Richard Baer

Predictors of Patency after Balloon Angioplasty in Hemodialysis Fistulas: A Systematic Review

Percutaneous transluminal angioplasty (PTA) is an established treatment for dysfunctional hemodialysis fistulas. This article systematically reviews evidence for predictors of patency after PTA. Outcomes assessed were primary, assisted primary, and secondary patency after intervention, and findings were summarized descriptively. This review included 11 nonrandomized observational studies of 965 fistulas in 939 patients. Follow-up ranged from 0 days to 10 years. Study quality was overall suboptimal. Newer fistulas and longer lesion length may be associated with primary patency loss after PTA. Further studies are needed to confirm these findings, to identify potentially modifiable factors, and to guide the testing of new endovascular devices.

Percutaneous maintenance and salvage of dysfunctional arteriovenous fistulae and grafts by nephrologists in Australia

Aim:  Percutaneous endovascular procedures can maintain and salvage dysfunctional arteriovenous fistulae and grafts used in haemodialysis. The aim of this study is to report the experience of nephrologists from a single centre in Australia with these procedures.

Factors Associated with Patency Following Angioplasty of Hemodialysis Fistulae

PURPOSE Patency after percutaneous transluminal angioplasty of native hemodialysis arteriovenous fistulae (AVFs) is highly variable. This study aimed to identify predictors of patency following angioplasty in native AVFs. MATERIALS AND METHODS All endovascular procedures performed in native AVFs between 2005 and 2013 at two institutions were retrospectively reviewed. Clinical, anatomic, biochemical, and medication variables were subjected to univariate and multivariate Cox regression analysis to identify predictors of postintervention primary and secondary patency. RESULTS During the study period, 207 patients underwent first angioplasty of their AVF. Follow-up ranged from 14 days to 8 years, during which another 247 endovascular interventions were performed to maintain patency. Postintervention primary patency rates at 6, 12, and 24 months were 66%, 49%, and 29%, respectively. Postintervention secondary patency rates at 6, 12, and 24 months were 94%, 84%, and 79%, respectively. On multivariate adjusted Cox regression analysis, upper-arm AVFs (P = .00072), AVFs less than 6 months of age (P = .0014), presence of multiple stenoses (P = .019), and degree of initial stenosis (P = .016) were significantly associated with shorter postintervention primary patency. A previously failed AVF was the only significant predictor of postintervention secondary patency loss (P = .0053). CONCLUSIONS Anatomic factors related to the AVF location, AVF age, and the extent of the lesion are important predictors of restenosis after balloon angioplasty. Traditional cardiovascular risk factors, metabolic and inflammatory markers, and medications were not associated with postintervention patency.

A survey of current procedural practices of Australian and New Zealand nephrologists.

The aim of this study was to describe the range and extent of current procedural practices of Nephrologists and trainees in Australia and New Zealand with a specific focus on renal biopsy. A web‐based survey was constructed based on a 2009 pilot survey conducted by the authors. The survey was distributed by email. A total of 118 responses were received from 60 centers, including six pediatric centers; Nephrologists or trainees performed the following procedures: urine microscopy 36.4%; diagnostic ultrasound 10.2%; renal biopsy 93.2%; simple vascath insertion 64.4%; cuffed vascath insertion 22%; peritoneal catheter insertion 16.9%; fistula ultrasound 20.3%; and fistulography 5%. Trainees performed most renal biopsies (67.8% of respondents) and real‐time ultrasound was the commonest technique (97%). The majority of respondents believe that renal biopsy is an essential skill for trainees (78.8%); 10–25 biopsies are required for trainee proficiency (59.3%); an online training module would assist in teaching renal biopsies (67.8%). Cuffed catheter insertion and fistulography were more often performed in nonmetropolitan than in metropolitan centers. Procedures are part of Australian and New Zealand Nephrology, including specialized procedures in a minority of centers. Vascular access procedures are more common in nonmetropolitan centers. Renal biopsy is an important skill, considered essential for trainees by most.

Non-candidal Fungal Peritonitis in Far North Queensland: A Case Series

♦ Background: Fungal peritonitis is a recognized complication in patients with end-stage renal failure treated with peritoneal dialysis (PD). Most infections are attributable to Candida species. In approximately one third of cases, the causative fungus is a non-Candida species. Recent reports in the literature show a rising incidence of non-candidal fungal peritonitis (NCFP). We report a case series of NCFP, together with two hitherto unreported species of fungi causing peritonitis, from a tropical geographic area (Far North Queensland). ♦ Methods: This series of 10 cases of NCFP was identified from the PD peritonitis database in Far North Queensland between 1998 and 2010. All 10 patients were from the Aboriginal and Torres Strait Islander ethnic group, 8 of whom lived in remote locations. All but 1 patient had type 2 diabetes mellitus. Of the 10 cases, 7 occurred while the patients received continuous ambulatory PD. Only 1 patient avoided catheter removal, and 5 patients were permanently transferred to hemodialysis. No patient died as a result of the fungal infection. All 10 fungi represented different species. Most (6 of 10) were saprophytic; only 2 were normal skin flora. Two of the causative species (Chaetomium and Beauveria) have rarely been associated with any form of human infection. In 7 patients, the infection occurred during the wet season (November - April). All cases met clinical criteria for peritonitis. ♦ Discussion and Conclusions: The NCFP cases described in this series involved a variety of previously known fungal species and also two new species that have not been reported to cause disease in humans. Indigenous patients from Far North Queensland are particularly predisposed to infection with these exotic fungi as a result of environmental and social factors. Further understanding is desirable to help devise preventive strategies to avoid the consequences of catheter failure.

Large urate cystolith associated with Proteus urinary tract infection

An 84-year-old woman presented three times in 4 months with acute confusion. She had no significant medical history and had satisfactory baseline cognition given her age, with a pre-morbid mini-mental state examination score of 28/30. At each presentation, she was diagnosed with urinary tract infection, treated with oral antibiotics, and discharged within 48 h. She had a post-void residual volume of 22 ml on a bladder scan performed before her first admission. All urine cultures grew Proteus mirabilis. During her last admission, a computed tomography (CT) scan of her kidneys, ureters, and bladder was performed, which revealed a 6.5 cm cystolith. Figure 1 is a reconstruction from the CT images, with arrows indicating the stone. The patient underwent a cystolithotomy, following which her cognition returned to baseline and she was discharged home. Figure 2 shows the stone, which was unexpectedly found to be composed wholly of ammonium urate. Twenty-four-hour urine collection for stone risk analysis was not done because of the patients frailty and poor compliance. A struvite (magnesium ammonium phosphate) stone was anticipated as it is often associated with recurrent urinary tract infections, especially those caused by Proteus. Proteus also causes urinary alkalinization, which does not favor urate stone formation. In addition, the patient did not have gout, or risk factors for hyperuricaemia or hyperuricosuria, and was on a normal diet. Because they are unable to be passed through the urethra, large cystoliths are paradoxically painless and serve as foci for urinary tract infections. Cystoliths are more common in the elderly, and are easily detected on imaging. Their existence should be suspected in patients presenting with recurrent urinary tract infections, especially when the same organism is cultured repeatedly.

Fibrillary glomerulonephritis: presenting as crescentic glomerulonephritis causing rapidly progressive renal failure

We report an unusual case of fibrillary glomerulonephritis (FGN) presenting as rapidly progressive renal failure and extensive crescent formation along with linear staining of capillary walls of the glomeruli on immunofluorescence, mimicking anti-glomerular basement membrane (anti-GBM) antibody-mediated disease. Laboratory results for circulating anti-GBM antibodies were negative. The subsequent electron microscopic findings were that of presence of electron-dense deposits in the glomerular mesangium and capillary walls, comprising of non-branching fibrils with an average diameter of 16 nm consistent with a diagnosis of FGN. This case illustrates the crucial role of electron microscopy in differential diagnosis of crescentic glomerulonephritis.

Clinical presentation, treatment and outcome of focal segmental glomerulosclerosis in Far North Queensland Australian adults

The aim is to describe the clinical features, treatment and outcomes in Australian adults with focal segmental glomerulosclerosis and identify predictors of disease progression and all‐cause mortality.

Endovascular stent placement for hemodialysis arteriovenous access stenosis

This study aims to report the outcomes of nitinol and polytetrafluoroethylene covered stent placement to treat hemodialysis arteriovenous access stenosis at a single center over a five-year period. Clinical and radiological information was reviewed retrospectively. Poststent primary and secondary patency rates were determined using Kaplan-Meier analysis. Ten clinical variables were subjected to multivariate Cox regression analysis to determine predictors of patency after stent placement. During the study period 60 stents were deployed in 45 patients, with a mean follow-up of 24.5 months. The clinical and anatomical success rate was 98.3% (59/60). Poststent primary patency rates at 6, 12, and 24 months were 64%, 46%, and 35%, respectively. Poststent secondary patency rates at 6, 12, and 24 months were 95%, 89%, and 85%, respectively. Stent placement for upper arm lesions and in access less than 12 months of age was associated with reduced primary patency (adjusted hazards ratio [HR] 5.1, p = 0.0084, and HR 3.5, p = 0.0029, resp.). Resistant or recurrent stenosis can be successfully treated by endovascular stent placement with durable long-term patency, although multiple procedures are often required. Stent placement for upper arm lesions and in arteriovenous access less than 12 months of age was associated with increased risk of patency loss.

Outcomes of Nephrologist-Inserted Peritoneal Catheters in Indigenous Patients from Far North Queensland

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