A Service Reconfiguration Bundle for Expanding Access to Peritoneal Dialysis Including for Older Frailer Patients.

INTRODUCTION: Rates of peritoneal dialysis (PD) have been traditionally low in Northern Ireland. With rising numbers of patients reaching end-stage kidney disease, PD is a more cost-effective treatment than haemodialysis and aligns with international goals to increase home-based dialysis options. The aim of our study was to highlight how a service reconfiguration bundle expanded access to PD in Northern Ireland. METHODS: The service reconfiguration bundle consisted of the appointment of a surgical lead, a dedicated interventional radiologist for fluoroscopically guided PD catheter insertion, and a nephrology-led ultrasound-guided PD catheter insertion service in an area of particular need. All patients in Northern Ireland who had a PD catheter inserted in the year following service reconfigurations were included and prospectively followed up for one-year. Patient demographics, PD catheter insertion technique, setting of procedure, and outcome data were summarised. RESULTS: The number of patients receiving PD catheter insertion doubled to 66 in the year following service reconfigurations. The range of approaches to PD catheter insertion (laparoscopic n = 41, percutaneous n = 24 and open n = 1) allowed a wide range of patients to benefit from PD. Six patients had emergency PD catheter insertion, with four receiving urgent or early start PD. Nearly half (48%, 29/60) of the PD catheters inserted electively were in smaller elective hubs rather than the regional unit. A total of 97% of patients successfully started PD. Patients who experienced percutaneous PD catheter insertion were older [median age 76 (range 37-88) vs. 56 (range 18-84), p < 0.0001] and had less previous abdominal surgery than patients who experienced laparoscopic PD catheter insertion (25%, 6/24 vs. 54%, 22/41, p = 0.05). DISCUSSION: Through a service reconfiguration bundle, we were able to double our annual incident PD population. This study highlights how flexible models of service delivery introduced as a bundle can quickly deliver expanded access to PD and home therapy.

Application of Enhanced Recovery After Surgery in Patients Undergoing Kidney Transplant: the Belfast Protocol.

BACKGROUND: The aim of this study was to assess the impact of the Belfast Protocol for enhanced recovery after surgery on hospital length of stay (LOS) after kidney transplant. METHODS: A prospectively collected database was analyzed for all consecutive renal transplant recipients in 2010 and compared with consecutive renal transplant recipients in 2018 before and immediately after the full implementation of the Belfast Protocol. RESULTS: There were 73 renal transplants in 2010 and 115 in 2018. Between 2010 and 2018 there was a significant decrease in LOS from 12 to 7 days (P < .0001). Compared with 2010, in 2018 there was a significant increase in donor age (47 vs 54 years, P < .0001) and kidney transplant from donation after circulatory death donors (0% vs 9%, P < .0001). Although there was no change in the proportion of living donors (59% vs 50%, P = .32), in 2018 there were more blood group incompatible living donors (0% vs 7%, P = .21). Compared with 2010, in 2018 there was a significant increase in recipient age (43 vs 54 years, P = .0002), diabetic nephropathy (5% vs 16%, P = .03), and recipient body mass index >35 kg/m2 (0% vs 9%, P = .02). CONCLUSIONS: Implementation of the Belfast Protocol has decreased LOS in renal transplant recipients despite increasingly complex donor and recipient profiles.

Arterial stiffness alone does not explain arteriovenous fistula outcomes.

INTRODUCTION: Marked arterial adaptation is critical in permitting and sustaining the increased blood flow within an arteriovenous fistula (AVF). The aim of this investigation was to evaluate markers of arterial disease and their association with the early post-operative AVF outcomes. METHODS: We included all patients in whom an AVF had been performed after enrolment to the Renal Impairment In Secondary Care (RIISC) study. Primary AVF failure (PFL) was defined as thrombosis at six-week review. All patients underwent BP Tru and Vicorder pulse wave analysis assessments and also had assays of advanced glycation end-products prior to AVF formation. These were correlated with the short-term AVF outcomes. RESULTS: One hundred and eight AVFs were created in 86 patients. The primary patency (PPT) group were found to have significantly higher body mass index (BMI) (p = 0.01). Intraluminal vein diameter was significantly greater in the PPT group than the PFL group (p≤0.01). Mean augmentation index and augmentation index 75 was significantly higher in the PPT group than the PFL group (p = 0.03 and 0.03, respectively). Aortic pulse wave velocity was slower in the PPT group at 10.2 m/s than the PFL group at 10.8 m/s (p = 0.32). Advanced glycation end-product measurements did not vary significantly between the PPT and PFL groups (p = 0.4). Logistic regression analysis provided a predictive model, which demonstrated a predictive value of 78.1% for AVF patency at 6 weeks. CONCLUSIONS: All patients in this end-stage renal disease cohort have significant aortic stiffness. The results for pulse wave velocity were slower in the PPT group suggesting a tendency towards stiffer vessels and PFL.

Predictive models for arteriovenous fistula maturation.

PURPOSE: Haemodialysis (HD) is a lifeline therapy for patients with end-stage renal disease (ESRD). A critical factor in the survival of renal dialysis patients is the surgical creation of vascular access, and international guidelines recommend arteriovenous fistulas (AVF) as the gold standard of vascular access for haemodialysis. Despite this, AVFs have been associated with high failure rates. Although risk factors for AVF failure have been identified, their utility for predicting AVF failure through predictive models remains unclear. The objectives of this review are to systematically and critically assess the methodology and reporting of studies developing prognostic predictive models for AVF outcomes and assess them for suitability in clinical practice. METHODS: Electronic databases were searched for studies reporting prognostic predictive models for AVF outcomes. Dual review was conducted to identify studies that reported on the development or validation of a model constructed to predict AVF outcome following creation. Data were extracted on study characteristics, risk predictors, statistical methodology, model type, as well as validation process. RESULTS: We included four different studies reporting five different predictive models. Parameters identified that were common to all scoring system were age and cardiovascular disease. CONCLUSIONS: This review has found a small number of predictive models in vascular access. The disparity between each study limits the development of a unified predictive model.

Systematic review of drug eluting balloon angioplasty for arteriovenous haemodialysis access stenosis.

BACKGROUND: Native or prosthetic arteriovenous (AV) fistulas are preferred for permanent haemodialysis (HD) access. These are marked with circuit steno-occlusive disease leading to dysfunction or even failure. Late failure rates have been reported as high as 50%. Standard angioplasty balloons are an established percutaneous intervention for HD access stenosis. Reported restenosis rates remain high and practice guidelines recommend a wide 6-month primary patency (PP) of at least 50% for any intervention. Neointimal hyperplasia is one of the main causes for access circuit stenosis. Drug eluting balloon (DeB) angioplasty has been proposed as an alternative intervention to reduce restenosis by local drug delivery and possible inhibition of this process. PURPOSE: To systematically assess the reported efficacy and safety of DeB angioplasty in percutaneous management of prosthetic and autologous HD access stenosis. METHODS: Protocol for the review was developed following the PRISMA-P 2015 statement. An electronic database (Medline, EMBASE, Clinical Trials.gov and Cochrane CENTRAL) search was conducted to identify articles reporting on the use of DeB intervention in HD AV access. Backward and forward citation search as well as grey literature search was performed. The MOOSE statement and PRISMA 2009 statement were followed for the reporting of results. Data from the included studies comparing DeBs with non-DeBs were pooled using a random effects meta-analysis model and reported separately on randomised and non-randomised studies. RESULTS: Six studies reported on 254 interventions in 162 participants (mean 27 ± 10 SD). The pooled mean and median duration of follow-up was 12 and 13 months (range 6-24 months). These comprised two randomised control trials (RCTs) and four cohort studies. Participant's mean age was 64 ± 5 years and 61% were male. Target lesions (TLs) ranged from under 2 mm to 5.9 mm and 51 were reported as de novo stenosis. Device failure described as wasting of the DeB was reported in two studies (55% and 92.8%). At 6 months TL PP was reported between 70% to 97% for DeBs in the RCTs and cohort studies, and 0% to 26% for non-DeBs. TLs treated with DeBs were associated with a higher primary patency at 6 months as compared to non-DeB balloons (RCTs: odds ratio [OR] 0.25, 95% CI 0.08 to 0.77 and I2 = 19%, cohort studies: OR 0.10, 95% CI 0.03 to 0.31 and an I2 = 20%). No procedure-related major or minor complications were reported. CONCLUSIONS: Current literature reports DeBs as being safe and may convey some benefit in terms of improved rate of restenosis when used to treat AV access disease. However, this body of evidence is small and clinically heterogeneous. A large multicentre RCT may help to clarify the role of DeBs in the percutaneous treatment of AV HD access stenosis.

Use of biosynthetic grafts (Omniflow II) for high infection risk haemodialysis vascular access.

PURPOSE: Infective complications of patients requiring insertion of arteriovenous grafts for hemodialysis remain a challenge. In particular, patients who have exhausted autologous options and have had recent infective complications relating to alternative dialysis modalities such as peritonitis or central venous catheter-associated bacteremia can pose a significant dilemma. We present a series of challenging cases that represent examples of the use of biosynthetic grafts in patients with on-going infective risks. A review of available literature for the use of the Omniflow II graft in dialysis access is included. METHODS: Electronic databases were searched for studies assessing the use of the Omniflow II graft for dialysis in accordance with PRISMA published up to 31st March 2014. The primary outcomes for this study were 1-year primary and secondary patency rates. Secondary outcomes were rates of infection and aneurysmal degeneration. RESULTS: Three cases are described that were considered at high risk of infection and all successfully managed with the Omniflow II arteriovenous graft (AVG). None showed signs of infection and all grafts were patent at three months' follow-up. On review of the literature and following strict criteria, four studies were included with a total of 236 procedures. We found that the one-year primary patency rate for Omniflow II AVGs was 60.1% (53.6-66.5) with a secondary patency rate of 82.1% (76.7-86.9). Infection rates are reported at 0% to 5.7%, with aneurysmal rates ranging between 0% and 6.8%. CONCLUSIONS: This small series reports on the successful use of the Omniflow II graft in patients with high risk of infection and, whilst limited in its size and scientific design, it does support the limited existing literature for the potential benefits of the biosynthetic approach where concerns regarding infective complications of synthetic material exist.

Arteriovenous fistula outcomes in the elderly.

OBJECTIVE: Over several decades, there has been an increase in the number of elderly patients requiring hemodialysis. These older patients typically have an increased incidence of comorbidities including diabetes, hypertension, and peripheral vascular disease. We undertook a systematic review of the current literature to assess outcomes of arteriovenous fistula (AVF) formation in the elderly and to compare the results of radiocephalic AVFs vs brachiocephalic AVFs in older patients. METHODS: A literature search was performed using MEDLINE, Embase, PubMed, and the Cochrane Library. All retrieved articles published before December 31, 2014 (and in English) primarily describing the creation of hemodialysis vascular access for elderly patients were considered for inclusion. We report pooled AVF patency rates and a comparison of radiocephalic vs brachiocephalic AVF patency rates using odds ratios (ORs). RESULTS: Of 199 relevant articles reviewed, 15 were deemed eligible for the review. The pooled 12-month primary and secondary AVF patency rates were 53.6% (95% confidence interval [CI], 47.3-59.9) and 71.6% (95% CI, 59.2-82.7), respectively. Comparison of radiocephalic vs brachiocephalic AVF patency rates demonstrated that radiocephalic AVFs have inferior primary (OR, 0.72; 95% CI, 0.55-0.93; P = .01) and secondary (OR, 0.76; 95% CI, 0.58-1.00; P = .05) patency rates. CONCLUSIONS: This meta-analysis confirms that adequate 12-month primary and secondary AVF patency rates can be achieved in elderly patients. Brachiocephalic AVFs have both superior primary and secondary patency rates at 12 months compared with radiocephalic AVFs. These important data can inform clinicians' and patients' decision-making about suitability of attempting AVF formation in older persons.

End-stage vascular access failure: can we define and can we classify?

BACKGROUND: Renal replacement therapy using dialysis has evolved dramatically over recent years with an improvement in patient survival. With this increased longevity, a cohort of patients are in the precarious position of having exhausted the standard routes of vascular access. The extent of this problem of failed access or 'desperate measures' access is difficult to determine, as there are no uniform definitions or classification allowing standardization and few studies have been performed. The aim of this study is to propose a classification of end-stage vascular access (VA) failure and subsequently test its applicability in a dialysis population. METHODS: Using anatomical stratification, a simple hierarchical classification is proposed. This has been applied to a large dialysis population and in particular to patients referred to the complex access clinic dedicated to patients identified as having exhausted standard VA options and also those dialysing on permanent central venous catheters (CVC). RESULTS: A simple classification is proposed based on a progressive anatomical grading of (I) standard upper arm options exhausted, (II) femoral options exhausted and (III) other options exhausted. These are further subdivided anatomically to allow ease of classification. When applied to a complex group of patients (n = 145) referred to a dedicated complex access clinic, 21 patients were Class I, 26 Class II and 2 Class III. Ninety-six patients did not fall into the classification despite being referred as permanent CVC. CONCLUSIONS: The numbers of patients who have exhausted definitive access options will continue to increase. This simple classification allows the scope of the problem and proposed solutions to be identified. Furthermore, these solutions can be studied and treatments compared in a standardized fashion. The classification may also be applied if patients have the option of transplantation where iliac vessel preservation is desirable and prioritization policies may be instituted.

Aneurysms and pseudoaneurysms in dialysis access.

Aneurysms are a common and often difficult complication seen with arteriovenous vascular access for haemodialysis. The purpose of this narrative review is to define and describe the scale of the problem and suggested therapeutic strategies. A narrative review of the published literature illustrated by individual cases is presented with the aim of summarising the relevant literature. The definitions of aneurysm are inconsistent throughout the literature and therefore systematic review is impossible. They vary from qualitative descriptions to quantitative definitions using absolute size, relative size and also size plus characteristics. The incidence and aetiology are also ill defined but separation into true aneurysms and false, or pseudoaneurysms may be helpful in planning treatment, which may be conservative, surgical or radiological. The lack of useful definitions and classification along with the multitude of management strategies proposed make firm evidence based conclusions difficult to draw. Further robust well designed studies are required to define best practice for this common problem.

Revisiting the risks of MRI with Gadolinium based contrast agents-review of literature and guidelines.

UNLABELLED: Gadolinium based contrast agents (GBCA) have been linked to the occurrence of nephrogenic systemic fibrosis (NSF) in renal impaired patients. The exact interaction between the various different available formulations and occurrence of NSF is not completely understood, but has been postulated. This association has triggered public health advisory bodies to issue guidelines and best practice recommendations on its use. As a result, the reported incidence of NSF, as well as the published use of GBCA-enhanced magnetic resonance imaging in renal impairment, has seen a decline. Understanding of the events that led to these recommendations can increase clinical awareness and the implications of their usage. We present a review of published literature and a brief overview of practice recommendations, guidelines and manuals on contrast safety to aide everyday imaging practice. TEACHING POINTS: • Low risk gadolinium based contrast agents should be the choice in renal insufficiency. • Higher doses have been linked to NSF development. Doses should be as low as possible. • Clear documentation of date, dose and type of formulation used should be noted. • Post-scan dialysis should be arranged as soon as possible and feasible. • Pre- existing inflammatory state is a risk factor; liver insufficiency is not a contraindication.

Current tools for prediction of arteriovenous fistula outcomes.

It remains challenging to accurately predict whether an individual arteriovenous fistula (AVF) will mature and be useable for haemodialysis vascular access. Current best practice involves the use of routine clinical assessment and ultrasonography complemented by selective venography and magnetic resonance imaging. The purpose of this literature review is to describe current practices in relation to pre-operative assessment prior to AVF formation and highlight potential areas for future research to improve the clinical prediction of AVF outcomes.

Hypothermic machine perfusion permits extended cold ischemia times with improved early graft function.

OBJECTIVES: The logistics of deceased-donor renal transplants are largely affected by cold ischemia time. However, to attain successful outcomes, other issues must be considered. Extending cold ischemia time to accommodate these issues would be valuable. We investigated the role of hypothermic machine perfusion to extend cold ischaemia time. MATERIALS AND METHODS: Deceased-donor kidneys were allocated to a storage method, depending on predicted time to operation. Kidneys to be transplanted from 8:00 AM to 8:00 PM in the transplant room remained in static cold storage. If predicted operating time was out of hours, the kidney was transferred to hypothermic machine perfusion and transplanted at the earliest opportunity on the dedicated transplant list. RESULTS: There were 74 kidneys transplanted from hypothermic machine perfusion and 101 kidneys from static cold storage. Median cold ischemia time was 23.85 hours in the hypothermic machine perfusion group, compared with 13 hours in the static cold storage group (P ≤ .0001). There were 20 kidneys (27%) from hypothermic machine perfusion that had delayed graft function, compared with 47 kidneys (47%) in the static cold storage group (P = .012). There were no other significant differences in graft or postoperative complications. CONCLUSIONS: This study demonstrated that improved early graft outcomes can be achieved following longer cold ischemia time by using hypothermic machine perfusion rather than static cold storage. This effect is likely multifactorial including the inherent effects of hypothermic machine perfusion, improved recipient preparation, and possibly better perioperative conditions.

Patient survival following arteriovenous fistula formation.

PURPOSE: Efforts to promote arteriovenous fistulas (AVFs) have been successful in increasing the prevalence of AVF use as the primary vascular access for haemodialysis (HD). Sustained preference for AVF use may not be the most appropriate vascular access choice for all patient groups. Arteriovenous grafts (AVGs) offer advantages of earlier use and lower primary failure rates compared to AVFs so may be preferable for patients where short-term vascular access is needed. This study was designed to assess comparative mortality in different age groups following AVF formation. METHODS: A prospective cohort of patients having AVF creation was recruited. Patients were subdivided into three age groups: Group A: <50 years; Group B: 50-74 years and Group C: ≥75 years. Survival curves and Cox regression analysis were performed on each of these groups. RESULTS: One hundred and thirty-four patients (n = 134) were recruited into the study. The prevalence of diabetes increased significantly with age. As expected, mortality was higher in older age groups (log rank (Mantel-Cox) 19.227; p = 0.0001). Mortality rates at 1 year were 0% in group A, 12.5% in group B and 29.1% in group C. Medium-term mortality at 4 years was 7.9% in group A, 39.1% in group B and 54.8% in group C. CONCLUSIONS: We found a significantly higher mortality rate in patients ≥75 years in comparison to those <75 years. The choice of vascular access modality should be tailored to the individual with particular reference to the patient's expected survival.

Preserving arteriovenous fistula outcomes during surgical training.

PURPOSE: Arteriovenous fistulae (AVFs) are the preferred option for vascular access, as they are associated with lower mortality in hemodialysis patients than in those patients with arteriovenous grafts (AVGs) or central venous catheters (CVCs). We sought to assess whether vascular access outcomes for surgical trainees are comparable to fully trained surgeons. METHODS: A prospectively collected database of patients was created and information recorded regarding patient demographics, past medical history, preoperative investigations, grade of operating surgeon, type of AVF formed, primary AVF function, cumulative AVF survival and functional patency. RESULTS: One hundred and sixty-two patients were identified as having had vascular access procedures during the 6 month study period and 143 were included in the final analysis. Secondary AVF patency was established in 123 (86%) of these AVFs and 89 (62.2%) were used for dialysis. There was no significant difference in survival of AVFs according to training status of surgeon (log rank x2 0.506 p=0.477) or type of AVF (log rank x2 0.341 p=0.559). Patency rates of successful AVFs at 1 and 2 years were 60.9% and 47.9%, respectively. CONCLUSION: We have demonstrated in this prospective study that there are no significant differences in outcomes of primary AVFs formed by fully trained surgeons versus surgical trainees. Creation of a primary AVF represents an excellent training platform for intermediate stage surgeons across general and vascular surgical specialties.

Arteriovenous fistula aneurysms in patients with Alport's.

PURPOSE: Alport's syndrome is a rare but important cause of renal failure. It is characterized by Type IV collagen mutations resulting in connective tissue disorders and renal and cochlear dysfunction. Vascular basement membrane also contains collagen IV and the effect on arteriovenous fistulas (AVFs) is not reported. Anecdotally, we observed a high rate of aneurysm formation in Arteriovenous fistulas (AVF) of patients with Alport's and sought to determine whether this was the case within our population. METHODS: All patients with a diagnosis of Alport's were identified from a contemporaneously maintained database. AVFs formed in patients with Alport's were identified to define the incidence of aneurysms in this group. RESULTS: A total of 40 patients with a diagnosis of Alport's were identified. Of these, 20 patients had undergone AVF formation, the remainder opting for CAPD as renal replacement or had undergone pre-emptive transplantation. Of the 20 patients identified, 11 had an AVF and of these the rate of aneurysm formation was high (55%). CONCLUSIONS: While this finding of high rate of aneurysmal AVF in Alport's patients is a purely observational finding within our population further population study would be extremely interesting and could support enhanced surveillance or alternative dialysis modalities in Alport's syndrome patients.

Occult malignancy presenting as constrictive pericarditis.

Metastatic tumour progression to the pericardium is generally characterised by an effusional pericarditis. It is extremely rare for tumour to metastasise to the pericardium and cause constrictive pericarditis in the absence of a pericardial effusion. We report the recent case of a patient who was referred to our centre with constrictive pericarditis. Following pericardectomy and histopathological analysis this was found to be secondary to an occult metastatic adenocarcinoma.