Motohiro Miyagi

Impact of renal function on coronary plaque composition

BACKGROUND Recent studies have demonstrated that patients with chronic kidney disease are at high risk of atherosclerosis. Recently it has been found that coronary plaque components can be evaluated by integrated backscatter intravascular ultrasound (IB-IVUS), and lipid-rich plaque is associated with vulnerable plaque. The aim of the study was to investigate the relationship between renal function and tissue characterization of coronary plaque composition at the target stenotic site for percutaneous coronary intervention (PCI). METHODS We prospectively performed IB-IVUS before elective PCI in 89 consecutive patients with stable angina. According to estimated glomerular filtration rate (eGFR), they were divided into two groups (eGFR <60 ml/min/ 1.73 m(2) or eGFR > or =60 ml/min/1.73 m(2)). The tissue characteristics of the coronary plaque at each target stenotic site were evaluated by three-dimensional (3D) IB-IVUS just before PCI procedure. RESULTS The patients with eGFR <60 ml/min/1.73 m(2) had higher percentage of lipid volume and lower percentage of fibrous volume compared to the patients with eGFR > or = 60 ml/min/1.73 m(2) on the 3D IB-IVUS images (36.7 +/- 10.6% versus 28.7 +/- 9.3%, P < 0.001 and 59.1 +/- 8.7% versus 66.3 +/- 8.3%, P < 0.001, respectively). eGFR showed a significant negative correlation with lipid volume and had a significant positive correlation with fibrous volume in coronary plaques (r = -0.44, P < 0.0001, and r = 0.46, P < 0.0001, respectively). CONCLUSIONS Impaired renal function was related to higher percentage of lipid volume and lower percentage of fibrous volume in coronary plaque. Our findings may explain the increasing risk of cardiovascular events in patients with renal dysfunction.

Impact of night-time blood pressure on cerebral white matter hyperintensity in elderly hypertensive patients.

Cerebral white matter hyperintensity (WMH) is highly prevalent in the elderly population, and increases the risk of dementia and stroke. We investigated the relationship between ambulatory blood pressure monitoring levels and quantitatively measured WMH volumes among elderly hypertensive patients with well‐controlled blood pressure (BP) to re‐evaluated effective hypertension management methods to prevent the progression of WMH.

Left ventricular diastolic dysfunction is directly associated with cerebral white matter lesions in elderly patients.

Cerebral white matter lesions (WML) have been established to increase with age, and are associated with heightened risks of stroke, cognitive decline and depressive disorder. We previously reported that the severity of left ventricular (LV) diastolic dysfunction is associated with the volume of cerebral WML. However, the analysis could not be carried out by removing the effect of the common or specific risk factors that are known to be involved in the progression of LV diastolic dysfunction and/or cerebral WML, such as age, hypertension, diabetes mellitus, hyperlipidemia, smoking, obesity and so on. Consequently, whether LV diastolic dysfunction is directly associated with cerebral WML remained unclear. Therefore, to clarify this, we carried out a cross-sectional study by conducting further in-depth examination of these risk factors and also by increasing the study population. The study registration period was from April 2010 to October 2013. Participants comprised 133 outpatients between aged 65 and 75 years with normal LV contraction (ejection fraction >50%) and no signs or history of symptomatic heart failure, ischemic heart diseases, atrial fibrillation, stroke, or cognitive dysfunction. We also excluded those patients with ≥50% stenosis in the carotid arteries on ultrasonography with 2-D and Doppler analysis. The volume of cerebral WML was quantified on brain magnetic resonance imaging using a fully automatic segmentation program developed in the Department of Radiology at Leiden University Medical Center (Leiden, the Netherlands), and early diastolic mitral inflow and early diastolic mitral annular tissue velocity (E/E’) ratio, a parameter that indicates the severity of LV diastolic dysfunction, was measured by tissue Doppler echocardiography. A total of 20 4-h systolic and diastolic blood pressure were obtained by ambulatory blood pressure monitoring. In addition, LV ejection fraction, body mass index, estimated glomerular filtration rate, carotid intimal media thickness, and levels of plasma B-type natriuretic peptide, hemoglobin A1c and low density lipoprotein cholesterol were also determined. Values are shown as mean ± standard deviation unless otherwise stated. Data were analyzed using SPSS version 17.0 software (SPSS, Chicago, IL, USA). The study protocol was approved by the ethics/conflict of interest committee at the National Center for Geriatrics and Gerontology. Written informed consent was obtained from all participants before participation. Table A shows the patient characteristics. The results of linear regression analysis between cerebral WML volume and estimated factors are shown in Table B. These results showed that four factors (age, systolic blood pressure, plasma B-type natriuretic peptide and E/E’) had a significant correlation (P < 0.05) with cerebral WML volume. Based on the results, multivariate analysis was carried out in order to clarify the principal factors involved in the increase of the cerebral WML. As a result, E/E’ and age had been shown to be significantly correlated with cerebral WML volume (P < 0.01), with the correlation greater for E/E’ (P = 0.003) than for age (P = 0.03; Table C). The present study clarified the direct association between the severity of LV diastolic dysfunction and the volume of WML in elderly patients even after removing the effects of risk factors that were involved in the progression of LV diastolic dysfunction and/or cerebral WML. The results can be interpreted in two ways. The first interpretation is that a common, but unknown, factor exacerbates both cerebral WML and LV diastolic dysfunction, with this complicating factor being profoundly involved in the onset and progression of both diseases. The second interpretation involves chronic low cardiac output and chronic cerebral ischemia. Some reports in recent years have suggested that cerebral perfusion is impaired in patients with chronic low cardiac output. Thus, considering that cardiac output decreases with the decrease in blood flow into the LV from the left atrium as a result of the progression in LV diastolic dysfunction, and also considering that a chronic decrease in cerebral blood flow is thought to be the primary mechanism underlying cerebral WML formation, the present results can also be interpreted as suggesting that decreased cardiac output elicits chronic cerebral ischemia. Further investigation is necessary to clarify these points. Correspondence: Dr. Manabu Kokubo MD PhD, Department of Cardiology, National Center for Geriatrics and Gerontology, 7-430, Morioka-cho, Obu, Aichi 474-8511, Japan. Email: mkokubo@ncgg.go.jp Geriatr Gerontol Int 2015; 15 (Suppl. 1): 81–85 bs_bs_banner