Showing papers by "Mehmet Ozkahya published in 2011"

Comparison of 4- and 8-h dialysis sessions in thrice-weekly in-centre haemodialysis: A prospective, case-controlled study

Abstract: Background Longer dialysis sessions may improve outcome in haemodialysis (HD) patients. We compared the clinical and laboratory outcomes of 8- and 4-h thrice-weekly HD. Methods Two-hundred and forty-seven HD patients who agreed to participate in a thrice-weekly 8-h in-centre nocturnal HD (NHD) treatment and 247 age-, sex-, diabetes status- and HD duration-matched control cases to 4-h conventional HD (CHD) were enrolled in this prospective controlled study. Echocardiography and psychometric measurements were performed at baseline and at the 12th month. The primary outcome was 1-year overall mortality. Results Overall mortality rates were 1.77 (NHD) and 6.23 (CHD) per 100 patient-years (P = 0.01) during a mean 11.3 ± 4.7 months of follow-up. NHD treatment was associated with a 72% risk reduction for overall mortality compared to the CHD treatment (hazard ratio = 0.28, 95% confidence interval 0.09-0.85, P = 0.02). Hospitalization rate was lower in the NHD arm. Post-HD body weight and serum albumin levels increased in the NHD group. Use of antihypertensive medications and erythropoietin declined in the NHD group. In the NHD group, left atrium and left ventricular end-diastolic diameters decreased and left ventricular mass index regressed. Both use of phosphate binders and serum phosphate level decreased in the NHD group. Cognitive functions improved in the NHD group, and quality of life scores deteriorated in the CHD group. Conclusions Eight-hour thrice-weekly in-centre NHD provides morbidity and possibly mortality benefits compared to conventional 4-h HD.

Relations between malnutrition–inflammation–atherosclerosis and volume status. The usefulness of bioimpedance analysis in peritoneal dialysis patients

Abstract: Background Chronic fluid overload (FO) is frequently present in peritoneal dialysis (PD) patients and is associated with hypertension and left ventricular hypertrophy and dysfunction, which are important predictors of death in dialysis patients. In the present study, we investigated the relationship between nutrition, inflammation, atherosclerosis and body fluid volumes measured by multi-frequency bioimpedance analysis (m-BIA) in PD patients. In addition, we analysed the relationship of extracellular volume values by m-BIA to echocardiographic parameters in order to define its usefulness as a measure of FO. Methods Ninety-five prevalent PD patients (mean age 50 ± 13 years, 10 of them diabetic) were enrolled. Extracellular water (ECW), total body water (TBW), dry lean mass (DLM) and phase angle (PA) were measured by m-BIA. Volume status was determined by measuring left atrium diameter (LAD) and left ventricular end-diastolic diameter (LVEDD). Measurement of carotid artery intima-media thickness (CA-IMT) was used to assess the presence of subclinical atherosclerosis. Serum albumin was used as a nutritional marker, and serum C-reactive protein (CRP) was used as an inflammatory marker. Results Mean ECW/height was 10.0 ± 1.0 L/m for whole group and 9.3 ± 0.6 L/m in patients with normal clinical hydration parameters. In correlation analysis, markers of nutrition, inflammation and atherosclerosis correlated well with m-BIA parameters. When we used echographically measured LAD (> 40 mm) or LVEDD (> 55 mm) as a confirmatory parameter, a cut-off value of 10.48 L/m ECW/height (78% specificity, with a sensitivity of 77% for LAD and 72% specificity, with a sensitivity of 70% for LVEDD) was found in ROC analysis for the diagnosis of FO. Patients with FO were older and had higher systolic blood pressure, cardiothoracic index, serum CRP level and mean CA-IMT than patients without FO. Patients with inflammation had higher CA-IMT values. In multivariate analysis, only two factors-low urine output and ECW/height-were independently associated with the presence of inflammation. Conclusions FO defined by m-BIA is significantly correlated with markers of malnutrition, inflammation and atherosclerosis in PD patients. The indices obtained from m-BIA, especially ECW/height, correlated well with volume overload as assessed by echocardiography and might be a measure worth testing in a properly designed clinical study.

Associations of Triiodothyronine Levels with Carotid Atherosclerosis and Arterial Stiffness in Hemodialysis Patients

Abstract: Summary Background and objectives 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. Design, setting, participants, & measurements 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. Results 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). Conclusions 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. Clin J Am Soc Nephrol 6: 2240–2246, 2011. doi: 10.2215/CJN.02540311

The link between bone and coronary calcifications in CKD-5 patients on haemodialysis

Abstract: Background. Vascular calcifications are frequent in Stage 5 chronic kidney disease (CKD-5) patients receiving haemodialysis. The current study was designed to evaluate the associations between bone turnover/volume and coronary artery calcifications (CAC). Methods. In 207 CKD-5 patients, bone biopsies, multislice computed tomography of the coronary arteries and blood drawings for relevant biochemical parameters were done. The large number of CKD-5 patients enrolled allowed separate evaluation of patients with CAC versus patients without CAC and adjustment for traditional and non-traditional risk factors for CAC. Results. When all patients were analysed, associations were found between CAC and bone turnover, bone volume, age, gender and dialysis vintage. When only patients with CAC were included, there was a U-shaped relationship between CAC and bone turnover, whilst the association with bone volume was lost. In these patients, the relationship of CAC with age, gender and dialysis vintage remained. Conclusions. Beyond the non-modifiable risk factors of age, gender and dialysis vintage, these data show that bone abnormalities of renal osteodystrophy amenable to treatment should be considered in the management of patients with CAC.

Nutritional State Alters the Association between Free Triiodothyronine Levels and Mortality in Hemodialysis Patients

Abstract: Background: Serum free triiodothyronine (fT3) level is suggested to be a risk factor for mortality in unselected dialysis patients We investigated the prognostic value of serum fT3

Plasmapheresis therapy in renal transplant patients: five-year experience.

Abstract: Introduction Plasma exchange (PE) and double-filtration plasmapheresis (DFPP) have been used successfully in renal transplant patients as well as those with various other diseases over the last decade. In this retrospective study, we sought to explore the outcomes of plasmapheresis in renal transplant patients. Patients and methods We investigated 58 patients who received PE or DFPP therapy between 2005 and 2010. PE was performed using a Fresenius AS.TEC 204 device and DFPP, by an INFOMED HF 440 device. Indications for therapy, biopsy findings, number of PE/DFPP sessions, laboratory data, medications, complications as well as graft and patient survivals were recorded. Results Overall mean age of subjects was 34.1 ± 8.8 years and 55% were female. Sixteen patients underwent 95 DFPP sessions and 42 underwent 215 PE sessions. Indications for therapy were acute humoral rejection (n = 39), recurrent focal segmental glomerulosclerosis (FSGS; n = 8), thrombotic microangiopathy (n = 6), and chronic humoral rejection (n = 5). Responses to therapy were 24/39 for acute humoral rejection, 1/5 for chronic rejection, 4/8 for FSGS, and 3/6 for thrombotic microangiography. No complication was observed in any patient. Conclusion PE/DFPP is a safe and succesful method for treatment of acute humaral rejection as less so for recurrent FSGS and thrombotic microangiopathy. The outcomes among subjects with chronic humoral rejection were not satisfactory.

Bioimpedance spectroscopy for the detection of hypervolemia in peritoneal dialysis patients.

Abstract: A practical, inexpensive, and reliable method is needed for the assessment of volume status in peritoneal dialysis (PD) patients. In the present study, we investigated the efficiency of bioimpedance spectroscopy (BIS) for detection of hypervolemia. The study enrolled 79 prevalent PD patients (mean age: 47 +/- 14 years; PD duration: 30 +/- 17 months; 55% men; 19% with diabetes) from a single center. Echocardiography and body composition analysis using the BIS technique [50 frequencies (Body Composition Monitor: Fresenius Medical Care, Bad Homburg, Germany)] were performed. Overhydration (OH) and extracellular water (ECW) in liters and OH/ECW ratio were used as volume indices. The mean left ventricular (LV) mass index was 117 +/- 37 g/m2, and 46% of patients had LV hypertrophy (LVH). Mean OH and OH/ECW ratio were 1.3 +/- 1.7 L and 7.6% +/- 9.3% respectively The OH/ ECW ratio correlated with LV mass index (r = 0.237, p < 0.036) and with left atrium index (r = 0.354, p < 0.001). Compared with patients not having LVH, patients with LVH had higher OH values (1.79 +/- 1.82 L vs 0.93 +/- 1.62 L, p = 0.003). In linear regression analysis, the OH/ECW ratio was an independent risk factor for LVH (t = 2.558, p = 0.01). In PD patients, BIS is a reliable method for evaluating volume status. The OH/ECW measured by BIS is a major determinant of LV mass. Control of hypervolemia and blood pressure is associated with better cardiac condition.

The Impact of Strict Volume Control Strategy on Patient Survival and Technique Failure in Peritoneal Dialysis Patients

Abstract: Strict volume control strategy provides better cardiac functions and control of hypertension in dialysis patients. We investigated the effect of this strategy on mortality and technique failure in peritoneal dialysis patients over a 10-year period. 243 patients were enrolled. Strict volume control by dietary salt restriction and ultrafiltration was applied. Mean systolic and diastolic blood pressures decreased from 138.4 ± 29.9 and 86.3 ± 16.8 to 114.9 ± 32.3 and 74.7 ± 18.3 mm Hg, respectively. Overall and cardiovascular mortality rates were 48.4 and 29.6 per 1,000 patient-years, respectively. In multivariate analysis, age, diabetes and baseline serum albumin level were independent predictors of overall mortality, and age, diabetes and baseline serum calcium of cardiovascular mortality. Residual diuresis and peritoneal equilibration test values were not related to mortality. Strict volume control leads to lower mortality than comparable series in the literature. Technique survival is better during the first 3 years, but not after 5 years.

Biochemical Parameters, Renal Function, and Outcome of Pregnancy in Kidney Transplant Recipient

Abstract: Introduction The number of women who would like to have a baby after renal transplantation has increased. The aim of this study was to evaluate the effects of pregnancy on the lipid profiles and renal functions among transplantation patients as well as the maternal and fetal results of pregnancy. Materials and Methods We searched files of female patients who underwent renal transplantation between 1998 and 2008 to discover 31 pregnancies among 24 women. Results Mean duration of dialysis and age at transplantation for the 24 cases were 22.7 ± 24.1 months (range, 0–72) and 21.2 ± 4.6 years (range, 13–34), respectively. The time between transplantation and conception as well as age at conception were 5.2 ± 1.9 and 26.4 ± 4.4 years, respectively. Creatinine levels in the second trimester were significantly lower (P = .000). Gestational bicarbonate and albumin levels were significantly lower (P = .009 and P = .001, respectively). There were significant differences between the preconception triglyceride (TG) and those in the second and third trimesters (P = .006 and P = .00, respectively). TG levels increased as trimesters progressed (P = .000). Moreover, TG levels were higher among patients taking cyclosporine. Of pregnancies that passed the first trimester, 88.4% resulted in live births. There were 23 (74.19%) live births among 31 pregnancies with a cesarean section rate of 58%. Of the cases, 16.1% delivered preterm and 19.4% of babies had low birth weights. Conclusion We believe that women with renal transplants can have healthy babies with close monitoring during pregnancy and without any effect on graft survival.

Ventricular arrhythmia in dialysis patients: a link with higher hemoglobin levels?

Abstract: We investigated the frequencies and associated risk factors of cardiac arrhythmias and heart rate variability (HRV) in hemodialysis (HD) patients. One hundred fifty prevalent HD patients underwent 48-hour Holter monitoring. Holter monitoring was analyzed in 4 phases: early post-HD phase (12 hours), late post-HD phase (20 hours), pre-HD phase (12 hours), and HD phase (4 hours). Echocardiography was applied to measure the left ventricular mass index in a subgroup of patients (n: 52). Patients with ventricular premature contraction (VPC) were significantly older, had a longer HD duration, and higher hemoglobin (Hb) levels. Left ventricular mass index was significantly correlated with the frequency of VPC, during the HD and pre HD phases (r: 0.435, 0.312, respectively). In logistic regression analysis, patients with Hb level >11.9 g/dL (high tertile) had a 4.5-fold increased risk of VPC compared with those with Hb levels <10.8 g/dL (P: 0.04). In HRV analysis, age (P<0.001), and diabetes (P: 0.03) were found to be independent predictors of low standard deviation of all mean normal-to-normal RR intervals. Increased left ventricular mass index is associated with a high frequency of VPC in the pre-HD and HD periods. The occurrence of VPC is predicted by older age, longer dialysis duration, and higher Hb levels, while older age and diabetes are the determinants of HRV. The relation between higher Hb levels and the frequency of VPC might provide a clue for the explanation of the detrimental effect of higher Hb levels on HD patients.