Pulse wave velocity as an indicator of arteriosclerosis in hemodialysis patients

Predictive Performance and Optimal Cut-Off Points of Blood Pressure for Identifying Arteriosclerosis among Adults in Eastern China

This study aimed to assess the predictive performance and establish optimal cut-off points of blood pressure for identifying arteriosclerosis in eastern Chinese adults. Brachial–ankle pulse wave velocity (baPWV) was utilized to evaluate arteriosclerosis. The predictive performance of blood pressure for arteriosclerosis was determined by the area under the curve (AUC) of receiver operating characteristics; the optimal blood pressure cut-off points were determined by Youden’s index. A logistic regression model was used to acquire the odds ratio (OR) of blood pressure for arteriosclerosis. The AUCs of blood pressure for identifying arteriosclerosis were 0.868 (95%CI: 0.860–0.875) for systolic blood pressure (SBP) and 0.835 (95%CI: 0.827–0.843) for diastolic blood pressure (DBP), both p < 0.01. The AUCs of women were higher than that of men (0.903 vs. 0.819 for SBP; 0.847 vs. 0.806 for DBP; Z test p < 0.05). The AUCs in the 18–39.9-years group were higher than that in the 40–59.9-years and 60–84-years groups (0.894 vs. 0.842 and 0.818 for SBP; 0.889 vs. 0.818 and 0.759 for DBP; Z test p < 0.05). The total optimal cut-off points of blood pressure for predicting arteriosclerosis were 123.5/73.5 mmHg (SBP/DBP) overall; 123.5/73.5 and 126.5/79.5 mmHg for women and men, respectively; and 120.5/73.5, 123.5/76.5, and 126.5/75.5 mmHg for 18–39.9-years, 40–59.9-years, and 60–84-years groups, respectively. Blood pressure indexes had a high predictive performance for identifying arteriosclerosis with the optimal cut-off point of 123.5/73.5 mmHg (SBP/DBP) in eastern Chinese adults. Women or the younger population have a higher predictive performance and lower cut-off points to identify arteriosclerosis.

Toxin Removal and Inflammatory State Modulation during Online Hemodiafiltration Using Two Different Dialyzers (TRIAD2 Study)

Uremic toxins play a pathological role in atherosclerosis and represent an important risk factor in dialysis patients. Online hemodiafiltration (HDF) has been introduced to improve the clearance of middle- and large-molecular-weight solutes (>500 Da) and has been associated with reduced cardiovascular mortality compared to standard hemodialysis. This non-randomized, open-label observational study will explore the efficacy of two dialyzers currently used for online HDF, a polysulfone-based high-flux membrane, and a cellulose triacetate membrane, in hemodialysis patients with signs of middle-molecule intoxication or intradialytic hypotension. In particular, the two filters will be evaluated for their ability in uremic toxin removal and modulation of inflammatory status. Sixteen subjects in standard chronic bicarbonate hemodialysis requiring a switch to online HDF in view of their clinical status will be enrolled and divided into two treatment arms, according to the previous history of hypersensitivity to polysulfone/polyethersulfone dialysis filters and hypersensitivity to drugs or other allergens. Group A will consist of 16 patients without a previous history of hypersensitivity and will be treated with a polysulfone filter (Helixone FX100), and group B, also consisting of 16 patients, with a previous history of hypersensitivity and will be treated with asymmetric triacetate (ATA; SOLACEA 21-H) dialyzer. Each patient will be followed for a period of 24 months, with monthly assessments of circulating middle-weight toxins and protein-bound toxins, markers of inflammation and oxidative stress, lymphocyte subsets, activated lymphocytes, and monocytes, cell apoptosis, the accumulation of advanced glycation end-products (AGEs), variations in arterial stiffens measured by pulse wave velocity (PWV), and mortality rate. The in vitro effect on endothelial cells of uremic serum collected from patients treated with the two different dialyzers will also be investigated to examine the changes in angiogenesis, cell migration, differentiation, apoptosis and proliferative potential, and gene and protein expression profile. The expected results will be a better awareness of the different effects of polysulfone gold-standard membrane for online HDF and the new ATA membrane on the removal of uremic toxins removal and inflammation due to blood-membrane interaction.

Physical activity is favorably associated with arterial stiffness in patients with obesity and elevated metabolic risk

OBJECTIVES

Physical activity and cardiorespiratory fitness (CRF) are relevant modifiers of cardiovascular risk. Their independent effects on arterial stiffness have not been assessed in people with obesity. This study aimed to assess the independent effects of light (LPA) and moderate-to-vigorous (MVPA) physical activity and CRF on Pulse wave velocity (PWV).

METHODS

Brachial-ankle PWV (baPWV) was measured cross-sectionally in 55 subjects (43.0 ± 13.8 years; 66% women) with moderate cardiovascular risk. Body composition was assessed with bioelectrical impedance-analysis. Daily minutes of LPA and MVPA were measured by accelerometry and CRF (peak oxygen uptake [VO₂ peak]) with spiroergometry. Independent effects of LPA, MVPA, and VO₂ peak on baPWV were analyzed in an age-, sex-, body fat mass-, and blood pressure-adjusted ANOVA.

RESULTS

Every 10 minutes increase of daily MVPA was associated with a 2.8% (0.32m/s [-0.64 to 0.001 m/s], P = .05) reduction of baPWV, whereas LPA and VO₂ peak had only a little or no relevant effects on baPWV.

CONCLUSIONS

Higher MVPA is associated with lower composite arterial stiffness independent of CRF and the number of metabolic risk factors in patients with obesity and further metabolic risk factors. Thus, lifestyle interventions should aim for an increase in MVPA. BaPWV may improve the monitoring of favorable effects of MVPA, even if an improvement of VO₂ peak cannot be obtained.

Femoral Artery Sclerosis Evaluation by Tissue Doppler in Patients with Hypertension

Background

The aim of this study was to evaluate the early femoral sclerosis in hypertensive patients by using tissue Doppler imaging (TDI).

Material/Methods

One hundred patients with hypertension were recruited and divided into group A (femoral artery intima-media thicknesses (IMT) ≥1.0 mm) and group B (femoral artery IMT <1.0 mm) with 50 cases in each group based on the femoral IMT. In addition, 50 healthy controls were also included in this study. Femoral wall structure and femoral artery IMT were examined by using high frequency ultrasound. Pulsed wave (PW)-TDI was used to obtain the motion curve of the posterior wall of the femoral artery. First (T1) and second (T2) peak duration were also obtained.

Results

The IMT of group A, group B, and the healthy control group were 1.17±0.12 mm, 0.74±0.11 mm, and 0.71±0.09 mm respectively with significant statistical difference (P<0.05). The first peak duration (T1) of the 3 groups (group A, group B, and healthy control group) were 135.6±16.6 ms, 134.5±18.5 ms, and 129.8±12.4 ms, respectively without statistical difference (F=1.868 P=0.158). The second peak duration (T2) of group A, group B, and the healthy control group were 234.7±39.8 ms, 209.3±34.9 ms, and 169.8±19.5 ms respectively with statistically significant difference (F=50.411 P=0.000). The diagnostic sensitivity, specificity area under the curve (AUC) and cutoff value for early arteriosclerosis diagnosis of femoral artery by T1 was 56.0% (95% CI: 41.3–70.0%), 66.0% (95% CI: 51.2–78.8%), AUC=0.54 (95% CI: 0.42–0.66) and 130.5 ms respectively. And it was 64.0% (95% CI: 49.2–77.1%), 62.0% (95% CI: 47.2–75.4%), AUC=0.69 (95% CI: 0.59–0.80) and 214.5 ms respectively for T2.

Conclusions

TDI can be used as an effective index for early femoral artery sclerosis before femoral artery IMT changes.

Beraprost Sodium Protects Against Diabetic Nephropathy in Patients with Arteriosclerosis Obliterans: A Prospective, Randomized, Open-label Study

BACKGROUND

Inhibition of the renin-angiotensin system (RAS) has been used to treat diabetic nephropathy. However, RAS inhibition increases the risk of renal complications. In this study, we evaluated the effect of combining RAS inhibitor treatment with beraprost sodium (BPS), a prostaglandin I2 analog, in diabetic nephropathy with arteriosclerosis obliterans.

METHODS

This study was a prospective, randomized, open-label study. Twenty-six Japanese patients (age >30 years) with diabetic nephropathy and arteriosclerosis obliterans were randomly assigned to the BPS group (n=13), which received the combination of an RAS inhibitor and BPS (120 μg/day) therapy, or the control group (n=13), which received only an RAS inhibitor. Patients were followed up for 1 year. The primary endpoint was the effect of BPS on renal function.

RESULTS

In the control group, serum creatinine (1.64±0.87 to 2.34±1.53 mg/dL, p<0.001), 1/creatinine (0.82±0.47 to 0.65±0.47, p=0.003) cystatin C (1.77±0.61 to 2.18±0.86 mg/L, p<0.001), and the estimated glomerular filtration rate (43.9±26.1 to 34.0±24.6 mL/min/1.73 m(2), p=0.004) were significantly worsened 48 weeks after the start of treatment. Conversely, in the BPS group, serum creatinine (1.71±0.75 to 1.66±0.81 mg/dL, p=0.850), 1/creatinine (0.66±0.19 to 0.71±0.25, p=0.577), cystatin C (1.79±0.55 to 1.80±0.57 mg/L, p=0.999), and the estimated glomerular filtration rate (35.8±10.8 to 38.7±14.4 mL/min/1.73 m(2), p=0.613) were unchanged.

CONCLUSIONS

Combination treatment with BPS and an RAS inhibitor prevented the progression of diabetic nephropathy. These observations should be confirmed in large-scale studies with long-term follow-up.

Central blood pressure and chronic kidney disease

In this review, we focused on the relationship between central blood pressure and chronic kidney diseases (CKD). Wave reflection is a major mechanism that determines central blood pressure in patients with CKD. Recent medical technology advances have enabled non-invasive central blood pressure measurements. Clinical trials have demonstrated that compared with brachial blood pressure, central blood pressure is a stronger risk factor for cardiovascular (CV) and renal diseases. CKD is characterized by a diminished renal autoregulatory ability, an augmented direct transmission of systemic blood pressure to glomeruli, and an increase in proteinuria. Any elevation in central blood pressure accelerates CKD progression. In the kidney, interstitial inflammation induces oxidative stress to handle proteinuria. Oxidative stress facilitates atherogenesis, increases arterial stiffness and central blood pressure, and worsens the CV prognosis in patients with CKD. A vicious cycle exists between CKD and central blood pressure. To stop this cycle, vasodilator antihypertensive drugs and statins can reduce central blood pressure and oxidative stress. Even in early-stage CKD, mineral and bone disorders (MBD) may develop. MBD promotes oxidative stress, arteriosclerosis, and elevated central blood pressure in patients with CKD. Early intervention or prevention seems necessary to maintain vascular health in patients with CKD.

Risk factors for carotid artery distensibility in middle-aged and elderly hemodialysis patients

BACKGROUND

Carotid intima media thickness (CIMT) and stiffness are taken as useful surrogate markers of atherosclerosis. In China, the number of elderly patients undergoing hemodialysis has increased year by year, with the increase of dialysis-related cardiovascular events. This study was undertaken to examine carotid stiffness in elderly hemodialysis patients by the ultrasound techniques in order to find out the possible risk factors.

METHODS

From January 2006 to February 2010, a total of 87 patients (41 males and 46 females) treated with routine hemodialysis at the 97th Hospital of People's Liberation Army were enrolled in this study. The distensibility coefficient (DC) of the carotid artery was detected by Doppler ultrasonic diagnosis apparatus (Philips HBI5000, frequency 12 MHz) for evaluation of arterial stiffness. Serum albumin, total cholesterol (TC), high density lipoprotein (HDL), low density lipoprotein (LDL), triglyceride (TG), glucose, creatinine, calcium, phosphorus, and intact parathyroid hormone (iPTH) were examined with standard methods. The liner correlation and multiple stepwise regression analysis were used to find correlations between them.

RESULTS

In this study, the systolic blood pressure was 153.33±25.98 mmHg, DBP 84.22± 10.39 mmHg, TC 4.39±1.05 mmol/L, TG 1.36±0.72 mmol/L, LDL 2.47±0.77 mmol/L, Cr 889.82± 207.38 Mmol/L, Glu 5.36±1.87 mmol/L, Ca I 2.00±2.19±0.21 mmol/L, and DC 13.39±5.32×10(-3)/kPa. DC was associated with age (r=-0.459, P<0.001), SBP (r=-0.527, P<0.001), and serum calcium (r=-0.273, P=0.011). The multiple stepwise regression analysis showed that SBP, age, increased serum calcium level, and diabetes were independent risk factors for decreasing DC.

CONCLUSION

Systolic blood pressure, age, increased serum calcium level and diabetes in elderly hemodialysis patients are independent risk factors for increased carotid arterial stiffness.

Paradoxical Distribution of Augmentation Index Level in Chronic Kidney Diseases

Pulse wave velocity (PWV) and augmentation index (AI) are used as indexes of arterial stiffness and cardiovascular survival. Although PWV is known to increase as the stage of chronic kidney disease (CKD) advances, how this is related to AI and CKD stage has not yet been well defined.

A sub-analysis was performed using the data from the Antihypertensive and Blood Pressure of Central Artery in Japan study. This was a cross-sectional study on hypertensive patients. All the patients with available serum creatinine levels were selected, and estimated glomerular filtration rate (eGFR) was calculated according to the modification of diet in renal disease equation for a Japanese population. Augmentation indexes at different stages of CKD were compared.

Data from 1392 patients were pooled and analyzed. In addition to eGFR, there were differences in age (P<0.0001), pulse rate (P<0.0001), vasodilator antihypertensive drugs (P<0.005), systolic (P<0.005) and diastolic (P<0.01) blood pressure at 5 CKD stages. Multivariate regression showed that AI correlated to age (0.19%/year), pulse rate (-0.54%/bpm), systolic blood pressure (0.18%/mmHg) and vasodilator antihypertensive drugs (-2.42%/class). Therefore, AI was adjusted for these confounding factors. Adjusted AI in stage 5 (77±20%) was lower than that in stage 1 (84±19%, P<0.05).

These data indicate that AI varies according to CKD stage, and suggest that a cut-off value of AI should be set for each stage of CKD to detect cardiovascular disease.

A NEW APPROACH FOR ASSESSMENT OF PULSE WAVE VELOCITY AT RADIAL ARTERY IN YOUNG AND MIDDLE-AGED HEALTHY HUMANS

Pulse wave velocity (PWV), based on two-site measurement, is a well-known predictor of arterial stiffness. Interest focused increasingly on simplifying the PWV measurement results in attempts at determining it at a single site. We aimed to validate a new tonometric method (IIM-2010A) for assessment of PWV at radial artery in healthy subjects <65 years of age. PWV measurements were performed in 46 healthy adults (25 men and 21 women) aged 21–65 years (39.6 ± 15.5 years) using Complior device and IIM-2010A respectively. In a subgroup of 21 humans, the measurements were repeated after 1 week using IIM-2010A with the same protocol. There was a strong correlation between PWV obtained by IIM-2010A and PWV obtained by Complior, as well as between pulse transit time (PTT) measurements (r = 0.79 and r = 0.85, respectively, P < 0.01 for both). Although PTT was significantly lower measured by IIM-2010A, no significant difference was found in PWV. The mean difference of PWV with SD was -0.1 ± 1.2 m/s between two repeated measurements at intervals of 1 week. Bland–Altman's plot indicated no trend for the reproducibility of measurements to vary with their underlying mean value. Intraclass correlation coefficient (= 0.87) confirmed this excellent week-to-week reproducibility of PWV. The method provides a simple, easily-obtainable, and reproducible measurement of PWV in young and middle-aged subjects, and has potential to detect premature arterial aging for the management of primary prevention.

Aliskiren reduces morning blood pressure in hypertensive patients with diabetic nephropathy

Diabetic nephropathy (DN) is a leading disease that requires renal replacement therapy. The progression of renal dysfunction in DN is faster than the other renal diseases. While antihypertensive therapy reduces albuminuria, a good indicator for the progression, hypertension in DN is treatment resistant. Among patients with DN who took angiotensin receptor blockers (ARBs), 27 patients who exhibited poor control of albuminuria were enrolled into the study. Angiotensin receptor blocker was exchanged to aliskiren (150-300 mg/d) and clinical parameters were followed for 6 months. Exchange to aliskiren decreased albuminuria (1.57 ± 0.68 to 0.89 ± 0.45 g/gCr, P < .01) without changes in estimated glomerular filtration rate and office blood pressure (BP). Body weight and hemoglobin A1c were not altered. Aliskiren also reduced plasma renin activity (2.0 ± 0.9 to 1.2 ± 0.6 ng/mL/h, P < .01). While evening BP was unchanged, morning systolic BP (139 ± 8 to 132 ± 7 mm Hg, P < .01) and diastolic BP (81 ± 7 to 76 ± 6 mm Hg, P < .05) were decreased significantly after 6 months. Our results indicated that aliskiren decreased BP, especially morning BP in hypertensive patients with DN. The present data suggest that aliskiren exerts renoprotective actions including reduction in albumin excretion for patients with DN.

Height constitutes an important predictor of mortality in end-stage renal disease

Aim. Height is an important determinant of augmentation index (AI) that anticipates cardiovascular prognosis. There is a scanty of the data whether short height predicts survival in patients with end-stage renal diseases, a high risk population. Methods. Fifty two hypertensive patients with type 2 diabetic nephropathy receiving hemodialysis and 52 patients with nondiabetic nephropathy were enrolled. In addition to AI estimated with radial artery tonometry, classical cardiovascular risk factors were considered. Patients were followed for 2 years to assess cardiovascular prognosis. Results. Cox hazards regression revealed that both smoking and shortness in height independently contributed to total mortality and indicated that smoking as well as the presence of left ventricular hypertrophy predicted cardiovascular mortality. Our findings implicated that high AI, the presence of diabetes, and low high-density lipoprotein cholesterol were significant contributors to cardiovascular events. Conclusions. Our findings provide new evidence that shortness in height independently contributes to total mortality in hemodialysis patients.

Factors associated with aortic stiffness and its change over time in peritoneal dialysis patients

BACKGROUND

An increase in aortic stiffness, as reflected by an increase in pulse wave velocity (PWV), is an important predictor of cardiovascular mortality in dialysis patients. Decreased serum concentration of calcification inhibitor, such as fetuin-A, is inversely related to mortality in haemodialysis patients. Our aim is to investigate the factors associated with aortic stiffness and its change over time in peritoneal dialysis (PD) patients.

METHODS

As a prospective observational study, we analysed 67 PD patients, aged 50 ± 14 years (mean ± SD) and with dialysis duration of 26 (5-58) months (median, interquartile range). At baseline, age, mean arterial pressure (MAP), left ventricular mass (LVM) index, diabetes, serum albumin, calcium (Ca), phosphorus (P) and intact parathyroid hormone (iPTH), uric acid, total bilirubin, high-sensitivity C-reactive protein (hsCRP), fetuin-A, and residual renal function were included in association analysis with aortic stiffness represented by heart-to-femoral PWV (hfPWV). We also evaluated simple vascular calcification score (SVCS) with plain radiograph of the pelvis and both hands. PWV was measured both at baseline and at 1 year. Change of aortic stiffness was determined by △PWV (difference between 1-year PWV and baseline PWV). Time-averaged concentrations were used to evaluate the relation between biologic markers and changes of aortic stiffness.

RESULTS

hfPWV was 1022 ± 276 cm/s at baseline, and hfPWV determined at 1 year was 1069 ± 317 cm/s. Mean serum fetuin-A concentration was 0.34 ± 0.08 g/L. At baseline, aortic PWV positively correlated with age, smoking status, diabetes, MAP, total cholesterol and LDL cholesterol. On the other hand, aortic PWV inversely correlated with fetuin-A, log PTH, haemoglobin and albumin. In a multiple regression model, association of serum fetuin-A (β = -0.329, P = 0.003) with aortic PWV remained significant, along with age (β = 0.512, P < 0.001), MAP (β = 0.215, P = 0.047) and log PTH (β = -0.269, P = 0.025). At follow-up, △MAP (β = 0.500, P < 0.001) and time-averaged TG (aTG) (β = 0.259 P = 0.019) were determinants of △PWV.

CONCLUSIONS

For our PD patients, serum fetuin-A was an independent determinant of aortic stiffness, as well as age, MAP and log PTH. Although 1 year is not sufficient to observe the change of aortic stiffness, some patients exhibited >15% increase of PWV during this period. △MAP and aTG were factors affecting the change of PWV. Follow-up over a longer period is necessary to elucidate factors that determine changes of aortic stiffness over time from PD patients.

Brachial-ankle pulse wave velocity and cardiovascular risk factors in the non-diabetic and newly diagnosed diabetic Chinese: Guangzhou Biobank Cohort Study-CVD

BACKGROUND

Increased arterial stiffness is an important cause of cardiovascular disease (CVD). We examined determinants of arterial stiffness in subjects across strata of glycaemic status.

METHODS

A total of 1249 subjects from a sub-study of the Guangzhou Biobank Cohort Study (GBCS-CVD) had brachial-ankle pulse wave velocity (baPWV) measured by automatic oscillometric method. Major cardiovascular risk factors including glycosylated haemoglobin A1c (HbA(1c)), high sensitivity C-reactive protein (hsCRP), fasting triglyceride, low- and high-density lipoprotein cholesterol and both fasting and post 2-h oral glucose-load glucose, systolic and diastolic blood pressure were assessed.

RESULTS

In all, 649, 479 and 121 subjects were classified into normoglycaemia, impaired glucose metabolism (IGM) and newly diagnosed diabetes groups, respectively. Both age and systolic blood pressure were significantly associated with increased baPWV in all three groups (all p < 0.001). In both normoglycaemic and IGM groups, hsCRP and HbA(1c) were positively associated with baPWV (p from 0.04 to < 0.001), whereas current smoking and triglyceride were associated with baPWV in the normoglycaemic and IGM group, respectively (p = 0.04 and 0.001). No gender difference in baPWV was observed in the normoglycaemic or IGM groups. However, in the newly diagnosed diabetes group, men had higher baPWV than women (p = 0.01).

CONCLUSIONS

In the normoglycaemic and IGM subjects, after adjusting for age, blood pressure and other confounders, increasing HbA(1c) was associated with increased baPWV, suggesting a pathophysiological role of chronic glycaemia that can contribute to vascular disease risk in persons without diabetes.

Time for reflection predicts the progression of renal dysfunction in patients with nondiabetic chronic kidney disease

Our previous data indicated that both home blood pressure and arterial stiffness predicted the progression of renal dysfunction in the patients with chronic kidney diseases. In the present study, we examined both home blood pressure and the parameters of arterial stiffness as the indicator to the progression of chronic kidney diseases. Forty-two nondiabetic chronic kidney disease patients were enrolled and followed for 1 year. Anti-hypertensive therapy was adjusted to achieve office blood pressure below 130/80 mmHg. Home blood pressure was examined twice a day in the morning and evening. Pulse wave velocity (PWV) and augmentation index (AI) were measured as the index of arterial stiffness. The time for reflection (TR) was also determined. The relationship of annual changes in serum creatinine (Scr) with the above parameters was assessed. Multivariate regression analysis revealed that TR inversely correlated to annual increase in Scr (beta = -0.03, p < 0.05). Home blood pressure did not correlate to annual changes in Scr in the present study. The present data indicated that arterial stiffness is elevated despite good blood pressure control in chronic kidney disease, especially among the dippings. In addition, our data suggest that PWV and AI correlated to each other, while they were influenced differently by hemodynamic factors. Finally, the present findings provide the evidence that the arterial stiffness parameter is more sensitive than home blood pressure as an indicator to the progression of chronic kidney disease.

Cardio-ankle vascular index to screen cardiovascular diseases in patients with end-stage renal diseases

BACKGROUND

Cardiovascular diseases constitute major causes of death in patients with chronic kidney diseases. An increase in arterial stiffness predicts the presence of cardiovascular diseases; however, non-invasive arterial stiffness parameters such as pulse wave velocity are confounded by blood pressure.

METHODS

A new arterial stiffness parameter beta for the arterial tree, cardio-ankle vascular index (CAVI), was measured. To examine the usefulness of CAVI to screen for the presence of cardiovascular diseases, cross-sectional studies were performed on 68 patients undergoing chronic hemodialysis.

RESULTS

Stepwise regression analysis indicated that CAVI significantly correlated to age (beta=0.05, p<0.01) but not blood pressure. In addition, CAVI was higher in diabetics than non-diabetics (8.39+/-0.37 vs 7.63+/-0.57, p<0.05). Furthermore, CAVI was markedly elevated in patients with a history of cardiovascular diseases (8.69+/-0.23 vs 6.66+/-0.28, p<0.01). Analysis using the ROC curve has demonstrated that CAVI of 7.55 constitutes the cut-off value for the presence of cardiovascular diseases with both sensitivity and specificity of 0.79.

CONCLUSION

The present findings suggest that CAVI can be used as a screening test to detect for the presence of cardiovascular diseases in patients undergoing hemodialysis.

Arterial wave reflection is elevated in evening hemodialysis patients

AIM

Cardiovascular disease constitutes a major cause of death in patients with chronic kidney diseases and is related to enhanced arterial stiffness. It has been reported that daytime hemodialysis patients show better prognosis than evening hemodialysis patients.

METHODS

Aortic augmentation index (AI) and radial AI were measured in 20 non-diabetic hemodialysis patients, using SphygmoCor (PWV Medical) and HEM-9010AI (Omron Healthcare) as markers of arterial stiffness. Cardiovascular prognosis was followed for two years.

RESULTS

Mean age, blood pressure, pulse rate, and aortic and radial AI were 52 +/- 4 y/o, 142 +/- 6/74 +/- 4 mmHg, 78 +/- 4 bpm, 21 +/- 2, and 71 +/- 4%, respectively, in 10 daytime hemodialysis patients, and they averaged 52 +/- 3 y/o, 146 +/- 6/76 +/- 4 mmHg, 74 +/- 3 bpm, 26 +/- 2, and 73 +/- 3% in 10 evening hemodialysis patients, respectively. Thus, aortic AI was higher in evening hemodialysis patients (p < 0.05). In all, one patient was hospitalized due to cardiovascular complications in daytime hemodialysis patients, as well as three patients from those dialyzed in the evening.

CONCLUSION

Although a larger scale study is required to draw a definite conclusion, our findings suggest that a better prognosis in daytime hemodialysis non-diabetic patients is related to the lower AI.

Vascular compliance is secured under angiotensin inhibition in non-diabetic chronic kidney diseases

Cardiovascular diseases constitute major cause of death in chronic kidney diseases (CKDs). We examined the effects of angiotensin inhibition either with angiotensin-converting enzyme inhibitor or with angiotensin receptor blocker on patient prognosis and heart-ankle pulse wave velocity (haPWV) in CKDs. Randomized controlled study was performed on 102 patients with non-diabetic CKDs. Patients were divided into two groups with or without angiotensin inhibition, and followed until death, creatinine clearance was halved or starting renal replacement therapy, whichever occurred first. For 4 years, haPWV was assessed repeatedly in the surviving patients. While both groups showed well blood pressure control throughout 4 years (129+/-1 to 131+/-2/71+/-1 to 73+/-2 mm Hg), renal prognosis was better in angiotensin inhibition group (P<0.05). In addition, angiotensin inhibition reduced cardiovascular and renal death (P<0.05). Age, sex, heart rate, systolic blood pressure and proteinuria were correlated to haPWV (R(2)=0.76, P<0.0001). Although haPWV was similar between two groups at the start of the study (1098+/-31 vs 1094+/-37 cm/s), it was higher in patients without angiotensin inhibition than that with angiotensin inhibition 4 years later (1034+/-38 cm/s (n=28) vs 1242+/-37 cm/s (n=23), P<0.01). The present results provided the evidence that angiotensin inhibition arrested a time-dependent elevation of haPWV in non-diabetic CKDs, conferring organ protection. Furthermore, our data indicated that angiotensin inhibition improved patient prognosis in non-diabetic chronic kidney diseases with mild-to-moderate renal dysfunction.

Key role of insulin resistance in vascular injury among hemodialysis patients

Insulin resistance prevails not only among diabetic patients but also among hypertensive and obese patients. The relationship between insulin resistance and cardiovascular diseases was investigated in hemodialysis (HD) patients. Eighty-one maintenance HD patients were enrolled. The homeostasis model assessment of insulin resistance (HOMA-IR) method was used to assess insulin resistance. The relationship of HOMA-IR with cardiovascular and all-cause events was assessed. Compared with nondiabetic patients (n = 55), diabetic patients (n = 26) showed higher HOMA-IR (2.5 +/- 0.3 vs 1.4 +/- 0.2, P < .05), lower ankle-brachial pressure index (ABI, 0.85 +/- 0.09 vs 1.12 +/- 0.02, P < .01), and shorter HD duration (3 +/- 1 vs 9 +/- 1 years, P < .01), although their body mass index was similar (22.3 +/- 0.5 vs 21.5 +/- 0.4 kg/m(2)). Nondiabetic patients taking angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (n = 36) had lower HOMA-IR (1.2 +/- 0.2 vs 1.8 +/- 0.4, P < .05) and higher ABI (1.18 +/- 0.02 vs 1.02 +/- 0.05, P < .01) than those without (n = 17). Cardiovascular events were less common in HD patients with normal HOMA-IR (P < .05) or ABI (P < .01). Our data indicate that 69% of diabetic and 27% of nondiabetic patients have HOMA-IR greater than 1.6, implying reduced insulin sensitivity in HD patients. The present results provide evidence that angiotensin inhibition improves insulin resistance, possibly preventing vascular injury in HD patients. Finally, our findings suggest that insulin resistance is prognostic of cardiovascular events in HD patients.

Determinants of Arterial Wall Stiffness and Peripheral Artery Occlusive Disease in Nondiabetic Hemodialysis Patients

Aortic pulse wave velocity (Ao-PWV) and ankle-brachial blood pressure index (ABPI) are significant prognostic factors in patients with end-stage renal disease (ESRD). Diabetes mellitus (DM) promotes changes in arterial walls, including marked increases in Ao-PWV and decreases in ABPI. To determine the prevalence of peripheral arterial occlusive disease (PAOD) as well as the clinical variables useful in predicting these changes in nondiabetic patients with ESRD undergoing hemodialysis (HD), we performed a cross-sectional study in a cohort of 143 patients. Ao-PWV and ABPI were measured simultaneously and compared with several annual biochemical measurements and other clinical variables. The prevalence of PAOD in our cohort was 30.5%. In univariate regression analysis, Ao-PWV correlated positively with age, heart rate (HR), blood pressure (BP), pulse pressure (PP) and HbA1c, and negatively with serum albumin and ABPI. ABPI correlated negatively with age, HD duration, systolic BP, PP, low-density lipoprotein (LDL) cholesterol and hypersensitive C-reactive protein (hs-CRP), and positively with serum albumin and bone mineral density. In a step-down multiple regression analysis, HbA1c was identified as an independent determinant of Ao-PWV along with age, HD duration, HR and mean BP, while hs-CRP was an independent contributor to ABPI along with age, HD duration, PP and LDL cholesterol. Our results suggest that HD promotes aortic wall stiffness and PAOD progression. We recommend the monitoring of HbA1c to allow the prediction of aortic wall stiffness in nondiabetic ESRD patients. Our results did not confirm the influence of insulin resistance on the development of arterial sclerosis lesions.

New strategy to attenuate pulse wave velocity in haemodialysis patients

BACKGROUND

Pulse wave velocity (PWV) is commonly elevated in haemodialysis (HD) patients having cardiovascular diseases. Disturbances in calcium-phosphate metabolism are among the established cardiovascular risk factors in HD patients. The present study was performed to assess the effect of sevelamer on PWV in HD patients.

METHODS

Fifteen patients, who had been treated with calcium carbonate as a phosphate binder, were entered into the study. Changes in PWV during the 6 months before sevelamer administration were compared with PWV changes during 6 months of receiving sevelamer. Serum biochemistry parameters were also assessed.

RESULTS

Compared with the preceding control period, the sevelamer period resulted in decreased serum calcium (9.9+/-0.1 to 9.6+/-0.1 mg/dl, n = 15; P<0.01) in association with reductions in oral calcium load (4.3+/-0.4 to 2.3+/-0.6 g/day; P<0.001). Serum phosphorus and whole parathyroid hormone remained unchanged. Sevelamer reduced serum total cholesterol (167+/-7 to 148+/-6 mg/dl; P<0.001) and LDL-cholesterol (85+/-8 to 65+/-7 mg/dl; P<0.001), without modifying HDL-cholesterol or triglycerides. Finally, sevelamer reversed the increase in PWV observed during the control period (from 46+/-16 to -20+/-9 cm/s/month; P<0.01).

CONCLUSIONS

In chronic HD patients, sevelamer decreased serum total- and LDL-cholesterol as well as calcium. Moreover, our findings suggest that treatment with sevelamer attenuates the progressive increase in PWV observed during calcium carbonate treatment.

Young Hemodialysis Patients Are Exposed to Hyperhomocysteinemia

OBJECTIVE

Homocysteine is one of the cardiovascular risk factors in hemodialysis (HD) patients. Studies were performed to assess the effects of folic acid on pulse wave velocity (PWV) in HD patients.

METHODS

In a cross-sectional study, plasma total homocysteine (tHcy) was measured in 49 patients on maintenance HD. Ten HD patients younger than 45 years old entered the prospective study. Monthly changes in PWV were compared before and during folic acid treatment.

RESULTS

Younger HD patients had higher tHcy (r = -0.53, n = 49, P < .001). Patients who manifested myocardial ischemia (37 +/- 3 nmol/mL) possessed higher tHcy than those who did not (30 +/- 3 nmol/mL, P < .05). In prospective study, folic acid treatment (10 to 20 mg/d) failed to alter blood pressure and biochemical parameters, including lipids, calcium, phosphate, and parathormone. However, in association with a decrease in tHcy (46 +/- 5 to 27 +/- 3 nmol/mL, n = 10, P < .005), progressive increases in PWV (33 +/- 8 to 3 +/- 6 cm/sec/month, P < .01) were stopped.

CONCLUSIONS

The present findings indicate that young HD patients are exposed to severe hyperhomocysteinemia, and suggest that relatively large doses of folic acid attenuate progressive increases in PWV of young or middle-age HD patients.

Reduced baroreflex sensitivity is associated with increased vascular calcification and arterial stiffness

INTRODUCTION

Vascular calcification is a critical determinant of cardiovascular morbidity and mortality in chronic haemodialysis (HD) patients. The pathophysiology underlying this observation remains obscure. Baroreceptor sensitivity (BRS) is important in the maintenance of an appropriate cardiovascular status both at rest and under the physiological stress of HD. BRS is determined by both the mechanical properties of the vascular wall, mediating the transfer of transmural pressure, and afferent and efferent autonomic function. We aimed to study the association between arterial structure, function and BRS in chronic HD patients.

METHODS

We studied 40 chronic HD patients mean age 62+/-2 (26-86) years who had received HD for a mean 40+/-4 (9-101) months. Spontaneous BRS was assessed using software studying the relationship between inter-beat variability and beat to beat changes in systolic blood pressure. Functional characteristics of conduit arteries (pulse wave analysis) were studied with applanation tonometry at the radial artery. Arterial calcification was assessed in lower limbs using reconstructed multi-slice computed tomography and quantified with volume-corrected calcification scores within the superficial femoral artery.

RESULTS

Mean BRS was 4.43+/-0.44 ms/mmHg, with a wide range from 1.0 to 11.5 ms/mmHg. This correlated with arterial stiffness as measured by time to shoulder calculated from the central pulse wave analysis (r = 0.4, P = 0.01). BRS was also associated with vascular calcification (P = 0.01) but not by other factors such as dialysis vintage, age or pre-dialysis systolic/diastolic blood pressure.

CONCLUSION

The reduction in BRS and the resulting aberrant blood pressure response to the physiological stress and volume changes of HD may be important in the further understanding of the pathophysiology of the increased mortality in HD patients with vascular calcification.

Alteration of proximal aorta biophysical properties in patients with end stage renal disease

OBJECTIVE

To present a novel, non-invasive echocardiographic application to assess the structural and functional properties of the complex composition of the proximal aorta in patients with end stage renal disease (ESRD).

METHODS

71 haemodialysis patients (mean (SD) age 61.3 (9.3) years, dialysis duration 79.2 (51.6) months) and 62 age matched controls were studied. From the suprasternal view, the distance between ascending and descending aorta was measured with two dimensional ultrasound. The aortic flow wave transit time was measured with pulsed wave Doppler. M mode echocardiography, with simultaneous blood pressure estimates, was used to assess the diameters of the aortic annulus and of the ascending aorta. Pulse pressure, pulse wave velocity (PWV), pressure strain elastic modulus, characteristic impedance, and beta index were calculated.

RESULTS

Patients had increased pulse pressure (68.0 (7.2) v 51.4 (5.0) mm Hg, p < 0.001), PWV (6.1 (1.1) v 3.9 (0.6) m/s, p < 0.001), characteristic impedance (174 (58) v 111 (31) m/s.cm2, p < 0.001), pressure strain elastic modulus (872 (254) v 541 (140) mm Hg, p < 0.001), and beta index (8.9 (3.4) v 5.5 (1.4), p < 0.001) compared with controls. In patients PWV was correlated with age and time on haemodialysis (r = 0.44, p < 0.001, and r = 0.51, p < 0.001, respectively).

CONCLUSION

A novel application of duplex ultrasound of the proximal aorta showed that patients with ESRD have impaired proximal aortic function compared with controls. The data indicate that these non-invasive measurements can be used to describe status and change in aortic biophysical properties and may be used as a marker for cardiovascular disease risk.