Ferumoxytol MR Angiography versus Duplex US for Vascular Mapping before Arteriovenous Fistula Surgery for Hemodialysis.

Background Duplex US is performed routinely for vascular mapping prior to arteriovenous fistula (AVF) creation for hemodialysis but cannot demonstrate the central vasculature. Ferumoxytol, an iron oxide nanoparticle, provides an alternative to gadolinium contrast material for MR angiography for safe use in chronic kidney disease (CKD). Purpose To assess the clinical utility of ferumoxytol-enhanced MR angiography compared with duplex US for vascular mapping before upper limb AVF creation in participants with CKD. Materials and Methods In a prospective comparative study (ClinicalTrials.gov: NCT02997046) from December 2016 to August 2018, participants with CKD underwent ferumoxytol-enhanced MR angiography and duplex US. Two independent readers evaluated vessels for diameter, stenosis or occlusion, arterial disease, and central stenosis. Intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to assess intra- and interreader variability. On the basis of accepted standards for AVF creation, an algorithm was developed to predict AVF outcome based on imaging findings. Multivariable regression models used AVF success as the dependent variable and age, sex, and duplex US or ferumoxytol-enhanced MR angiography findings as independent variables. Results Fifty-nine participants with CKD (mean age, 59 years ± 13 [standard deviation]; 30 women) were evaluated. A total of 51 fistulas were created, of which 24 (47%) were successful. Ferumoxytol-enhanced MR angiography showed excellent inter- and intrareader repeatability (ICC, 0.84-0.99) for all variables assessed. In addition to revealing 15 central vasculature stenoses, ferumoxytol-enhanced MR angiography resulted in characterization of 88 of 236 (37%) of the arterial sections examined as unsuitable for AVF creation compared with 61 of 236 (26%) sections with duplex US (P = .01). Ferumoxytol-enhanced MR angiography independently predicted AVF success in models including (odds ratio, 6.5; 95% confidence interval: 1.7, 25; P = .006) and those excluding (odds ratio, 4.6; 95% confidence interval: 1.3, 17; P = .02) the central vasculature. Conclusion In addition to enabling identification of central vessel pathologic features, ferumoxytol-enhanced MR angiography revealed peripheral arterial disease not recognized with duplex US and was more predictive than duplex US of the outcome of arteriovenous fistula surgery. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Finn in this issue.

The management of lower limb arteriovenous grafts in the perioperative period following renal transplantation.

BACKGROUND: The presence of a lower limb arteriovenous graft (LL-AVG) is indicative of a group of complex hemodialysis patients who have precarious long-term vascular access. The aim of this study is to describe our experience of the clinical decisions and interactions between LL-AVG and renal transplantation. METHODS: The records of 23 patients who received a transplant in the presence of a LL-AVG between 2010 and 2018 were analyzed: firstly, to determine whether patients with a LL-AVG received extended criteria transplants, the implantation procedure, and the management of the LL-AVG in the post-operative period. RESULTS: Seventeen patients (74%) had "end-stage access" and were thus considered for all offer stratified by the kidney donor profile index (KDPI) and donor type (DBD or DCD). In eleven patients (48%), a kidney with a high risk of delayed graft function was transplanted. Same-sided renal transplantation occurred in only 35% of cases, and of these, only one LL-AVG was ligated immediately to improve transplant perfusion. CONCLUSION: A patient-based approach applied in decision-making on management of the LL-AVG post-transplantation should include (a) the likelihood of delayed graft function, (b) the need for post-operative hemodialysis, (c) the side of proposed transplant compared to the LL-AVG, and (d) local complications.

Early Cannulation ePTFE Arteriovenous Access Grafts are Associated with a Low Incidence of Pseudoaneurysm Formation.

BACKGROUND: Pseudoaneurysm formation is common in standard thin-walled polytetrafluoroethylene (sPTFE) grafts, occurring in up to 10% of grafts, and is reported as the most common cause of graft loss for grafts more than 2 years old. The Gore® Acuseal™ graft is an early cannulation graft, needled before incorporation, and thus may be especially prone to pseudoaneurysm formation. In addition, as this is a relatively new product, there are limited data on long-term outcomes such as pseudoaneurysm. We report one center's experience of the incidence and etiological factors associated with pseudoaneurysm formation over 5 years and 265 grafts. METHODS: A total of 265 Acuseal grafts were placed in the last 5 years. All patients had prospective data entered into an electronic searchable patient record. Surveillance was performed with 3 monthly imaging (digital subtraction angiography or ultrasound), clinical examination, and hemodynamic performance. Data examined included the incidence, causative factors, and outcomes of pseudoaneurysm. RESULTS: Eleven grafts (4.15%) developed a pseudoaneurysm, with 2 patients developing significant hemorrhage. The median time to development of a pseudoaneurysm was 25 months interquartile range (IQR, 20-28 months). Several common etiological factors were identified. All but one patient had overuse of needling sites (n = 10; 90.9%). Other factors associated with pseudoaneurysm formation were inadequate surveillance (n = 9; 81.8%), venous outflow stenosis (n = 9; 81.8%), and anticoagulation/dual antiplatelet therapy (n = 7; 63.6%). Management included observation and needle rotation (n = 5; 45.5%), stent grafting (n = 3; 27.3%), or excision (n = 1; 9.1%) of the pseudoaneurysm. Surgical or endovascular augmentation of the venous outflow was required in 9 patients (81.8%). Graft ligation and explantation were required in 5 patients (45.5%) with graft preservation achieved in 6/11 patients (54.5%). CONCLUSIONS: Pseudoaneurysm formation occurs less frequently in Acuseal grafts compared with historical data for standard PTFE grafts. Pseudoaneurysm formation did not occur in any graft within the first 13 months after implantation, suggesting early cannulation before incorporation is not by itself a risk factor for pseudoaneurysm development. Poor needling, venous stenosis, inadequate surveillance, and anticoagulation/dual antiplatelet therapy are remediable factors, and graft preservation is possible. Acuseal is a robust graft with lower rates of pseudoaneurysm formation on long-term follow-up than standard PTFE grafts.

Arteriovenous Access Graft Infection: Standards of Reporting and Implications for Comparative Data Analysis.

There is presently a lack of organization and standardized reporting schema for arteriovenous graft (AVG) infections. The purpose of this article is to evaluate the various types of treatment modalities for access site infections through an analysis of current publications on AVG. Key proposals are made to support standardization in a data-driven manner to make infection reporting more uniform and thereby facilitate more meaningful comparisons between various dialysis modalities and AVG technologies.

The Neglectable Impact of Delayed Graft Function on Long-term Graft Survival in Kidneys Donated After Circulatory Death Associates With Superior Organ Resilience.

OBJECTIVE: To explore putative different impacts of delayed graft function (DGF) on long-term graft survival in kidneys donated after brain death (DBD) and circulatory death (DCD). BACKGROUND: Despite a 3-fold higher incidence of DGF in DCD grafts, large studies show equivalent long-term graft survival for DBD and DCD grafts. This observation implies a differential impact of DGF on DBD and DCD graft survival. The contrasting impact is remarkable and yet unexplained. METHODS: The impact of DGF on DBD and DCD graft survival was evaluated in 6635 kidney transplants performed in The Netherlands. DGF severity and functional recovery dynamics were assessed for 599 kidney transplants performed at the Leiden Transplant Center. Immunohistochemical staining, gene expression profiling, and Ingenuity Pathway Analysis were used to identify differentially activated pathways in DBD and DCD grafts. RESULTS: While DGF severely impacted 10-year graft survival in DBD grafts (HR 1.67; P < 0.001), DGF did not impact graft survival in DCD grafts (HR 1.08; P = 0.63). Shorter dialysis periods and superior posttransplant eGFRs in DBD grafts show that the differential impact was not caused by a more severe DGF phenotype in DBD grafts. Immunohistochemical evaluation indicates that pathways associated with tissue resilience are present in kidney grafts. Molecular evaluation showed selective activation of resilience-associated pathways in DCD grafts. CONCLUSIONS: This study shows an absent impact of DGF on long-term graft survival in DCD kidneys. Molecular evaluation suggests that the differential impact of DGF between DBD and DCD grafts relates to donor-type specific activation of resilience pathways in DCD grafts.

A national study of autogenous arteriovenous access use and patency in a contemporary hemodialysis population.

OBJECTIVE: The predicted outcomes of autogenous arteriovenous (AV) hemodialysis access creation are predominantly based on historical data; however, both the hemodialysis population and clinical practices have changed significantly during the last decade. This study examined contemporary AV access clinical use and patencies. METHODS: A multicenter observational cohort study was performed of all new AV accesses created in Scotland in 2015. The primary end point was efficacy assessed by successful AV access use for a minimum of 30 days and primary, primary assisted, and secondary patency at 1 year. Data obtained included all interventions to maintain or to restore patency. Predictors of patency loss including demographics, comorbid conditions, dialysis status, AV access location, duplex ultrasound surveillance, procedures, prior access, and antiplatelets were assessed. Kaplan-Meier and competing risks analyses were performed to estimate the probability of AV access failure. All patients were followed up for at least 1 year or had a censoring event. RESULTS: A total of 582 AV accesses were created in 537 patients (mean age, 60 [standard deviation, 14] years; 60% men; 42% with diabetes) in nine adult renal centers. Mean follow-up was 11.8 (standard deviation, 7.6) months. By the end of the follow-up, 322 (55.3%) AV accesses were successfully used for dialysis. At 1 year, 48% (95% confidence interval [CI], 44-52) of AV accesses had primary patency, (95% CI, 63-71) had primary assisted patency, and 69% (95% CI, 65-73) had secondary patency. The leading cause of primary patency loss was primary failure (30%). An average of 0.48 intervention per patient-year was required to maintain patency. On multivariable analysis, patency was better for an upper arm than for a forearm AV access (1-year secondary patency of upper arm vs forearm AV accesses, 74% vs 58%). The cumulative hazard and incident functions for AV access failure were 31% (95% CI, 27-35) and 23% (95% CI, 20-27) at 1 year, respectively. CONCLUSIONS: Despite advances in recent years with preoperative vessel assessment and surveillance, patency rates have not improved, with primary failure remaining the major obstacle. Competing events should be taken into consideration; otherwise, biases may occur with overestimation of the probability of AV access failure.

Ferumoxytol magnetic resonance angiography: a dose-finding study in patients with chronic kidney disease.

OBJECTIVES: Ferumoxytol is an alternative to gadolinium-based compounds as a vascular contrast agent for magnetic resonance angiography (MRA), particularly for patients with chronic kidney disease (CKD). However, dose-related efficacy data are lacking. We aimed to determine the optimal (minimum effective) dose of ferumoxytol for MRA in patients with CKD. METHODS: Ferumoxytol-enhanced MRA (FeMRA) was performed at 3.0 T in patients with CKD after dose increments up to a total of 4 mg/kg. Image quality was assessed by contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) in the abdominal aorta and inferior vena cava. Quadratic regression analyses were performed to estimate the effects of dose increments on CNR and SNR. RESULTS: Twenty-three patients underwent FeMRA (mean age 60 [SD 13] years, 87% men, 48% had diabetic nephropathy) with cumulative doses of 0, 1, 2, 3 and 4 mg/kg of ferumoxytol. On regression analyses, a parabolic relationship was observed between ferumoxytol dose and signal with progressive signal loss using doses exceeding 4 mg/kg. A dose of 3 mg/kg achieved ≥ 75% of predicted peak CNR and SNR and images were deemed of excellent diagnostic quality. CONCLUSIONS: In patients with CKD undergoing FeMRA, a dose of 3 mg/kg provides excellent arterial and venous enhancement. The benefits of increasing the dose to a theoretically optimal value of 4 mg/kg appear to be negligible and likely of minimal, if any, diagnostic value. KEY POINTS: • Ferumoxytol is used off-label as an MRI contrast agent but dose-related data are lacking. • In patients with CKD requiring MR angiography, a dose of 3 mg/kg provides excellent vascular enhancement.

Maintaining lower limb access with the HeRO device.

Central venous catheters (CVC) remain a mainstay of vascular access particularly for incident patients,but lead to central vein stenosis (CVS) in up to 1 in 6 patents. This often leads to establishing dialysis access in the groin which in turn may result in development of CVS in the lower body, although this is poorly reported. The HeRO device was designed to address CVS by bypassing the stenosed veins with a nitinol-reinforced silicone tube into the right atrium, which acts as an outflow conduit attached to an arterial inflow. The efficacy and safety of the HeRO device in the upper limb is well established, but there is no data on its use in the lower limb. We describe 2 cases of HeRO in the lower limb, one primary and one secondary, which remain in use. Lower limb HeRO is feasible in the lower limb and can work well either as de novo (to achieve vascular access) or as a salvage procedure (to maintain vascular access).

The first 365 days on haemodialysis: variation in the haemodialysis access journey and its associated burden.

Background: The modality by which haemodialysis (HD) is delivered [arteriovenous fistula (AVF), arteriovenous graft (AVG) or central venous catheter (CVC)] varies widely and is influenced by clinical evidence, patient factors and the prevailing service configuration. The aim of this study was to determine the outcome and impact of access strategy on patient outcome by mapping out the HD journey in a cohort of incident patients. Methods: A 2-year cohort of consecutive incident HD patients from the point of referral for first dialysis access to completion of the first 365 days of HD was prospectively reviewed. Data were sought on access type; radiological, surgical and other access-related activity; bacteraemic events; admission rates and cumulative financial cost. Results: A total of 144 patients started RRT for the first time with HD over the 2-year period. All were followed up to 1 year after starting HD, generating a total of 47 753 observed HD days. Activity prior to starting HD for the full cohort was found to average 0.92 arteriovenous (AV) access creation procedures, 0.40 CVC insertions, 0.14 interventional radiology procedures and 0.41 ultrasound examinations per patient. The small number of patients who started on an AVG had a tendency towards higher pre-HD surgical and imaging activity than those who started on an AVF or CVC. Activity after starting HD varied greatly with the access type used at the start of HD, with AVF patients experiencing less hospitalization, procedure and imaging activity and financial costs compared with those who start HD with a CVC. Patients who started on an AVG had a tendency towards lower surgical activity rates and financial costs than those who started on a CVC. Conclusions: Providing, maintaining and dealing with the complications of HD vascular access places a significant burden of activity that is shared across nephrology, surgery and imaging services. A well-functioning AVF is associated with the lowest burden, whereas a failed AVF or CVC access is associated with the highest burden. Patient journeys are shaped by the vascular access that they use and we suggest that the contemporary pursuit of HD access should focus on delivering personalized access solutions.

Ferumoxytol-enhanced magnetic resonance angiography for the assessment of potential kidney transplant recipients.

OBJECTIVES: Traditional contrast-enhanced methods for scanning blood vessels using magnetic resonance imaging (MRI) or CT carry potential risks for patients with advanced kidney disease. Ferumoxytol is a superparamagnetic iron oxide nanoparticle preparation that has potential as an MRI contrast agent in assessing the vasculature. METHODS: Twenty patients with advanced kidney disease requiring aorto-iliac vascular imaging as part of pre-operative kidney transplant candidacy assessment underwent ferumoxytol-enhanced magnetic resonance angiography (FeMRA) between December 2015 and August 2016. All scans were performed for clinical indications where standard imaging techniques were deemed potentially harmful or inconclusive. Image quality was evaluated for both arterial and venous compartments. RESULTS: First-pass and steady-state FeMRA using incremental doses of up to 4 mg/kg body weight of ferumoxytol as intravenous contrast agent for vascular enhancement was performed. Good arterial and venous enhancements were achieved, and FeMRA was not limited by calcification in assessing the arterial lumen. The scans were diagnostic and all patients completed their studies without adverse events. CONCLUSIONS: Our preliminary experience supports the feasibility and utility of FeMRA for vascular imaging in patients with advanced kidney disease due for transplant listing, which has the advantages of obtaining both arteriography and venography using a single test without nephrotoxicity. KEY POINTS: • Evaluation of vascular disease is important in planning kidney transplantation. • Standard vascular imaging methods are often problematic in kidney disease patients. • FeMRA has the advantage of arteriography and venography in a single test. • FeMRA is safe and non-nephrotoxic. • FeMRA is not limited by arterial calcification.

A randomized controlled trial and cost-effectiveness analysis of early cannulation arteriovenous grafts versus tunneled central venous catheters in patients requiring urgent vascular access for hemodialysis.

OBJECTIVE: Early cannulation arteriovenous grafts (ecAVGs) are proposed as an alternative to tunneled central venous catheters (TCVCs) in patients requiring immediate vascular access for hemodialysis (HD). We compared bacteremia rates in patients treated with ecAVG and TCVC. METHODS: The study randomized 121 adult patients requiring urgent vascular access for HD in a 1:1 fashion to receive an ecAVG with or without (+/-) an arteriovenous fistula (AVF; n = 60) or TCVC+/-AVF (n = 61). Patients were excluded if they had active systemic sepsis, no anatomically suitable vessels, or an anticipated life expectancy <3 months. The primary end point was the culture-proven bacteremia rate at 6 months, with the trial powered to detect a reduction in bacteremia from 24% to 5% (α = .05, ß = .8). Secondary end points included thrombosis, reintervention, and mortality. A cost-effectiveness analysis was also performed. RESULTS: Culture-proven bacteremia developed in 10 patients (16.4%) in the TCVC arm ≤6 months compared with two (3.3%) in the ecAVG+/-AVF arm (risk ratio, 0.2; 95% confidence interval, 0.12-0.56; P = .02). Mortality was also higher in the TCVC+/-AVF cohort (16% [n = 10] vs 5% [n = 3]; risk ratio, 0.3; 95% CI, 0.08-0.45; P = .04). The difference in treatment cost between the two arms was not significant (£11,393 vs £9692; P = .24). CONCLUSIONS: Compared with TCVC+/-AVF, a strategy of ecAVG+/-AVF reduced the rate of culture-proven bacteremia and mortality in patients requiring urgent vascular access for HD. The strategy also proved to be cost-neutral.

The Role of Qutenza® (Topical Capsaicin 8%) in Treating Neuropathic Pain from Critical Ischemia in Patients with End-Stage Renal Disease: An Observational Cohort Study.

Objective: Current treatment strategies for painful critical ischemia in patients with end-stage renal disease (ESRD) are suboptimal. A drug that is non-renally excreted has minimal systemic absorption and does not require dose adjustment in renal failure is attractive. The aim of this study was to evaluate the safety and efficacy of Qutenza® (topical capsaicin 8%) for chronic neuropathic pain from critical ischemia in patients with ESRD. Design and Setting: A prospective cohort study was conducted in a single-center, university teaching hospital. Patients: Twenty patients with ESRD were treated with Qutenza® for neuropathic pain from critical limb ischemia. Methods: Patients were followed-up at 1, 6 and 12 weeks post-treatment. The primary end point was the difference in visual analog scale (VAS) between baseline and week 12. Secondary end points were Brief Pain Inventory questionnaire (BPI) scores, quality of life assessment (EQ-5D) and patient global impression of change (PGIC). Safety and tolerability data were also collected. The trial was prospectively registered with clinical trials databases (EudraCT: 2012-001586-32; NCT01704313). Results: There was significant reduction in VAS from baseline to week 12 (-20+/-7%; P = 0.02). There was a significant reduction in all seven domains of the BPI. Quality of life also improved at 12 weeks following treatment in two of the EQ-5D domains (mobility and pain). Qutenza® was well tolerated with no significant side effects in this patient cohort, which included 20% diabetics. Conclusions: In this small, observational study Qutenza® treatment has been shown to be effective and well-tolerated to treat neuropathic pain from critical ischemia in patients with ESRD.

Changes in the demographics of intravenous drug users with mycotic common femoral artery pseudoaneurysm as a consequence of self-injection does not influence outcome following emergency ligation.

Objectives The reported annual incidence of mycotic pseudoaneurysm of the common femoral artery in intravenous drug users has been estimated at 0.03%. Over the past 5 years in Scotland, the proportion of people receiving specialist attention for heroin use over the age of 40 years has increased from 15 to 22%. Although routinely managed with arterial ligation (without reconstruction), some series have reported rates of major limb amputation of up to 10%. We sought to define whether this management strategy was still acceptable in an older population. Methods Retrospective review of patients presenting to a tertiary vascular service with mycotic pseudoaneurysm of the common femoral artery due to arterial injection by intravenous drug users between October 2010 and March 2016. Variables of interest included patient demographics and requirement for major amputation. Results There were 55 patients identified. The annual incidence of mycotic pseudoaneurysm of the common femoral artery in intravenous drug users was 2.1%. It was more common in men (3:1) and the mean age at presentation was 41 years (standard deviation ± 8 years). Three patients underwent major limb amputation during the index admission for severe limb ischaemia (two transfemoral amputations; one hip-disarticulation). Following discharge two patients were readmitted (134 and 200 days, respectively, following primary ligation) for major limb amputation due to of critical limb ischaemia. Conclusions Despite the increasing age of intravenous drug users presenting with mycotic pseudoaneurysm of the common femoral artery primary ligation of pseudoaneurysm would seem to remain an appropriate therapeutic intervention.

Brachiobasilic fistulae: an upper limb autologous option for everyone?

PURPOSE: Autologous arteriovenous fistulae (AVF) are the vascular access option of choice. However, Brachiobasilic fistula (BBF) are complex procedures with variable outcomes reported in the literature. Our aim was to evaluate outcomes and morbidity associated with BBF in our population. METHODS: Retrospective analysis of prospectively collected data was undertaken for all 51 BBF created in our institution between January 2010 and March 2013. These were compared to an age and sex-matched group of brachiocephalic fistula (BCF) created over a similar time period. Demographic, operative and outcome data was collected for all patients. The primary end points were primary functional patency, primary-assisted patency and secondary patency at 3, 6 and 12 months. Continuous data was compared using Student's t-test and categorical data using chi-squared test (p < 0.05 is significant). RESULTS: Mean patient age was 57 years (range: 21-82). About 45% were male. About 73% of patients were already on hemodialysis (HD) at the time of BBF creation. BBF was the secondary or tertiary access procedure in 60.8% of patients (n = 31). BBF were associated with significant operative burden with 82% of patients requiring a general anaesthetic and median hospital admission of 2 days (range: 1-4). About 75% had a single-stage procedure. About 23.5% (n = 12) required operative revision (superficialization or anastomotic revision for stenosis). Patients with BBF spent an additional 3.45 days/year in hospital as a result of access related complications compared to 0.56 days/year in the BCF group. Primary-assisted patency at 3, 6 and 12 months was better in the BCF group than BBF group (86%, 72% and 48% vs. 71%, 59%, 33%, respectively; p < 0.01) Primary functional and secondary patency rates at 3, 6 and 12 months were 74%, 58% and 32% and 78%, 63% and 41%, respectively, with an average of 0.33 procedures per AVF to maintain patency (10 fistuloplasties, 4 IR thrombectomy and 3 surgical thrombectomy). About 32% (n = 17) of BBF were never used for HD (seven patients had a patent AVF but did not require HD >18 months following creation; nine failed to adequately mature and one patient refused second stage superficialization). CONCLUSIONS: BBF are associated with a significant initial operative burden and higher complication and poorer patency rates than BCF. About one-third of BBF created in this series were never used. Given the morbidity associated with this procedure, careful consideration should be given to creation of BBF in pre-dialysis patients particularly those in whom the rate of decline in renal function is slow.

A randomized controlled trial of interrupted versus continuous suturing techniques for radiocephalic fistulas.

OBJECTIVE: Continuous suturing techniques have conventionally been used for the end-to-side anastomoses of radiocephalic fistulas (RCFs); however, primary patency rates are poor. Only 50% to 60% of RCFs ever achieve functional patency. We hypothesized that a hybrid interrupted-continuous suturing technique (as used in many microsurgical procedures) may improve outcomes in fistulas constructed from small vessels. METHODS: A randomized controlled trial comparing hybrid interrupted-continuous (n = 42) with continuous (n = 36) suturing techniques for RCF was undertaken. Patients were excluded if vessels were <1.8 mm in diameter or if previous ipsilateral fistula had been attempted. A priori power calculation indicated that a sample size of 78 patients was required to detect an improvement in patency from 50% to 80% (α = .05, ß = .8). The primary end point was primary patency at 6 weeks (assessed by a blinded observer for the presence of thrill and bruit). Secondary end points were immediate patency, functional patency (assessed clinically and by ultrasound) at 6 weeks, and presence of anastomotic stenosis. RESULTS: Groups were comparable for basic patient demographics, operating surgeon, and vessel diameter as measured on preoperative ultrasound (mean age, 58.9 ± 13 years; 68% male). Primary patency at 6 weeks was higher in the hybrid interrupted-continuous suturing technique group (71% vs 47%; P = .01). Immediate patency was also higher in the hybrid interrupted-continuous suturing technique group (93% vs 67%; P < .001). There was no significant difference in functional patency at 6 weeks (52% vs 36%; P = .18). Three patients developed an anastomotic stenosis. All were in the hybrid interrupted-continuous suturing technique group. One patient from the interrupted suturing technique cohort required re-exploration for bleeding. CONCLUSIONS: A hybrid interrupted-continuous suturing technique yielded higher immediate and 6-week primary patency rates for RCF. The hybrid interrupted-continuous suturing technique may improve anastomotic compliance and reduce the narrowing and puckering that can occur on suture tightening in small-caliber vessels. Based on these findings, consideration should be given to performing hybrid interrupted-continuous anastomoses for RCFs.

Diagnosing nephrogenic systemic fibrosis in the post-FDA restriction era.

The emergence of an association between gadolinium-based contrast agents (GBCA) and the rare condition nephrogenic systemic fibrosis (NSF) led to a warning in 2006 from the Food and Drug Administration (FDA) restricting the use of the GBCAs to patients with an estimated glomerular filtration rate of >30 mL/min/1.73m(2) . We discuss our experience with a post-FDA restriction presentation of NSF and subsequent patient death in which the prolonged lead-time of ∼5.5 years led to challenges in ensuring a secure diagnosis of NSF and establishing risk exposures. Accurate contemporary records of contrast administration and clinical factors alongside clinical and pathological expertise ensured that we were able to confidently diagnose NSF, despite the length of lead time and confounding factors.

Predictors of sustained arteriovenous access use for haemodialysis.

BACKGROUND: Guidelines encourage early arteriovenous (AV) fistula (AVF) planning for haemodialysis (HD). The aim of this study was to estimate the likelihood of sustained AV access use taking into account age, sex, comorbidity, anatomical site of first AVF and, for pre-dialysis patients, eGFR and proteinuria. METHODS: 1,092 patients attending our centre who had AVF as their first AV access procedure between January 1, 2000 and August 23, 2012 were identified from the electronic patient record. The primary end-point was time to first sustained AV access use, defined as use of any AV access for a minimum of 30 consecutive HD sessions. RESULTS: 52.9% (n = 578) of the patients ultimately achieved sustained AV access use. The main reasons for AV access non-use were AVF failure to mature and death. The 3-year Kaplan-Meier probability of sustained AV access use was 68.8% for those not on renal replacement therapy (RRT) (n = 688) and 74.2% for those already on RRT (n = 404) at the time of first AVF. By multivariate analysis in patients not on RRT, male sex (HR 2.22; p < 0.001), uPCR (HR 1.03; p = 0.03) and eGFR (hazard ratio, HR 0.85; p < 0.001) were independent predictors of AV access use. In patients already on RRT, age (HR 0.98; p < 0.001) and peripheral vascular disease (HR 0.48; p = 0.02) were independent predictors of AV access use. CONCLUSION: Our data suggest that refinement of the current guideline for timing of AV access creation in planning RRT is justified to take into account individual factors that contribute to the likelihood of technical success and clinical need.

Renal function, uraemia and early arteriovenous fistula failure.

BACKGROUND: Guidance varies regarding the optimal timing of arteriovenous fistula (AVF) creation. The aim of this study was to evaluate the association between uraemia, haemodialysis and early AVF failure. METHODS: Immunoblotting and cell proliferation assays were performed on vascular smooth muscle cells (VSM) cells isolated from long saphenous vein samples to evaluate the cells' ability to proliferate when stimulated with uraemic (post-dialysis) and hyperuraemic (pre-dialysis) serum. Clinical data was collected prospectively for 569 consecutive radiocephalic (RCF) and brachiocephalic (BCF) fistulae. The primary outcome was AVF failure at 6 weeks. Dialysis status (haemodialysis (HD); pre-dialysis (Pre-D)), eGFR and serum urea were evaluated to determine if they affected early AVF failure. RESULTS: Human VSM cells demonstrated increased capacity to proliferate when stimulated with hyperuraemic serum. There was no significant difference in early failure rate of either RCF or BCF depending on dialysis status (pre-D RCF 31.4% (n=188); pre-D BCF 22.4% (n=165); HD RCF 29.3% (n=99); HD BCF 25.9% (n=116); p=0.34). There was no difference in mean eGFR between those patients with early AVF failure and those without (11.2+/-0.2 ml/min/1.73 m2 vs. 11.6+/-0.4 ml/min/1.73 m2; p=0.47). Uraemia was associated with early AVF failure (serum urea: 35.0+/-0.7 mg/dl vs. 26.6+/-0.3 mg/dl (p<0.001)). CONCLUSIONS: We present the first in vivo evidence of an association between adverse early AVF outcomes and uraemia. This is supported mechanistically by in vitro work demonstrating a pro-mitogenic effect of hyperuraemic serum. We hypothesise that uraemia-driven upregulation of VSM cell proliferation at the site of surgical insult in contributes to higher early AVF failure rates.