Richard Fluck

A Meta-analysis of Hemodialysis Catheter Locking Solutions in the Prevention of Catheter-Related Infection

BACKGROUND Catheter-related infection (CRI) is associated with increased all-cause mortality and morbidity in hemodialysis patients and may be reduced by using antimicrobial lock solutions (ALSs). STUDY DESIGN We performed a meta-analysis of studies identified from a search conducted in February 2007 of the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature, databases of ongoing trials, major renal journals, and reference lists of relevant reports. SETTING & POPULATION Patients receiving acute or long-term hemodialysis through a tunneled or nontunneled central venous catheter. SELECTION CRITERIA FOR STUDIES We included all prospective randomized studies that compared ALS with heparin. INTERVENTION Administration of antibiotic and/or antimicrobial catheter locking solution. OUTCOME MEASURES Primary outcome was CRI rate in patients using ALSs compared with those using heparin alone. We also examined effects of ALS use on mortality, adverse events, and catheter thrombosis. RESULTS 7 studies were identified with a total of 624 patients and 819 catheters (448 tunneled, 371 nontunneled). CRI was 7.72 (95% confidence interval, 5.11 to 10.33) times less likely when using ALS. There were no consistent suggestions of adverse outcomes with ALS use; in particular, rates of catheter thrombosis did not increase. There was no evidence of antibiotic resistance developing during a maximum follow-up of 12 months. LIMITATIONS The major limitation of this review is the relatively short duration of follow-up of the included studies, which does not allow complete reassurance regarding the development of antibiotic resistance. Lack of direct comparisons means that determination of the most efficient ALS is not possible. CONCLUSIONS This review confirms that antibiotic locking solutions reduce the frequency of CRI without significant side effects.

Use of Electronic Results Reporting to Diagnose and Monitor AKI in Hospitalized Patients

BACKGROUND AND OBJECTIVES Many patients with AKI are cared for by non-nephrologists. This can result in variable standards of care that contribute to poor outcomes. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS To improve AKI recognition, a real-time, hospital-wide, electronic reporting system was designed based on current Acute Kidney Injury Network criteria. This system allowed prospective data collection on AKI incidence and outcomes such as mortality rate, length of hospital stay, and renal recovery. The setting was a 1139-bed teaching hospital with a tertiary referral nephrology unit. RESULTS An electronic reporting system was successfully introduced into clinical practice (false positive rate, 1.7%; false negative rate, 0.2%). The results showed that there were 3202 AKI episodes in 2619 patients during the 9-month study period (5.4% of hospital admissions). The in-hospital mortality rate was 23.8% and increased with more severe AKI (16.1% for stage 1 AKI versus 36.1% for stage 3) (P<0.001). More severe AKI was associated with longer length of hospital stay for stage 1 (8 days; interquartile range, 13) versus 11 days for stage 3 (interquartile range, 16) (P<0.001) and reduced chance of renal recovery (80.0% in stage 1 AKI versus 58.8% in stage 3) (P<0.001). Utility of the Acute Kidney Injury Network criteria was reduced in those with pre-existing CKD. CONCLUSIONS AKI is common in hospitalized patients and is associated with very poor outcomes. The successful implementation of electronic alert systems to aid early recognition of AKI across all acute specialties is one strategy that may help raise standards of care.

Markers of arterial stiffness are risk factors for progression to end-stage renal disease among patients with chronic kidney disease stages 4 and 5.

Background: Factors associated with chronic kidney disease (CKD) contribute to an increased risk of cardiovascular disease and death. The impact of vascular disease on CKD progression is, however, less well studied. Methods: We examined the effect of markers of vascular disease on the risk of progression to end-stage renal disease (ESRD) in 35 patients with CKD stages 4–5. Superficial femoral artery calcification was assessed by CT scan. Augmentation index (AI) and pulse wave velocity (PWV) were measured by applanation tonometry. Results: After 12.4 (5.5–28.4) months, 22/35 patients (63%) had commenced dialysis. Cox regression analysis identified baseline estimated glomerular filtration rate (hazard ratio, HR, 0.54; 95% CI 0.41–0.70; p < 0.0001), urinary protein (HR 1.84; 95% CI 1.32–2.58; p = 0.0005), PWV (HR 1.30; 95% CI 1.07–1.60; p = 0.01), AI (HR 1.08; 95% CI 1.04–1.14; p = 0.0001) and pack years of smoking (HR 1.01; 95% CI 1.00–1.03; p = 0.02) as independent risk factors for time to ESRD (–2 log likelihood = 86.7; χ2 = 30.9; p < 0.0001). Repeat analysis using AI as a categorical variable revealed an HR of 17.5 (95% CI 4.43–68.9; p < 0.0001) for time to ESRD in those with AI above versus below the median. Conclusions: We have identified two markers of arterial stiffness as independent risk factors for progression to ESRD suggesting that vascular disease may contribute to CKD progression.

Skin Autofluorescence and the Association with Renal and Cardiovascular Risk Factors in Chronic Kidney Disease Stage 3

BACKGROUND AND OBJECTIVES Tissue advanced glycation end products (AGE) accumulation is a measure of cumulative metabolic stress. Assessment of tissue AGE by skin autofluorescence (SAF) correlates well with cardiovascular (CV) outcomes in diabetic, transplant, and dialysis patients, and may be a useful marker of CV risk in earlier stages of chronic kidney disease (CKD). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS 1707 patients with estimated GFR 59 to 30 ml/min per 1.73 m(2) were recruited from primary care practices for the Renal Risk In Derby (RRID) study. Detailed medical history was obtained, and each participant underwent clinical assessment as well as urine and serum biochemistry tests. SAF was assessed (mean of three readings) as a measure of skin AGE deposition using a cutaneous AF device (AGE Reader™, DiagnOptics, Groningen, The Netherlands). RESULTS Univariate analysis revealed significant correlations between AF readings and several potential risk factors for cardiovascular disease (CVD) and progression of CKD. SAF readings (arbitrary units) were also significantly higher among males (2.8 ± 0.7 versus 2.7 ± 0.6), diabetics (3.0 ± 0.7 versus 2.7 ± 0.6), patients with evidence of self-reported CVD (2.9 ± 0.7 versus 2.7 ± 0.6), and those with no formal educational qualifications (2.8 ± 0.6 versus 2.6 ± 0.6; P < 0.01 for all). Multivariable linear regression analysis identified hemoglobin, diabetes, age, and eGFR as the most significant independent determinants of higher SAF (standardized coefficients -0.16, 0.13, 0.12, and -0.10, respectively; R(2) = 0.17 for equation). CONCLUSION Increased SAF is independently associated with multiple CV and renal risk factors in CKD 3. Long-term follow-up will assess the value of SAF as a predictor of CV and renal risk in this population.

Diagnosis, prevention and treatment of haemodialysis catheter-related bloodstream infections (CRBSI) : a position statement of European Renal Best Practice (ERBP)

Nephrology Section, Department of Internal Medicine, University Hospital, Gent, Belgium, Nephrology, Dialysis and Intensive Care Unit, Lapeyronie University Hospital, Montpellier, France, Department of Renal Medicine, Royal Derby Hospital, Derby, UK, Nephrology, Cliniques Universitaires Saint-Luc, Universite Catholique de Louvain, Brussels, Belgium, Nephrology Department, Consorcio Hospital General Universitario, Valencia, Spain and Vascular Surgery, Department of Surgery, Maastricht University Medical Center, Maastricht, the Netherlands

Effects of arteriovenous fistula formation on arterial stiffness and cardiovascular performance and function

BACKGROUND Native arteriovenous fistula (AVF) is the vascular access of choice and its use cf. catheters is associated with sustained reduction in mortality. This may be due to factors beyond dialysis catheter-associated sepsis. This study aimed to investigate the impact of AVF formation on the spectrum of cardiovascular factors that might be important in the pathophysiology of cardiovascular diseases in chronic kidney disease (CKD) patients. METHODS We recruited 43 pre-dialysis patients who underwent AVF formation. Patients were studied 2 weeks prior to AVF operation and 2 weeks and 3 months post-operatively. Haemodynamic variables were measured using pulse wave analysis, carotid femoral pulse wave velocity (CF-PWV) by applanation tonometry and AVF blood flow by Doppler ultrasound. Bioimpedence analysis was performed and patients underwent serial transthoracic echocardiography. RESULTS AVF formation was successful in 30/43 patients. Two weeks post-operatively, total peripheral resistance decreased (-17 ± 18%, P = 0.001), stroke volume tended to rise (12 ± 30 mL, P = 0.053) and both heart rate (4 ± 8 bpm, P = 0.01) and cardiac output (1.1 ± 1.5 L/min, P = 0.001) increased. Systolic and diastolic blood pressures (BPs) reduced (-9 ± 18 mmHg; -9 ± 10 mmHg; ≤ P = 0.006) and CF-PWV reduced (-1.1 ± 1.5 m/s, P = 0.004). Left ventricular ejection fraction (LVEF) increased (6 ± 8%, P < 0.001). All the observed changes were largely maintained after 3 months. No change in hydration status/body composition was observed. CONCLUSIONS AVF formation resulted in a sustained reduction in arterial stiffness and BP as well as an increase in LVEF. Overall, post-AVF adaptations might be characterized as potentially beneficial in these patients and supports the widespread use of native vascular access, including older or cardiovascular compromised individuals.

Online conductivity monitoring: Validation and usefulness in a clinical trial of reduced dialysate conductivity

Relatively low dialysate conductivity (Cndi) may improve outcomes by reducing the overall sodium burden in dialysis patients. Excess sodium removal, however, could lead to hemodynamic instability. We performed a randomized controlled trial of reduction of Cndi. For the study, 28 patients were randomized to maintenance of Cndi at 13.6 mS/cm (equivalent to 135 mmol/L of Na+) or serial reduction of Cndi in steps of 0.2 mS/cm, guided by symptoms and blood pressure. Sodium removal estimated from pre- and postplasma concentrations correlated well with removal measured by conductivity monitoring as ionic mass balance (R2 0.66, p < 0.0001). Of the 16 patients randomized to reduction of Cndi, 6 achieved Cndi 13.4 mS/cm, 6 achieved 13.2 mS/cm, and 4 achieved 13.0 mS/cm. No episodes of disequilibrium occurred. Interdialytic weight gain was reduced from 2.34 ± 0.10 kg to 1.57 ± 0.11 kg (p < 0.0001). Predialysis systolic blood pressure fell from 144 ± 3 mm Hg to 137 ± 4 mm Hg (p < 0.05). The reduction in convective sodium removal was balanced by an increase in diffusive sodium removal (95 ± 9 mmol cf. 175 ± 14 mmol, p < 0.0001). Reduction in Cndi monitored by IMB is safe and practical and leads to improved interdialytic weight gains and blood pressure control, while avoiding excessive sodium removal.

Catheter-related blood stream infections (CRBSI): a European view

Nephrology Section, Department of Internal Medicine, University Hospital, Gent, Belgium, Nephrology, Dialysis and Intensive Care Unit, Lapeyronie University Hospital, Montpellier, France, Department of Renal Medicine, Royal Derby Hospital, Derby, UK, Nephrology, Cliniques Universitaires Saint-Luc, Universite Catholique de Louvain, Brussels, Belgium, Nephrology Department, Consorcio Hospital General Universitario, Valencia, Spain and Vascular Surgery, Department of Surgery, Maastricht University Medical Center, Maastricht, The Netherlands

Renal Association Clinical Practice Guideline on vascular access for haemodialysis.

Vascular access remains a key component of haemodialysis. The ideal vascular access should provide safe and effective therapy by enabling the removal and return of blood via an extracorporeal circuit. Vascular access should be easy to use, reliable and have minimal risk to the individual receiving haemodialysis. However, the provision of good quality access, whilst it is a fundamental aspect of the treatment of haemodialysis patients, remains difficult to achieve. Native access, in particular arteriovenous fistulae, requires prior planning yet has a high primary failure rate. Arteriovenous grafts utilising replacement of synthetic or biological material in conjunction with native vessels again require planning and surgical expertise yet have a high demand to maintain them and a high rate of complications. Venous catheters (both tunnelled and non-tunnelled) are in common usage both as temporary access and in a smaller number of patients as the only form of access that is available, yet offer inferior therapy. Vascular access via central venous catheters provides poorer solute clearance related to the limited achieved blood flow and also a higher rate of complications. This guideline updates the section on vascular access in the haemodialysis module of the 4th edition of the RA guidelines published on-line at www.renal.org in 2007. These guideline recommendations are based on a literature review from relevant publications in journals cited on MEDLINE, PubMed and UpToDate up to 1st May 2010. The modified GRADE system has been adopted by the Renal Association Clinical Practice Guidelines Committee and has been used to grade the recommendations in all of the modules in the 5th edition of the Renal Association guidelines. It explicitly describes both the strength of the recommendations and the quality of the underlying evidence, with the aim of maximising applicability to standard clinical practice [1–4]. The modified GRADE system grades level of expert recommendation as ‘strong’ (Grade 1) or ‘weak’

Tissue-Advanced Glycation End Product Concentration in Dialysis Patients

BACKGROUND AND OBJECTIVES Tissue-advanced glycation end products (AGE) are a measure of cumulative metabolic stress. Assessment of tissue AGE by skin autofluoresence (AF) correlates well with cardiovascular outcomes in hemodialysis (HD) patients. This study aimed to measure and compare tissue AGE levels in HD and peritoneal dialysis (PD) patients and to evaluate the impact of systemic PD glucose exposure. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Tissue AGE were measured in 115 established dialysis patients (62 HD and 53 PD) using a cutaneous AF device (AGE Reader; DiagnOptics). Values were compared with an age-matched non-chronic kidney disease database. Review of all previous PD solution delivery/prescription data determined PD glucose exposure. RESULTS PD patients were similar in age to HD patients but had a shorter dialysis vintage. There were no differences in ischemic heart disease or smoking history, statin or angiotensin-converting enzyme inhibitor (ACEi) use, lipids, biochemistry, or prevalence of diabetes. More than 90% of both groups had met current dialysis adequacy targets. Skin AF values in PD and HD patients were similar and strongly correlated with historical PD glucose exposure. Skin AF correlated with age in both groups but with dialysis vintage only in PD patients CONCLUSIONS Cumulative metabolic stress and transient hyperglycemia results in grossly elevated levels of tissue AGE in dialysis patients. In PD patients, this high level of AGE deposition is associated with historical glucose exposure. This observation provides a previously unappreciated potential link between PD exposure to glucose and systemic cardiovascular disease.