0 mm. Conclusions: The association between echogenicity of carotid plaque and incident vascular events is dependent on the plaque size. Echolucent medium-to-large plaques, but not small plaques, are associated with the risk of future total cardiovascular events. This finding suggests that measurement of echolucency in medium-to-large carotid plaques may improve selection of patients at high risk for total vascular events. © 2014 S. Karger AG, Basel.
    Cerebrovascular Diseases 11/2014; 38(5):354-361. DOI:10.1159/000365651 · 3.70 Impact Factor
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    ABSTRACT: The association between vascular risk factors and dementia is of interest. Several studies have shown that cerebral small vessel disease (SVD) is associated with dementia. However, the association between cerebral large vessel disease (LVD) and dementia has not been thoroughly examined.
    European Journal of Neurology 08/2014; DOI:10.1111/ene.12553 · 3.85 Impact Factor
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    ABSTRACT: Background and Purpose-Limited information is available on the long-term effects of interleukin-6 (IL-6) on systemic atherosclerosis. The purpose of the present study was to clarify the relationship between chronic elevation of IL-6 and the long-term progression of carotid atherosclerosis. Methods-We prospectively evaluated 210 patients with >= 1 vascular risk factors for 9.0 +/- 1.0 years. Carotid mean-maximal intima-media thickness (mmIMT), the serum high-sensitivity C-reactive protein (hs-CRP) level, and the serum IL-6 level were measured at baseline and every 3 years. The associations between the progression of mmIMT and the long-term average levels of hs-CRP and IL-6 were analyzed. Results-Carotid mmIMT increased throughout the study period (0.031 +/- 0.026 mm/y). Baseline mmIMT was significantly associated with baseline hs-CRP (P=0.002) and baseline IL-6 (P<0.001) levels. Progression of mmIMT was positively correlated with average hs-CRP (P=0.001) and average IL-6 (P<0.001) levels. When adjusted for age, sex, traditional risk factors, and baseline mmIMT, mmIMT progression remained significantly associated only with the average IL-6 level (standardized beta=0.17; P=0.02), but not with the average hs-CRP level (standardized beta=0.10; P=0.18). Conclusions-Chronic elevation of serum IL-6 was associated with the progression of atherosclerosis in patients with vascular risk factors. IL-6 could be used as a quantitative marker and a potential therapeutic target for accelerated atherosclerosis.
    Stroke 08/2014; 45(10). DOI:10.1161/STROKEAHA.114.005991 · 6.02 Impact Factor
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    ABSTRACT: To investigate whether cerebral microbleeds (CMBs) are independently associated with incident dementia in patients with vascular risk factors.METHODS: Using data from a Japanese cohort of participants with vascular risk factors in an observational study from 2001, we evaluated the association between CMBs at baseline and incident dementia. Baseline brain MRI was used to determine small-vessel disease (CMBs, lacunar infarcts, and white matter hyperintensities) and brain atrophy. Cox proportional hazards analyses were performed for predictors of dementia adjusting for age, sex, APOE ε4 allele, educational level, baseline Mini-Mental State Examination score, cerebrovascular events, vascular risk factors, and MRI findings.RESULTS: Of the 524 subjects (mean age 68 ± 8.3 years, 57.6% male, 12.8 ± 2.6 years of schooling, 21.6% CMBs), 44 patients with incident dementia (20 Alzheimer disease, 18 vascular dementia, 3 mixed-type, and 3 other) were diagnosed during the median 7.5-year follow-up. In multivariate analysis, the presence of overall CMBs was not associated with an increased risk of incident all-cause dementia (p = 0.15). However, multiple CMBs (≥2) or mixed (lobar and deep) CMBs were associated with the increased risk of all-cause dementia, whereas strictly lobar CMBs showed no association with any dementia.CONCLUSIONS: Multiple CMBs or mixed CMBs independently showed higher risk of all-cause dementia. Our results reinforce the hypothesis that CMBs exert deleterious effects on dementia incidence, suggesting that this association may be mediated by vascular burden.
    Neurology 07/2014; 83(7). DOI:10.1212/WNL.0000000000000692 · 8.30 Impact Factor
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    ABSTRACT: Carotid intima-media thickness (CIMT) is a marker of cardiovascular risk. It is unclear whether measurement of mean common CIMT improves 10-year risk prediction of first-time myocardial infarction or stroke in individuals with elevated blood pressure. We performed an analysis among individuals with elevated blood pressure (ie, a systolic blood pressure ≥140 mm Hg and a diastolic blood pressure ≥ 90 mm Hg) in USE-IMT, a large ongoing individual participant data meta-analysis. We refitted the risk factors of the Framingham Risk Score on asymptomatic individuals (baseline model) and expanded this model with mean common CIMT (CIMT model) measurements. From both models, 10-year risks to develop a myocardial infarction or stroke were estimated. In individuals with elevated blood pressure, we compared discrimination and calibration of the 2 models and calculated the net reclassification improvement (NRI). We included 17 254 individuals with elevated blood pressure from 16 studies. During a median follow-up of 9.9 years, 2014 first-time myocardial infarctions or strokes occurred. The C-statistics of the baseline and CIMT models were similar (0.73). NRI with the addition of mean common CIMT was small and not significant (1.4%; 95% confidence intervals, -1.1 to 3.7). In those at intermediate risk (n=5008, 10-year absolute risk of 10% to 20%), the NRI was 5.6% (95% confidence intervals, 1.6-10.4). There is no added value of measurement of mean common CIMT in individuals with elevated blood pressure for improving cardiovascular risk prediction. For those at intermediate risk, the addition of mean common CIMT to an existing cardiovascular risk score is small but statistically significant.
    Hypertension 03/2014; DOI:10.1161/HYPERTENSIONAHA.113.02683 · 7.63 Impact Factor
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    ABSTRACT: To determine whether chronic kidney disease (CKD) is associated with incident dementia independent of cerebral small-vessel disease (SVD) in patients with vascular risk factors. Using data from a Japanese cohort of participants with vascular risk factors in an ongoing observational study from 2001, we evaluated the association between CKD at baseline and incident dementia. Baseline brain MRI was used to determine SVD (lacunar infarction, white matter hyperintensities), medial-temporal atrophy, and subcortical atrophy. Cox proportional hazards analyses were performed for predictors of dementia adjusting for age, sex, APOE ε4 allele, educational level, baseline Mini-Mental State Examination score, cerebrovascular events, vascular risk factors, and MRI findings. Of the 600 subjects (mean age 68 ± 8.3 years, 57% male, 12.8 ± 2.6 years of education; CKD: 29%), 50 patients with incident dementia (Alzheimer disease: 24; vascular dementia: 18; mixed-type dementia: 5; other types: 3) were diagnosed during the median 7.5-year follow-up. CKD at baseline was associated with an increased risk of all-cause dementia in models adjusted for age, sex, educational level, and APOE ε4 allele. The associations of CKD at baseline remained significant even after additional adjusting for MRI findings and confounding variables (hazard ratio: 1.96 [1.08-3.58], p = 0.026). CKD is independently related to the risk of all-cause dementia in patients with vascular risk factors. Our results reinforce the hypothesis that CKD exerts deleterious effects on dementia incidence.
    Neurology 02/2014; 82(12). DOI:10.1212/WNL.0000000000000251 · 8.30 Impact Factor
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    ABSTRACT: The risk of neurological deterioration during valve surgery using cardiopulmonary bypass under systemic heparinization in infective endocarditis (IE) patients with intracranial haemorrhage (ICH) is unknown. The objective of this retrospective study was to investigate the stratified risk related to the timing of valve surgery on neurological outcomes in patients with active IE and preoperative ICH. From 2004 to 2012, 246 patients underwent valve surgery for IE in hospitals enrolled in the Osaka Cardiovascular Research Group. Of these, a group of 30 patients had preoperative ICH, and they included 18 patients with cerebral haemorrhage, 8 with subarachnoid haemorrhage and 4 with haemorrhagic infarction. The preoperative characteristics, neurological statuses and postoperative results of these patients were retrospectively explored to analyse the effects of the timing of surgery on neurological outcomes. Twenty-one patients had symptomatic ICH, and the median modified Rankin score was 1.5 (95% confidence interval [CI] 1.2-2.8). Eight patients were diagnosed with mycotic aneurysms, and 7 of these patients underwent aneurysm resection or clipping before valve surgery. All 30 patients underwent valve surgery, and the median interval between ICH onset and surgery was 22.5 (95% CI 15.5-39.4) days. Four patients died of multiple organ dysfunction or heart failure. The interval between ICH onset and valve surgery was within 7 days for 5 cases, between 8 and 14 days for 6, between 15 and 28 days for 9 and >29 days for 10. Postoperative neuroimaging showed that neither neurological deterioration nor exacerbation of haemorrhagic lesions had occurred among the 30 patients, regardless of the timing of surgery. However, 2 cases who underwent valve surgery 8 and 81 days after the onset of ICH developed new ectopic asymptomatic haemorrhages postoperatively. The risk of postoperative neurological deterioration resulting from the exacerbation of haemorrhagic lesions seemed relatively low, even in IE patients who underwent valve surgery within 2 weeks of ICH onset. However, further evaluation of the sizes and aetiologies of haemorrhagic lesions is vital to establish a safe interval between the ICH onset and surgery.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 01/2014; 45(6). DOI:10.1093/ejcts/ezt547 · 2.81 Impact Factor
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    ABSTRACT: Aim: Patients with gynecological neoplasms often suffer ischemic stroke. This study aimed to clarify the underlying mechanisms of ischemic stroke in patients with gynecological tract tumors. Methods: We retrospectively reviewed 6 patients with gynecologic tumors and hypercoagulability who were being treated for acute ischemic stroke between 2006 and 2012. Diffusion-weighted magnetic resonance imaging (DW-MRI), cardiovascular risk factors including plasma D-dimer levels, and histologic examination of the patients' solid tumors were performed. All 6 patients underwent transesophageal echocardiography (TEE) for nonbacterial thrombotic endocarditis (NBTE) and paradoxical embolism. Results: All 6 patients showed elevated plasma D-dimer levels. In 1 patient, paradoxical embolism was diagnosed. In the remaining 5 patients, DW-MRI scans showed numerous lesions in multiple vascular territories, and in 4 of these 5 patients, TEE demonstrated vegetations on the mitral valve, leading to the diagnosis of NBTE. Interestingly, 2 of these 4 patients had benign uterine tumors, whereas the other 2 had ovarian cancer. Conclusions: NBTE was the main etiology for ischemic stroke in patients with gynecologic tract tumors and coagulopathy. Both malignant and benign tumors of the gynecologic tract can cause NBTE. © 2013 S. Karger AG, Basel.
    European Neurology 09/2013; 70(5-6):304-307. DOI:10.1159/000353799 · 1.36 Impact Factor
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    ABSTRACT: OBJECTIVE: Basilar arterial (BA) dolichoectasia is associated with cerebral small-vessel disease and stroke. However, the association between moderate dilation of the BA and cerebral small-vessel disease or subsequent cardiovascular events remains unclear. This study aims to clarify the factors related to BA diameter and to clarify whether the BA diameter is an independent predictor of cardiovascular events. APPROACH AND RESULTS: The study subjects comprised 493 outpatients with atherosclerotic risk factors. BA diameter, lacunar infarct, severity of deep white matter hyperintensities, and intracranial steno-occlusive lesions were assessed with MRI and magnetic resonance angiography. Then, we prospectively evaluated the association between BA diameter and cardiovascular events. The BA diameter ranged from 1.1 to 5.2 mm, and only 0.8% of the patients had dolichoectasia. Male sex, the presence of lacunar infarcts, the severity of deep white matter hyperintensities, the fetal-type variation of the circle of Willis, and intracranial steno-occlusive lesions were independently associated with BA diameter. In the mean follow-up of 6.0 years, 91 patients developed cardiovascular events. BA diameter was independently associated with total cardiovascular events after adjusting for age, sex, and conventional risk factors (hazard ratio, 1.55 per 1 mm increase in BA diameter; P=0.009). CONCLUSIONS: Increased BA diameter within the normal range is related to both large-vessel disease and cerebral small-vessel disease, and it could be a new predictor of cardiovascular events.
    Arteriosclerosis Thrombosis and Vascular Biology 05/2013; 33(9). DOI:10.1161/ATVBAHA.113.301467 · 5.53 Impact Factor
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    ABSTRACT: AIMS/HYPOTHESIS: The aim of this work was to investigate whether measurement of the mean common carotid intima-media thickness (CIMT) improves cardiovascular risk prediction in individuals with diabetes. METHODS: We performed a subanalysis among 4,220 individuals with diabetes in a large ongoing individual participant data meta-analysis involving 56,194 subjects from 17 population-based cohorts worldwide. We first refitted the risk factors of the Framingham heart risk score on the individuals without previous cardiovascular disease (baseline model) and then expanded this model with the mean common CIMT (CIMT model). The absolute 10 year risk for developing a myocardial infarction or stroke was estimated from both models. In individuals with diabetes we compared discrimination and calibration of the two models. Reclassification of individuals with diabetes was based on allocation to another cardiovascular risk category when mean common CIMT was added. RESULTS: During a median follow-up of 8.7 years, 684 first-time cardiovascular events occurred among the population with diabetes. The C statistic was 0.67 for the Framingham model and 0.68 for the CIMT model. The absolute 10 year risk for developing a myocardial infarction or stroke was 16% in both models. There was no net reclassification improvement with the addition of mean common CIMT (1.7%; 95% CI -1.8, 3.8). There were no differences in the results between men and women. CONCLUSIONS/INTERPRETATION: There is no improvement in risk prediction in individuals with diabetes when measurement of the mean common CIMT is added to the Framingham risk score. Therefore, this measurement is not recommended for improving individual cardiovascular risk stratification in individuals with diabetes.
    Diabetologia 04/2013; DOI:10.1007/s00125-013-2898-9 · 6.88 Impact Factor
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    ABSTRACT: Background: Acute brain infarction affects the timing and regimen of cardiac surgery in patients with infective endocarditis (IE). We aimed to identify preoperative brain MRI characteristics, incidence, and related factors for acute ischemic lesions in left-sided IE patients undergoing cardiac surgery. Furthermore, we investigated whether preoperative acute ischemic lesions are associated with postoperative neurological complications in IE patients. Methods: We retrospectively reviewed consecutive patients with a definite left-sided IE who underwent cardiac surgery in 6 university-affiliated hospitals from January 2004 to November 2011. Preoperative brain MRI evaluations were systematically performed on all patients without contraindications, regardless of neurological complications, with the aim of preventing perioperative complications. Patients were included if diffusion-weighted imaging and fluid-attenuated inversion recovery sequences were performed within 14 days after diagnosis. Associations between acute ischemic lesions and related factors were analyzed. Neurological complications within 30 days after surgery were evaluated for postoperative outcome analyses. Results: Of 139 consecutive patients with left-sided IE who underwent cardiac surgery, 85 patients were evaluated in this study. The mean age was 58 ± 16 years, and 22 patients (26%) were women. Preoperative MRI revealed acute ischemic lesions in 47 patients (55%), and 19 of these patients developed neurological symptoms. Among the patients with ischemic lesions, 24 (60%) had small lesions (<10 mm), 36 (77%) had multiple lesions, and 30 (64%) had lesions in multiple vascular territories. Compared to patients without ischemic lesions, patients with acute ischemic lesions were older and had significantly higher white blood cell counts and plasma C-reactive protein (CRP) levels, but lower hemoglobin levels. Logistic regression analyses showed that the white blood cell count and plasma CRP level were independently associated with acute ischemic lesions [adjusted OR per 1-SD increase were 2.21 (95% CI: 1.23-4.35) and 2.33 (95% CI: 1.27-4.96), respectively]. Three patients developed postoperative neurological complications, but preoperative acute ischemic lesions and postoperative complications were not associated. Conclusions: Preoperative MRI detected a high incidence of asymptomatic ischemic lesions in IE patients. Acute ischemic lesions were often small, multiple, and located in multiple vascular territories. Inflammatory reactions may play an important role in the development of ischemic lesions in IE patients.
    Cerebrovascular Diseases 02/2013; 35(2):155-162. DOI:10.1159/000346101 · 3.70 Impact Factor
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    ABSTRACT: Background: Plasma D-dimer level may reflect the activity of thrombus formation in the left atrium of patients with nonvalvular atrial fibrillation (NVAF). Proper anticoagulation with warfarin dramatically decreases the rate of cerebral embolism, reduces stroke severity and subsequent risk of death, as well as the level of D-dimer in NVAF patients. However, the predictive value of D-dimer level on cerebral embolism severity has not been examined. Thus, the purpose of this study was to investigate the association between plasma D-dimer level at admission and infarct size in NVAF patients. Methods: We identified 124 patients with consecutive ischemic stroke and NVAF who were admitted within 48 h of symptom onset. We measured infarction volume from CT taken after 3 ± 1 days from the onset. Plasma D-dimer levels were measured at the time of admission. Relationships were analyzed between infarction volume and plasma D-dimer levels, cardiovascular risk factors, preadmission medications and admission conditions. We also assessed the influence of D-dimer level on functional outcome in patients with preadmission modified Rankin Scale (mRS) score of 0-1 and patients by tertile of D-dimer level (≤0.83, 0.83-2.16 and ≥2.16 µg/ml). Results: Infarction volume significantly correlated with D-dimer level (r = 0.309, p < 0.001), systolic blood pressure (r = 0.201, p = 0.026), diastolic blood pressure (r = 0.283, p = 0.002), National Institutes of Health Stroke Scale (NIHSS) score on admission (r = 0.546, p < 0.001) and mRS score at discharge (r = 0.557, p < 0.001). Multivariate regression analyses showed that the D-dimer level was significantly associated with infarction volume after adjusting for age, sex, current smoker or not, prothrombin time-international normalized ratio ≥1.6, diastolic blood pressure, CHADS(2) score and NIHSS score on admission. In patients with a preadmission mRS score of 0-1 (n = 108), D-dimer level was significantly associated with NIHSS score at admission (r = 0.318, p < 0.001) and mRS score at discharge (r = 0.310, p = 0.001). Patients in the highest D-dimer tertile group showed worse outcome than those in the middle (p = 0.041) and lowest (p < 0.001) tertiles. Conclusions: Plasma D-dimer level on admission is significantly related to infarction volume and functional outcome, following cardioembolic stroke in NVAF patients.
    Cerebrovascular Diseases 01/2013; 35(1):64-72. DOI:10.1159/000345336 · 3.70 Impact Factor
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    ABSTRACT: OBJECTIVE: The objective of this study was to examine the association of inflammatory markers with risk of first-ever cerebrovascular events (CVEs), while simultaneously evaluating subclinical vascular disease. METHODS AND RESULTS: We enrolled 464 outpatients who had vascular risk factors without any preexisting cardiovascular disease. We examined the presence of silent lacunar infarction (SLI) by magnetic resonance imaging; carotid intima-media thickness by ultrasound; and measured high-sensitivity C-reactive protein, interleukin (IL)-6, and IL-18 at baseline, and assessed their associations with CVEs using Cox proportional hazards models of 4.8±2.6 years follow-up. We further calculated measures of reclassification and discrimination. In age- and sex-adjusted analysis, IL-6, but neither high-sensitivity C-reactive protein nor IL-18, was associated with CVEs. The association remained significant after adjustment for conventional risk factors, intima-media thickness, and SLI (hazard ratios: 1.80, per 1-SD increase in log IL-6, P=0.03). Compared with the patients with below median IL-6 without SLI, those with above median IL-6 and SLI had a higher risk of CVEs (hazard ratios: 4.14, P=0.0014). The combination of IL-6 and SLI resulted in the net reclassification improvement of 14.3% (P=0.04), and the integrated discrimination improvement gain of 2.1% (P=0.05). CONCLUSIONS: IL-6 levels were independently associated with CVEs and could improve reclassification in those with SLI.
    Arteriosclerosis Thrombosis and Vascular Biology 11/2012; 33(2). DOI:10.1161/ATVBAHA.112.300350 · 5.53 Impact Factor
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    ABSTRACT: The evidence that measurement of the common carotid intima-media thickness (CIMT) improves the risk scores in prediction of the absolute risk of cardiovascular events is inconsistent. To determine whether common CIMT has added value in 10-year risk prediction of first-time myocardial infarctions or strokes, above that of the Framingham Risk Score. Relevant studies were identified through literature searches of databases (PubMed from 1950 to June 2012 and EMBASE from 1980 to June 2012) and expert opinion. Studies were included if participants were drawn from the general population, common CIMT was measured at baseline, and individuals were followed up for first-time myocardial infarction or stroke. Individual data were combined into 1 data set and an individual participant data meta-analysis was performed on individuals without existing cardiovascular disease. We included 14 population-based cohorts contributing data for 45,828 individuals. During a median follow-up of 11 years, 4007 first-time myocardial infarctions or strokes occurred. We first refitted the risk factors of the Framingham Risk Score and then extended the model with common CIMT measurements to estimate the absolute 10-year risks to develop a first-time myocardial infarction or stroke in both models. The C statistic of both models was similar (0.757; 95% CI, 0.749-0.764; and 0.759; 95% CI, 0.752-0.766). The net reclassification improvement with the addition of common CIMT was small (0.8%; 95% CI, 0.1%-1.6%). In those at intermediate risk, the net reclassification improvement was 3.6% in all individuals (95% CI, 2.7%-4.6%) and no differences between men and women. The addition of common CIMT measurements to the Framingham Risk Score was associated with small improvement in 10-year risk prediction of first-time myocardial infarction or stroke, but this improvement is unlikely to be of clinical importance.
    JAMA The Journal of the American Medical Association 08/2012; 308(8):796-803. DOI:10.1001/jama.2012.9630 · 30.39 Impact Factor
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    ABSTRACT: We report a case of internal carotid artery (ICA) occlusion caused by arterial dissection triggered by an elongated styloid process. A 43-year-old man presented with a headache followed by speech disturbance. Magnetic resonance imaging and magnetic resonance angiography scans revealed acute infarction and right ICA occlusion. A T1-weighted magnetic resonance imaging scan revealed a hyperintensity in the occluded ICA, suggesting intramural hematoma. Computed tomographic angiography also revealed ICA occlusion and bilateral elongated styloid processes. We performed transoral carotid ultrasonography, which revealed the absence of flow signal in the double lumen of the dilated extracranial ICA. We diagnosed his condition as arterial dissection and treated him with antithrombotic drugs. Six months later, the occluded ICA recanalized spontaneously, and computed tomographic angiography at that time revealed a close relation between the tip of the styloid process and the recanalized ICA. This finding suggests that an elongated styloid process is involved in arterial dissection. In patients with ICA occlusion of unknown etiology, an evaluation for intramural hematoma and styloid process length are useful for the diagnosis of dissection and its etiology.
    Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 06/2012; 21(8). DOI:10.1016/j.jstrokecerebrovasdis.2012.05.014 · 1.99 Impact Factor

Publication Stats

270 Citations
164.19 Total Impact Points

Institutions

  • 2009–2015
    • Osaka City University
      • • Department of Cardiovascular Medicine
      • • Department of Cardiovascular Surgery
      Ōsaka, Ōsaka, Japan
  • 2010–2014
    • Osaka University
      • Division of Neurology
      Suika, Ōsaka, Japan
    • National Cerebral and Cardiovascular Center
      • Department of Cardiovascular Medicine
      Ōsaka, Ōsaka, Japan