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Cenk Demirci,
Mehmet Ozkahya,
Meltem Sezis Demirci, Gulay Asci,
Timur Kose,
Taskin Colak,
Soner Duman,
Huseyin Toz,
Pinar Ergin,
Siddik Momin Adam,
Ercan Ok
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ABSTRACT: Background: This prospective cohort study compared the changes in body water composition and nutritional parameters measured with multifrequency bioimpedance analysis between 8-hour three times weekly nocturnal hemodialysis (NHD) and 4-hour conventional hemodialysis (CHD) patients. Patients and Methods: 55 patients on CHD and 57 patients on NHD were included in the study. Multifrequency bioimpedance analysis was performed at baseline and at the 12th month. The primary outcomes of the study were changes in extracellular water (ECW), fat mass, dry lean mass and phase angle. Secondary outcomes of the study included changes in blood pressure and biochemical parameters related to nutrition and inflammation. Results: ECW/height values decreased in the NHD group, while they increased in the CHD group. Fat mass, dry lean mass, and serum albumin increased and high sensitive CRP decreased in the NHD group but did not change in the CHD group. When changes in parameters from baseline to the 12th month between the groups were compared, NHD was associated with improvement in volume parameter including ECW/height (difference -0.44 l/m, p < 0.001). Change in blood pressure was not different between the groups, however requirement for antihypertensive medication decreased from 26.5 to 8.5% in the NHD group (p = 0.002). NHD was also associated with increases in fat mass (difference 1.8 kg, p < 0.001), dry lean mass (difference 0.6 kg, p = 0.006), serum albumin (difference 0.19 g/dl, p < 0.001) and cholesterol (difference 18.8 mg, p < 0.001). Phase angle values decreased in the CHD group but did not change in the NHD group (difference between the groups 0.37°, p = 0.04). Conclusion: This study revealed that longer HD facilitates volume control and improves nutritional status.
American Journal of Nephrology 05/2013; 37(6):559-567. · 2.54 Impact Factor
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ABSTRACT: Backgrounds and aims: Paraoxonase 1 (PON1) is a novel marker that has been shown to exert protective functions on atherosclerosis by preventing oxidative modification of serum lipoproteins. In this study, we investigated the effects of PON1 on CA-IMT in renal transplant patients. Methods: A total of 98 adult renal transplant recipients was enrolled in the study. CA-IMT was determined by B-mode Doppler ultrasonography. PON-1 activity was assessed by the rate of enzymatic hydrolysis of paraoxon to p-nitrophenol. Results: Mean age was 39.4 ± 9.6 years and 10% of the patients were diabetic. Time after transplant was 76 ± 59 months. Mean PON1 level was 62.1 ± 43.3 U/l. PON1 levels were negatively correlated with CA-IMT and positively with HDL cholesterol. Mean CA-IMT was 0.62 ± 0.10 mm (0.40 - 0.98). CA-IMT was positively correlated with age, male gender and negatively with proteinuria and PON1 levels. In linear regression analysis, PON1 levels were associated with CA-IMT. Conclusion: Reduced PON1 activity is significantly associated with increased carotid atherosclerosis in renal transplant patients.
Clinical nephrology 04/2013; · 1.17 Impact Factor
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Ender Hur,
Mehmet Usta,
Huseyin Toz, Gulay Asci,
Peter Wabel,
Serdar Kahvecioglu,
Meral Kayikcioglu,
Meltem Sezis Demirci,
Mehmet Ozkahya,
Soner Duman,
Ercan Ok
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ABSTRACT: BACKGROUND: Fluid overload is the main determinant of hypertension and left ventricular hypertrophy in hemodialysis patients. However, assessment of fluid overload can be difficult in clinical practice. We investigated whether objective measurement of fluid overload with bioimpedance spectroscopy is helpful in optimizing fluid status. STUDY DESIGN: Prospective, randomized, and controlled study. SETTING & PARTICIPANTS: 156 hemodialysis patients from 2 centers were randomly assigned to 2 groups. INTERVENTION: Dry weight was assessed by routine clinical practice and fluid overload was assessed by bioimpedance spectroscopy in both groups. In the intervention group (n = 78), fluid overload information was provided to treating physicians and used to adjust fluid removal during dialysis. In the control group (n = 78), fluid overload information was not provided to treating physicians and fluid removal during dialysis was adjusted according to usual clinical practice. OUTCOMES: The primary outcome was regression of left ventricular mass index during a 1-year follow-up. Improvement in blood pressure and left atrial volume were the main secondary outcomes. Changes in arterial stiffness parameters were additional outcomes. MEASUREMENTS: Fluid overload was assessed twice monthly in the intervention group and every 3 months in the control group before the mid- or end-week hemodialysis session. Echocardiography, 48-hour ambulatory blood pressure measurement, and pulse wave analysis were performed at baseline and 12 months. RESULTS: Baseline fluid overload parameters in the intervention and control groups were 1.45 ± 1.11 (SD) and 1.44 ± 1.12 L, respectively (P = 0.7). Time-averaged fluid overload values significantly decreased in the intervention group (mean difference, -0.5 ± 0.8 L), but not in the control group (mean difference, 0.1 ± 1.2 L), and the mean difference between groups was -0.5 L (95% CI, -0.8 to -0.2; P = 0.001). Left ventricular mass index regressed from 131 ± 36 to 116 ± 29 g/m2 (P < 0.001) in the intervention group, but not in the control group (121 ± 35 to 120 ± 30 g/m2; P = 0.9); mean difference between groups was -10.2 g/m2 (95% CI, -19.2 to -1.17 g/m2; P = 0.04). In addition, values for left atrial volume index, blood pressure, and arterial stiffness parameters decreased in the intervention group, but not in the control group. LIMITATIONS: Ambulatory blood pressure data were not available for all patients. CONCLUSIONS: Assessment of fluid overload with bioimpedance spectroscopy provides better management of fluid status, leading to regression of left ventricular mass index, decrease in blood pressure, and improvement in arterial stiffness.
American Journal of Kidney Diseases 02/2013; · 5.43 Impact Factor
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Ercan Ok, Gulay Asci,
Huseyin Toz,
Ebru Sevinc Ok,
Fatih Kircelli,
Mumtaz Yilmaz,
Ender Hur,
Meltem Sezis Demirci,
Cenk Demirci,
Soner Duman,
Ali Basci,
Siddig Momin Adam,
Ismet Onder Isik,
Murat Zengin,
Gultekin Suleymanlar,
Mehmet Emin Yilmaz,
Mehmet Ozkahya
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ABSTRACT: Background
Online haemodiafiltration (OL-HDF) is considered to confer clinical benefits over haemodialysis (HD) in terms of solute removal in patients undergoing maintenance HD. The aim of this study was to compare postdilution OL-HDF and high-flux HD in terms of morbidity and mortality.Methods
In this prospective, randomized, controlled trial, we enrolled 782 patients undergoing thrice-weekly HD and randomly assigned them in a 1:1 ratio to either postdilution OL-HDF or high-flux HD. The mean age of patients was 56.5 ± 13.9 years, time on HD 57.9 ± 44.6 months with a diabetes incidence of 34.7%. The follow-up period was 2 years, with the mean follow-up of 22.7 ± 10.9 months. The primary outcome was a composite of death from any cause and nonfatal cardiovascular events. The major secondary outcomes were cardiovascular and overall mortality, intradialytic complications, hospitalization rate, changes in several laboratory parameters and medications used.ResultsThe filtration volume in OL-HDF was 17.2 ± 1.3 L. Primary outcome was not different between the groups (event-free survival of 77.6% in OL-HDF versus 74.8% in the high-flux group, P = 0.28), as well as cardiovascular and overall survival, hospitalization rate and number of hypotensive episodes. In a post hoc analysis, the subgroup of OL-HDF patients treated with a median substitution volume >17.4 L per session (high-efficiency OL-HDF, n = 195) had better cardiovascular (P = 0.002) and overall survival (P = 0.03) compared with the high-flux HD group. In adjusted Cox-regression analysis, treatment with high-efficiency OL-HDF was associated with a 46% risk reduction for overall mortality {RR = 0.54 [95% confidence interval (95% CI) 0.31-0.93], P = 0.02} and a 71% risk reduction for cardiovascular mortality [RR = 0.29 (95% CI 0.12-0.65), P = 0.003] compared with high-flux HD.Conclusions
The composite of all-cause mortality and nonfatal cardiovascular event rate was not different in the OL-HDF and in the high-flux HD groups. In a post hoc analysis, OL-HDF treatment with substitution volumes over 17.4 L was associated with better cardiovascular and overall survival.
Nephrology Dialysis Transplantation 12/2012; · 3.40 Impact Factor
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ABSTRACT: BACKGROUNDS/AIMS: Atherosclerotic cardiovascular diseases are among the major causes of mortality in renal transplant (RT) patients. Oxidative stress plays an important role in the pathogenesis of atherosclerosis. In this study, we investigated the role of asymmetric dimethylarginine (ADMA) along with oxidized LDL (oxLDL) and antioxidized LDL (anti-oxLDL) on the extent and progression of atherosclerosis measured by carotid artery intima-media thickness (CA-IMT) in RT patients. METHODS: One hundred and eighty renal transplant patients were studied. Baseline and 25th month CA-IMT were determined by B-mode Doppler ultrasonography. ADMA, oxLDL and anti-oxLDL were measured by commercially available ELISA. RESULTS: The mean age of the patients was 41 ± 9 years. The mean CA-IMT at baseline was 0.61 ± 0.15 mm. Age, cardiovascular disease and diabetes history, proteinuria and triglyceride levels were positively correlated, whereas HDL and albumin were negatively correlated with baseline CA-IMT. Ninety-two patients underwent a second CA-IMT measurement at a mean follow-up of 25th months. The mean second CA-IMT was 0.68 ± 0.18 mm. Serum ADMA levels, HCV positivity and albumin levels were predictors for CA-IMT progression in the multivariate analysis that included age, HCV positivity ADMA, albumin, glucose and proteinuria. OxLDL and anti-oxLDL were not associated with both CA-IMT presence and progression. CONCLUSION: Serum ADMA levels predict progression of atherosclerosis in RT patients.
International Urology and Nephrology 12/2012; · 1.47 Impact Factor
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Mehmet Nuri Turan,
Ozkan Gungor, Gulay Asci,
Fatih Kircelli,
Turker Acar,
Mustafa Yaprak,
Naim Ceylan,
Meltem Sezis Demirci,
Selen Bayraktaroglu,
Huseyin Toz,
Mehmet Ozkahya,
Ercan Ok
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ABSTRACT: OBJECTIVE: Epicardial adipose tissue (EAT) is proposed as a cardiovascular risk marker in non-uremic subjects. However, little is known about its role in patients with higher cardiovascular risk profile such as chronic kidney disease. The aim of this study was to investigate the relationship between EAT and several cardiovascular surrogate markers (coronary artery calcification (CAC), arterial stiffness and atherosclerosis) in patients on maintenance hemodialysis. METHODS: A total of 191 prevalent hemodialysis patients were enrolled in this cross-sectional study. EAT and CAC scores (CACs) were determined by multi-slice computerized tomography, arterial stiffness by carotid-femoral pulse wave velocity (PWV), and carotid artery intima-media thickness (CA-IMT) by B-mode doppler ultrasonography. RESULTS: Mean age was 59 ± 13 years and time on hemodialysis 75 ± 44 months. Twenty percent of the patients had diabetes. Mean EAT volume was 62.6 ± 26.8 cm(3)/m(2). Mean CA-IMT and PWV values increased across the EAT tertiles. EAT was correlated with age, female gender, body mass index, albumin and lipid parameters. Additionally, CA-IMT and PWV values were positively correlated with EAT. EAT volume was significantly higher in patients with CACs >10 compared to the patients with CACs ≤10. Despite the univariate associations between EAT and cardiovascular surrogate markers, only age, body mass index and total cholesterol levels were associated with EAT in adjusted models. CONCLUSIONS: In prevalent hemodialysis patients, EAT is correlated with atherosclerosis, arterial stiffness and the presence of CAC. However, this correlation is not independent of other risk factors.
Atherosclerosis 11/2012; · 3.79 Impact Factor
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ABSTRACT: Background: Cardiovascular disease is the main cause of mortality after renal transplantation. Soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) and fibroblast growth factor-23 (FGF-23) are two novel molecules that have been associated with atherosclerosis in different populations. In this cross-sectional study, we investigated the associations between sTWEAK, FGF-23, and carotid artery intima-media thickness (CA-IMT) in renal transplant patients. Methods: A total of 117 renal transplant patients were studied. CA-IMT was determined by B-mode Doppler ultrasonography. Serum sTWEAK and FGF-23 were measured by a commercially available enzyme-linked immunosorbent assay (ELISA). Results: Mean age was 39.6 ± 9.6 years and 51% of the patients were male. Mean sTWEAK level was 595 ± 225 pg/mL (158-1140), FGF-23 level was 92 ± 123 RU/mL (9.6-1006), and CA-IMT level was 0.62 ± 0.11 mm (0.40-0.98). sTWEAK level was positively correlated with CA-IMT. There was no association between sTWEAK and FGF-23 levels. FGF-23 was also associated with CA-IMT. In adjusted models using linear regression analysis, only age and serum TWEAK levels were predictors for CA-IMT. Conclusion: There is a positive correlation between CA-IMT and sTWEAK, but not with FGF-23 levels in renal transplant patients.
Renal Failure 10/2012; · 0.82 Impact Factor
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ABSTRACT: BACKGROUND: New-onset diabetes after transplantation (NODAT) is a common complication in renal transplant (RT) patients. The clinical significance of pre-transplant HbA1c level remains unclear in RT patients. Thus, we investigated the predictive role of pre-transplant HbA1c levels for the NODAT diagnosed in 1 year after renal transplantation. METHODS: Two hundred and four RT patients older than 18 years were analyzed. NODAT diagnosis during the 1-year follow-up after RT was based on the 2003 modified criteria of the ADA. HbA1c level was measured at pre-transplantation period and every 3 months after RT. RESULTS: Mean age was 39.3 ± 10.7 (20-73) years and 36 % were female. Mean pre-transplant HbA1c level was 4.9 ± 0.5 % (4.0-6.4 %). Pre-transplant HbA1c level was positively correlated with age, pre-transplant body mass index (BMI) and cholesterol level. Fifty-four patients (25.9 %) developed NODAT and 33.8 % had impaired fasting blood glucose levels. Patients with NODAT were significantly older and had higher pre-transplant BMI and HbA1c than those without. Use of Tacrolimus was also higher in patients with NODAT. In stepwise logistic regression analysis, pre-transplant HbA1c level was an independent predictor for the development on NODAT (OR = 4.63, 95 % CI: 2.09-10.2, p < 0.001) together with age, Tacrolimus-based regimen and pre-transplant fasting blood glucose level. CONCLUSIONS: Assessment of pre-transplant HbA1c levels may be a valuable tool for early diagnosis of NODAT in RT recipients.
International Urology and Nephrology 10/2012; · 1.47 Impact Factor
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Mehmet Tanrisev, Gulay Asci,
Ozkan Gungor,
Fatih Kircelli,
Ebru Sevinc Ok,
Mumtaz Yilmaz,
Osman Z Sahin,
Kezban Pinar Ozen,
Gultekin Suleymanlar,
Huseyin Toz,
Ercan Ok
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ABSTRACT: BACKGROUND: Recently, low serum estradiol levels have been associated with increased cardiovascular risk and mortality in non-uremic patient populations. We investigated the predictive value of serum estradiol levels for mortality in female hemodialysis patients. METHODS: One hundred and forty-seven prevalent female hemodialysis patients were included in March 2005 and followed up for 32 ± 16 months. Serum estradiol levels were determined by ELISA at baseline and studied in relation to cardiovascular and overall mortality. RESULTS: Mean serum estradiol level was 28.6 ± 15.4 pg/ml (5.7-81.3). Patients in the higher estradiol tertile were likely to be more often diabetic and to have more cardiovascular diseases and higher body mass index (BMI). Serum estradiol was inversely correlated with age and urea reduction rate and positively correlated with postdialysis body weight, BMI and hs-CRP levels. During the follow-up period, 52 (35.6 %) patients died. Patients who died were older, had shorter dialysis vintage, were more likely to have a history of diabetes and cardiovascular disease, and lower serum creatinine, albumin, hemoglobin, and higher hs-CRP levels than those who survived. In Cox regression analysis, estradiol levels, in a bimodal (U-shaped) distribution, along with diabetes, low serum albumin and high hs-CRP levels, were predictors for overall mortality. CONCLUSIONS: A U-shaped association between serum estradiol levels and cardiovascular and overall mortality was found in postmenopausal hemodialysis patients.
International Urology and Nephrology 04/2012; · 1.47 Impact Factor
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Ozkan Gungor,
Fatih Kircelli, Gulay Asci,
Juan Jesus Carrero,
Erhan Tatar,
Meltem Sezis Demirci,
Süreyya Süha Ozbek,
Naim Ceylan,
Huseyin Toz,
Mehmet Ozkahya,
Ercan Ok
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ABSTRACT: Background: Reduced soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) levels follow declining renal function, are strongly associated with endothelial dysfunction and predict cardiovascular events in nondialyzed chronic kidney disease patients. In contrast, elevated levels of sTWEAK predict poor survival in hemodialysis (HD) patients. Recent evidence suggests a role for sTWEAK in the pathophysiology of vascular calcification. The aim of the study was to investigate plausible links between sTWEAK, atherosclerosis, arterial stiffness and vascular calcification in HD patients. Methods: Coronary artery calcification score (CACs) determined by multislice computed tomography, arterial stiffness by pulse wave velocity (PWV) and carotid artery intima-media thickness (CA-IMT) by carotid Doppler ultrasonography were assessed in 131 long-term prevalent HD patients. sTWEAK levels were measured by ELISA (Bender MedSystems, Vienna, Austria). Results: Mean serum sTWEAK level was 237.0 ± 147.5 pg/mL (range 78-937). sTWEAK level was inversely correlated with CA-IMT at a borderline significance (r=-0.168, p=0.05). Neither carotid-radial PWV nor carotid-femoral PWV values correlated with sTWEAK. sTWEAK level was higher in patients with severe vascular calcification (CACs =400) compared to patients with CACs <400 (264.5 ± 146.8 pg/mL vs. 205.04 ± 122.4 pg/mL, p=0.02).The association between sTWEAK and vascular calcification persisted after multivariate adjustment. Conclusions: There exists a weak inverse correlation between sTWEAK and carotid atherosclerosis and a positive correlation with coronary artery calcification in long-term HD patients. Our data give support for a role for sTWEAK in the pathogenesis of vascular injury in HD patients.
Journal of nephrology 04/2012; · 1.65 Impact Factor
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Ebru Sevinc Ok,
Fatih Kircelli, Gulay Asci,
Ekrem Altunel,
Muhittin Ertilav,
Savas Sipahi,
Devrim Bozkurt,
Soner Duman,
Mehmet Ozkahya,
Huseyin Toz,
Ercan Ok
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ABSTRACT: It is anticipated that oxidized low-density lipoprotein (oxLDL) and anti-oxLDL are associated with atherosclerosis and mortality. However, data on this issue are controversial and limited. We aimed to investigate the effect of these two markers on the extent and progression of atherosclerosis and mortality in a group of hemodialysis patients. In this prospective observational study with a follow-up of 36 months, 124 hemodialysis patients were studied. Ninety-five patients underwent carotid intima media thickness (CA-IMT) measurement by B-Mode ultrasonography both at baseline and at the end of the study. oxLDL and anti-oxLDL were measured by enzyme-linked immunosorbent assay. The extent and progression of CA-IMT, along with overall and cardiovascular mortality, were assessed. The mean age at baseline was 54.0 ± 14.8 years, 57.3% male and 20% diabetic. The mean oxLDL and anti-oxLDL levels were 8.11 ± 3.16 mU/L and 1.30 ± 0.31, respectively. Baseline mean CA-IMT was 0.82 ± 0.20 mm. Fifteen patients died during a follow-up period of 28.5 ± 6.6 months, 11 from cardiovascular causes. Only oxLDL, not anti-oxLDL, was correlated with the extent of atherosclerosis at baseline. However, both had no role in the progression of atherosclerosis. Also, in unadjusted and adjusted models, both parameters were not associated with overall or cardiovascular mortality. Neither oxLDL nor anti-oxLDL level is associated with the progression of atherosclerosis or mortality in hemodialysis patients.
Hemodialysis International 04/2012; 16(3):334-41. · 1.54 Impact Factor
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ABSTRACT: Posterior reversible encephalopathy syndrome (PRES) is a rare but if diagnosed late an irreversible disease. The majority of the patients present with severe hypertension, and effective blood pressure control is the mainstay of therapy. In this case report, we present three cases with PRES, treated successfully with strict volume control policy and propose that strict volume control policy may be a key element for the treatment of PRES.
Hemodialysis International 02/2012; · 1.54 Impact Factor
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ABSTRACT: INTRODUCTION: Vascular calcification is frequent in dialysis patients and is associated with increased mortality. Impaired glucose metabolism is proposed as a contributing factor for vascular calcification. We investigated whether glucose exposure via dialysate may have a role in vascular calcification in non-diabetic peritoneal dialysis patients. METHOD: We measured coronary artery calcification by multi-slice computerized tomography in 50 prevalent non-diabetic peritoneal dialysis patients and assessed its relations with fasting blood glucose, homeostasis model assessment of insulin resistance (HOMA-IR), and glucose exposure from peritoneal dialysis fluid. RESULTS: Twenty-four patients (48%) had no coronary calcification. When patients were grouped according to the presence or absence of calcification, patients with calcification were mostly men and had higher burden of cardiovascular disease history, vitamin D dose intake, serum calcium, total glucose exposure from dialysis solution, and lower total weekly Kt/V (urea). In multivariate analysis, dialysate glucose exposure was an independent predictor of coronary artery calcification score, besides serum calcium and Kt/V (urea). CONCLUSION: These data suggest that high glucose exposure from dialysis solution, which is potentially correctable, is a risk factor for vascular calcification in non-diabetic PD patients.
International Urology and Nephrology 02/2012; · 1.47 Impact Factor
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Mettem Sezis Demirci,
Ozkan Gungor,
Fatih Kircelli,
Juan Jesus Carrero,
Erhan Tatar,
Cenk Demirci,
Meral Kayikcioglu, Gulay Asci,
Huseyin Toz,
Mehmet Ozkahya,
Ercan Ok
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ABSTRACT: Arterial stiffness is an important contributor to the increased cardiovascular burden of uremia. The aim of the study was to identify determinants of arterial stiffness progression in peritoneal dialysis (PD) patients with strict volume control. PaTIENTS AND METHODS: 89 prevalent PD patients were enrolled. Assessment of arterial stiffness was performed at baseline and after nine months on average (range 8 - 12 months) by carotid-femoral pulse wave velocity (cf-PWV).
Mean age was 51 ± 13 y; preceeding time on PD was 40 ± 34 months. 57% of the patients were men and 9% were diabetic. At baseline, mean cf- PWV was 8.7 ± 2.7 m/s and was significantly higher in patients with diabetes and on automated PD therapy. Cf-PWV was positively correlated with age, history of cardiovascular disease, mean arterial pressure (MAP), blood glucose, left atrium diameter and left ventricular mass index. Sixty patients underwent a second cf-PWV measurement. 36% had progression of arterial stiffness. Delta cf- PWV value was 2.08 ± 1.89 m/s for progressors and -1.25 ± 1.43 m/s; p < 0.01 for nonprogressors (p < 0.01). In logistic regression analysis, the change in MAP was the only predictor for progression of arterial stiffness.
MAP is the main determinant of arterial stiffness progression. Our results suggest that efficient blood pressure control may contribute to preserved or reduced arterial stiffness in PD patients.
Clinical nephrology 02/2012; 77(2):105-13. · 1.17 Impact Factor
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Meltem Sezis Demirci,
Gulperi Celik,
Mehmet Ozkahya,
Murat Tumuklu,
Huseyin Toz, Gulay Asci,
Soner Duman,
Ali Basci,
Fatih Kircelli,
Oner Ozdogan,
Cenk Demirci,
Levent Can,
Ismet Onder Isik,
Ercan Ok
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ABSTRACT: In this study, we compared the changes in arterial stiffness in chronic hemodialysis patients treated with 8-h vs. 4-h thrice weekly in-center hemodialysis.
Sixty prevalent chronic hemodialysis patients assigned to 8-h nocturnal in-center thrice weekly HD (NHD) and 60 control cases assigned to 4-h thrice weekly conventional HD (CHD) were followed for one year. Radial-carotid pulse wave velocity, augmentation index and echocardiography were performed at baseline and 12th month.
Mean age of the patients was 49±11 years, 30.8% were female, 27.5% had diabetes mellitus and mean dialysis vintage was 57±47 months. Baseline demographical, clinical and laboratory parameters were similar between groups. During a mean follow-up of 15.0±0.1 months, blood pressure remained similar in both groups while the number of mean daily anti-hypertensive substances decreased in the NHD group. In the NHD group, time-averaged serum phosphorus and calcium-phosphorus product were lower than the CHD group. Pulse wave velocity and augmentation index decreased in the NHD group (from 11.02±2.51 m/s to 9.61±2.39 m/s and from 28.8±10.3% to 26.2±12.1%; p=0.008 and p=0.04, respectively). While augmentation index increased in the CHD group (28.0±9.4 to 31.0±10.7%, p=0.02), pulse wave velocity did not change. Subendocardial viability ratio and ejection duration improved in the NHD group (from 135±28 to 143±25%, p=0.01 and from 294±34 ms to 281±34 ms, p=0.003, respectively), accompanied by regression of left ventricular mass index. In multiple stepwise linear regression analyses, NHD was associated with improvements in augmentation index, ejection duration and subendocardial viability ratio.
These data indicate that arterial stiffness is ameliorated by implementation of longer hemodialysis sessions.
Atherosclerosis 11/2011; 220(2):477-85. · 3.79 Impact Factor
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ABSTRACT: Low serum sodium levels have been associated with mortality both in patients with and without chronic kidney disease. In this study, we investigated this association in relation to glycemic control in hemodialysis (HD) patients.
Between March and September 2005, 697 prevalent HD patients were enrolled in this prospective observational study and followed up for all-cause and cardiovascular mortality. The associations of serum sodium concentration with both overall and cardiovascular survival rates were studied.
At baseline, mean predialysis serum sodium concentration was 138.4 ± 2.3 mEq/L (range: 130-145 mEq/L). Mild hyponatremia (< 135 mEq/L) was present in only 41 subjects (5.9%), and no patient had serum sodium level < 130 mEq/L. During 20.2 ± 6.2 months of follow-up, 119 patients (15.9%) died, 68 from CV causes. In adjusted Cox regression analysis, lowest sodium quartile was associated with 2.13-fold increased risk of overall mortality (95% confidence interval (CI) 1.14-3.98, P = 0.01, model chi-square 114.6, P < 0.001). As a continuous variable, each 1 mEq/L increase in predialysis sodium concentration was associated with a hazard ratio (HR) of 0.87 for overall mortality (95% CI 0.81-0.95, P = 0.002) and 0.86 for cardiovascular mortality (95% CI 0.78-0.96, P = 0.007). The predictivity of low serum sodium was prominent in diabetic subjects but not in nondiabetics. However, relationship between serum sodium and patient survival in diabetics was lost after adjustment for the HbA1c level: HR 0.91 (95% CI 0.78-1.05, P = 0.20).
Low serum sodium concentration is associated with mortality only in those with diabetes. Furthermore, the impact of serum sodium on survival in these patients seems to be derived from poor glucose control.
European Journal of Clinical Investigation 10/2011; 42(5):534-40. · 3.02 Impact Factor
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Erhan Tatar,
Fatih Kircelli, Gulay Asci,
Juan Jesus Carrero,
Ozkan Gungor,
Meltem Sezis Demirci,
Suha Sureyya Ozbek,
Naim Ceylan,
Mehmet Ozkahya,
Huseyin Toz,
Ercan Ok
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ABSTRACT: End-stage renal disease is linked to alterations in thyroid hormone levels and/or metabolism, resulting in a high prevalence of subclinical hypothyroidism and low triiodothyronine (T3) levels. These alterations are involved in endothelial damage, cardiac abnormalities, and inflammation, but the exact mechanisms are unclear. In this study, we investigated the relationship between serum free-T3 (fT3) and carotid artery atherosclerosis, arterial stiffness, and vascular calcification in prevalent patients on conventional hemodialysis.
137 patients were included. Thyroid-hormone levels were determined by chemiluminescent immunoassay, carotid artery-intima media thickness (CA-IMT) by Doppler ultrasonography, carotid-femoral pulse wave velocity (c-f PWV), and augmentation index by Sphygmocor device, and coronary artery calcification (CAC) scores by multi-slice computerized tomography.
Mean fT3 level was 3.70 ± 1.23 pmol/L. Across decreasing fT3 tertiles, c-f PWV and CA-IMT values were incrementally higher, whereas CACs were not different. In adjusted ordinal logistic regression analysis, fT3 level (odds ratio, 0.81; 95% confidence interval, 0.68 to 0.97), age, and interdialytic weight gain were significantly associated with CA-IMT. fT3 level was associated with c-f PWV in nondiabetics but not in diabetics. In nondiabetics (n = 113), c-f PWV was positively associated with age and systolic BP but negatively with fT3 levels (odds ratio = 0.57, 95% confidence interval 0.39 to 0.83).
fT3 levels are inversely associated with carotid atherosclerosis but not with CAC in hemodialysis patients. Also, fT3 levels are inversely associated with surrogates of arterial stiffness in nondiabetics.
Clinical Journal of the American Society of Nephrology 08/2011; 6(9):2240-6. · 5.23 Impact Factor
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ABSTRACT: The association between thyroid hormones and arterial stiffness is unclear. In this study, we investigated, for the first time in a large cohort of euthyroid peritoneal dialysis patients, the relationship between thyroid hormone levels and arterial stiffness.
Fifty-seven patients were enrolled. Serum TSH, free T3 and free T4 levels were measured by chemiluminescence immunoassay method. Pulse wave analysis [augmentation index (AIx) and subendocardial viability ratio (SEVR)] were measured to assess arterial stiffness.
Mean age was 49 ± 12.3 years, and 56.1% were female. Mean TSH, fT3 and fT4 levels were 1.97 ± 0.99 mIU/ml, 2.80 ± 0.42 pg/ml and 1.22 ± 0.16 ng/dl, respectively. Mean AIx and SEVR were 22.3 ± 11.3 and 136 ± 21%, respectively. AIx was negatively correlated with residual urine volume (r = -0.372, P: 0.03) and fT3 levels (r = -0.382, P: 0.005). SEVR was correlated only with TSH level (r = -0.394, P: 0.003). In linear regression analysis adjusted for age, gender, history of diabetes and cardiovascular disease and residual diuresis, fT3 level (t = -3.949, P < 0.001) remained associated with AIx. Only TSH level (t = -2.409, P: 0.02) was related to SEVR.
Low serum fT3 level is associated with arterial stiffness, and high TSH level within the normal range is related to lower SEVR in euthyroid PD patients.
International Urology and Nephrology 07/2011; 44(2):601-6. · 1.47 Impact Factor
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ABSTRACT: Carotid artery intima media thickness (CA-IMT) measurement has been shown to be a safe and reproducible method to assess severity of atherosclerosis. The association between nephrosclerosis and systemic atherosclerosis is not clear. In this study, we investigated the association between CA-IMT and nephrosclerosis in a group of kidney transplant donors.
Forty seven potential kidney transplant donors were included. CA-IMT was measured by B-Mode ultrasonography. Kidney allograft biopsy samples were obtained during the transplantation operation and chronic glomerular, vascular and tubulointertitial changes were semiquantitatively scored according to the Banff classification.
Mean age was 52 ± 12 years and 55% of the cases were younger than 55 years. Mean CA-IMT was 0.74 ± 0.19 mm and 48% had IMT values > 0.75 mm. Chronicty index was ≥5 in 55% of the cases. Chronicity index was higher in cases older than 55 years. Age and CA-IMT were significantly correlated with chronic vascular changes and chronicity index. CA-IMT > 0.75 mm had a 46% sensitivity and 90% specificity to predict nephrosclerosis. Positive and negative predictive values were 85% and 57%, respectively.
Aging leads to detrimental changes in every part of the vasculature of the human body. CA-IMT is correlated with the level of nephrosclerosis. Measurement of CA-IMT reflects nephrosclerosis especially in older patients.
Nephrology 07/2011; 16(8):720-4. · 1.31 Impact Factor
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ABSTRACT: Vascular calcification (VC), mainly due to elevated phosphate levels, is one major problem in patients suffering from chronic kidney disease. In clinical studies, an inverse relationship between serum magnesium and VC has been reported. However, there is only few information about the influence of magnesium on calcification on a cellular level available. Therefore, we investigated the effect of magnesium on calcification induced by β-glycerophosphate (BGP) in bovine vascular smooth muscle cells (BVSMCs).
BVSMCs were incubated with calcification media for 14 days while simultaneously increasing the magnesium concentration. Calcium deposition, transdifferentiation of cells and apoptosis were measured applying quantification of calcium, von Kossa and Alizarin red staining, real-time reverse transcription-polymerase chain reaction and annexin V staining, respectively.
Calcium deposition in the cells dramatically increased with addition of BGP and could be mostly prevented by co-incubation with magnesium. Higher magnesium levels led to inhibition of BGP-induced alkaline phosphatase activity as well as to a decreased expression of genes associated with the process of transdifferentiation of BVSMCs into osteoblast-like cells. Furthermore, estimated calcium entry into the cells decreased with increasing magnesium concentrations in the media. In addition, higher magnesium concentrations prevented cell damage (apoptosis) induced by BGP as well as progression of already established calcification.
Higher magnesium levels prevented BVSMC calcification, inhibited expression of osteogenic proteins, apoptosis and further progression of already established calcification. Thus, magnesium is influencing molecular processes associated with VC and may have the potential to play a role for VC also in clinical situations.
Nephrology Dialysis Transplantation 07/2011; 27(2):514-21. · 3.40 Impact Factor
