Association of Arterial Stiffness With Chronic Kidney Disease Progression and Mortality

Chronic kidney disease (CKD) is a major public health concern. Despite many potentially life-threatening conditions that can accompany kidney disease, cardiovascular disease (CVD) remains the leading cause of death in these patients. Adjusted-for-age mortality from CVD in patients with end-stage renal disease is 10-30 times higher than in the general population. A decrease in renal function accelerates the development of cardiac pathology. Simultaneous exposure of CVD and CKD plays an important role in the relationship between arterial stiffness (AS) and estimated glomerular filtration rate. But there is a controversy as to whether the AS causes deterioration in kidney function, if renal dysfunction leads to AS, or the relationship is reciprocal. Hence, several studies that recruited high-risk populations reached a conclusion that comorbidities might lead to both AS and decline in kidney function over time. A number of studies have shown that several markers of AS, such as pulse pressure, central and peripheral pressure are associated with the development of CKD. This review takes into account the theoretical background, current status, and future potential of the techniques that measure AS within context of CKD assessment and management.

Targeting mitochondrial fitness as a strategy for healthy vascular aging

Cardiovascular diseases (CVD) are the leading cause of death worldwide and aging is the primary risk factor for CVD. The development of vascular dysfunction, including endothelial dysfunction and stiffening of the large elastic arteries (i.e., the aorta and carotid arteries), contribute importantly to the age-related increase in CVD risk. Vascular aging is driven in large part by oxidative stress, which reduces bioavailability of nitric oxide and promotes alterations in the extracellular matrix. A key upstream driver of vascular oxidative stress is age-associated mitochondrial dysfunction. This review will focus on vascular mitochondria, mitochondrial dysregulation and mitochondrial reactive oxygen species (ROS) production and discuss current evidence for prevention and treatment of vascular aging via lifestyle and pharmacological strategies that improve mitochondrial health. We will also identify promising areas and important considerations ('research gaps') for future investigation.

Healthy lifestyle-based approaches for successful vascular aging

This review summarizes a presentation given at the 2016 Gerontological Society of America Annual Meeting as part of the Vascular Aging Workshop. The development of age-related vascular dysfunction increases the risk of cardiovascular disease as well as other chronic age-associated disorders, including chronic kidney disease and Alzheimer's disease. Healthy lifestyle behaviors, most notably regular aerobic exercise and certain dietary patterns, are considered "first-line" strategies for the prevention and/or treatment of vascular dysfunction with aging. Despite the well-established benefits of these strategies, however, many older adults do not meet the recommended guidelines for exercise or consume a healthy diet. Therefore, it is important to establish alternative and/or complementary evidence-based approaches to prevent or reverse age-related vascular dysfunction. Time-efficient forms of exercise training, hormetic exposure to mild environmental stress, fasting "mimicking" dietary paradigms, and nutraceutical/pharmaceutical approaches to favorably modulate cellular and molecular pathways activated by exercise and healthy dietary patterns may hold promise as such alternative approaches. Determining the efficacy of these novel strategies is important to provide alternatives for adults with low adherence to conventional healthy lifestyle practices for healthy vascular aging.

Contrast-enhanced CT imaging in patients with chronic kidney disease

Renal microvascular rarefaction characterizes chronic kidney disease (CKD). In murine models of CKD, micro-CT imaging reflected capillary rarefaction using quantification of renal relative blood volume (rBV). In addition, micro-CT imaging revealed morphological alterations of the intrarenal vasculature including reduced vascular branching and lumen diameter. Here, we retrospectively quantified rBV in contrast-enhanced CT angiography in patients and found that, compared to non-CKD patients, those with CKD and renal fibrosis had significantly reduced rBV in the renal cortex. rBV values closely mirrored capillary rarefaction in the corresponding nephrectomy specimens. In patients with follow-up CT angiography, reduction of renal function was paralleled by a decline in rBV. Using virtual autopsy, i.e., postmortem CT angiography, morphometry of intrarenal arteries in 3D-rendered CT images revealed significantly reduced arterial diameter and branching in CKD compared to non-CKD cases. In conclusion, in CKD patients, contrast-enhanced CT imaging with quantification of rBV correlates with functional renal vasculature, whereas virtual autopsy allows morphometric analyses of macrovascular changes. Importantly, the observed vascular alterations in CKD patients mirror those in animals with progressive CKD, suggesting a high relevance of animal models for studying vascular alterations in CKD and renal fibrosis.

Relationship Between Carotid Atherosclerosis and Pulse Pressure with Renal Hemodynamics in Hypertensive Patients

BACKGROUND

Structural atherosclerotic damage, arterial stiffness, pulse pressure (PP), and renal hemodynamics may interact and influence each other. Renal resistance index (RRI) appears as a good indicator of systemic vascular changes. The aim of our study was to assess the independent relationships of carotid intima-media thickness (cIMT), aortic pulse wave velocity (aPWV), and peripheral PP with RRI in hypertensives with various degrees of renal function.

METHODS

We enrolled 463 hypertensive patients (30-70 years) with normal renal function (group 0; n = 280) and with chronic kidney disease (groups I-V; n = 183). All subjects underwent ultrasonographic examination of intrarenal and carotid vasculature, as well as a 24-h ambulatory blood pressure monitoring.

RESULTS

A statistically significant difference in RRI, cIMT, aPWV, and clinic PP was observed in the different 6 groups (all P < 0.001), even after adjustment for age. RRI correlated with cIMT (r = 0.460, P < 0.001), aPWV (r = 0.386, P < 0.001), clinic PP (r = 0.279, P < 0.001), and 24-h PP (r = 0.229, P < 0.001) in the entire study population. These correlations were similar in subjects with and without renal dysfunction. In the overall study population, the association between RRI, cIMT, and clinic PP remained statistically significant even after adjustment for various confounding factors, whereas the relationship between RRI and aPWV was lost in multivariate analysis.

CONCLUSIONS

cIMT and clinic PP rather than directly aPWV are associated with intrarenal hemodynamics. Our results confirm that in hypertensives RRI not only detects derangement of intrarenal circulation but may also be considered as a sensor of systemic vascular changes, independently of level of renal function.

Arterial Stiffness and Chronic Kidney Disease

Chronic kidney disease (CKD) is a major public health concern due to the high prevalence of associated cardiovascular (CV) disease. CV mortality is 10-30 times higher in end-stage renal disease patients than in the age-adjusted general population. The last 20 years have been marked by a huge effort in the characterization of the vascular remodeling process associated with CKD and its consequences on the renal, CV and general prognosis. By comparison with patients with normal renal function, with or without hypertension, an increase in large artery stiffness has been described in end-stage renal disease as well as in CKD stages 2-5. Most clinical studies are consistent with the observation that damage to large arteries may contribute to the high incidence of CV disease. By contrast, the impact of large artery stiffening and remodeling on CKD progression is still a matter of debate. Concomitant exposure to other CV risk factors, including diabetes, seems to play a major role in the association between aortic stiffness and estimated GFR. The conflicting results obtained from longitudinal studies designed to evaluate the impact of baseline aortic stiffness on GFR progression are detailed in the present review. Only pulse pressure, central and peripheral, is almost constantly associated with incident CKD and GFR decline. Kidney transplantation improves patients' CV prognosis, but its impact on arterial stiffness is still controversial. Donor age, living kidney donation and mean blood pressure appear to be the main determinants of improvement in aortic stiffness after kidney transplantation.

Reduction of NO-mediated Relaxing Effects in the Thoracic Aorta in an Experimental Chronic Kidney Disease Mouse Model

AIM

Chronic kidney disease (CKD) is known to frequently cause cardiovascular events. However, it is unclear how renal dysfunction affects the vascular response. We herein studied the effects of renal dysfunction on the aortic behavior in adenine-fed mice, investigating mechanisms underlying the occurrence of cardiovascular events in CKD patients.

METHODS

Biochemical analyses of the plasma creatinine, blood urea nitrogen (BUN) and glucose levels and measurements of the blood pressure were performed using C57BL/6 mice fed with and without an adenine-containing diet. The relaxing effects of acetylcholine (ACh) or sodium nitropurusside (SNP) and effects of NO synthase (NOS) inhibitors on the contractions induced by phenylephrine (PE) were measured in endothelium-intact aortas obtained from both mice.

RESULTS

The mice fed 0.25% adenine for four weeks showed greater plasma creatinine and BUN concentrations than the control mice, suggesting that adenine-fed mice are a useful CKD model. Furthermore, ACh relaxed the PE-stimulated, endothelium-intact aortas, the effect of which was less potent in the adenine-fed mice than in the control mice. In contrast, the degree of SNP-induced relaxation of the aortas was the same in the adenine-fed mice and control mice. The α1-adrenergic agonist, PE, induced more potent absolute tension of the endothelium-intact aortas in the CKD model mice than in the control mice, while the NOS inhibitors, N-nitro-L-arginine (LNA) and asymmetric dimethylarginine (ADMA) enhanced the contraction effects of PE in both mice.

CONCLUSIONS

The findings of this study indicate that spontaneous and stimulated NO release from the endothelium is decreased in the CKD model mouse aorta. The NO-mediated correlation between renal and elastic arterial endothelial dysfunction is suggested to be a cause of cardiovascular events in patients with CKD.

Assessment of volume status and arterial stiffness in chronic kidney disease

AIM

There is limited information about arterial stiffness in chronic kidney disease (CKD) which is an independent risk factor for cardiovascular events. Pulse wave velocity (PWV), augmentation index (AIx) are using to determine arterial stiffness. We aimed to study PWV, AIx, volume status in patients with stage 3B-5 CKD and continuous ambulatory peritoneal dialysis (CAPD).

METHODS

Sixty-six stage 3B-5 CKD patients, 21 CAPD patients, 34 healthy controls were included. Pulse wave velocity, AIx, volume status was evaluated by Mobil-O-Graph®, and bioimpedance spectroscopy, respectively.

RESULTS

The Median PWV was 7.5 m/s in CKD, 6.2 m/s in CAPD, 5.9 m/s in healthy controls, and while PWV was found to have increased significantly in CKD patients (p = 0.002), the Alx values were similar in all groups. The median extracellular fluid excess was higher in both the CKD and, CAPD patients when compared with healthy controls (1.26 and 1.21 L, respectively). Overhydration was more prevalent in CKD and CAPD patients (p < 0.001). Age, central systolic blood pressure, body mass index, fat mass, overhydration, CKD, eGFR were the major determinants of PWV.

CONCLUSION

Increased PWV was found in stage 3B-5 CKD patients. Overhydration may contribute this increment.

Does chronic kidney disease modify the association between body mass index and cardiovascular disease risk factors

BACKGROUND

Excess weight is paradoxically associated with better cardiovascular disease (CVD) outcomes and mortality in end-stage renal disease (ESRD) patients treated with hemodialysis. This association has been observed in chronic kidney disease (CKD) as well. One potential explanation for this inverse relationship is that the usual positive correlation between severity of CVD risk factors and higher body mass index (BMI) is reversed in CKD. To test this hypothesis, we determined the relationship between BMI and CVD risk factors in patients with and without CKD.

METHODS

This was a cross-sectional study of the nationally representative US National Health and Nutrition Examination Survey (NHANES) 1999-2006. CKD was defined as glomerular filtration rate <60 ml/min per 1.73 m2. Covariates were age, race/ethnicity, sex and use of relevant prescription medications. Outcome variables were total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, systolic blood pressure (SBP), diastolic blood pressure (DBP), C-reactive protein (CRP) and fasting glucose (FG).

RESULTS

There were 1,895 and 32,431 patients with and without CKD, respectively. Those with CKD were older and had higher BMI. The shapes of the association between BMI and total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, SBP, CRP and FG were similar in those with or without CKD. In a sensitivity analysis excluding patients taking relevant prescription medications, our results did not differ substantially.

CONCLUSIONS

CKD did not alter the shapes of the association between higher BMI and CVD risk factors. Inverse associations between BMI and CVD risk factors are unlikely to explain why CKD patients with higher BMI may have better outcomes.

Comparison of serum albumin, serum C-reactive protein, and pulse wave velocity as predictors of the 4-year mortality of chronic hemodialysis patients

AIM

Although serum albumin and C-reactive protein (CRP) levels and pulse wave velocity (PWV) are known to be associated with the clinical outcome of hemodialysis (HD) patients, it is unknown which of these parameters are more predictive of the long-term mortality of such patients.

METHODS

We measured biochemical parameters, including serum albumin and CRP, and the PWV of 202 patients on maintenance HD therapy and followed their course for 4 years, and 186 of the patients were enrolled in the current study analyses. We divided the 186 patients into three tertiles according to their serum albumin and CRP levels and PWV values, and conducted multivariate analyses to examine the impact of the tertiles on 4-year mortality.

RESULTS

Twenty-three (12.4%) patients died during the follow-up period, and the serum albumin of the group that died was significantly lower than in the group that survived, but the CRP levels and PWV were significantly higher in the group that died. The results of Kaplan-Meier analyses revealed a significantly higher risk of all-cause mortality in HD patients with higher CRP based on the results of Cox proportional hazards analyses; however, the serum albumin and PWV values were not associated with all-cause mortality.

CONCLUSION

The results of this study suggest that serum CRP levels are a better mortality predictor than serum albumin or PWV values of chronic HD patients.

Multimodality vascular imaging in CKD: divergence of risk between measured parameters

BACKGROUND

High cardiovascular risk in chronic kidney disease (CKD) patients appears only partly attributable to atherosclerosis, with much of the remaining risk being ascribed to other vasculature abnormalities, including endothelial dysfunction, arterial stiffness and vascular calcification (VC). To date, these factors have been primarily studied in isolation or in dialysis patients. This study performed a global vascular assessment in moderate CKD and assessed the relationships with both traditional and novel risk factors.

METHODS

This was a prospective cross-sectional analysis of 120 patients (age 60 ± 10 years; estimated glomerular filtration rate 25-60 mL/min/1.73m(2)). Demographic, clinical and biochemical characterization was performed. VC was characterized by lateral lumbar radiograph; arterial stiffness by aortic pulse-wave velocity (PWV); atheroma burden by carotid intima-media thickness (cIMT) and endothelial function by flow-mediated dilation (FMD) of the brachial artery.

RESULTS

VC was highly prevalent (74%), and FMD generally poor (FMDΔ 3.3 ± 3.3%). There were significant correlations between all vascular parameters; although these were predominantly explained by age. cIMT was independently associated with classical risks and also PWV (adjusted standardized β = 0.31, P = 0.001). However, traditional risks showed almost no independent associations with other vascular measurements. In contrast, serum phosphate and 1,25-dihydroxyvitamin D (1,25-OHD) correlated with PWV and the presence of VC, respectively. After adjustment, every 1 pg/mL increase in 1,25-OHD was related to a 3% reduction in the chance of VC (odds ratio 0.97; 95% confidence interval 0.94-1.00, P = 0.03). Medication use, HOMA-IR and C-reactive protein did not correlate with any of the vascular measures.

CONCLUSIONS

This study demonstrates extensive vascular disease across multimodality imaging in moderate CKD. Atherosclerotic burden correlated with traditional risks and PWV, while higher 1,25-OHD was associated with less VC. The lack of association between renal function and imaging indices raises the possibility of a threshold, rather than graded uraemic effect on vascular health that warrants further exploration.

Adults with late stage 3 chronic kidney disease are at high risk for prevalent silent brain infarction: a population-based study

BACKGROUND AND PURPOSE

The close relationship between stroke and chronic kidney disease (CKD) has been well-documented. However, few studies have focused on silent brain infarction (SBI) in CKD. We investigated the prevalence of SBI in different stages of CKD.

METHODS

We included 1312 participants aged 30 to 93 years who came from either a random sample of residents or from a group of physically examined subjects in the same community. Basic information, clinical evaluations, laboratory tests, and MRI images were assessed. Subjects were divided into groups 1, 2, 3a, and 3b, corresponding to the estimated glomerular filtration rate (eGFR) levels of ≥ 90.0, 60.0 to 89.9, 45.0 to 59.9, and 30.0 to 44.9 mL/min/1.73 m².

RESULTS

The crude prevalence was 4.7%: 2.6% (20 of 759 subjects) in group 1; 6.3% (32 of 506) in group 2; 12.9% (4 of 31) in group 3a; and 37.5% (6 of 16) in group 3b (P<0.001). Additionally, SBI also correlated with age, male sex, hypertension, diabetes, moderate carotid plaque, higher blood pressures, obesity, and levels of triglyceride, high-density lipoprotein cholesterol, high-sensitivity C-reactive protein, and uric acid (all P<0.05). The effects for SBI risk in each eGFR group versus group 1 did not increase except for group 3b (OR, 9.34; P<0.001).

CONCLUSIONS

A close association exists between SBI and eGFR. We have found a significant increase in prevalence of SBI when eGFR is between 30.0 and 44.9 mL/min/1.73 m². Adults with late stage 3 CKD are at high risk for prevalent SBI.

Association of arterial stiffness indexes, determined from digital volume pulse measurement and cardiovascular risk factors in chronic kidney disease

BACKGROUND

Progression of atherosclerosis with increased arterial stiffness is associated with increased cardiovascular morbidity and mortality in patients with chronic kidney disease (CKD). Compliance index (CI) derived from digital volume pulse (DVP), measuring the relationship between volume and pressure changes in fingertip, can evaluate the local arterial stiffness. The purpose of this study was to measure the stiffness of different arteries and determine the relationships of CI-DVP with clinical characteristics and renal function in CKD patients.

METHODS

This cross-sectional pilot study included 186 CKD and 46 healthy subjects. Evaluation of different arterial stiffness was performed by DVP using dual-channel photoplethysmography and measured as CI (CI-DVP) and pulse wave velocity (PWV)-DVP.

RESULTS

CKD patients had lower CI-DVP and higher PWV-DVP than that in the healthy group. There was a trend of stepwise decrease in CI-DVP and increase in PWV-DVP related to the advance of CKD from early to late stage. Decrease of CI-DVP was associated with the increase in number of cardiovascular risk factors. Multivariate linear regression analysis revealed that CI-DVP (B = 4.59, P < 0.01) was independently associated with estimated glomerular filtration rate (eGFR). Male gender, eGFR, and systolic blood pressure (BP) were independent determinants for CI-DVP (B = -0.25, P = 0.01; B = 0.007, P = 0.03; and B = -0.03, P < 0.0001; whole model R(2) = 0.28, P < 0.0001).

CONCLUSIONS

Our data demonstrate a significant association between CI-DVP, a new surrogate marker of arterial stiffness different from PWV, and renal function and cardiovascular risk factors in CKD patients.

Asymmetric dimethylarginine as a risk factor for cardiovascular disease in Japanese patients with type 2 diabetes mellitus

AIMS

Although asymmetric dimethylarginine (ADMA) is known to be involved in the developing process of cardiovascular diseases (CVD), little is known about the effects of ADMA on atherosclerosis in Asian patients with diabetes, who have the racial feature of lower body mass index (BMI) and decreased capacity of insulin secretion and sensitivity.

METHODS

We employed 55 Japanese patients with type 2 diabetes mellitus (mean age, 64·2 years; 56% men) in a 6-month-longitudinal study and 450 patients (mean age, 62·7 years; 56% men) in a cross-sectional study and examined the association of serum ADMA with atherosclerosis parameters [intima-media thickness (IMT) and brachial-ankle pulse wave velocity (baPWV)] as well as with the presence of CVD.

RESULTS

In the longitudinal study, multiple regression analysis showed that basal serum ADMA level had a significantly positive association with changes in IMT (β=0·35, P=0·03) independently of age, duration of diabetes, BMI, blood pressure, low-density lipoprotein and high-density lipoprotein (LDL and HDL) cholesterol, HbA(1c) , and renal function. In the cross-sectional study, the serum ADMA level was significantly and positively associated with the presence of CVD (odds ratio=7·22, 95% confidence interval 1·29-40·40, P=0·02, by logistic analysis) and with baPWV (β=0·14, P <0·01, by multiple regression analysis). In contrast, serum symmetric dimethylarginine level, a structural isomer of ADMA, was associated neither with parameters for atherosclerosis nor with the presence of CVD in both studies.

CONCLUSIONS

Serum ADMA is a predictor of atherosclerosis and associated with the presence of CVD in Japanese patients with type 2 diabetes mellitus.

Blood pressure and not uraemia is the major determinant of arterial stiffness and endothelial dysfunction in patients with chronic kidney disease and minimal co-morbidity

INTRODUCTION

Patients with chronic kidney disease (CKD) have increased risk of cardiovascular disease to which co-morbidity and associated conventional risk factors contribute. We hypothesised that arterial stiffness (AS) and endothelial dysfunction (ED), as surrogates of cardiovascular risk, would worsen as renal function declined even in patients without co-morbidity and that this would relate to emerging cardiovascular risk factors.

METHODS

Carotid-femoral pulse wave velocity (PWV), as a measure of AS, and flow-mediated dilatation (FMD) of the brachial artery, as a measure of ED, were assessed in CKD patients without established cardiovascular disease or diabetes mellitus.

RESULTS

PWV increased linearly as renal function declined (r(2) = 0.08, p < 0.01) whereas FMD was reduced only in patients with advanced kidney disease. In multivariable analysis, blood pressure was the major determinant of PWV and FMD. High-sensitivity C-reactive protein and asymmetric dimethylarginine, and isoprostanes and endothelin-1, were independent predictors of PWV and FMD, respectively. However, renal function did not independently predict either AS or ED.

CONCLUSIONS

These findings suggest that declining renal function, in the absence of significant co-morbidity, is associated with progressive arterial stiffness, but only patients close to dialysis exhibit endothelial dysfunction. Whilst blood pressure remains the major determinant of PWV and FMD, inflammation, oxidative stress and endothelin-nitric oxide balance contribute to cardiovascular risk, in this non-comorbid cohort.

Acute reversible changes of brachial-ankle pulse wave velocity in children with acute poststreptococcal glomerulonephritis

Acute poststreptococcal glomerulonephritis (APSGN) is the most common form of postinfectious nephritis worldwide. The relationship between inflammation and arterial stiffness has been described elsewhere, but there have been no studies that have analyzed the association between arterial compliance and APSGN. The aim of this study is to assess brachial-ankle pulse wave velocity (baPWV) in pediatric patients with APSGN, and the value of baPWV in predicting the outcome. We evaluated 16 children diagnosed with APSGN, 11 children with acute pyelonephritis (APN), and 25 healthy individuals in our hospital. The baPWV of all candidates was measured. In addition, follow-up of the APSGN group was conducted for baPWV, blood pressure and biochemical parameters. Significantly increased baPWV was observed in the APSGN group at initial diagnosis (P<0.001), in comparison with the APN group and healthy controls. Of these, 13 patients received sequential measurement of baPWV. Overwhelmingly, baPWV was rapidly normalized in 11 patients, whereas 2 boys presented with persistently higher baPWV. During the follow-up period of 2-3 years, both had consistency of proteinuria, and consequently, they progressed to either chronic renal insufficiency or end-stage renal disease (ESRD). In conclusion, the results demonstrate that APSGN involves not only the kidney, but also the arteries outside the kidney. Acute arterial stiffness might persist in patients who do not recover, but develop chronic kidney disease (CKD).

Correlations between aortic stiffness and parasympathetic autonomic function in healthy volunteers

Cardiovascular autonomic dysfunction and alterations in vascular elasticity are known complications of several disorders, including diabetes mellitus, hypertension, hypercholesterolemia, aging, and chronic kidney disease. The current study was designed to test whether a relationship existed between pulse wave velocity (PWV), augmentation index (AIx), aortic elastic properties, and cardiovascular autonomic function in healthy volunteers. The study comprised 25 healthy volunteers, whose aortic strain, distensibility, and stiffness index were measured by echocardiography, whereas PWV and AIx were evaluated by Arteriograph (TensioMed, Budapest, Hungary) in all cases. Autonomic function was assessed by means of 5 standard cardiovascular reflex tests. We found that heart rate response to deep breathing, as the most reproducible cardiovascular reflex test to characterize parasympathetic function, showed low to moderate correlations with PWV (r = -0.431, p = 0.032), aortic strain (r = 0.594, p = 0.002), distensibility (r = 0.407, p = 0.043), and stiffness index (r = -0.453, p = 0.023). Valsalva ratio and autonomic neuropathy score (ANS) correlated with PWV (r = -0.557, p = 0.004 and r = -0.421, p = 0.036, respectively) and AIx (r = -0.461, p = 0.020 and r = -0.385, p = 0.057, respectively), while ANS correlated with even aortic stiffness index (r = -0.457, p = 0.022). Cardiovascular reflex tests mainly characterizing sympathetic function had no correlation with aortic stiffness parameters (p = NS for all correlations). Correlations exist between parameters characterizing aortic elasticity and parasympathetic autonomic function, as shown by standard cardiovascular reflex tests in healthy volunteers.

Arterial stiffness is strongly associated with insulin resistance in Chinese--a population-based study (Taichung Community Health Study, TCHS)

AIM

Few studies have investigated the association between insulin resistance and arterial stiffness in Chinese. We aimed to investigate this relationship in a population-based study of middle-aged Chinese.

METHODS

A total of 2,188 subjects aged 40 years and older were recruited in 2004 in Taiwan. The association between arterial stiffness (measured by brachial-ankle pulse wave velocity (baPWV)) and insulin resistance (represented by homeostasis model assessment (HOMA-IR) and fasting glucose levels) was studied by multiple logistic and linear regression analyses.

RESULTS

The respective prevalence of diabetes and impaired fasting glucose (IFG) was 13.9% and 30.6% in males and 10.4% and 20.8% in females. Using multiple linear regression analyses, we found baPWV to be strongly associated with age, gender, body mass index (BMI), waist circumference (WC), systolic blood pressure (BP), diastolic BP, fasting glucose, and triglycerides. Compared to the lowest HOMA-IR tertile I and adjusting for age, BMI, WC, gender, triglycerides, systolic BP, diastolic BP, smoking, alcohol drinking, betel nut chewing, and physical activity, the odds ratios (95% confidence interval) of arterial stiffness for the higher HOMA-IR tertiles II and III were 1.15 (0.77-1.71) and 1.60 (1.05-2.46), respectively. Using a general linear model with adjustment for age, systolic BP, diastolic BP, BMI, WC, and triglycerides, baPWV was significantly lower in the diabetic group by 90.3 cm/sec in males and 100.5 cm/sec in females compared to the IFG group. When comparing the IFG group to the normal glucose group, baPWV was 28.5 cm/sec lower in males and 14.4 cm/sec lower in females.

CONCLUSIONS

Arterial stiffness is independently associated with insulin resistance in Chinese middle-aged adults. Subjects with diabetes or IFG have higher baPWV than normoglycemic subjects.

Brachial-ankle pulse wave velocity predicts silent cerebrovascular diseases in patients with end-stage renal diseases

AIM

Cerebrovascular disease (CVD) is a major determinant of the prognosis in end-stage renal diseases (ESRD). The purpose of this study was to examine whether factors associated with arterial stiffness contributed to the development of CVD in patients with ESRD.

METHODS

CVD (lacunes and carotid/intracranial artery stenosis) was evaluated with brain magnetic resonance imaging (MRI), and carotid/intracranial artery magnetic resonance angiography (MRA) in 44 pre-dialytic patients. The severity of CVD was evaluated by the number of lacunes and the degree of stenosis, respectively. The association between CVD and atherosclerotic parameters was evaluated.

RESULTS

Patients with severe lacunes (n=18) manifested older age, lower diastolic blood pressure, serum creatinine and albumin, and higher CRP and serum calcium than those with absent-moderate lacunes (n=26). When assessed by multivariate analysis, only baPWV was adopted as an independent risk factor for severe lacunes. Furthermore, baPWV and i-PTH were associated with the severity of carotid/intracranial artery stenosis, both of which were independent of other risk factors, including age and diabetes.

CONCLUSIONS

Arterial stiffness may constitute a novel determinant predicting the severity of CVD in pre-dialytic patients besides classical risk factors.

Chronic kidney disease, all-cause mortality and cardiovascular mortality among Chinese patients with established cardiovascular disease

AIM

This study was conducted to investigate the role of chronic kidney disease (CKD) in 1-year all cause mortality and cardiovascular mortality among Chinese patients who were at least 50 years old and had a history of coronary artery disease (CAD), stroke, or peripheral vascular disease (PAD), or with two or more cardiovascular risks.

METHODS

Of 3,732 hospitalized patients enrolled, 3,423 patients (91.7%) with complete data were eligible for 1-year follow-up. CKD was defined as an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m(2).

RESULTS

1,166 (34.1%) were diagnosed with CKD. Most cases were unrecognized. Patients having an eGFR of <30 mL/min/1.73 m(2) were less likely to be prescribed beta-blockers, statins, or aspirin (all p<0.001). A powerful relationship was observed between the severity of renal dysfunction and all causes of death or cardiovascular death. Adjusted for other covariates, the hazard ratio (HR) for all causes of death and for cardiovascular death among patients with an eGFR of 30-45 mL/min/1.73 m(2) was 1.70 (95% CI, 1.18-2.45) and 1.85 (95% CI, 1.12-3.01) as compared with 2.93 (95% CI, 1.96-4.38) and 3.47 (95% CI, 1.91-6.31) for patients with an eGFR of <30 mL/min/1.73 m(2).

CONCLUSIONS

One third of Chinese patients at high risk for atherosclerotic events were diagnosed with CKD. Most of these cases were unrecognized and undertreated. An eGFR of <45 mL/min/1.73 m(2) was an independent predictor of all causes of death and of cardiovascular death.