Gursharan Dogra

Prevention of Tunneled Hemodialysis Catheter-Related Infections Using Catheter-Restricted Filling with Gentamicin and Citrate: A Randomized Controlled Study

Tunneled catheters are widely used for the provision of hemodialysis. Long-term catheter survival is limited by tunneled catheter-related infections (CRI). This study assesses the efficacy of catheter-restricted filling with gentamicin and citrate in preventing CRI in hemodialysis patients. A double-blind randomized study was conducted to compare heparin (5000 U/ml) with gentamicin/citrate (40 mg/ml and 3.13% citrate; ratio 2:1) as catheter-lock solutions. A total of 112 tunneled catheters in 83 patients were enrolled at the time of catheter insertion for commencement or maintenance of hemodialysis. The primary end point was CRI. Catheter malfunction, defined as blood flow rate of <200 ml/min for three consecutive dialyses and/or the use of urokinase, was also assessed as a secondary end point. Infection rates per 100 catheter-days were 0.03 in the gentamicin group versus 0.42 in the heparin group (P = 0.003). Kaplan-Meier survival analyses showed mean infection-free catheter survival of 282 d (95% CI, 272 to 293 d) in the gentamicin group versus 181 d (95% CI, 124 to 237 d) in the heparin group (log rank, 9.58; P = 0.002). Cox regression analyses showed a relative risk for infection-free catheter survival of 0.10 (95% CI, 0.01 to 0.92) in the gentamicin group when adjusted for gender, race, diabetes mellitus, catheter malfunction, and hemoglobin (P = 0.042). The incidence of catheter malfunction was not significantly different between groups. Predialysis gentamicin levels were significantly higher in patients randomized to gentamicin (gentamicin/citrate: median 2.8 mg/L [range, 0.6 to 3.5 mg/L], n = 5; heparin: median <0.2 mg/L [range <0.2 to 0.2 mg/L], n = 5; P = 0.008). Tunneled hemodialysis catheter-restricted filling with gentamicin and citrate is a highly effective strategy for prevention of CRI. Although citrate as a catheter-lock solution provides adequate anticoagulation for the interdialytic period, gentamicin levels suggest significant risk for chronic aminoglycoside exposure and associated ototoxicity. Before this technique is adopted, these preliminary observations warrant replication in future studies that will examine the efficacy and safety of lower doses of gentamicin or alternative agents with a reduced potential for toxicity.

Endothelium-dependent and independent vasodilation studied at normoglycaemia in Type I diabetes mellitus with and without microalbuminuria

Aims/hypothesis. We examined whether endothelial function is impaired in patients with Type I (insulin-dependent) diabetes mellitus under conditions of near-normoglycaemia compared with age-matched healthy control subjects. Our aim was to determine whether microalbuminuria is associated with endothelial dysfunction in Type I diabetes. Methods. Endothelial function, measured as post-ischaemic flow-mediated dilatation of the brachial artery using ultrasound, was compared among 17 microalbuminuric and 17 normoalbuminuric diabetic patients, and 17 control subjects. Glyceryl trinitrate-mediated dilatation of the brachial artery was used to measure endothelium-independent function. All diabetic patients were studied at near-normoglycaemia, using insulin and 5 % dextrose infusions to maintain blood glucose between 3.5 and 8.0 mmol/l. Results. Flow-mediated dilatation was significantly lower in microalbuminuric diabetic patients (3.2 ± 0.3 %) compared with normoalbuminuric diabetic patients (5.4 ± 0.6 %) and control subjects (7.9 ± 0.6 %, p < 0.001). Normoalbuminuric diabetic patients also had significantly lower flow-mediated dilatation than control subjects (p = 0.01). Glyceryl trinitrate mediated dilatation was significantly lower in the microalbuminuric patients compared with the control subjects (11.9 ± 1.1 % vs 20.0 ± 1.2 %, p = 0.001). Albumin excretion rate and glycated haemoglobin showed a significant negative independent correlation with flow-mediated dilatation (both p < 0.05). Conclusion/interpretation. Type I diabetic patients show endothelial dysfunction at near-normoglycaemia compared with the control subjects, and this abnormality is more marked in diabetic patients with microalbuminuria. Endothelial dysfunction in Type I diabetes is related to the albumin excretion rate and glycaemic control. The presence of endothelial dysfunction in normoalbuminuric diabetic patients suggests it could precede microalbuminuria as an early risk marker for cardiovascular disease. [Diabetologia (2001) 44: 593–601]

The effects of [omega]3 fatty acids and coenzyme Q10 on blood pressure and heart rate in chronic kidney disease: a randomized controlled trial

Background and objective Chronic kidney disease (CKD) associates with increased cardiovascular disease (CVD) risk. Hypertension is a major determinant of progression of CKD. Omega-3 fatty acids (ω3FA) protect against CVD via improvements in blood pressure, heart rate, vascular reactivity and serum lipids. Coenzyme Q10 (CoQ) may improve blood pressure and vascular function. This study determined whether ω3FA and CoQ have independent or additive effects in improving the cardiovascular profile, particularly blood pressure and heart rate, in nondiabetic patients with CKD stages 3–4. Methods In a double-blind, placebo-controlled intervention, patients were randomized to either ω3FA (4 g), CoQ (200 mg), both supplements or control (4 g), daily for 8 weeks. Results Eighty-five patients aged 56.5 ± 1.4 years; BMI 27.3 ± 0.5 kg/m2; supine blood pressure 125.0/72.3 mmHg; and glomerular filtration rate 35.8 ± 1.2 ml/min/1.73 m2, were randomized. Seventy-four completed the study. ω3FA, but not CoQ, reduced 24-h ambulatory heart rate (P < 0.0001) and blood pressure (P < 0.0001). Main effects for ω3FA on 24-h measurements were −3.3 ± 0.7/−2.9 ± 0.5 mmHg and −4.0 ± 0.5 bpm. Postintervention blood pressure showed significant interactions between treatments. ω3FA reduced triglycerides 24% (P < 0.001). There were no changes in glomerular filtration rate, urinary albumin or total protein excretion, cholesterol, HDL-cholesterol (C), LDL-C, glucose, insulin, or high-sensitivity C-reactive protein. Conclusion This study has shown that ω3FA reduce blood pressure, heart rate and triglycerides in patients with CKD. CoQ had no independent effect on blood pressure but increased heart rate. These results show that ω3FA lower blood pressure and may reduce cardiovascular risk in nondiabetic patients with moderate-to-severe CKD.

Statin therapy improves brachial artery vasodilator function in patients with Type 1 diabetes and microalbuminuria

Aims  Type 1 diabetes mellitus patients with microalbuminuria have endothelial dysfunction associated with the degree of albuminuria but not with LDL‐cholesterol levels. Lipid‐lowering agents such as statins may still be of benefit as they can correct endothelial dysfunction by both lipid and non‐lipid mechanisms. We therefore examined the effects of atorvastatin on brachial artery endothelial dysfunction in these patients.

Hypercoagulability in chronic kidney disease is associated with coagulation activation but not endothelial function

INTRODUCTION Patients with chronic kidney disease exhibit features of a hypercoagulable state and have endothelial dysfunction, which may contribute to their increased cardiovascular risk. We examined the relationship between coagulation activation and vascular function in patients with chronic kidney disease. MATERIALS AND METHODS We measured parameters of the tissue factor pathway of blood coagulation (tissue factor, factor VIIc and factor X); natural inhibitors (tissue factor pathway inhibitor, protein C, free and total protein S, antithrombin III) and markers of coagulation activation (thrombin-antithrombin complexes, prothrombin fragment 1+2) in 66 stage 4&5 chronic kidney disease patients and 36 healthy controls. Their relationship with markers of vascular function (flow mediated dilatation, soluble E-selectin and thrombomodulin) and a mediator of inflammation (interleukin-6) was determined. RESULTS Up-regulation of the tissue factor pathway (increased tissue factor and factor VIIc), increased prothrombin fragment 1+2 and significant reductions in antithrombin III and the ratio of free protein S: total protein S were found in patients compared to healthy controls. Increased tissue factor antigen was significantly and independently correlated with creatinine and interleukin-6 (P<0.001). Factor X and antithrombin III were both reduced in chronic kidney disease and correlated (r=0.58; P<0.001). Changes in coagulation and anti-coagulation were independent of all measures of endothelial function. CONCLUSIONS Significant activation of the TF pathway of coagulation and depletion or reduction of some natural anticoagulants in chronic kidney disease was correlated with the degree of renal dysfunction, but not correlated with the abnormalities of vascular function. These data are consistent with a hypercoagulable state in chronic kidney disease that may be independent of endothelial based regulation but associated with an inflammatory state.

Compared with younger peritoneal dialysis patients, elderly patients have similar peritonitis-free survival and lower risk of technique failure, but higher risk of peritonitis-related mortality

♦ Background: The number of elderly patients with end-stage kidney disease (ESKD) is increasing worldwide, but the proportion of elderly patients commencing peritoneal dialysis (PD) is falling. The reluctance of elderly ESKD patients to consider PD may be related to a perception that PD is associated with greater rates of complications. In the present study, we compared outcomes between younger and older PD patients. ♦ Methods: Using Australia and New Zealand Dialysis Registry data, all adult ESKD patients commencing PD between 1991 and 2007 were categorized into under 50, 50 – 64.9, and 65 years of age or older groups. Time to first peritonitis, death-censored technique failure, and peritonitis-associated and all-cause mortality were evaluated by multivariate Cox proportional hazards model analysis. ♦ Results: Of the 12 932 PD patients included in the study, 3370 (26%) were under 50 years of age, 4386 (34%) were 50 – 64.9 years of age, and 5176 (40%) were 65 years of age or older. Compared with younger patients (<50 years), elderly patients (≥65 years) had a similar peritonitis-free survival and a lower risk of death-censored technique failure [hazard ratio (HR): 0.85; 95% confidence interval (CI): 0.79 to 0.93], but they had higher peritonitis-related (HR: 2.31; 95% CI: 1.68 to 3.18) and all-cause mortality (HR: 2.90; 95% CI: 2.60 to 3.23). ♦ Conclusions: Not unexpectedly, elderly patients have higher peritonitis-related and all-cause mortality, which is likely a consequence of a greater prevalence of comorbid disease. However, compared with younger patients, elderly patients have superior technique survival and similar peritonitis-free survival, suggesting that PD is a viable renal replacement therapy in this group of patients.

Preventing AVF thrombosis: the rationale and design of the Omega-3 fatty acids (Fish Oils) and Aspirin in Vascular access OUtcomes in REnal Disease (FAVOURED) study.

BackgroundHaemodialysis (HD) is critically dependent on the availability of adequate access to the systemic circulation, ideally via a native arteriovenous fistula (AVF). The Primary failure rate of an AVF ranges between 20–54%, due to thrombosis or failure of maturation. There remains limited evidence for the use of anti-platelet agents and uncertainty as to choice of agent(s) for the prevention of AVF thrombosis. We present the study protocol for a randomised, double-blind, placebo-controlled, clinical trial examining whether the use of the anti-platelet agents, aspirin and omega-3 fatty acids, either alone or in combination, will effectively reduce the risk of early thrombosis in de novo AVF.Methods/DesignThe study population is adult patients with stage IV or V chronic kidney disease (CKD) currently on HD or where HD is planned to start within 6 months in whom a planned upper or lower arm AVF is to be the primary HD access. Using a factorial-design trial, patients will be randomised to aspirin or matching placebo, and also to omega-3 fatty acids or matching placebo, resulting in four treatment groups (aspirin placebo/omega-3 fatty acid placebo, aspirin/omega-3 fatty acid placebo, aspirin placebo/omega-3 fatty acid, aspirin/omega-3 fatty acid). Randomisation will be achieved using a dynamic balancing method over the two stratification factors of study site and upper versus lower arm AVF. The medication will be commenced pre-operatively and continued for 3 months post surgery. The primary outcome is patency of the AVF at three months after randomisation. Secondary outcome measures will include functional patency at six and twelve months, primary patency time, secondary (assisted) patency time, and adverse events, particularly bleeding.DiscussionThis multicentre Australian and New Zealand study has been designed to determine whether the outcome of surgery to create de novo AVF can be improved by the use of aspirin and/or omega-3 fatty acids. Recently a placebo-controlled trial has shown that clopidogrel is effective in safely preventing primary AVF thrombosis, but ineffective at increasing functional patency. Our study presents significant differences in the anti-platelet agents used, the study design, and surgical and patient demographics that should contribute further evidence regarding the efficacy of anti-platelet agents.Trial RegistrationAustralia & New Zealand Clinical Trials Register (ACTRN12607000569404).

Efficacy and safety of oral versus intravenous ascorbic acid for anaemia in haemodialysis patients.

Background:  Intravenous (i.v.) ascorbic acid (AA) improves anaemia in iron‐overloaded, erythropoietin (rEPO) hyporesponsive haemodialysis patients. While oral AA is readily attainable, the efficacy and safety of oral versus i.v. AA has not been examined.

Plasma apolipoprotein C-III metabolism in patients with chronic kidney disease

Moderate chronic kidney disease (CKD) (defined by an estimated glomerular filtration rate of 30–60 ml/min) is associated with mild hypertriglyceridemia related to delayed catabolism of triglyceride-rich lipoprotein particles. Altered apolipoprotein C-III (apoC-III) metabolism may contribute to dyslipidemia in CKD. To further characterize the dyslipidemia of CKD, we investigated the kinetics of plasma apoC-III in 7 nonobese, nondiabetic, non-nephrotic CKD subjects and 7 age- and sex-matched healthy controls, using deuterated leucine ([5, 5, 5, 2H3]leucine), gas chromatography-mass spectrometry, and multicompartmental modeling. Compared with controls, CKD subjects had higher concentrations of plasma and VLDL triglycerides and plasma and VLDL apoC-III (P < 0.05). The increased plasma apoC-III concentration was associated with a decreased apoC-III fractional catabolic rate (FCR) (1.21 ± 0.15 vs. 0.74 ± 0.12 pools/day, P = 0.03). There were no differences between apoC-III production rates of controls and those of CKD subjects. In CKD subjects, plasma apoC-III concentration was significantly and negatively correlated with apoC-III FCR (r = −0.749, P = 0.05) but not with apoC-III production rate. Plasma apoC-III concentration was positively correlated with plasma and VLDL triglycerides and VLDL apoB concentrations and negatively correlated with VLDL apoB FCR (P < 0.05 for all). ApoC-III FCR was negatively correlated with plasma and VLDL triglycerides and VLDL apoB concentration and positively correlated with VLDL apoB FCR (P < 0.05 for all). Altered plasma apoC-III metabolism is a feature of dyslipidemia in moderate CKD. Modification of apoC-III catabolism may be an important therapeutic target for reducing cardiovascular disease risk in moderate CKD.

Chronic kidney disease delays VLDL-apoB-100 particle catabolism: potential role of apolipoprotein C-III

To determine the relative contribution of obesity and/or insulin resistance (IR) in the development of dyslipidemia in chronic kidney disease (CKD), we investigated the transport of apolipoprotein (apo) B-100 in nonobese, nondiabetic, nonnephrotic CKD subjects and healthy controls (HC). We determined total VLDL, VLDL1, VLDL2, intermediate density lipoprotein (IDL), and LDL-apoB-100 using intravenous D3-leucine, GC-MS, and multicompartmental modeling. Plasma apoC-III and apoB-48 were immunoassayed. In this case control study, we report higher plasma triglyceride, IDL-, VLDL-, VLDL1-, and VLDL2-apoB-100 concentrations in CKD compared with HC (P < 0.05). This was associated with decreased fractional catabolic rates [FCRs (pools/day)] [IDL:CKD 3.4 (1.6) vs. HC 5.0 (3.2), P < 0.0001; VLDL:CKD 4.8 (5.2) vs. HC 7.8 (4.8), P = 0.038; VLDL1:CKD 10.1 (8.5) vs. HC 29.5 (45.1), P = 0.007; VLDL2:CKD 5.4 (4.6) vs. HC 10.4 (3.4), P = 0.001] with no difference in production rates. Plasma apoC-III and apoB-48 were significantly higher in CKD (P < 0.001) and both correlated with impaired FCRs of VLDL, VLDL1, and VLDL2 apoB-100 (P < 0.05). In CKD, apoC-III concentration was the only independent predictor of clearance defects in VLDL and its subfractions. Moderate CKD in the absence of central adiposity and IR is associated with mild hypertriglyceridemia due to delayed catabolism of triglyceride rich lipoproteins, IDL, and VLDL, without changes in production rate. Altered apoC-III metabolism may contribute to dyslipidemia in CKD, and this requires further investigation.