Diabetes mellitus, aortic stiffness, and cardiovascular mortality in end-stage renal disease

The combination of chronic kidney disease and increased arterial stiffness is a predictor for stroke and cardiovascular disease in hypertensive patients

To clarify the clinical utility of pulse wave velocity (PWV) and chronic kidney disease (CKD) in hypertension, we analyzed the prognostic impact of PWV and CKD on cerebrocardiovascular disease in hypertensive patients. This study consisted of 531 patients with essential hypertension (male/female=292/239, mean age=61.7±12.3, mean follow-up=7.0±3.0 years) and was performed between January 1998 and June 2004. We used questionnaires to assess stroke (n=57), cardiovascular diseases (CVDs; myocardial infarction, angina and congestive heart failure; n=44) and death (n=53) as primary end points. At baseline, we evaluated the carotid-femoral PWV (9.1±1.8 m s(-1)), the glomerular filtration rate and urinary protein excretions. We divided these subjects into those in the highest quartile of PWV and other subjects and into CKD (n=149) and non-CKD (n=458). We evaluated the prognostic influences of PWV and CKD with Kaplan-Meier analysis and Cox's proportional hazard model. PWV in CKD (9.6±1.9 m s(-1)) was higher than in non-CKD (8.8±1.6 m s(-1); P<0.0001), and creatinine was slightly decreased in the highest PWV group (1.09±0.35 mg dl(-1), P<0.0001). On the basis of Kaplan-Meier analysis, the highest PWV group (PWV>10.1 m s(-1); P=0.0003) and the CKD group (P=0.0005) showed significantly higher proportions of stroke and CVD events. In addition, the highest PWV group showed the highest percentage of stroke (P=0.0007), and the CKD group showed the highest proportion of CVD (P<00001). High PWV and CKD were independent predictors for stroke and CVD (P=0.0332) by Cox's proportional hazard model. These data suggest that increased aortic stiffness and CKD may be predictors for stroke and cardiovascular events in hypertensive patients.

Arterial stiffness predicts cardiovascular outcome in a low-to-moderate cardiovascular risk population: the EDIVA (Estudo de DIstensibilidade VAscular) project

BACKGROUND

Pulse wave velocity (PWV) is a recognized marker of arterial stiffness, although little knowledge exists of their relationship to long-term cardiovascular risk in general populations.

METHODS AND RESULTS

A prospective, multicenter, observational study included 2200 Portuguese nationals (1290 men), aged between 18 and 91 years (mean 46.33±13.76 years). They underwent clinical assessment and annual PWV measurement using a Complior device, and major adverse cardiovascular events (MACEs)--death, stroke, myocardial infarction, unstable angina, peripheral arterial disease, revascularization, or renal failure--were recorded. During a mean follow-up of 21.42±10.76 months, there were 47 nonfatal MACEs (2.1% of the sample). PWV was significantly higher in individuals with events than in those without events (11.76±2.13 vs. 10.01±2.01 m/s, respectively, P<0.001). The study population was divided into two groups by PWV, classified as normal (PWV<95th percentile) or high (PWV>95th percentile), according to predefined criteria for normality. Cumulative event-free survival at 2 years was 99.3% in the normal PWV group and 95% in the high PWV group. The hazard ratio for MACE in the high PWV group was 9.901 [95% confidence interval (CI) 5.00-19.59, P<0.001], and 4.832 (95% CI 2.35-9.94, P<0.001) when adjusted for other risk factors. For absolute PWV, the adjusted hazard ratio (per 1 m/s change) was 1.316 (95% CI 1.13-1.53, P<0.001).

CONCLUSION

The results of the initial analysis of this study highlight the clinical relevance of PWV as a cardiovascular risk marker and demonstrate that PWV measurement can make an important contribution to assessment of cardiovascular prognosis.

Smoking in dialysis patients: a systematic review and meta-analysis of mortality and cardiovascular morbidity

BACKGROUND

Cigarette smoking is associated with increased cardiovascular morbidity and mortality in the general population, but the effect of smoking on these outcomes in the dialysis population is less well studied.

STUDY DESIGN

Systematic review and meta-analysis of cohort studies.

SETTING & POPULATION

Adults treated with long-term hemodialysis or peritoneal dialysis. SELECTION CRITERIA FOR INCLUDED STUDIES: Cohort studies of unselected dialysis patients reporting the association between smoking status and cardiovascular morbidity and/or mortality.

PREDICTOR

Smoking status (determined using patient report).

OUTCOMES

(1) All-cause or cardiovascular mortality; (2) incident cardiovascular events.

RESULTS

We identified 34 studies that fulfilled all inclusion criteria. Of these, 26 studies provided data for smoking and mortality and 10 (n = 6,538) were included in a meta-analysis. The pooled HR for all-cause mortality in smokers compared with nonsmokers was 1.65 (95% CI, 1.26-2.14; P < 0.001). 11 studies provided data for smoking and incident cardiovascular events; 5 (pooled n = 845) were included in a meta-analysis. The pooled HR for composite cardiovascular events in smokers compared with nonsmokers was 1.01 (95% CI, 0.98-1.05; P = 0.4).

LIMITATIONS

Data for these meta-analyses were heterogeneous. Few individual studies assessed smoking as the primary variable of interest.

CONCLUSIONS

Active smoking is associated with a significant increase in all-cause mortality in dialysis patients, although there was no corresponding increased risk of cardiovascular events.

Aortic stiffness is associated with vascular calcification and remodeling in a chronic kidney disease rat model

Increased aortic pulse-wave velocity (PWV) reflects increased arterial stiffness and is a strong predictor of cardiovascular risk in chronic kidney disease (CKD). We examined functional and structural correlations among PWV, aortic calcification, and vascular remodeling in a rodent model of CKD, the Lewis polycystic kidney (LPK) rat. Hemodynamic parameters and beat-to-beat aortic PWV were recorded in urethane-anesthetized animals [12-wk-old hypertensive female LPK rats ( n = 5)] before the onset of end-stage renal disease and their age- and sex-matched normotensive controls (Lewis, n = 6). Animals were euthanized, and the aorta was collected to measure calcium content by atomic absorption spectrophotometry. A separate cohort of animals ( n = 5/group) were anesthetized with pentobarbitone sodium and pressure perfused with formalin, and the aorta was collected for histomorphometry, which allowed calculation of aortic wall thickness, medial cross-sectional area (MCSA), elastic modulus (EM), and wall stress (WS), size and density of smooth muscle nuclei, and relative content of lamellae, interlamellae elastin, and collagen. Mean arterial pressure (MAP) and PWV were significantly greater in the LPK compared with Lewis (72 and 33%, respectively) animals. The LPK group had 6.8-fold greater aortic calcification, 38% greater aortic MCSA, 56% greater EM/WS, 13% greater aortic wall thickness, 21% smaller smooth muscle cell area, and 20% less elastin density with no difference in collagen fiber density. These findings demonstrate vascular remodeling and increased calcification with a functional increase in PWV and therefore aortic stiffness in hypertensive LPK rats.

Elevated non-high-density lipoprotein cholesterol (non-HDL-C) predicts atherosclerotic cardiovascular events in hemodialysis patients

BACKGROUND AND OBJECTIVES

Dialysis patients show "reverse causality" between serum cholesterol and mortality. No previous studies clearly separated the risk of incident cardiovascular disease (CVD) and the risk of death or fatality after such events. We tested a hypothesis that dyslipidemia increases the risk of incident atherosclerotic CVD and that protein energy wasting (PEW) increases the risk of fatality after CVD events in hemodialysis patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was an observational cohort study in 45,390 hemodialysis patients without previous history of myocardial infarction (MI), cerebral infarction (CI), or cerebral bleeding (CB) at the end of 2003, extracted from a nationwide dialysis registry in Japan. Outcome measures were new onsets of MI, CI, CB, and death in 1 year.

RESULTS

The incidence rates of MI, CI, and CB were 1.43, 2.53, and 1.01 per 100 person-years, and death rates after these events were 0.23, 0.21, and 0.29 per 100 person-years, respectively. By multivariate logistic regression analysis, incident MI was positively associated with non-HDL cholesterol (non-HDL-C) and inversely with HDL cholesterol (HDL-C). Incident CI was positively associated with non-HDL-C, whereas CB was not significantly associated with these lipid parameters. Among the patients who had new MI, CI, and/or CB, death risk was not associated with HDL-C or non-HDL-C, but with higher age, lower body mass index, and higher C-reactive protein levels.

CONCLUSIONS

In this hemodialysis cohort, dyslipidemia was associated with increased risk of incident atherosclerotic CVD, and protein energy wasting/inflammation with increased risk of death after CVD events.

Doppler ultrasound in the measurement of pulse wave velocity: agreement with the Complior method

Aortic stiffness is an independent predictor factor for cardiovascular risk. Different methods for determining pulse wave velocity (PWV) are used, among which the most common are mechanical methods such as SphygmoCor or Complior, which require specific devices and are limited by technical difficulty in obtaining measurements. Doppler guided by 2D ultrasound is a good alternative to these methods. We studied 40 patients (29 male, aged 21 to 82 years) comparing the Complior method with Doppler. Agreement of both devices was high (R = 0.91, 0.84-0.95, 95% CI). The reproducibility analysis revealed no intra-nor interobserver differences. Based on these results, we conclude that Doppler ultrasound is a reliable and reproducible alternative to other established methods for the measurement of aortic PWV.

Advanced glycation end products, carotid atherosclerosis, and circulating endothelial progenitor cells in patients with end-stage renal disease

Numbers of endothelial progenitor cells (EPCs) have been shown to be decreased in subjects with end-stage renal disease (ESRD), the mechanism of which remained poorly understood. In this study, mutual association among circulating EPC levels, carotid atherosclerosis, serum pentosidine, and skin autofluorescence, a recently established noninvasive measure of advanced glycation end products accumulation, was examined in 212 ESRD subjects undergoing hemodialysis. Numbers of circulating EPCs were measured as CD34+ CD133+ CD45(low) VEGFR2+ cells and progenitor cells as CD34+ CD133+ CD45(low) fraction by flow cytometry. Skin autofluorescence was assessed by the autofluorescence reader; and serum pentosidine, by enzyme-linked immunosorbent assay. Carotid atherosclerosis was determined as intimal-medial thickness (IMT) measured by ultrasound. Circulating EPCs were significantly and inversely correlated with skin autofluorescence in ESRD subjects (R = -0.216, P = .002), but not with serum pentosidine (R = -0.079, P = .25). Circulating EPCs tended to be inversely associated with IMT (R = -0.125, P = .069). Intimal-medial thickness was also tended to be correlated positively with skin autofluorescence (R = 0.133, P = .054) and significantly with serum pentosidine (R = 0.159, P = .019). Stepwise multiple regression analyses reveal that skin autofluorescence, but not serum pentosidine and IMT, was independently associated with low circulating EPCs. Of note, skin autofluorescence was also inversely and independently associated with circulating progenitor cells. Thus, tissue accumulated, but not circulating, advanced glycation end products may be a determinant of a decrease in circulating EPCs in ESRD subjects.

Impact of arterial stiffness on adverse cardiovascular outcomes and mortality in peritoneal dialysis patients

BACKGROUND

Cardiovascular (CV) disease is a major cause of morbidity and mortality in patients with end-stage renal disease. In recent years, arterial stiffness has taken on great importance in the pathophysiology of CV diseases. The independent predictive value of arterial stiffness for CV events and for all-cause and CV mortality has been demonstrated in the general population and in hemodialysis patients. Our aim in this study was to determine the relationship of arterial stiffness with mortality and fatal and nonfatal CV events in peritoneal dialysis (PD) patients.

METHODS

In this prospective observational cohort study with 2 years of follow-up, we studied a cohort of 156 PD patients with a mean follow-up of 19.2 ± 6.4 months. At baseline, echocardiography and standard clinical and biochemical analyses were performed in all patients and in 28 healthy subjects. Aortic stiffness index beta (ASIβ, a surrogate marker of arterial stiffness) was calculated as follows: ASIβ = ln (systolic blood pressure / diastolic blood pressure) / [(systolic diameter – diastolic diameter) / diastolic diameter].

RESULTS

During the follow-up period, 25 of the patients (16.0%) died, and 10 of those deaths had CV causes. Nonfatal CV events occurred in 15 patients. The median ASIβ was greater in PD patients than in control subjects (4.2 vs. 3.5; interquartile range: 3.2 - 5.5 vs. 2.5 - 4.8; p = 0.028]. In the fully adjusted multivariate Cox regression analysis (co-variates: age, sex, albumin, hemoglobin, diabetes mellitus, comorbid CV disease, left ventricular mass index, residual glomerular filtration rate, dialysate-to-plasma ratio of creatinine, Kt/V urea, left ventricular ejection fraction, duration of dialysis, smoking), ASIβ independently predicted fatal and nonfatal CV events (hazard ratio: 1.239; 95% confidence interval: 1.103 to 1.392), but not all-cause mortality.

CONCLUSIONS

Our results provide the first direct evidence that arterial stiffness is an independent risk predictor of adverse CV outcome in PD patients.

The combined effect of hypertension and smoking on arterial stiffness

Arterial stiffness plays a critical role in the function of the cardiovascular system as it represents the coupling of the left ventricle and arterial tree. Increased arterial stiffness is associated with a number of cardiovascular complications. Increased stiffness occurs with age and with the development of chronic conditions (e.g., hypertension) and the presence of vascular risk factors (e.g., smoking). Measuring arterial stiffness is increasingly gaining popularity as a method of assessing cardiovascular health and treatment efficacy. The purpose of this review was to assess the combined effect of hypertension and smoking on arterial stiffness. A systematic review of the literature revealed four relevant studies; hypertension and smoking were found to be independent detrimental factors for raising arterial stiffness, and combined they raise arterial stiffness more than either solitary factor. However, a need was identified for future studies to determine the extent to which smoking cessation therapy combined with the appropriate anti-hypertensive medication can lead to stabilization or even reversal of arterial stiffness.

Pulse wave velocity predicts mortality in renal transplant patients

Background

Measuring arterial stiffness using pulse wave velocity (PWV) has become an important tool to assess vascular function and cardiovascular mortality. For subject with hypertension, end-stage renal disease and diabetes, PWV has been shown to predict cardiovascular and all-cause mortality. We hypothesize that PWV would also predict mortality in subjects who have undergone kidney transplantation.

Methods

A cohort of 330 patients with renal transplantation was studied with a mean age at entry 51.4 ± 0.75 years. Mean follow-up was 3.8 years (± 0.7 years); 16 deaths occurred during follow-up. At entry, together with standard clinical and biochemical parameters, PWV was determined from pressure tracing over carotid and femoral arteries.

Results

With increasing PWV, there was a significant increase in age, systolic blood pressure and pulse pressure. In addition, subjects with higher PWV also exhibited more frequently the presence of coronary heart disease. On the basis of Cox analyses, PWV and systolic blood pressure emerged as predictors of all-cause mortality.

Conclusion

These results provide evidence that PWV is a strong predictor of all-cause mortality in the population of renal transplant recipients.

Surrogate markers of cardiovascular disease in CKD: what's under the hood?

Although clinical cardiovascular outcomes, such as heart attack, stroke, and sudden cardiac death, have a dramatic onset, they result from prolonged exposure to an ever-growing array of risk factors. Several noninvasive procedures are available to assess the cumulative effect of these exposures with the goal of more precisely estimating a person's cardiovascular risk. These include ankle-brachial index, which provides an estimation of obstruction in major-vessel lumen caliber; carotid ultrasound, which evaluates carotid intima-media thickness and plaque, visibly quantifying atherosclerotic burden; aortic pulse wave velocity, which provides a measure of large-artery stiffness; and echocardiography, which measures left ventricular mass, providing a measure of subclinical hypertensive heart disease. In this narrative review, we discuss the role of each of these measures, with a particular emphasis on patients with chronic kidney disease.

The method of distance measurement and torso length influences the relationship of pulse wave velocity to cardiovascular mortality

BACKGROUND

The method of estimating distance traveled by the pulse wave, used in the calculation of pulse wave velocity (PWV), is not standardized. Our objective was to assess whether different methods of distance measurement influenced the association of PWV to cardiovascular mortality in hemodialysis (HD) patients.

METHODS

Ninety-eight chronic HD patients had their PWV measured using three methods for distance estimation; PWV1: suprasternal notch-to-femoral site minus suprasternal notch-to-carotid site, PWV2: carotid-to-femoral site, PWV3: carotid-to-femoral site minus suprasternal notch-to-carotid site. Carotid-to-femoral distance was used to approximate torso length. Patients were followed for a median of 30 months and the association of PWV and cardiovascular mortality was assessed using survival analysis before and after stratification for torso length.

RESULTS

The three methods resulted in significantly different PWV values. During follow-up 50 patients died, 32 of cardiovascular causes. In log-rank tests, only tertiles of PWV1 was significantly related to outcome (P values 0.017, 0.257, 0.137, for PWV1, PWV2, and PWV3, respectively). In adjusted Cox, proportional hazards regression only PWV1 was related to cardiovascular mortality. In stratified analysis, however, among patients with below median torso length all PWV values were related to outcome, whereas in patients with above median torso length none of the PWV methods resulted in significant relationship to outcome.

CONCLUSIONS

PWV calculated using suprasternal notch-to-femoral distance minus suprasternal notch-to-carotid distance provides the strongest relationship to cardiovascular mortality. Longer torso weakens the predictive value of PWV, possibly due to more tortuosity of the aorta hence, more error introduced when using surface tape measurements.

The relationship between coronary artery calcification score, plasma osteoprotegerin level and arterial stiffness in asymptomatic type 2 DM

Because T2DM increases the risk of coronary atherosclerosis and CAD and new noninvasive techniques to assess CVD risk have gained considerable popularity, it is important to know how these tools relate to each other. The aim of this study was to evaluate the relationship between the extent of coronary artery calcification measured by MDCT, plasma OPG levels, baPWV and the established cardiovascular risk factors in Korean patients with T2DM. From November 2006 to December 2007, 110 asymptomatic Korean patients with T2DM without prior evidence of CAD were assessed (mean age 57.2 years). CAC imaging was performed using a 40-slice MDCT. Serum OPG levels were measured by an enzyme-linked immunosorbent assay (Oscotec, Korea) from the serum samples of each subject. We measured the baPWV as an index of arterial stiffness. In addition, we measured fasting glucose, HbA(1)C, hsCRP and lipid profiles. A total of 74 patients (67.3%) had minimal or insignificant CAC (<10). The CACS, OPG and baPWV showed significant positive correlations with each other. The CACS was significantly associated with the baPWV, smoking and use of a statin. The baPWV was significantly associated with age, duration of DM, total cholesterol and CACS by multiple linear regression models of the dependent variables of CACS or baPWV. CAC and baPWV were significant predictors of each other (r = 0.359, P = 0.014 and r = 0.361, P = 0.004). The results of this study showed that CAC, baPWV and serum OPG levels were significantly correlated with each other in asymptomatic Korean patients with T2DM. Furthermore, our results suggest that arterial stiffness, as determined by baPWV, may predict the extent of coronary calcification by MDCT.

Survival predictability of lean and fat mass in men and women undergoing maintenance hemodialysis

BACKGROUND

Larger body size is associated with greater survival in maintenance hemodialysis (MHD) patients. It is not clear how lean body mass (LBM) and fat mass (FM) compare in their associations with survival across sex in these patients.

OBJECTIVE

We examined the hypothesis that higher FM and LBM are associated with greater survival in MHD patents irrespective of sex.

DESIGN

In 742 MHD patients, including 31% African Americans with a mean (± SD) age of 54 ± 15 y, we categorized men (n = 391) and women (n = 351) separately into 4 quartiles of near-infrared interactance-measured LBM and FM. Cox proportional hazards models estimated death hazard ratios (HRs) (and 95% CIs), and cubic spline models were used to examine associations with mortality over 5 y (2001-2006).

RESULTS

After adjustment for case-mix and inflammatory markers, the highest quartiles of FM and LBM were associated with greater survival in women: HRs of 0.38 (95% CI: 0.20, 0.71) and 0.34 (95% CI: 0.17, 0.67), respectively (reference: first quartile). In men, the highest quartiles of FM and percentage FM (FM%) but not of LBM were associated with greater survival: HRs of 0.51 (95% CI: 0.27, 0.96), 0.45 (95% CI: 0.23, 0.88), and 1.17 (95% CI: 0.60, 2.27), respectively. Cubic spline analyses showed greater survival with higher FM% and higher "FM minus LBM percentiles" in both sexes, whereas a higher LBM was protective in women.

CONCLUSIONS

In MHD patients, higher FM in both sexes and higher LBM in women appear to be protective. The survival advantage of FM appears to be superior to that of LBM. Clinical trials to examine the outcomes of interventions that modify body composition in MHD patients are indicated.

Mid-arm muscle circumference and quality of life and survival in maintenance hemodialysis patients

BACKGROUND AND OBJECTIVES

Maintenance hemodialysis (MHD) patients with larger body or fat mass have greater survival than normal to low mass. We hypothesized that mid-arm muscle circumference (MAMC), a conveniently measured surrogate of lean body mass (LBM), has stronger association with clinical outcomes than triceps skinfold (TSF), a surrogate of fat mass.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

The associations of TSF, MAMC, and serum creatinine, another LBM surrogate, with baseline short form 36 quality-of-life scores and 5-year survival were examined in 792 MHD patients. In a randomly selected subsample of 118 subjects, LBM was measured by dual-energy x-ray absorptiometry.

RESULTS

Dual-energy x-ray absorptiometry-assessed LBM correlated most strongly with MAMC and serum creatinine. Higher MAMC was associated with better short form 36 mental health scale and lower death hazard ratios (HRs) after adjustment for case-mix, malnutrition-inflammation-cachexia syndrome, and inflammatory markers. Adjusted death HRs were 1.00, 0.86, 0.69, and 0.63 for the first to fourth MAMC quartiles, respectively. Higher serum creatinine and TSF were also associated with lower death HRs, but these associations were mitigated after multivariate adjustments. Using median values of TSF and MAMC to dichotomize, combined high MAMC with either high or low TSF (compared with low MAMC/TSF) exhibited the greatest survival, i.e., death HRs of 0.52 and 0.59, respectively.

CONCLUSIONS

Higher MAMC is a surrogate of larger LBM and an independent predictor of better mental health and greater survival in MHD patients. Sarcopenia-correcting interventions to improve clinical outcomes in this patient population warrant controlled trials.

Chronic kidney disease is associated with increased carotid artery stiffness without morphological changes in participants of health check-up programs

BACKGROUND AND METHODS

Patients with chronic kidney disease (CKD) show a much higher risk of cardiovascular disease. However, the mechanisms underlying this association and the impact of CKD on behaviors of the vascular walls have not been fully clarified. Using ultrasonography, this study investigated associations of CKD (estimated glomerular filtration rate <60 ml/min/1.73 m(2) and/or presence of proteinuria) with both elasticity (stiffness β index) of the carotid artery and intimal atherosclerotic changes in participants of health check-up programs (n=3406, 63% men; mean age, 58.8 years).

RESULTS

Stiffness β was significantly higher in CKD subjects (7.49 ± 0.14) than in non-CKD subjects (6.87 ± 0.05, P<0.001). This significant difference was maintained in a multiple adjusted model including conventional risk factors such as hypertension, diabetes mellitus, dyslipidemia, smoking and obesity (7.20 ± 0.14 vs. 6.91 ± 0.05, P=0.043). No significant differences in intima-media complex thickness or plaque score were seen between CKD and non-CKD subjects.

CONCLUSION

In participants of health check-up programs, CKD was associated with increased carotid arterial stiffness without intimal disease, independently of conventional risk factors. These findings indicate that CKD may predispose the carotid arteries to earlier development of arteriosclerosis, characterized by increased arterial stiffness.

Head-to-head comparison of the cardio-ankle vascular index between patients with acute coronary syndrome and stable angina pectoris

We aimed to evaluate whether there was a difference in the arterial stiffness assessed by the cardio-ankle vascular index (CAVI) between patients with acute coronary syndrome (ACS) and those with stable angina pectoris (SAP). A total of 199 consecutive patients, 79 with ACS and 120 with SAP, who underwent emergency or elective coronary revascularization were enrolled. The CAVI was measured within 2 days after the procedures, and was compared between the ACS and SAP patients. As parameters related to arteriosclerosis, carotid intima-media thickness (IMT) and number of stenotic coronary vessels were also evaluated. Although IMT was significantly greater in SAP patients (2.1±1.1 vs. 2.4±0.9; P=0.022), CAVI was significantly higher in ACS patients (10.0±1.7 vs. 9.3±1.3; P=0.0012). After an adjustment for the clinical parameters with a significant difference between the two patient groups, CAVI remained significantly higher in ACS patients than in SAP patients (odds ratio 1.92, 95% confidence interval 1.30-3.02; P=0.0023). A multiple linear regression analysis revealed that age (β=0.44; P<0.0001) and ACS (β=0.3; P<0.0001) were the independent determinants of CAVI. A significant decrease in CAVI was observed at 6 months of follow-up as compared with the acute phase in 18 patients with ACS (10.9±1.6 vs. 10.0±1.5; P=0.019). In conclusion, CAVI was significantly and independently higher in patients with ACS than in those with SAP, which might result from a transient increase in the CAVI caused by acute myocardial ischemia.

Chronic Kidney Disease Japan Cohort study: baseline characteristics and factors associated with causative diseases and renal function

BACKGROUND

Prevalence of chronic kidney disease (CKD) is estimated to be 13.3 million in Japan, but patient characteristics during the predialysis period (CKD stages 3-5) are not well studied.

METHODS

We established the Chronic Kidney Disease Japan Cohort (CKD-JAC) to study the incidence of cardiovascular disease (CVD), end-stage renal disease (ESRD), and all-cause mortality in predialysis patients treated by nephrologists for 4 years. The inclusion criteria were (1) Japanese and Asian patients living in Japan, (2) age 20-75 years, and (3) estimated glomerular filtration rate (eGFR) 10-59 ml/min/1.73 m(2).

RESULTS

We analyzed 2977 participants for baseline characteristics. Mean eGFR was 28.6 ± 11.8 ml/min/1.73 m(2), and mean albuminuria was 976 ± 1340 mg/g Cr. In our study, 91.9% of participants had hypertension, but it was well controlled (131/76 mmHg). Angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) were used by most participants. Less than 15% of participants had history of ischemic heart disease, and 11.5% had history of stroke. Heart failure and arteriosclerosis obliterans were present in 3.9% and 3.6% of patients, respectively. Indicators of arteriosclerosis, higher pulse wave velocity (PWV), and high pulse pressure were associated with diabetes and particularly with diabetic nephropathy. Patients included due to glomerulonephritis seemed to be at low risk for atherosclerosis and also to show lower levels of hypertension.

CONCLUSIONS

The difference between causative diseases is associated with different comorbidity and level of arteriosclerosis. Future analysis of the cohort will clarify whether incidence of ESRD and CVD differs among causative diseases.

AGEs/RAGE in CKD: irreversible metabolic memory road toward CVD?

BACKGROUND

Cardiovascular disease is the major cause of death in patients with renal insufficiency, accounting for 50% of all deaths in renal replacement therapy patients. Mortality from cardiovascular diseases in these patients is approximately 9% per year, which is about 30 times the risk in the general population. So far, intensive interventions to the general risk factors, such as high LDL-cholesterol or C-reactive protein, have not been successful in improving their cardiovascular outcomes, suggesting that the beneficial effect of risk reduction may be overwhelmed by accumulated risk memorized by long-term exposure to oxidative stress during the progression of renal failure.

DESIGN

In this review, we propose that this irreversible memory effect in renal failure may be mediated by advanced glycation end-products (AGEs).

RESULTS

The generation of AGEs has been implicated to be deeply associated with increased oxidative stress. Moreover, interaction of the receptor for AGEs (RAGE) with AGEs leads to crucial biomedical pathway generating intracellular oxidative stress and inflammatory mediators, which could result in further amplification of the pathway involved in AGE generation. Several lines of evidence suggest that AGEs/RAGE axis can profoundly be involved in cardiovascular diseases. Recent advances in AGEs and RAGE measurements led us to be capable of understanding more about the role of AGEs/RAGE axis as a risk for cardiovascular diseases in patients with renal failure.

CONCLUSION

AGEs/RAGE axis could be a crucial mediator of oxidative stress in renal failure. RAGE could be not only a useful biomarker, but also a potentially therapeutic target to overcome the accumulated adverse metabolic memory in renal failure.

Vascular cryografts offer better biomechanical properties in chronically hemodialyzed patients: role of cryograft type, arterial pathway, and diabetic nephropathy as matching determinants

This study aimed to characterize the following: (i) in chronically hemodialyzed subjects (CHDSs), with and without diabetic nephropathy (DN), and in healthy subjects (non-CHDSs) different arterial pathways stiffness to determine potential pathology-dependent, etiology- and/or pathway-dependent differences; and (ii) the biomechanical mismatch (BM) between arteries from non-CHDSs or CHDSs (with and without DN) and arterial cryografts, venous cryografts, and synthetic prosthesis to determine arterial pathway, pathology, and/or etiology-related differences in the substitute of election in terms of BM. Carotid-femoral and carotid-brachial pulse wave velocity (PWV) were measured in 30 non-CHDSs and 71 CHDSs (11 with DN). In addition, PWV was measured in arterial (elastic and muscular) and venous cryografts and in expanded polytetrafluorethylene prosthesis. The arterial pathways regional differences and the subjects' arterial pathways-substitutes BM were calculated. Arterial stiffness levels and regional differences were higher in CHDS than in non-CHDS. Among CHDS, those with DN showed higher stiffness in the aorto-femoral pathway and larger regional differences. Cryografts showed always the least BM. Non-CHDS and CHDS differed in the cryograft of election. In CHDS, the BM was related with the cryograft type, arterial pathway, and renal disease etiology. The BM could be minimized, selecting the most adequate cryograft type, taking into account the recipient specific characteristic (i.e., arterial pathway and renal disease etiology).

Brachial-ankle pulse wave velocity as an index of central arterial stiffness

AIM

Stiffness of the central arteries plays an important role in the pathophysiology of cardiovascular disease, and pulse wave velocity (PWV) of the aorta has been used as the standard measure of central arterial stiffness. An automated device for brachial-ankle (ba) PWV is available, although information is limited whether baPWV reflects the stiffness of central or peripheral arteries. We therefore addressed this question in the present study.

METHODS

The subjects were 2,806 consecutive participants in our non-invasive vascular laboratory, excluding those with an ankle-brachial index (ABI) lower than 0.95. PWV measurements were simultaneously performed using an automated device for the ba, heart-femoral (hf, aorta), heart-carotid (hc), heart-brachial (hb), and femoral-ankle (fa) segments. Correlational analyses were performed (1) among these PWV values, (2) between PWV and individual risk factors, and (3) between PWV and the Framingham risk score (FRS), a surrogate index for integrated cardiovascular risk.

RESULTS

The correlation of baPWV was the highest with hfPWV (r=0.796) and the lowest with hcPWV (r=0.541). Among the known factors preferentially affecting central arterial stiffness, higher age, diabetes mellitus, and chronic kidney disease (CKD) were also closely associated with increased baPWV. Finally, FRS was more closely correlated with hfPWV (r=0.613) and baPWV (r=0.609) than with hbPWV (r=0.523), hcPWV (r=0.509), and faPWV (r=0.393).

CONCLUSION

These results indicate that baPWV is an index of arterial stiffness showing similar characteristics to those of aortic PWV.

[Significance of arterial stiffness parameters for predicting cardiovascular mortality in hemodialysis patients: a prospective cohort study]

Previous studies demonstrated that different parameters of arterial stiffness are related to cardiovascular mortality in hemodialysis patients. The relative prognostic value of these parameters has not previously been evaluated in one cohort.

PATIENTS AND METHODS

Carotid-femoral pulse wave velocity, carotid augmentation index, carotid pulse pressure and carotid-brachial pulse pressure amplification were measured in 98 patients before and after hemodialysis. Patients were followed for a median of 29 months (1-34) and the association of these parameters with cardiovascular mortality was assessed using log-rank tests and Cox proportional hazards regressions.

RESULTS

During follow-up, 40 patients died (mortality rate 20.7/100 patient-year), of which 25 died of cardiovascular causes. Increasing pre- and postdialysis pulse wave velocity tertiles and decreasing predialysis pulse pressure amplification tertiles were significantly related to cardiovascular mortality (p-values are 0.012 and 0.011 for pre- and postdialysis pulse wave velocity, and <0.001 and 0,321 for pre- and postdialysis pulse pressure amplification, respectively). Neither the carotid augmentation index nor carotid pulse pressure was related to cardiovascular mortality. In the Cox-regression, the adjusted hazard ratios for 1 m/s higher pre- and postdialysis pulse wave velocity were 1.24 (1.07-1.44) and 1.17 (1.06-1.28), respectively. The hazard ratio for 10% lower predialysis pulse pressure amplification was 1.41 (1.03-1.92). When included in the same model, both predialysis pulse wave velocity and pulse pressure amplification remained significantly associated with cardiovascular mortality (relative risk: 1.23 [1.07-1.42] and 1.39 [1.02-1.89]).

CONCLUSION

Among different stiffness parameters, pulse wave velocity is consistently related to cardiovascular mortality, irrespective of the timing of measurement. Predialysis pulse pressure amplification seems to provide additional prognostic information.

Arterial stiffness in the young: assessment, determinants, and implications

Arterial stiffness describes the rigidity of the arterial wall. Its significance owes to its relationship with the pulsatile afterload presented to the left ventricle and its implications on ventricular-arterial coupling. In adults, the contention that arterial stiffness as a marker and risk factor for cardiovascular morbidity and mortality is gaining support. Noninvasive methods have increasingly been adopted in both the research and clinical arena to determine local, segmental, and systemic arterial stiffness in the young. With adoption of these noninvasive techniques for use in children and adolescents, the phenomenon and significance of arterial stiffening in the young is beginning to be unveiled. The list of childhood factors and conditions found to be associated with arterial stiffening has expanded rapidly over the last decade; these include traditional cardiovascular risk factors, prenatal growth restriction, vasculitides, vasculopathies associated with various syndromes, congenital heart disease, and several systemic diseases. The findings of arterial stiffening have functional implications on energetic efficiency, structure, and function of the left ventricle. Early identification of arterial dysfunction in childhood may provide a window for early intervention, although longitudinal studies are required to determine whether improvement of arterial function in normal and at-risk paediatric populations will be translated into clinical benefits.

Prediction of cardiovascular events and all-cause mortality with arterial stiffness: a systematic review and meta-analysis

OBJECTIVES

The purpose of this study was to calculate robust quantitative estimates of the predictive value of aortic pulse wave velocity (PWV) for future cardiovascular (CV) events and all-cause mortality by meta-analyses of longitudinal studies.

BACKGROUND

Arterial stiffness is increasingly recognized as a surrogate end point for CV disease.

METHODS

We performed a meta-analysis of 17 longitudinal studies that evaluated aortic PWV and followed up 15,877 subjects for a mean of 7.7 years.

RESULTS

The pooled relative risk (RR) of clinical events increased in a stepwise, linear-like fashion from the first to the third tertile of aortic PWV. The pooled RRs of total CV events, CV mortality, and all-cause mortality were 2.26 (95% confidence interval: 1.89 to 2.70, 14 studies), 2.02 (95% confidence interval: 1.68 to 2.42, 10 studies), and 1.90 (95% confidence interval: 1.61 to 2.24, 11 studies), respectively, for high versus low aortic PWV subjects. For total CV events and CV mortality, the RR was significantly higher in high baseline risk groups (coronary artery disease, renal disease, hypertension) compared with low-risk subjects (general population). An increase in aortic PWV by 1 m/s corresponded to an age-, sex-, and risk factor-adjusted risk increase of 14%, 15%, and 15% in total CV events, CV mortality, and all-cause mortality, respectively. An increase in aortic PWV by 1 SD was associated with respective increases of 47%, 47%, and 42%.

CONCLUSIONS

Aortic stiffness expressed as aortic PWV is a strong predictor of future CV events and all-cause mortality. The predictive ability of arterial stiffness is higher in subjects with a higher baseline CV risk.

The effect of smoking on arterial stiffness

A systematic literature review was conducted using PubMed, Embase and the Cochrane Library to determine the effect of acute, chronic and passive smoking on arterial stiffness and to determine whether these effects are reversible after smoking cessation. A total of 39 relevant studies were identified and included. Acute smoking was found to cause an acute increase in arterial stiffness. Similarly, passive smoking increased arterial stiffness acutely and chronically. The majority of studies identified chronic smoking as a risk factor for increasing arterial stiffness. However, some studies found no statistical difference in arterial stiffness between nonsmokers and long-term smokers, although chronic smoking seems to sensitize the arterial response to acute smoking. In addition, whether arterial stiffness is reversed after smoking cessation and the timeline in which this may occur could not be determined from the identified literature. The effect of smoking discontinuation on arterial stiffness remains to be established by prospective smoking cessation trials.

Aortic stiffness is independently associated with rate of renal function decline in chronic kidney disease stages 3 and 4

Aortic stiffness and chronic kidney disease are closely linked by shared risk factors and associated increased cardiovascular mortality. At lower levels of renal function, aortic stiffness is independently associated with glomerular filtration rate. However, the longitudinal impact of aortic stiffness on renal function has not been reported previously. A cohort of 133 patients with chronic kidney disease stages 3 and 4 (estimated glomerular filtration rate: 15 to 59 mL/min per 1.73 m(2)) underwent prospective measurement of arterial stiffness parameters and monitoring of renal function. Aortic pulse wave velocity measurement was performed in 120 patients. The mean age was 69+/-12 years (mean+/-SD; 103 men, 30 women, and 23.3% diabetic). Mean systolic blood pressure was 155+/-21 mm Hg, and mean diastolic blood pressure was 83+/-11 mm Hg. The mean Modification of Diet in Renal Disease estimated glomerular filtration rate was 32+/-11 mL/min per 1.73 m(2). Change in renal function was measured using reciprocal creatinine plots and the dichotomous combined end point of > or = 25% decline in renal function or start of renal replacement therapy. After stepwise multivariate analysis, aortic pulse wave velocity was independently associated with gradient of reciprocal creatinine plot (r=0.46; P=0.014). In multivariate analysis of the end point of > or = 25% decline in renal function or start of renal replacement therapy, independent predictors were aortic pulse wave velocity (r=0.48; P=0.002), systolic blood pressure (r=0.17; P=0.039), and urine protein:creatinine ratio (r=0.20; P=0.021). We, therefore, conclude that aortic stiffening is independently associated with rate of change in renal function in patients with chronic kidney disease stages 3 and 4.

De-stiffening drug therapy and blood pressure control

In hypertensive subjects, cardiovascular risk reduction is critically related to the decrease of systolic blood pressure (SBP). De-stiffening therapy means that, in a controlled therapeutic trial of long duration, a selective reduction of SBP has been obtained in the studied group by comparison with the control group, and that this SBP reduction is due to a decrease of either arterial stiffness, or wave reflections, or both. Central SBP reduction and cardiovascular remodeling are specifically involved. Most protocols require the presence of an angiotensin II blocker, potentially associated with a diuretic compound and/or a calcium-channel blocker. Cardiovascular outcomes are significantly reduced by comparison with the control group, particularly when this latter group involves administration of a beta-blocking agent.

Improved assessment of aortic calcification in Japanese patients undergoing maintenance hemodialysis

OBJECTIVE

Vascular calcification is a feature of arteriosclerosis and in hemodialysis (HD) patients it may be severe, even at a relatively young age, and is closely related to the overall prognosis. We used the aortic calcification area index (ACAI), derived from the aortic calcification index (ACI), to evaluate and analyze the risk factors for abdominal aortic calcification in HD patients.

PATIENTS AND METHODS

Subjects comprised 137 patients on maintenance HD. ACAI was measured on abdominal plain computed tomography: 10 slices of the abdominal aorta were obtained at 1-cm intervals from the bifurcation of the common iliac artery and the area of the aortic cross-section and calcification was measured using image software. The calcification area was divided by the cross-sectional area and expressed as a percentage (%). The mean value for the 10 slices was also calculated. Patients were divided into 2 groups according to ACAI being lower or higher than the mean value and the risk factors in each group were compared by multivariate analysis. Results Group comparison showed significant differences in age, systolic blood pressure, serum calcium, and lipoprotein(a). On multiple regression analysis, age, systolic blood pressure, and serum calcium were independent risk factors. On logistic regression analysis, age, duration of dialysis, systolic blood pressure, and serum calcium were independent risk factors.

CONCLUSION

Risk factors for abdominal aortic calcification in HD patients include age, systolic blood pressure, and serum calcium, according to ACAI evaluation. The ACAI was accurate and useful for evaluating abdominal calcification.

Exercise and end-stage kidney disease: functional exercise capacity and cardiovascular outcomes

This review examined published reports of the impact of extradialytic and intradialytic exercise programs on physiologic aerobic exercise capacity, functional exercise endurance, and cardiovascular outcomes in individuals with ESKD. Studies spanning 30 years from the first published report of exercise in the ESKD population were reviewed. Studies conducted in the first half of the publication record focused on the efficacy of exercise training programs performed "off"-dialysis with respect to the modification of traditional cardiovascular risk factors, aerobic capacity, and its underlying determinants. In the latter half of the record, there had been a shift to include other client-centered goals such as physical function and quality of life. There is evidence that both intra- and extradialytic programs can significantly enhance aerobic exercise capacity, but moderate-intensity extradialytic programs may result in greater gains in those individuals who initially have extremely poor aerobic capacity. Functionally, substantive improvements in exercise endurance in excess of the minimum clinical significant difference can occur following either low- or moderate-intensity exercise regardless of the initial level of performance. Reductions in blood pressure and enhanced vascular functioning reported after predominantly intradialytic exercise programs suggest that either low- or moderate-intensity exercise programs can confer cardiovascular benefit. Regardless of prescription model, there was an overall lack of evidence regarding the impact of exercise-induced changes in exercise capacity, endurance, and cardiovascular function on a number of relevant health outcomes (survival, morbidity, and cardiovascular risk), and, more importantly, there is no evidence on the long-term impact of exercise and/or physical activity interventions on these health outcomes.

Pre-diabetes and arterial stiffness in uraemic patients

BACKGROUND

In order to address factors of relevance for new onset diabetes mellitus and cardiovascular disease after kidney transplantation, we investigated the presence of pre-diabetes, arterial stiffness and endothelial dysfunction in patients with end-stage renal disease (ESRD) accepted for kidney transplantation.

METHODS

Pre-diabetes and an insulin sensitivity index were estimated by an oral glucose tolerance test in 66 consecutive uraemic patients, without diabetes, being on the waiting list for the first renal transplantation. Mean age was 43 +/- 13 years. Duration of ESRD was 32 +/- 27 months. A control group consisted of 14 healthy subjects. Arterial stiffness was measured by aorta pulse wave velocity (PWV) and aorta augmentation index (AIX). Endothelial function was evaluated by flow-mediated vasodilatation (FMD) and plasma concentrations of von Willebrand factor antigen (vWF). Mean arterial blood pressure (MAP) was measured in supine resting position.

RESULTS

Twenty-seven uraemic patients (41%) had pre-diabetes (IFG+IGT), and 39 had normal glucose tolerance. The uraemic patients were more insulin resistant with lower insulin sensitivity index compared to healthy controls (6.1 +/- 3 vs. 15 +/- 7, P < 0.0001) but with no difference between patients with and without pre-diabetes. HbA1c and fasting plasma glucose was comparable in uraemic patients with and without pre-diabetes. PWV was higher in pre-diabetic compared to normoglycaemic uraemic patients (9.1 +/- 3 vs. 7.3 +/- 2 m/s, P = 0.03) and healthy controls (9.1 +/- 3 vs. 6.7 +/- 1, P = 0.01), while AIX did not differ (24.9 +/- 13 vs. 23.2 +/- 12 vs. 17 +/- 16, P = NS). Presence of pre-diabetes was positively associated to PWV in a univariate analysis. Multivariable analysis revealed age and MAP as independent predictors of PWV in uraemic patients. FMD and vWF were impaired in uraemic patients compared to healthy controls (3 +/- 4 vs. 7 +/- 3, P = 0.007 and 1.8 +/- 0.7 vs. 0.96 +/- 0.3 kIU/L, P = 0.0002, respectively) but with no difference between the two groups of uraemic patients. In conclusion, a high prevalence of pre-diabetes, impaired insulin resistance, increased arterial stiffness of aorta as well as impaired augmentation index and vasodilatation was demonstrated in uraemic patients prior to kidney transplantation. Increased arterial stiffness of aorta and augmentation index were independently associated with age and blood pressure.

Effectiveness and tolerability of rosiglitazone on insulin resistance and body composition in nondiabetic Thai patients undergoing continuous ambulatory peritoneal dialysis: A 12-week pilot study

BACKGROUND

Patients with chronic renal insufficiency, especially those undergoing continuous ambulatory peritoneal dialysis (CAPD), normally have insulin resistance due to deficiencies in insulin secretion and degradation, as well as tissue resistance to insulin at both receptor and postreceptor levels.

OBJECTIVE

The aim of this study was to investigate the effectiveness and tolerability of rosiglitazone on insulin resistance and body composition in patients without diabetes mellitus (DM) undergoing CAPD.

METHODS

This pilot study included a pretest and posttest with a repeated-measure design in a small number of patients. CAPD patients without DM received rosiglitazone 2-mg tablets BID for 12 weeks. Homeostasis Model Assessment Index of Insulin Resistance (HOMA-IR) and bioelectrical impedance analysis (BIA) were used to assess insulin resistance and body composition, respectively. Tolerability was assessed using laboratory analyses as well as physical examination findings to evaluate peripheral edema. Peripheral edema was assessed by the study investigators.

RESULTS

Thirteen Thai patients (mean [SD] age, 54.17 [11.42] years [range, 35-85 years]; body mass index [BMI], >20 to <30 kg/m(2); fasting blood glucose [FBG] concentration, <5.39 mmol/L) were included in the study. One patient was withdrawn due to illness unrelated to the study. No significant difference was found in FBG concentration between baseline and posttreatment (after 12 weeks of treatment) (5.45 [0.59] vs 5.24 [0.51] mmol/L), but fasting plasma insulin concentrations (28.50 [23.70] vs 10.15 [4.22] μIU/mL; P = 0.005) and HOMA-IR score (6.70 [5.23] vs 2.40 [1.15]; P = 0.011) were significantly lower. There were no significant changes in weight or BMI from baseline to posttreatment. Seven subjects (58.3%) experienced weight gain at week 4, while 2 patients (16.7%) still had weight gain after 12 weeks of treatment. A significant increase was found between baseline and posttreatment in total body water (38.03 [4.55] vs 42.44 [5.99] L; P = 0.018), extracellular fluid (20.24 [3.75] vs 26.22 [8.69] L; P = 0.005), plasma fluid (4.29 [0.80] vs 5.20 [0.93] L; P = 0.005), and interstitial fluid (14.99 [2.78] vs 17.68 [3.07] L; P = 0.040). Using BIA, no significant changes were observed in intracellular fluid, fat mass, or liver function. After 12 weeks of rosiglitazone administration, 2 patients (16.7%) had mild edema.

CONCLUSIONS

Rosiglitazone 2 mg BID for 12 weeks was associated with significantly improved insulin resistance in this small group of nondiabetic Thai patients undergoing CAPD. There was a significant increase in total body water and extracellular fluid after administration of rosiglitazone for 12 weeks. There were no significant changes in FBG, weight, or BMI.

Intensified large artery and microvascular response to cold adrenergic stimulation in African blacks

BACKGROUND

Arterial stiffening is more accelerated in blacks than in whites. Whether this is attributed to an enhanced vascular reactivity to environmental stress stimulation remains unknown. We therefore decided to test the hypothesis that cold pressor test (CPT) elicits a greater increase in arterial stiffness and an enhanced sympathetic skin vasoconstriction in African blacks than in whites normotensives.

METHODS

A total of 17 young normotensive African blacks and 17 normotensive whites were recruited. All underwent continuous assessment of blood pressure (BP), heart rate, and carotid-femoral pulse wave velocity (PWVc-f) at rest, during and after hand immersion in iced water (CPT). Concomitantly, skin microvascular blood flow was monitored by laser Doppler flowmetry on the opposite hand.

RESULTS

At baseline, African blacks exhibited higher values of PWVc-f than whites (7.2 +/- 0.3 vs. 6.5 +/- 0.2 m/s, respectively, P = 0.04). During CPT the increases in systolic BP and PWVc-f were greater in African blacks than in whites (systolic BP 17 +/- 2 mm Hg vs. 9 +/- 3 mm Hg, P < 0.001 and PWVc-f 0.62 +/- 0.1 m/s vs. 0.26 +/- 0.1 m/s, P = 0.03, respectively). However, there was no significant difference in the PWVc-f responses among the groups during CPT after adjustment for the increments in mean BP. Finally, CPT induced a more pronounced skin microvascular vasoconstriction in African blacks than in whites (-54.4 +/- 5 % vs. -31.3 +/- 6 %, P < 0.001).

CONCLUSIONS

CPT provokes a more pronounced increase in PWVc-f in normotensive African blacks than in whites, that appears to be due to a greater increase in mean BP. Additionally, African blacks present an intensified skin microvascular response to the CPT as compared to their whites counterparts.

Dialysis modality is independently associated with circulating endothelial progenitor cells in end-stage renal disease patients

BACKGROUND

Numbers of endothelial progenitor cells (EPC) have been shown to be decreased in subjects with end-stage renal disease (ESRD). It is not clear, however, whether dialysis modality affects circulating EPCs in ESRD subjects.

METHODS

We examined the number of circulating EPCs in 67 continuous ambulatory peritoneal dialysis (CAPD) patients and age- and gender-matched 142 haemodialysis (HD) patients, and 78 subjects without chronic kidney disease. Arterial stiffness was analysed as pulse-wave velocity (PWV) for these patients, and their mutual relationship with circulating EPCs was examined. EPCs were measured as CD34(+) CD133(+) CD45(low) VEGFR2(+) cells determined by flow cytometry.

RESULTS

The EPC numbers exhibited a strong correlation (R(2) = 0.866) with endothelial-colony forming units on culture assay. The levels of EPCs in HD or CAPD subjects were significantly lower than those in control subjects. Among ESRD subjects, the levels of EPC were significantly higher in CAPD subjects than those in HD subjects. In ESRD subjects, PWV levels tended to be associated with EPCs (Rs = -0.131, P = 0.058). However, the significant relationship between dialysis modality and circulating EPCs was independent of the levels of PWV. The association of circulating EPCs with dialysis modality was significant even after adjusting for other potential confounders, including age, gender, blood pressure, history of cardiovascular diseases, presence of diabetes, blood haemoglobin level and treatments with angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker or statin.

CONCLUSIONS

CAPD treatment could be a positive regulator of number of circulating EPCs in subjects with ESRD, with the relationship independent of the status of arteriosclerosis.

Plasma Fatty Acid Composition as a Predictor of Arterial Stiffness and Mortality

Aortic stiffness predicts cardiovascular mortality and may be influenced by dietary fat composition. The hypothesis that plasma fat composition influences arterial stiffness and subsequent mortality was tested here in a prospective study. A total of 174 randomly sampled nondiabetic participants aged 45 to 74 years were recruited from local populations, stratified by ethnicity and gender, and followed up for mortality. Aortic pulse wave velocity (PWV), blood pressure, and fatty acid composition of plasma lipids were measured at baseline. PWV was associated with increased cardiovascular mortality and inversely related to the proportions of docosahexaenoic (ρ=−0.22; P =0.02) and arachidonic acids (ρ=−0.25; P <0.001) in plasma lipids. Principal component analyses identified a cluster characterized by higher proportions of palmitate, palmitoleic and oleic acid and lower proportions of linoleic, dihomo-γ linolenic, and arachidonic acids. This cluster was positively associated with PWV, central adiposity, smoking, and increased mortality (hazard ratio: 1.13; 95% CI: 1.01 to 1.27). A second cluster, with higher proportions of arachidonic, eicosapentaenoic, and docosahexaenoic and lower proportions of oleic, palmitic, and linoleic acid levels, was associated with lower PWV and systolic blood pressure but also decreased risk of mortality (hazard ratio: 0.57; 95% CI: 0.39 to 0.82), independent of PWV and blood pressure. These data suggest that plasma fatty acid profiles characterized by a higher proportion of long-chain polyunsaturated fatty acids are associated with decreased cardiovascular mortality, independent of the impact of aortic PWV. The results are consistent with an effect of dietary sources of n-3 long-chain polyunsaturates influencing arterial stiffness and mortality.

Hypertension, systolic blood pressure, and large arteries

This article discusses the following: (1) factors modulating central and peripheral SBP and PP in hypertensive subjects; (2) mechanisms enhancing PP variations in this population; (3) Analysis of pulsatile arterial hemodynamics as predictors of CV risk; and (4) Pulsatile hemodynamics and strategies lowering CV risk in the treatment of hypertension.

Cystatin C associates with arterial stiffness in older adults

Large arteries commonly become stiff in kidney failure, but few studies have investigated arterial stiffness in earlier stages of kidney disease. We evaluated the association between kidney function and aortic pulse wave velocity (aPWV) and its potential modification by race, diabetes, or coronary heart disease in older adults. We measured aPWV in 2468 participants in the Health Aging and Body Composition (Health ABC) study; mean age was 73.7 yr, 40% were black, and 24% had diabetes. After categorizing kidney function into three groups on the basis of cystatin C level, multivariable analysis revealed that the medium and high cystatin C groups associated with a 5.3% (95% confidence interval 0.8 to 10.0%) and 8.0% (95% confidence interval 2.2 to 14.1%) higher aPWV than the low cystatin C group; however, chronic kidney disease, as defined by estimated GFR <60 ml/min per 1.73 m(2), did not significantly associate with aPWV. We did not identify interactions between cystatin C and race, diabetes, or coronary heart disease. In conclusion, stiffness of large arteries, a major risk factor for cardiovascular disease, may partially mediate the association between cystatin C and cardiovascular risk in older adults.