A Patient-Centered Approach to Hemodialysis Vascular Access in the Era of Fistula First

The primary vascular access options for the hemodialysis population are arteriovenous fistulas (AVF), arteriovenous grafts, and cuffed central venous catheters (CVC). AVFs are associated with the most favorable outcomes with respect to complications, interventions required to maintain functionality and patency, and overall cost. These population-based outcomes, in conjunction with the efforts of the Fistula First Breakthrough Initiative, have propelled the prevalence of AVFs in the US hemodialysis population. While this endeavor remains steadfast in assuring the continued dominance of this policy for AVF preference, it fails to take into account a subset of the dialysis population who will fail to see the benefits of an AVF. This subset of patients may include the elderly, those with poor vasculature anatomy, those with slowly progressive CKD who are more likely to die than progress to ESRD, and those with an overall poor long-term prognosis and shortened life expectancy. Thus, in an effort to avoid numerous unnecessary surgical and interventional procedures with minimal to no gains in clinical outcomes, an individualized patient approach must be adopted. The Centers for Medicare and Medicaid Services-instituted quality incentive program is designed to reward high AVF prevalence while also penalizing high CVC prevalence. The current model is devoid of case-based adjustment, thus penalties are disbursed to dialysis providers in accordance with a "one-size-fits-all" fistula only approach. The most suitable access for a patient remains the one that takes into account the characteristics unique to the individual patient with a primary focus on patient comfort, satisfaction, quality of life, and clinical outcomes.

Catheter Insertion and Perioperative Practices Within the ISPD North American Research Consortium

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BACKGROUND

In general, efforts to standardize care based on group consensus practice guidelines have resulted in lower morbidity and mortality. Although there are published guidelines regarding insertion and perioperative management of peritoneal dialysis (PD) catheters, variation in practice patterns between centers may exist. The objective of this study is to understand variation in PD catheter insertion practices in preparation for conducting future studies. ♦

METHODS

An electronic survey was developed by the research committee of the International Society for Peritoneal Dialysis - North American Research Consortium (ISPD-NARC) to be completed by physicians and nurses involved in PD programs across North America. It consisted of 45 questions related to 1) organizational characteristics; 2) PD catheter insertion practices; 3) current quality-improvement initiatives; and 4) interest in participation in PD studies. Invitation to participate in the survey was given to nephrologists and nurses in centers across Canada and the United States (US) identified by participation in the inaugural meeting of the ISPD-NARC. Descriptive statistics were applied to analyze the data. ♦

RESULTS

Fifty-one ISPD-NARC sites were identified (45% in Canada and 55% in the US) of which 42 responded (82%). Center size varied significantly, with prevalent PD population ranging from 6 - 300 (median: 60) and incident PD patients in the year prior to survey administration ranging from 3 - 180 (median: 20). The majority of centers placed fewer than 19 PD catheters/year, with a range of 0 - 50. Availability of insertion techniques varied significantly, with 83% of centers employing more than 1 insertion technique. Seventy-one percent performed laparoscopic insertion with advanced techniques (omentectomy, omentopexy, and lysis of adhesions), 62% of sites performed open surgical dissection, 10% performed blind insertion via trocar, and 29% performed blind placement with the Seldinger technique. Use of double-cuff catheters was nearly universal, with a near even distribution of catheters with pre-formed bend versus straight inter-cuff segments. There was also variation in the choice of perioperative antibiotics and perioperative flushing practices. Although 86% of centers had quality-improvement initiatives, there was little consensus as to appropriate targets. ♦

CONCLUSIONS

There is marked variability in PD catheter insertion techniques and perioperative management. Large multicenter studies are needed to determine associations between these practices and catheter and patient outcomes. This research could inform future trials and guidelines and improve practice. The ISPD-NARC is a network of PD units that has been formed to conduct multicenter studies in PD.

Success of Urgent-Start Peritoneal Dialysis in a Large Canadian Renal Program

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BACKGROUND

Many patients start renal replacement therapy urgently on in-center hemodialysis via a central venous catheter, which is considered suboptimal. An alternative approach to manage these patients is to start them on peritoneal dialysis (PD). In this report, we describe the first reported Canadian experience with an urgent-start PD program. Additionally we reviewed the literature in this area. ♦

METHODS

In this prospective observational study, we report on our experience in a single academic center. This program started in July 2010. We included patients who initiated PD urgently, that is within 2 weeks of catheter insertion. We followed all incident PD patients until October 2013 for mechanical and infectious complications. Peritoneal dialysis catheters were inserted either percutaneously or laparoscopically and dialysis was initiated in either an inpatient or outpatient setting. ♦

RESULTS

Thirty patients were started on urgent PD during our study period. Follow-up ranged from 28 to 1,050 days. Twenty insertions (66.7%) were done percutaneously and 10 (33.3%) were laparoscopic. Dialysis was initiated within 2 weeks (range: 0-13 days, median = 6 days). Twenty-four patients (80%) started PD in an outpatient setting and 6 patients (20%) required immediate inpatient PD start. Three patients (10%) developed a minor peri-catheter leak during the first week of training that was managed conservatively. There were no episodes of peritonitis or exit-site/tunnel infection during the first 4 weeks post-insertion. Four patients (13.3%) from the percutaneous insertion group and 2 patients (6.7%) from laparoscopic insertions developed catheter dysfunction due to migration, which was managed by repositioning, without need for catheter replacement or modality switch. ♦

CONCLUSIONS

Our results are consistent with other studies in this area and demonstrate that urgent-start PD is an acceptable and safe alternative to hemodialysis in patients who need to start dialysis urgently without established dialysis access.

Effect of Neutral-pH, Low-Glucose Degradation Product Peritoneal Dialysis Solutions on Residual Renal Function, Urine Volume, and Ultrafiltration: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

Neutral-pH, low-glucose degradation products solutions were developed in an attempt to lessen the adverse effects of conventional peritoneal dialysis solutions. A systematic review was performed evaluating the effect of these solutions on residual renal function, urine volume, peritoneal ultrafiltration, and peritoneal small-solute transport (dialysate to plasma creatinine ratio) over time.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Multiple electronic databases were searched from January of 1995 to January of 2013. Randomized trials reporting on any of four prespecified outcomes were selected by consensus among multiple reviewers.

RESULTS

Eleven trials of 643 patients were included. Trials were generally of poor quality. The meta-analysis was performed using a random effects model. The use of neutral-pH, low-glucose degradation products solutions resulted in better preserved residual renal function at various study durations, including >1 year (combined analysis: 11 studies; 643 patients; standardized mean difference =0.17 ml/min; 95% confidence interval, 0.01 to 0.32), and greater urine volumes (eight studies; 598 patients; mean difference =128 ml/d; 95% confidence interval, 58 to 198). There was no significant difference in peritoneal ultrafiltration (seven studies; 571 patients; mean difference =-110; 95% confidence interval, -312 to 91) or dialysate to plasma creatinine ratio (six studies; 432 patients; mean difference =0.03; 95% confidence interval, 0.00 to 0.06).

CONCLUSIONS

The use of neutral-pH, low-glucose degradation products solutions results in better preservation of residual renal function and greater urine volumes. The effect on residual renal function occurred early and persisted beyond 12 months. Additional studies are required to evaluate the use of neutral-pH, low-glucose degradation products solutions on hard clinical outcomes.

Impact of modality choice on rates of hospitalization in patients eligible for both peritoneal dialysis and hemodialysis

BACKGROUND

Hospitalization rates are a relevant consideration when choosing or recommending a dialysis modality. Previous comparisons of peritoneal dialysis (PD) and hemodialysis (HD) have not been restricted to individuals who were eligible for both therapies. ♢

METHODS

We conducted a multicenter prospective cohort study of people 18 years of age and older who were eligible for both PD and HD, and who started outpatient dialysis between 2007 and 2010 in four Canadian dialysis programs. Zero-inflated negative binomial models, adjusted for baseline patient characteristics, were used to examine the association between modality choice and rates of hospitalization. ♢

RESULTS

The study enrolled 314 patients. A trend in the HD group toward higher rates of hospitalization, observed in the primary analysis, became significant when modality was treated as a time-varying exposure or when the population was restricted to elective outpatient starts in patients with at least 4 months of pre-dialysis care. Cardiovascular disease, infectious complications, and elective surgery were the most common reasons for hospital admission; only 23% of hospital stays were directly related to complications of dialysis or kidney disease. ♢

CONCLUSIONS

Efforts to promote PD utilization are unlikely to result in increased rates of hospitalization, and efforts to reduce hospital admissions should focus on potentially avoidable causes of cardiovascular disease and infectious complications.

Higher dose versus lower dose of antiviral therapy in the treatment of herpes zoster infection in the elderly: a matched retrospective population-based cohort study

Background

Higher versus lower doses of antiviral drugs used to treat herpes zoster infection may lead to more adverse drug events in older adults, particularly those with chronic kidney disease.

Methods

We conducted a matched retrospective population-based cohort study of older adults (mean 77 years) in Ontario, Canada who initiated in the outpatient setting a higher (n = 23,256) or lower (n = 3,876) dose of one of three oral antivirals for the treatment of herpes zoster between 2002 and 2011. The primary outcome was hospitalization within 30 days with evidence of a computed tomography (CT) scan of the head (a proxy for acute neurotoxicity). The secondary outcome was 30-day all-cause mortality.

Results

A higher compared to lower dose of antiviral drug was not associated with an increased risk of hospitalization with an urgent CT scan of the head (247 [1.06%] events with higher dose versus 43 [1.11%] events with lower dose, relative risk 0.96, 95% confidence interval 0.69 to 1.33, p-value 0.79) and was not associated with a higher risk of all-cause mortality (63 [0.27%] events versus 15 [0.39%] events, relative risk 0.70, 95% confidence interval 0.40 to 1.23, p-value 0.21). Results were consistent in all subgroups, including those with and without chronic kidney disease.

Conclusions

Initiating a higher compared to a lower dose of an antiviral drug for the treatment of herpes zoster was not associated with an increased risk of adverse drug events. The findings support the safety of these drugs in older adults as currently prescribed in routine care.

Peritoneal dialysis and the process of modality selection

The process of modality selection and how it works is a critical determinant of peritoneal dialysis (PD) utilization. This very complex process has not been well analyzed. Here, we break it down into 6 steps and point out how problems at each step can significantly reduce the proportion of endstage renal disease patients initiating PD. It is important that any program wishing it to grow its use of PD understand the steps and the points at which problems may be arising. Examples are presented.

Timing of peritoneal dialysis initiation and mortality: analysis of the Canadian Organ Replacement Registry

BACKGROUND

Several observational studies of hemodialysis patients show an association between early dialysis therapy initiation and increased mortality. Few studies have examined this association among peritoneal dialysis patients.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

A cohort of 8,047 incident peritoneal dialysis patients who started dialysis therapy in 2001-2009 and were treated in Canada.

PREDICTOR

Estimated glomerular filtration rate (eGFR) at dialysis therapy initiation. Defined early, mid, and late starts as eGFR>10.5, 7.5-10.5, and <7.5mL/min/1.73m(2), respectively.

OUTCOMES

Time to death.

MEASUREMENTS

Proportional piecewise exponential survival models to compare mortality (overall and early) for the 3 predictor groups.

RESULTS

Between 2001 and 2009, the proportion of patients starting peritoneal dialysis therapy as early starts increased from 29% (95% CI, 26%-32%) to 44% (95% CI, 41%-47%). Compared with the late-start group, the overall mortality rate was not higher for the early- (adjusted HR, 1.08; 95% CI, 0.96-1.23) or mid-start (adjusted HR, 0.96; 95% CI, 0.86-1.09) groups. However, when examined yearly, patients in the early-start group were significantly more likely to die within the first year of dialysis therapy compared with those in the late-start group (adjusted HR, 1.38; 95% CI, 1.10-1.73), but not in subsequent years.

LIMITATIONS

Bias and residual confounding may have influenced the observed relationship between predictor and outcome.

CONCLUSIONS

Patients are initiating peritoneal dialysis therapy at increasingly higher eGFRs. Contrary to most observational studies assessing hemodialysis, the early initiation of peritoneal dialysis therapy, at eGFR>10.5mL/min/1.73m(2), is not associated with increased mortality.

Warfarin use in hemodialysis patients with atrial fibrillation: decisions based on uncertainty

BACKGROUND

Warfarin prescribing patterns for hemodialysis patients with atrial fibrillation vary widely amongst nephrologists. This may be due to a paucity of guiding evidence, but also due to concerns of increased risks of warfarin use in this population. The literature lacks clarity on the balance of warfarin therapy between prevention of thrombotic strokes and the increased risks of bleeding in hemodialysis patients with atrial fibrillation.

METHODS

We performed a survey of Canadian Nephrologists, assessing warfarin prescribing practice, and measured the certainty in making these choices.

RESULTS

Respondents were consistently uncertain about warfarin use for atrial fibrillation. This uncertainty increased with a history of falls or starting hemodialysis, even when a high CHADS2 or CHA2DS2VASc score was present. The majority of respondents agreed that clinical equipoise existed about the use of oral anticoagulation in hemodialysis patients with atrial fibrillation (72.2%) and that the results of a randomized controlled trial would be relevant to their practice (98.2%).

CONCLUSIONS

A randomized controlled trial of warfarin use in hemodialysis patients with atrial fibrillation would clarify the risks and benefits of warfarin use in this population.

Dialysis search filters for PubMed, Ovid MEDLINE, and Embase databases

BACKGROUND AND OBJECTIVES

Physicians frequently search bibliographic databases, such as MEDLINE via PubMed, for best evidence for patient care. The objective of this study was to develop and test search filters to help physicians efficiently retrieve literature related to dialysis (hemodialysis or peritoneal dialysis) from all other articles indexed in PubMed, Ovid MEDLINE, and Embase.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A diagnostic test assessment framework was used to develop and test robust dialysis filters. The reference standard was a manual review of the full texts of 22,992 articles from 39 journals to determine whether each article contained dialysis information. Next, 1,623,728 unique search filters were developed, and their ability to retrieve relevant articles was evaluated.

RESULTS

The high-performance dialysis filters consisted of up to 65 search terms in combination. These terms included the words "dialy" (truncated), "uremic," "catheters," and "renal transplant wait list." These filters reached peak sensitivities of 98.6% and specificities of 98.5%. The filters' performance remained robust in an independent validation subset of articles.

CONCLUSIONS

These empirically derived and validated high-performance search filters should enable physicians to effectively retrieve dialysis information from PubMed, Ovid MEDLINE, and Embase.

High prevalence of elevated lead levels in pediatric dialysis patients

BACKGROUND

After parents raised concerns about potential lead (Pb) contamination of calcium carbonate for treatment of hyperphosphatemia in chronic kidney disease (CKD), we measured blood Pb using high-resolution sector field inductively coupled mass spectrometry in a quality-assurance investigation of ten pediatric dialysis patients (nine on hemodialysis) and six patients before dialysis.

METHODS

We assessed the kidney function as cystatin C estimated glomerular filtration rate (eGFR), blood Pb levels, calcium carbonate dose, and standard laboratory parameters, as well as Pb levels in the dialysis feed water.

RESULTS

Mean blood Pb concentration in the 16 pediatric CKD patients was 21.1 ± 15.8 µg/l with a maximum of 58 µg/l, which was significantly higher than that of 467 apparently healthy controls (median 6.35 µg/l, interquartile range 4.47, 8.71) and comparable to that of ten adult peritoneal dialysis (PD) patients. Lead levels correlated with red blood cell distribution width, eGFR, and calcium carbonate dose. Pb in dialysate feed water was always <0.00018 mg/l, which is below the accepted limit for water for dialysis of 0.005 mg/l.

CONCLUSIONS

We found a high prevalence of elevated Pb levels in pediatric CKD patients that correlated with the calcium carbonate dose and GFR. Lead levels should be monitored in these patients.

PP137. Posterior reversible encephalopathy syndrome (PRES) is a constant component of eclampsia

INTRODUCTION

Posterior reversible encephalopathy syndrome (PRES) has been reported to occur in patients with eclampsia. In both conditions there is evidence to suggest disordered cerebral autoregulation.

OBJECTIVES

We sought to investigate the concurrence of PRES with eclampsia and to describe the associated obstetric, radiologic and critical care correlates.

METHODS

Single center 2001-2010 retrospective cohort study of all patients with eclampsia who underwent neuroimaging via magnetic resonance imaging (MRI) or computerized tomography (CT) with or without contrast. The medical records of all patients with eclampsia during the study interval were identified, evaluated and extracted for pertinent data; a diagnosis of PRES was made by radiologists using standard criteria.

RESULTS

Forty-six of forty-seven (97.9%) patients with eclampsia revealed PRES on neuroimaging using one or more modalities: MRI without contrast=41 (87.2%), MRI with contrast=27 (57.4%), CT without contrast=16 (34%), CT with contrast=7 (14.8%) and/or MRA/MRV=2 (4.3%). PRES was identified within the parietal (36, 78.3%), occipital (35, 76.1%), frontal (29, 63%), temporal (13, 28.3%) and basal ganglia/ brainstem/cerebellum (12, 26.1%). Eclampsia occurred antepartum in 23 patients, postpartum in 24 patients with 22 vaginal/25 cesarean deliveries at a mean maternal age of 21.8 years (range 15-39) and a mean gestational age of 33.9 weeks (range 22.4-41.7 weeks). Ethnicity was African-American in 38 patients. Headache was the most common presenting symptom (87.2%) followed by altered mental status (51.1%), visual disturbances (34%) and nausea/vomiting (19.1%). Severe systolic hypertension was present in 22 (47%) of patients.Use of antihypertensives (87%), magnesium sulfate (100%), diuretics (66%) and corticosteroids (50%) facilitated maternal recovery in all cases with usually a brief hospitalization (mean 3.9 days, range 1-20 days).

CONCLUSION

The common finding of PRES in patients with eclampsia suggests that PRES may be part of the pathogenesis of eclampsia. We speculate that therapy targeted at prevention or reversal of PRES pathogenesis will prevent or facilitate recovery from eclampsia.