Biomedical subjects

Yuhei Kawano

Publications and source records attributed to Yuhei Kawano.

82 records · Page 5Linked to original sources

PubMed2002

Effects of the creation of arteriovenous fistula for hemodialysis on cardiac function and natriuretic peptide levels in CRF.

BACKGROUND: Cardiac failure occasionally is caused by the creation of vascular access for hemodialysis. However, the influence of an arteriovenous (AV) fistula on cardiac function has not been fully elucidated. The present study investigated serial changes in cardiac function and hormonal levels after the AV fistula operation. METHODS: Sixteen patients with chronic renal failure underwent echocardiographic studies before and 3, 7, and 14 days after the AV fistula operation. Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) concentrations were measured before and 1, 3, 6, 10, and 14 days after the operation. RESULTS: Creation of an AV fistula produced significant elevations in left ventricular (LV) end-diastolic diameter (+4%), fractional shortening (+8%), and cardiac output (CO; +15%). In LV inflow velocities measured by Doppler echocardiography, deceleration time of the early diastolic filling wave shortened (-12%) and the ratio of the peak velocity of early diastolic to atrial filling (E-A ratio) increased (+18%). The difference in duration of LV inflow and pulmonary venous flow at atrial contraction, a marker of LV end-diastolic pressure, significantly shortened day 14 after the operation (-37%). That is, creation of an AV fistula induced LV diastolic dysfunction toward a restrictive filling pattern. Both ANP and BNP levels increased after the operation, and maximal percentages of increase were observed after 10 days (ANP, +48%; BNP, +68%). In the relationship between cardiac function and hormonal response, the increase in CO was associated with elevation of ANP levels (r = 0.61; P = 0.01), but not BNP levels. Conversely, the increase in E-A ratio correlated only with BNP level elevation (r = 0.60; P = 0.01). CONCLUSION: Our observations indicate that creation of an AV fistula has significant effects on cardiac systolic and diastolic performance, and ANP release is induced by volume loading, but BNP release is stimulated by LV diastolic dysfunction.

Adult↗

PubMed2002

Role of blood pressure monitoring in non-pharmacological management of hypertension.

Ambulatory blood pressure monitoring (ABPM) and home blood pressure (BP) measurement appear to be useful in the assessment of the effects of non-pharmacological treatment of hypertension because they can detect small changes in BP without observer bias. We studied the effects of various lifestyle modifications using ABPM and home BP measurement in Japanese patients with hypertension. Weight reduction by a hypocaloric diet (average 4 kg) was associated with decreases in 24-h BP (10/4 mmHg) as well as casual BP (9/6 mmHg). The reductions in daytime and night-time BPs were comparable. The effects of daily walking without weight loss on office, home, and 24-h BPs were 2-3/1-2 mmHg. The changes in home and 24-h BPs were more significant than those in office BP. A low-salt diet (25 mmol/day versus 250 mmol/day) decreased 24-h BP by 9/4 mmHg. This hypotensive effect was observed throughout the day. Potassium supplementation (64 mmol/day) decreased office, home and 24-h BPs by 3-4/1-2 mmHg. The changes in home and 24-h BPs were highly significant compared with office BP. Supplementation of magnesium (20 mmol/day) also reduced those BPs significantly. However, the effects of calcium supplementation (25 mmol/day) were small (1-2/1 mmHg) and were significant only for home BP. Alcohol restriction for 4 weeks decreased daytime BP by 3/2 mmHg but increased night-time BP by 4/2 mmHg. Average 24-h BP did not change. Smoking cessation lowered daytime BP without affecting night-time BP. Monitoring of 24-h BP and home BP can detect small changes in BP produced by lifestyle modifications. Ambulatory BP monitoring is particularly suitable in the assessment of changes in lifestyle affecting the circadian pattern of BP such as alcohol consumption and smoking.

Alcohol Drinking↗

PubMed2002

Relationship between carotid artery intima-media thickness and atherosclerotic renal artery stenosis in type 2 diabetes with hypertension.

AIM: To assess the relation between intima-media thickness (IMT) of the common carotid artery and atherosclerotic renal artery stenosis (ARAS) > or =50% (one or both renal arteries) in type 2 diabetic patients with hypertension. METHODS: We performed a retrospective study of type 2 diabetic patients with hypertension who underwent magnetic resonance angiography or digital subtraction angiography for renal artery stenosis at the National Cardiovascular Center or at the Nagasaki Municipal Medical Center between May 1999 and May 2001. Renal artery stenosis was defined as a narrowing of the artery to at least 50% of normal. Thirty type 2 diabetic patients with hypertension (17 men and 13 women, mean age 65.4 +/- 7.6 years) were identified and divided into two groups: those with ARAS in one or both renal arteries (n = 15) and those without ARAS (n = 15). We used high-resolution B-mode ultrasonography to measure the IMT of the common carotid artery. RESULTS: With and without ARAS were 9 men and 6 women (mean age 65.0 +/- 7.6 years) and 8 men and 7 women (mean age 65.7 +/- 6.8 years), respectively. The IMT of the carotid artery was significantly greater in patients with ARAS than in patients without ARAS (1.07 +/- 0.10 vs. 0.84 +/- 0.12 mm, p < 0.01). However, the only clinical findings that statistically significantly differed were systolic blood pressure and plasma renin activity. CONCLUSION: Our findings suggest that the measurement of the IMT of the carotid artery may be useful as a noninvasive screening method for the defection of ARAS even in asymptomatic type 2 diabetic patients.

Aged↗

PubMed2002

Adrenomedullin inhibits doxorubicin-induced cultured rat cardiac myocyte apoptosis via a cAMP-dependent mechanism.

We previously reported that adrenomedullin produced by cardiac myocytes acts as a local modulator in some cardiac disorders. However, the role of adrenomedullin (AM) in cardiomyocyte apoptosis remains to be clarified. The present study investigated the effect of AM on doxorubicin-induced cardiac myocyte apoptosis. Doxorubicin increased the number of cells with pyknotic nuclei and lactate dehydrogenase release, and AM dose-dependently (10(-10)-10(-8)6 M) inhibited these increases produced by doxorubicin. Treatment with AM also suppressed doxorubicin-induced DNA fragmentation and caspase-3 activation. 8-Bromo-cAMP, a cAMP analog, mimicked these antiapoptotic effects of AM. An AM/calcitonin gene-related peptide (CGRP) receptor antagonist CGRP-(8-37) and a protein kinase A inhibitor H89 attenuated the antiapoptotic effect of AM. CGRP-(8-37) and H89 had no apoptotic effect alone, but accelerated doxorubicin-induced apoptosis. Under serum-free conditions, AM secretion into the culture medium and expression of AM mRNA were significantly increased after treatment with doxorubicin. Hydrogen peroxide scavenger catalase and antioxidant N-acetyl-L-cysteine inhibited the doxorubicin-mediated increase in AM secretion and its gene expression. These results indicate that AM inhibits doxorubicin-induced cardiac myocyte apoptosis through a cAMP-dependent mechanism and suggest that augmented production of AM by doxorubicin has an endogenous antiapoptotic effect. AM, as an autocrine factor, may play a protective role against cardiomyocyte injury by doxorubicin.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed2002

Relationship between home blood pressure and longitudinal changes in target organ damage in treated hypertensive patients.

Cross-sectional studies have shown that home blood pressure (BP) correlates with hypertensive target organ damage better than clinic BP. However, there have been few longitudinal studies regarding the predictive value of home BP on the changes in organ damage in treated hypertensive patients. Clinic and home BP over a 12-month period, antihypertensive medication use, echocardiographic and electrocardiographic results, and serum creatinine and urinary protein levels were examined in 209 treated hypertensive patients in 1993. These patients were prospectively followed for 5 years. The patients were divided into 4 subgroups according to hypertension control as follows: good control (<140/90 mmHg for clinic BP, <135/85 mmHg for home BP), improved, worsened, and poor control. The average clinic BP was 147.0+/-14.9/87.0+/-7.6 mmHg (mean+/-SD) in 1993 and 146.0+/-13.7/84.1+/-7.5 mmHg in 1998. The average home BP was 136.8+/-10.4/84.3+/-7.6 mmHg in 1993 and 136.1+/-9.7/81.2+/-7.7 mmHg in 1998. The left ventricular mass index (LVMI) positively correlated with both home systolic BP and clinic systolic BP in 1998 but not in 1993. The correlation tended to be closer for home BP than for clinic BP. LVMI did not change in patients with good or improved home systolic BP, while it increased in those with poor or worsened home systolic BP. The relationship between changes in LVMI and clinic BP was not significant. In conclusion, Home BP was more effective than clinic BP as a predictor of changes in left ventricular hypertrophy in treated hypertensive patients. Home BP should be controlled to below 135/85 mmHg to prevent cardiac hypertrophy.

Adult↗

PubMed2002

Increase in pulse pressure relates to diabetes mellitus and low HDL cholesterol, but not to hyperlipidemia in hypertensive patients aged 50 years or older.

Higher pulse pressure is associated with higher cardiovascular risk. We investigated the relationship between pulse pressure and known metabolic risk factors in hypertensive patients who had not experienced stroke or myocardial infarction. In a multicenter cross-sectional survey made in 1995, we registered 939 hypertensive patients aged > or = 50 years. Of these, 734 had never experienced stroke or myocardial infarction. We divided these 734 patients into two groups based on the value of their pulse pressures: 396 patients with a pulse pressure > or = 60 mmHg, and 338 patients with a pulse pressure<60 mmHg. The average pulse pressure value was 72 +/- 12 mmHg in the former group, and 49 +/- 8 mmHg in the latter group. The former group exhibited advanced age, a higher women-to-men ratio, lower high-density lipoprotein (HDL) cholesterol, and higher systolic and lower diastolic blood pressure. Diabetes mellitus (DM) and left ventricular hypertrophy were more frequently noticed in the former group than in the latter group. The prevalence of hyperlipidemia, however, was similar in the two groups. The association of pulse pressure with DM and low HDL cholesterol was statistically significant by multiple logistic analysis adjusted for age, sex, and other known cardiovascular risk factors. In conclusion, pulse pressure increases with advancing age. DM made a substantially larger contribution to the increase in pulse pressure than hyperlipidemia.

Adrenergic beta-Antagonists↗

PubMed2002

Fasting plasma glucose is an independent determinant of left ventricular diastolic dysfunction in nondiabetic patients with treated essential hypertension.

Left ventricular (LV) hypertrophy and LV diastolic dysfunction are common cardiac changes in hypertensive patients, and these changes are modified by various factors other than blood pressure. The present study was conducted to investigate the influence of mild abnormalities in glucose metabolism on LV structure and function in essential hypertension. In 193 nondiabetic patients with treated essential hypertension, two-dimensional and Doppler echocardiographic examinations were performed, and relative wall thickness (RWT), LV mass index (LVMI), fractional shortening, and the ratio of the peak velocity of atrial filling to early diastolic filling (A/E) were calculated. Fasting plasma glucose (FPG) and HbA1c levels were positively correlated with the A/E ratio and the deceleration time of the E wave. However, these plasma levels had no correlation with RWT, LVMI, or fractional shortening. Peak A wave velocity and the A/E ratio were significantly higher in patients who had FPG of > or = 100 mg/dl (and <126 mg/dl) than those who had FPG of <100 mg/dl, although age, blood pressure, RWT, LVMI, and fractional shortening did not differ between the two groups. In a multiple regression analysis of all subjects, only FPG and age were independent determinants of the A/E ratio. These observations suggest that FPG is a sensitive predictor for LV diastolic dysfunction in nondiabetic patients with treated hypertension. Since a slight increase in plasma glucose levels is associated with abnormalities in diastolic function independent of LV hypertrophy, an early stage of impaired glucose metabolism in hypertensive patients may specifically deteriorate cardiac diastolic function.

Adult↗

PubMed2002

Influence of plasma aldosterone on left ventricular geometry and diastolic function in treated essential hypertension.

Since aldosterone is known to promote interstitial fibrosis in cardiac tissues, it is possible that aldosterone may influence cardiac structure and function. In the present study, we investigated whether plasma aldosterone concentration (PAC) is related to the distinct patterns of left ventricular (LV) geometry and LV diastolic function in treated essential hypertension. In 92 patients with chronically treated essential hypertension, two-dimensional and Doppler echocardiographic examinations were performed and LV inflow velocities were measured for evaluation of LV diastolic function. When patients were divided into four groups by the different LV geometric patterns, PAC in patients with eccentric hypertrophy was significantly higher than in those with concentric hypertrophy (15.2+/-2.1 vs. 10.0+/-0.7 ng/dl, p<0.01). However, the ratio of the peak velocity of early diastolic filling to that of atrial filling (EIA), an index of LV diastolic function, was significantly decreased in patients with concentric hypertrophy compared with those showing normal geometry. In the relationship between PAC and LV diastolic function, PAC was negatively correlated with EIA (r=-0.35, p<0.05) only in the subgroup with normal relative wall thickness (i.e., without the concentric change in LV geometry). A multiple linear regression analysis showed that PAC was one of the independent determinants of E/A in the overall subject group. These observations indicate that PAC is associated with the eccentric change in LV geometry in patients with treated essential hypertension and also suggest that the increase in PAC participates in the impairment of LV diastolic function apart from the concentric change in LV geometry, although concentric hypertrophy clearly impairs LV diastolic function.

Aldosterone↗

PubMedDate not supplied

Effects of alcohol consumption and restriction on home blood pressure in hypertensive patients: serial changes in the morning and evening records.

To study the time course of alcohol effects on blood pressure (BP), we examined morning and late evening home BP for 4 weeks in a regular alcohol consumption period and for 4 weeks in a alcohol restriction period in 30 Japanese men with essential hypertension (52 +/- 2 years, m +/- SE) in a randomized crossover study. Mean daily intake of alcohol were 66.5 +/- 4.7 and 10.2 +/- 1.9 ml, respectively. At the end of the regular alcohol period, morning BP had increased by 4.4 +/- 1.1/2.9 +/- 0.8 mmHg but evening BP had decreased by 7.4 +/- 1.9/5.7 +/- 1.7 mmHg. The depressor effect of alcohol on the evening BP was evident from day 1 to week 4, while the pressor effect on the morning BP was significant from week 2 regardless of the order of the two periods. These results confirm the biphasic effect of alcohol on BP, and suggest that the status of alcohol intake may markedly influence the morning-evening BP difference.

Adult↗

PubMedDate not supplied

Clinical characteristics and survival in end-stage renal disease patients with arteriosclerosis obliterans.

BACKGROUND: Atherosclerotic disease (ASO) is considered a serious problem in dialysis patients. We tried to clarify the characteristics of ASO and to evaluate its impact on survival. METHODS: Between January 1990 and December 1999, 525 patients with end-stage renal disease were admitted to our hospital. Among these patients, 71 (59 male and 12 female) had ASO. Blood pressure and blood samples were measured before and after hemodialysis, and were compared with the hemodialysis patients without any cardiovascular diseases. Mortality findings were collected until April 30, 2000. RESULTS: Patients with ASO contained a larger percentage of males, hypertension, hyperlipidemia, diabetes mellitus, nephrosclerosis and smoking status. Their serum calcium, serum phosphate, triglyceride and C-reactive protein levels were also higher. During the follow-up period (2.8 +/- 0.2 years), the mortality rate of the patients with ASO was higher than the hemodialysis patients without any cardiovascular diseases. Among the patients with ASO, the significant covariates concerning the cardiovascular mortality rate were age, hyperlipidemia and smoking status according to the Cox Proportional Hazards regression analysis. CONCLUSIONS: Hemodialysis patients with ASO had many traditional risk factors and uremic risk factors. Their survival rate was poorer and dependent on these risk factors.

Adult↗