Effect of End-Stage Renal Disease Prospective Payment System on Utilization of Peritoneal Dialysis in Patients with Kidney Allograft Failure.

INTRODUCTION: The Center for Medicare and Medicaid Services (CMS) introduced an End Stage Renal Disease (ESRD) Prospective Payment System (PPS) in 2011 to increase the utilization of home dialysis modalities, including peritoneal dialysis (PD). Several studies have shown a significant increase in PD utilization after PPS implementation. However, its impact on patients with kidney allograft failure remains unknown. METHODS: We conducted an interrupted time series (ITS) analysis using data from the United States Renal Data System (USRDS) that include all adult kidney transplant recipients with allograft failure who started dialysis between 2005 and 2019. We compared the PD utilization in the pre-PPS period (2005-2010) to the fully implemented post-PPS period (2014 - 2019) for early (within 90 days) and late (91-365 days) PD experience. RESULTS: 27507 adult recipients with allograft failure started dialysis during the study period. There was no difference in early PD utilization between the pre-PPS and the post-PPS period in either immediate change (0.3% increase; 95%CI: -1.95%, 2.54%; p=0.79) or rate of change over time (0.28% increase per year; 95%CI: -0.16%, 0.72%; p=0.18). Subgroup analyses revealed a trend toward higher PD utilization post-PPS in for-profit and large-volume dialysis units. There was a significant increase in PD utilization in the post-PPS period in units with low PD experience in the pre-PPS period. Similar findings were seen for the late PD experience. CONCLUSION: PPS did not significantly increase the overall utilization of PD in patients initiating dialysis after allograft failure.

Arteriovenous Access Type and Risk of Mortality, Hospitalization, and Sepsis Among Elderly Hemodialysis Patients: A Target Trial Emulation Approach.

RATIONALE & OBJECTIVE: Evidence is mixed regarding the optimal choice of the first permanent vascular access for elderly patients receiving hemodialysis (HD). Lacking data from randomized controlled trials, we used a target trial emulation approach to compare arteriovenous fistula (AVF) versus arteriovenous graft (AVG) creation among elderly patients receiving HD. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Elderly patients included in the US Renal Data System who initiated HD with a catheter and had an AVF or AVG created within 6 months of starting HD. EXPOSURE: Creation of an AVF versus an AVG as the incident arteriovenous access. OUTCOMES: All-cause mortality, all-cause and cause-specific hospitalization, and sepsis. ANALYTICAL APPROACH: Target trial emulation approach, high-dimensional propensity score and inverse probability of treatment weighting, and instrumental variable analysis using the proclivity of the operating physician to create a fistula as the instrumental variable. RESULTS: A total of 19,867 patients were included, with 80.1% receiving an AVF and 19.9% an AVG. In unweighted analysis, AVF creation was associated with significantly lower risks of mortality and hospitalization, especially within 6 months after vascular access creation. In inverse probability of treatment weighting analysis, AVF creation was associated with lower incidences of mortality and hospitalization within 6 months after creation (hazard ratios of 0.82 [95% CI, 0.75-0.91] and 0.82 [95% CI, 0.78-0.87] for mortality and all-cause hospitalization, respectively), but not between 6 months and 3 years after access creation. No association between AVF creation and mortality, sepsis, or all-cause, cardiovascular disease-related, or infection-related hospitalization was found in instrumental variable analyses. However, AVF creation was associated with a lower risk of access-related hospitalization not due to infection. LIMITATIONS: Potential for unmeasured confounding, analyses limited to elderly patients, and absence of data on actual access use during follow-up. CONCLUSIONS: Using observational data to emulate a target randomized controlled trial, the type of initial arteriovenous access created was not associated with the risks of mortality, sepsis, or all-cause, cardiovascular disease-related, or infection-related hospitalization among elderly patients who initiated HD with a catheter.

Catheter Dependence After Arteriovenous Fistula or Graft Placement Among Elderly Patients on Hemodialysis.

RATIONALE & OBJECTIVE: Creation of an arteriovenous fistula (AVF), compared with an arteriovenous graft (AVG), is associated with longer initial catheter dependence after starting hemodialysis (HD) but longer access survival and lower long-term catheter dependence. The extent of these potential long-term benefits in elderly patients is unknown. We assessed catheter dependence after AVF or AVG placement among elderly patients who initiated HD without a permanent access in place. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Patients≥67 years of age identified in the US Renal Data System who had a first AVF (n=14,532) or AVG (n=3,391) placed within 1 year after HD initiation between May 2012 and May 2017. EXPOSURE: AVF versus AVG placement in the first year of HD. OUTCOME: Catheter dependence after AVF or AVG placement assessed using CROWNWeb data. ANALYTICAL APPROACH: Generalized estimating equations and negative binomial regression for catheter use over time and Cox proportional hazards models for mortality. RESULTS: Creation of an AVF versus AVG placement was associated with greater catheter dependence at 1 month (95.6% vs 92.5%) and 3 months (82.8% vs 41.2%), but lower catheter dependence at 12 months (14.2% vs 15.8%) and 36 months (8.2% vs 15.0%). Creation of an AVF, however, remained significantly associated with greater cumulative catheter-dependent days (80.1 vs 54.6 days per person-year) and a lower proportion of catheter-free survival time (78.1% vs 85.1%) after 3 years of follow-up. LIMITATIONS: Potential for unmeasured confounding and analyses limited to elderly patients. CONCLUSIONS: Creation of an AVF was associated with significantly greater cumulative catheter dependence than placement of an AVG in an elderly population initiating HD without a permanent access. As the long-term benefits in terms of catheter dependence of an AVF are not realized in many elderly patients, specific patient characteristics should be considered when making decisions regarding vascular access.

Hand Ischemia in a Patient With an Arteriovenous Fistula.

An ischemic digit causes significant morbidity due to its associated discomfort and potential for tissue necrosis. Historically, when this phenomenon was peripheral to an ipsilateral arteriovenous access in a hemodialysis patient, it was called "steal syndrome" and was usually treated with access ligation, resulting in loss of the access. We present a dialysis patient with hand pain due to ischemia that was referred for access ligation. Instead, a minimally invasive banding procedure was performed that resulted in access salvage and resolution of symptoms. We present images and a discussion of the diagnosis and treatment of distal hypoperfusion ischemia syndrome in this Imaging Teaching Case.

Erosion of the Silicone Peritoneal Dialysis Catheter with the Use of Gentamicin Cream at the Exit Site.

Infection remains the leading complication of peritoneal dialysis (PD). Topical mupirocin and gentamicin are frequently used to prevent infections. Mupirocin ointment has been reported to cause damage to both polyurethane and silicone PD catheters. Gentamicin cream has not been associated with physical damage to catheters.A 64-year-old woman on PD developed relapsing peritonitis with Staphylococcus epidermidis. Because of a drainage problem and white discoloration at the exit site, which is known as " frosting," she underwent catheter exchange. The catheter was found to be fractured within the area of frosting. Four more patients with frosting of the catheter were identified. On further questioning, it was recognized that they were applying excessive amounts of gentamicin cream directly on the catheter surface rather than at the exit site. All patients in the program were educated about the correct method of topical antibiotic application. After the change in practice, no further cases of catheter frosting were identified.Polyurethane catheters can undergo oxidation, mineralization, and environmental stress cracking, leading to physical damage such frosting, ballooning, and fracture. Polyethylene glycol, a component of the mupirocin ointment base, is thought to cause plasticization of polyurethane, reducing its tensile strength. Similar damage has been observed in silicone catheters. Previous reports have not found gentamicin cream to cause that type of damage. We observed that excessive amounts of cream applied directly to the catheter surface can damage it. Damage did not recur once patients had been educated about the proper method of application.

Prediction of Arteriovenous Fistula Dysfunction: Can it be Taught?

Physical examination (PE) is an excellent means of predicting arteriovenous fistula (AVF) dysfunction. Although quick and inexpensive, PE is seldom used as a tool to assess stenosis by general nephrologists, dialysis nurses, and dialysis technicians. Previous studies have demonstrated that PE can be taught to interventional specialists, but the perception remains that it is too complex to be performed by other health care professionals. We hypothesized that the physical exam can be taught to a nonmedical professional, and that, with time, it would be comparable to the physical exam performed by a full-time interventional specialist. An undergraduate student and an interventional specialist (MD) examined AVF for dysfunction in a tertiary care hospital over a 6-month period. PE was performed on patients who were suspected of having dialysis access dysfunction and were referred for angiography and intervention (n = 49). Physical exam findings were categorized blindly by each examiner into four categories of lesion location: inflow, outflow, both, or neither. Data were privately recorded and compared to the gold standard of angiographic results. Potential confounding variables, including age, gender, diabetic status, and location of AVF were recorded. Weighted Cohen's kappa value was used as a measurement of the level of agreement beyond chance between the diagnoses made by physical exam and angiography. The full-time interventional specialist demonstrated correct prediction of lesion location of 89.8% (kappa = 0.850), while the undergraduate student had a correct prediction of 77.6% (kappa = 0.625). The student's performance, however, differed significantly over time. The student correctly predicted the location of the lesion in 6 (42.9%) of the first 14 patients (kappa = 0.082), compared to 32 (91.4%) of the last 35 patients (kappa = 0.855). We suggest that physical exam of AVF can be taught to a nonmedical professional in a short duration of time and the predictive value of the exam can be similar to that of an interventional specialist.

A Meta-analysis of Stent Placement vs. Angioplasty for Dialysis Vascular Access Stenosis.

Dysfunction of arteriovenous fistulas (AVF) and arteriovenous grafts (AVG) contribute significantly to morbidity and hospitalization in the dialysis population. Despite advances in endovascular techniques, the incidence of vascular access stenosis remains problematic. Currently, the role of endovascular stent placement in the treatment of vascular access stenosis is poorly defined. This meta-analysis compares the primary patency rates of stenotic vascular access treated with stent placement vs. angioplasty. We searched Medline for English language publications from 1980 through December 2013, along with national conference proceedings and reference lists of all included publications. Inclusion criteria were a measure of primary patency, secondary patency, or access dysfunction. Studies were excluded if they were not in English or if they included pediatric patients. Ten studies with a total of 860 subjects met the inclusion criteria, including six experimental studies and four observational studies. There was significantly higher overall primary patency in those receiving stent placement than in those treated with angioplasty (pooled relative risk [RR] = 0.79; 95% confidence interval [CI]: 0.65-0.96). The estimate did not differ by study design. The effect of treatment differed significantly (p = 0.001) by the type of stents used, however. In studies including nitinol stents (six studies, 678 patients), 6-month patency was significantly better for stent placement than angioplasty (pooled RR = 0.67; 95% CI: 0.54-0.84), whereas there was no significant differences between stent placement and angioplasty in those studies using bare metal stents exclusively (four studies, 182 patients; pooled RR = 1.09; 95% CI: 0.91-1.32). There was significant heterogeneity between studies (I(2)  = 70.6%; p < 0.0001). Our results suggest that stent placement may confer an advantage over balloon angioplasty in primary patency of dialysis access stenoses.

The effect of buttonhole cannulation vs. rope-ladder technique on hemodialysis access patency.

The rope-ladder (RL) technique is the most common technique used for cannulation of arteriovenous fistulae (AVF). Buttonhole cannulation (BHC), or constant-site technique, is recommended by the National Kidney Foundation's Kidney Disease Outcome Quality Initiative (NKF/KDOQI) vascular access guidelines. We compared outcomes of primary patency, episodes of bacteremia, access blood flow (Qa), and quality of life (QoL) scores between RL and BHC patients. Using a prospectively collected, vascular access database, a total of 45 prevalent dialysis patients using BHC were compared with 38 patients using the RL technique over a median of 12 months (inter-quartile range: 4-27 months). The two groups did not differ significantly in demographics except that diabetes was more common in those using BHC as compared to rope-ladder (69% vs. 34%; p = 0.002). Risk factors associated with lack of primary patency were age (hazards ratio [HR] = 1.02 per decade; 95% CI: 1.00-1.03; p = 0.04) and female gender (HR = 1.92; 95% CI: 1.08-3.40; p = 0.03). Use of the buttonhole technique was not associated with improved primary patency (HR = 1.22, 95% CI: 0.65-2.28; p = 0.53). Episodes of bacteremia and mean scores from KDQOL-36 did not differ significantly between the groups. This study demonstrates for the first time that BHC use is not associated with improved access patency.

A case series of real-time hemodynamic assessment of high output heart failure as a complication of arteriovenous access in dialysis patients.

Congestive heart failure (CHF) is an important source of morbidity and mortality in end-stage renal disease patients. Although CHF is commonly associated with low cardiac output (CO), it may also occur in high CO states. Multiple conditions are associated with increased CO including congenital or acquired arteriovenous fistulae or arteriovenous grafts. Increased CO resulting from permanent AV access in dialysis patients has been shown to induce structural and functional cardiac changes, including the development of eccentric left ventricle hypertrophy. Often, the diagnosis of high output heart failure requires invasive right heart monitoring in the acute care setting such as a medical or cardiac intensive care unit. The diagnosis of an arteriovenous access causing high output heart failure is usually confirmed after the access is ligated surgically. We present for the first time, a case for real-time hemodynamic assessment of high output heart failure due to AV access by interventional nephrology in the cardiac catheterization suite.

Chronic total occlusion and successful drug-eluting stent placement in Takayasu arteritis-induced renal artery stenosis.

Takayasu arteritis-induced renal artery stenosis (TARAS) is a condition rarely described in the literature. Although percutaneous transluminal angioplasty and stenting has been well-described in the treatment of atherosclerotic renal artery stenosis, its role has not been established in non-atherosclerotic TARAS. We report a case of a female, age 17 years, with Takayasu arteritis who presented to the hospital with seizures and hypertensive crisis. A renal angiogram showed chronic total occlusion (CTO) of the left renal artery. Renal angioplasty and stenting was successfully performed after multiple attempts to deliver a wire distal to the CTO. After sequential balloon predilation, a drug-eluting stent was deployed, resulting in full reperfusion of the kidney. The patient's blood pressure improved dramatically, and patency of the stent was demonstrated with magnetic resonance angiography over 9 months after the procedure.

A case report of deferasirox-induced kidney injury and Fanconi syndrome.

Cases of kidney injury associated with the use of deferasirox chelation therapy during the course of treatment for iron overload have been reported infrequently. We present the case of a patient treated with deferasirox who had biopsy-proven tubular injury in the setting of clinical Fanconi syndrome. The patient required hospitalization for metabolic acidosis, electrolyte abnormalities, and associated symptoms. With supportive care and cessation of chelation therapy he improved, but has yet to fully recover. This is the first known case reporting biopsy-proven tubular damage in the setting of deferasirox use.

ASDIN white paper: Management of cephalic arch stenosis endorsed by the American Society of Diagnostic and Interventional Nephrology.

Brachiocephalic arteriovenous fistulas (AVF) makeup approximately one third of prevalent dialysis vascular accesses. The most common cause of malfunction with this access is cephalic arch stenosis (CAS). The accepted requirement for treatment of a venous stenosis lesion is ⩾50% stenosis associated with hemodynamically abnormalities. However, the correlation between percentage stenosis and a clinically significant decrease in access blood flow (Qa) is low. The critical parameter is the absolute minimal luminal diameter (MLD) of the lesion. This is the parameter that exerts the key restrictive effect on Qa and results in hemodynamic and functional implications for the access. CAS is the result of low wall shear stress (WSS) resulting from the effects of increased blood flow and the unique anatomical configuration of the CAS. Decrease in WSS has a linear relationship to increased blood flow velocity and neointimal hyperplasia exhibits an inverse relationship with WSS. The result is a stenotic lesion. The presence of downstream venous stenosis causes an inflow-outflow mismatch resulting in increased pressure within the access. Qa in this situation may be decreased, increased, or within a normal range. Over time, the increased intraluminal pressure can result in marked aneurysmal changes within the AVF, difficulties with cannulation and the dialysis treatment, and ultimately, increasing risk of access thrombosis. Complete characterization of the lesion both hemodynamically and anatomically should be the first step in developing a strategy for management. This requires both access flow measurement and angiographic imaging. Patients with CAS present a relatively broad spectrum as relates to both of these parameters. These data should be used to determine whether primary treatment of CAS should be directed toward the anatomical lesion (small MLD and low Qa) or the pathophysiology (large MLD and high Qa).

Impact of COVID-19 pandemic on hemodialysis access thrombosis.

BACKGROUND: Delay in care of suspected stenosis or thrombosis can increase the chance of losing a functioning hemodialysis access. Access to care and resources were restricted during the COVID-19 pandemic. To evaluate the impact of the pandemic on arteriovenous fistula (AVF) and arteriovenous graft (AVG) procedures we have assessed the number and success of thrombectomies done before and during the COVID-19 pandemic. METHODS: We examined all AVF and AVG angiograms with and without interventions, including thrombectomies, performed at a single center during April 2017-March 2021 (pre-COVID-19 era) and April 2020-March 2021 (COVID-19 era). RESULTS: The proportion of procedures that were thrombectomies was higher during the COVID-19 era compared to the pre-COVID-19 era (13.3% vs 8.7%, p = 0.009). The proportion of thrombectomy procedures was higher during COVID-19 for AVF (8.2% vs 3.0%, p < 0.001) but there was no difference for AVG (26.5% vs 27%, p = 0.99). There was a trend toward a higher likelihood of unsuccessful thrombectomy during COVID-19 (33.3% vs 20.4%, p = 0.08). CONCLUSIONS: More dialysis access thromboses and unsuccessful thrombectomies were noted during the COVID-19 pandemic. This difference could be due to a delay in patients getting procedures to maintain their dialysis accesses.

The rationale, implementation, and effect of the Medicare CKD education benefit.

Although it affects <1% of the US population, stage 4 chronic kidney disease (CKD) has increased in prevalence in the United States, grown 67% between the early 1990s and the first part of this decade. It is important to consider new strategies to slow or halt this increase. A frameshift in patient care delivery is underway in kidney health care in the United States with a Medicare education benefit for patients with stage 4 CKD. This Medicare benefit is a unique program that has the potential to inform patients and families about CKD and prepare them for transitions in health states and kidney health care. For the greatest value of this benefit to be realized, it is critical for the health care community to accurately gauge patient understanding of CKD and provide curricula that are comprehensible and actionable for patients. This type of benefit is patient centered, yet it will succeed only with a willingness to review its effectiveness and revise it if needed.

Retrograde occlusive arteriography of hemodialysis access: failure to detect inflow lesions?

Once thought to be a minor player in hemodialysis (HD) access dysfunction relative to outflow stenosis, inflow stenosis has recently come to be viewed as a major cause of access failure. Indeed, recent literature has shown that up to 40% of all accesses referred for dysfunction have an inflow lesion. Imaging of the inflow segment has been traditionally performed by interventional nephrologists via retrograde occlusive arteriography (ROA). Recent advances in our understanding of ROA have cast the technique in a negative light, with the possibility of vascular complications and poor diagnostic yield coming to the fore. Using a prospectively collected, vascular access database, we identified 18 consecutive patients who received imaging of inflow lesions by ROA and direct arteriogram (DA). The mean percent luminal stenoses were found to be 59.89 ± 24 and 79.06 ± 17.8 (p = 0.009) for the ROA vs. DA groups, respectively. Using multiple regression analysis, DA was found to be associated with detecting higher degree of luminal stenosis (ß = 19.17, 95% CI 6.28-32.05, p = 0.006). This small case series provides evidence on the theoretical concern that ROA does not adequately evaluate inflow lesions. We may conclude that by relying solely on ROA, interventional nephrologists may be failing to detect a subset of hemodynamically significant inflow lesions.

Mega Fistulae! A case series.

A mega fistula can be defined as generalized aneurysmal dilatation of arteriovenous fistula. Mega fistulae can lead to complications like high output cardiac failure, steal syndrome, skin ulceration and rupture. We describe a series of ten patients who were referred to our interventional nephrology practice for evaluation of mega fistula which had not been in use for a long time. Nine out of ten patients were post-transplant while one was pre dialysis. Five patients had Radiocephalic while four had Brachiocephalic and one had Brachial artery to Median Cubital vein fistula. All except one patient had severe outflow stenosis. The most common site of stenosis in Radiocepahlic and Brachiocepahlic fistula was cephalic vein at the elbow and cephalic arch respectively. Half of the patients had chronic total occlusion of the outflow vein. Successful angioplasty was done in only two patients. Seven patients underwent ligation while one had spontaneous thrombosis of the fistula. None of the patients had regular surveillance of their access for a long time as they were not on dialysis. Unrecognized and uncorrected outflow stenosis over a long time period can lead to creation of mega fistula. Once a mega fistula develops there are not many treatment options other than ligation. This leads to loss of the access which might be needed in future. Continuous access surveillance in patients who are not on dialysis is important to prevent complications like mega fistula.

Perspectives in Individualizing Solutions for Dialysis Access.

The vascular access is the lifeline for the hemodialysis patient. Previous national vascular access guidelines have emphasized placement of arteriovenous fistulas in most hemodialysis patients. However, the new Kidney Disease Outcomes Quality Initiative guidelines for vascular access, soon to be published, will focus on a patient's end-stage kidney disease "life plan" and take a patient "first" approach. One of the major themes of the new Kidney Disease Outcomes Quality Initiative guidelines is selecting the "right access, for the right patient, at the right time, for the right reason". Given the availability of new advances in biomedical technologies, techniques, and devices in the vascular access field, this shift to a more patient-centered vascular access approach presents unique opportunities to individualize the solutions and care for patients requiring a dialysis vascular access. This review article will address 3 potential areas where there is an unmet need to individualize solutions for dialysis vascular access care: (1) biological approaches to improve vascular access selection and selection of therapies, (2) vascular access care for the post-transplant patient, and (3) vascular access disparities in race, gender, and the elderly patient.

Recurrent atypical hemolytic uremic syndrome associated with factor I mutation in a living related renal transplant recipient.

Atypical hemolytic uremic syndrome, or the nondiarrheal form of hemolytic uremic syndrome, is a rare disorder typically classified as familial or sporadic. Recent literature has suggested that approximately 50% of patients have mutations in factor H (CFH), factor I (CFI), or membrane cofactor protein (encoded by CD46). Importantly, results of renal transplantation in patients with mutations in either CFH or CFI are dismal, with recurrent disease leading to graft loss in the majority of cases. We describe an adult renal transplant recipient who developed recurrent hemolytic uremic syndrome 1 month after transplantation. Bidirectional sequencing of CFH, CFI, and CD46 confirmed that the patient was heterozygous for a novel missense mutation, a substitution of a serine reside for a tyrosine residue at amino acid 369, in CFI. This report reemphasizes the importance of screening patients with atypical hemolytic uremic syndrome for mutations in these genes before renal transplantation and shows the challenges in the management of these patients.

How I do it: endovascular stent deployment using a novel technique that obviates the need for introducer-sheath upsizing.

A case is presented and a novel technique is described by which an endovascular stent is deployed in the venous outflow system of an arteriovenous fistula without the traditional exchange to a larger diameter introducer sheath.

Stent migration and folding in the subclavian vein during subclavian hemodialysis catheter placement.

The role of stent placement in hemodialysis (HD) access intervention continues to evolve. As more stents are placed, new and unusual complications are coming to light. We describe a case in which an unsuccessful attempt to place a left subclavian dialysis catheter resulted in the inadvertent migration and folding of a previously deployed subclavian stent. Attempts to remove the stent with a snare were unsuccessful. Patency was restored to the access circuit by placing a new stent through the struts of the folded one. Clinical vascular practice guidelines for vascular access on the use of fluoroscopy for temporary HD catheter placement may need to be re-evaluated with the reported increase in stent placement in the US HD population.