Athanasios Roumeliotis

Vascular access for hemodialysis: postoperative evaluation and function monitoring

SummaryVascular access (VA) survival is a crucial issue associated with morbidity and mortality of patients undergoing maintenance hemodialysis. The development of stenosis is the major factor that leads to VA failure. Strategies for early detection of lesions within a VA system before serious complications arise are therefore crucial. The implementation of a VA surveillance program could lead to timely detection of VA dysfunction and referral for correction, reduction in central venous catheter use and decrease in hospitalization and VA-related cost. Suggested methods for arteriovenous fistulae and grafts surveillance include blood flow measurement, static pressure evaluation and duplex ultrasonography. Physical examination is an accepted method in contrast to nonstandardized dynamic pressure measurement for grafts. Access recirculation (not urea based) and dynamic pressure measurements are accepted methods for fistulae. Decreasing URR or Kt/V (otherwise unexplained) and increased (negative) arterial pressure in the dialysis machine are methods of limited sensitivity and specificity for both fistulae and grafts. Measurement of access blood flow has been proposed as the gold standard for the screening of all types of VA. Access flow can be measured by various techniques which are direct or indirect. Several studies about VA surveillance programs have demonstrated conflicting results. Larger, randomized controlled trials need to be carried out in order to clarify whether surveillance programs are necessary and which is the best surveillance strategy for each type of VA.

Can dialysis modality influence quality of life in chronic hemodialysis patients? Low-flux hemodialysis versus high-flux hemodiafiltration: a cross-over study.

Background: Hemodiafiltration with online preparation of the substitution [online high-flux hemodiafiltration (OHDF)] and hemodiafiltration with prepared bags of substitution (HDF) are important, recently widely used renal replacement therapies in patients with end-stage renal disease. However, there is little information on the comparative impacts of these modalities versus conventional low-flux hemodialysis (HD) on the quality of life (QoL) of HD patients. This study investigates the effect of dialysis modality on QoL in chronic HD patients. Methods: In this prospective, randomized, cross-over, open label study, 24 patients were enrolled. Their age were 62 ± 13.34 years (mean ± SD), with the duration of dialysis of 31 ± 23.28 months (mean ± SD). Five of the patients were women. QoL was measured by the Short-Form Health Survey with 36 questions (SF-36) and subscale scores were calculated. Each patient received HD, OHDF, and HDF for 3 months, with the dialysis modality subsequently being altered. They completed the questionnaire of QoL at the end of each period. Results: There were statistical significant differences in QoL for the total SF-36 [36.1 (26.7–45.7) and 40.7 (30.2–62.8)], for classic low-flux HD and high-flux hemodiafiltration, for bodily pain [45 (26.9–66.9) and 55 (35.6–87.5)], and for role limitations due to emotional functioning [0 (0–33.3) and 33.3 (0–100)], respectively. The scores did not differ significantly between the two types of hemodiafiltration. Conclusions: Our study indicates that QoL differs significantly among patients receiving low-flux HD and high-flux hemodiafiltration, on total SF-36, bodily pain, and role limitations due to emotional functioning. Convective modalities may offer better QoL than diffusive HD.

Calcific Uremic Arteriolopathy Treated with Cinacalcet, Paricalcitol, and Autologous Growth Factors

Background: Calcific uremic arteriolopathy is an uncommon cutaneous ischemic necrotizing disease, most commonly associated with renal disease and hyperparathyroidism, bearing a high mortality rate. Objective and Method: A case of a 57-year-old female renal patient with hyperparathyroidism who was successfully treated with combined paricalcitol and cinacalcet systemically, while autologous growth factors were locally applied, is herein presented. Result and Conclusion: The combination of cinacalcet and paricalcitol is a reliable alternative to parathyroidectomy in patients with calcific uremic arteriolopathy and hyperparathyroidism. Meticulous débridement of necrotic tissues is essential and application of autologous growth factors promotes healing.

Adiponectin Plasma Levels and Albuminuria in Patients with Type 2 Diabetes and Different Stages of Diabetic Kidney Disease

Adiponectin is an inflammatory cytokine produced by adipose tissue and its protective role has been recognized in the pathogenesis of obesity. A lower concentration in obesity patients is noted, in conditions of resistance to insulin, diabetes mellitus, and CKD. Patients with type 2 diabetes mellitus have a potential risk of atherosclerosis, while low concentrations of adiponectin are considered as predictor for the occurrence of complications in patients with type 2 diabetes. The aim of this study was to investigate in patients with type 2 diabetes mellitus with and without diabetic nephropathy the correlation of adiponectin levels and CKD stage or degree of albuminuria. We studied 119 patients with type 2 diabetes mellitus with different stage of renal function, the levels of plasma adiponectin, and the BMI. A statistically significant difference of plasma adiponectin levels was noted between the initial and end stages of CKD, the highest levels seen in ESKD patients. Also, the levels of adiponectin were elevated in patients with greater albuminuria (statistically significant difference between groups 1 and 3, p=0.05). The levels of adiponectin were found to decrease with increasing the stage of obesity (ANOVA, p<0.05). Finally, the group of patients receiving glitazones had higher plasma adiponectin levels compared to those not receiving. It concluded that the levels of adiponectin increase with the deterioration of renal function and with enhancement of albuminuria, while decreasing as the stage of obesity worsens. The administration of glitazones was associated with increased plasma levels of adiponectin.

Matrix Gla protein T-138C polymorphism is associated with carotid intima media thickness and predicts mortality in patients with diabetic nephropathy

AIMS We sought to determine the predictive value of Matrix Gla Protein MGP T-138C polymorphism in relation to all-cause mortality, cardiovascular mortality and cardiovascular events in patients with diabetic nephropathy (DN). METHODS MGP T-138C polymorphism was assessed in 40 diabetic patients without nephropathy and 118 patients at different stages of DN, including patients on hemodialysis. Measurement of carotid intima-media thickness (cIMT) was performed using real-time B-mode ultrasonography. Plasma levels of dephoshorylated uncarboxylated Matrix Gla Protein (dp-ucMGP) were determined in a subgroup of 67 patients by ELISA. Mortality and cardiovascular events were assessed during a 7year follow-up. RESULTS TT homozygotes for the MGP T-138C polymorphism had higher values of cIMT compared to combined TC and CC genotypes (P=0.006) whereas no association was observed between cIMT and dp-ucMGP levels. MGP T-138C polymorphism was a strong independent predictor of cIMT (P<0.0001), after adjustment for several well-known atherosclerosis risk factors. Patients with TT genotype presented a significantly higher all-cause and cardiovascular mortality risk compared to patients with TC and CC genotypes (P=0.01 and P=0.04 respectively), after adjustment for several traditional risk factors. CONCLUSIONS MGP T-138C polymorphism is a strong and independent predictor of increased cIMT as well as all-cause and cardiovascular mortality in DN patients.

The effect of bicarbonate peritoneal dialysis solutions on cardiac structural and functional alterations

BACKGROUND The systemic effects of absorbed glucose degradation products (GDPs) contained within the conventional peritoneal dialysis solutions (cPDS) are largely unknown, while they appear to affect also cardiovascular function. The aim of the present study was to evaluate if the new bicarbonate-based less bioincompatible new peritoneal dialysis solutions ameliorate cardiac structural and functional status as well as the peritoneal net ultrafiltration (UF) and residual renal function. Patients and methods. This is a single centre, prospective cohort study of 12 stable continues ambulatory peritoneal dialysis patients (four women, eight men) mean aged 71.3 ± of 6.01 years and mean peritoneal dialysis (PD) duration 31.9 ± 21.33 months, treated with the usual cPDS (Medital Bieffe®, with increased GDPs, low pH and lactate as a buffer system). The patients changed for a 6-month period to the newer biocompatible PD solutions (BicaVera, Fresenius® low GDPs, normal pH, bicarbonate as a buffer) and at the end of this time, they returned to their previous schema of conventional solutions, for another 6 months. During the study period, the left ventricle ejection fraction (EF), left ventricle end systolic and diastolic diameter (LVESD, LVEDD), left ventricle mass index (LVMI), glyoxal serum and peritoneal concentrations, net UF and 24 h urine volume were repeatedly estimated: at the beginning of the study (T0), after 6 months with the biocompatible solutions (T6) and at the end of study (T12), after the 6-month period using again the cPDS. The UF volume and glyoxal concentrations were estimated at end of a 4 h dwell of an exchange with a PD solution of 2.27 % glucose. RESULTS There was a statistically significant difference between the mean levels of EF, LVESD, LVEDD, LVMI, UF and glyoxal serum and peritoneal concentrations at the beginning (T0) and in the middle of the study (T6) (for serum glyoxal P = 0.005, for peritoneal glyoxal P = 0.0004, for EF P = 0.0004, for LVESD P = 0.023, for LVEDD P = 0.002, for LVMI P = 0.0005 and for UF P = 0.005) as well as between the mean values in the middle (T6) and at the end of the evaluation period (T12) (for serum glyoxal P = 0.043, for peritoneal glyoxal P = 0.006, for EF P = 0.00009, for LVESD P = 0.012, for LVEDD P = 0.00014, for LVMI P = 0.00013 and for UF P = 0.048). On the other hand, no statistically significant difference was revealed between the T0 and T12 mean values of glyoxal (serum and peritoneal), EF, LVESD, LVEDD, LVMI and UF. During the study period, there was no statistically significant difference in daily urine volume and glomerular filtration rate. CONCLUSIONS The use of bicarbonate-based PDS induced a statistically significant improvement of left ventricle structure (LVESD, LVEDD and LVMI) and functional (EF) indicators. These beneficial effects on left ventricle in combination with the improvement of net UF may designate a protective role of the newer bicarbonate peritoneal solutions on cardiovascular function morbidity and mortality risk of PD patients.

Assessment of association between lipoxygenase genes variants in elderly Greek population and type 2 diabetes mellitus

Background: Inflammation plays a pivotal role in the pathogenesis of diabetes and its complications. Arachidonic acid lipoxygenases have been intensively studied in their role in inflammation in metabolic pathways. Thus, we aimed to explore variants of lipoxygenase genes (arachidonate lipoxygenase genes) in a diabetes adult population using a case-control study design. Methods: Study population consisted of 1285 elderly participants, 716 of whom had type 2 diabetes mellitus. The control group consisted of non-diabetes individuals with no history of diabetes history and with a glycated haemoglobin <6.5% (<48 mmol/mol)] and fasting plasma glucose levels <126 mg/dL. Blood samples were genotyped on Illumina Infinium PsychArray. Variants of ALOX5, ALOX5AP, ALOX12, ALOX15 were selected. All statistical analyses were undertaken within PLINK and SPSS packages utilising permutation analysis tests. Results: Our findings showed an association of rs9669952 (odds ratio = 0.738, p = 0.013) and rs1132340 (odds ratio = 0.652, p = 0.008) in ALOX5AP and rs11239524 in ALOX5 gene with disease (odds ratio = 0.808, p = 0.038). Rs9315029 which is located near arachidonate ALOX5AP also associated with type 2 diabetes mellitus (p = 0.025). No variant of ALOX12 and ALOX15 genes associated with disease. Conclusion: These results indicate a potential protective role of ALOX5AP and 5-arachidonate lipoxygenase gene in diabetes pathogenesis, indicating further the importance of the relationship between diabetes and inflammation. Larger population studies are required to replicate our findings.

Alterations of dialysate markers in chronic peritoneal dialysis patients treated with the new less bioincompatible bicarbonate solutions.

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