Effect of brachial plexus block-driven vascular access planning on primary distal arteriovenous fistula recruitment and outcomes.

OBJECTIVE: Hemodialysis vascular accesses (VAs) are traditionally planned based on the nondominant upper extremity preoperative physical and sonographic vascular findings. Clinical guidelines advocate the use of the most suitably distended vein in the most distal location. Brachial plexus block (BPB), through its sympathectomy-like effect, promotes vasodilation and can thus further optimize vein recruitment and operative strategy. However, studies on its role in driving primary distal autogenous arteriovenous fistula (AVF) placement are limited. We therefore evaluated a traditional approach of clinic-based VA planning against an on-table sonography-guided strategy under BPB. METHODS: This was a prospective observational study involving 110 consecutive end-stage renal disease multiethnic Asian patients referred for primary VA creation under BPB after preoperative venous mapping. Cases were grouped according to whether there was a preset operative plan for radial cephalic (RC) or brachial cephalic (BC) AVF creation based on artery and vein >2 mm and >2.5 mm size criteria respectively (group A) or vein size or length were suboptimal (2-2.5 mm and <5 cm respectively), thus precluding any operative plan till after BPB (group B). Group B also included cases with a preset VA plan but that subsequently underwent an on-table change in operative plan as a result of more favorable distal vein dilation post-BPB. RC AVF recruitment, maturation, and patency rates were compared in the two groups over a 1-year follow up. RESULTS: One hundred RC and BC AVF were available for analysis after excluding brachial AVFs and grafts: 41 in group A and 59 in group B. Twenty one (51%) primary RC AVFs were created according to a preset preoperative plan compared with 37 (63%) based upon on-table planning or plan modification (P > .05). Satisfactory post-BPB forearm vasodilation resulted in 44% of 36 plans for BC being changed to RC AVFs. RC AVF 6-week hemodynamic maturation and 3-month functional maturation in group A vs B were 48% vs 60% and 69% vs 57%, respectively (P > .05). One-year primary and secondary patency rates were 57% vs 50% and 73% vs 87%, respectively (log rank >.05). Outcomes of RC AVFs in group B were not inferior to those of BC AVFs. CONCLUSIONS: On-table BPB-driven VA planning and plan modification strategy contribute to considerable AVF recruitment but do not lead to significantly better distal AVF prevalence or outcomes over the traditional approach. An adequately powered randomized controlled study is, however, warranted to better assess the long-term clinical and cost benefits of such a strategy.

Effect of ultra-low dose and standard heparin locks on early tunnelled dialysis catheter outcomes in low-risk dialysis patients.

AIM: Initial heparin locks instilled after tunnelled dialysis catheter (TDC) insertion can leak causing systemic anticoagulation and also promote staphyloccocal biofilm formation, predisposing to catheter-related infection (CRI). The 1000 U/mL concentration is thus advocated as the optimal dose for preventing catheter bleeding and malfunction. The effect of lower heparin concentrations on further lowering these complications is not known. We compared early TDC outcomes between a non-standard ultra-low (500 U/mL) and standard initial heparin locks (1000 and 5000 U/mL). METHODS: This was a retrospective study on prospectively collected data on 238 de novo internal jugular TDCs placed by nephrologists. Cases were categorized into groups 1, 2 and 3, according to initial heparin lock: 500 [n = 30], 1000 [n = 180] and 5000 U/mL [n = 28] respectively. Bleeding and malfunction within 24 h of TDC insertion, 30 days CRI-free catheter survival and the effects of clinical and laboratory factors on bleeding were evaluated. RESULTS: Bleeding events were similar in groups 1, 2 and 3 (7 vs 14 vs 13%, respectively, P = 0.61). Malfunction was only seen in group 2 (3.3%). Thirty-day CRI-free catheter survival was comparable (96 vs 98 vs 97%, respectively, P = 0.22), giving a cumulative CRI rate of 0.76/1000 catheter days. All CRIs were staphylococcal. Univariate analysis did not reveal any significant predictors of catheter bleeding. CONCLUSION: Immediate TDC bleeding, malfunction and CRI rate are not influenced by heparin lock concentrations ≤5000 U/mL in this low-risk cohort. However this needs to be corroborated in higher risk patients.

Clinical experience with intraperitoneal sodium thiosulphate for calciphylaxis in peritoneal dialysis: A case series.

Calciphylaxis is an uncommon but life-threatening syndrome in end-stage kidney disease, characterised by painful medial and intimal calcification of the arterioles in the deep dermis and subcutaneous tissues. Intravenous sodium thiosulfate serves as an off-label but effective treatment in haemodialysis patients. However, this approach confers considerable logistical challenges for affected peritoneal dialysis patients. In this case series, we demonstrate that intraperitoneal administration can be a safe, convenient and long-term alternative.

Comparative outcomes of primary autogenous fistulas in elderly, multiethnic Asian hemodialysis patients.

BACKGROUND: The number of elderly (≥65 years) end-stage renal disease (ESRD) patients on hemodialysis is rapidly increasing. Vascular access outcomes remain contradictory and understudied across different elderly populations. We hypothesized age might influence primary autogenous fistula use and outcomes in a predominantly diabetic multiethnic Asian ESRD population. METHODS: Demographic and clinical factors affecting fistula patency and maturation were retrospectively compared among patients with incident ESRD aged <65 and ≥65 years at a single center. Fistula patency was estimated by Kaplan-Meier curves with log-rank test comparison. RESULTS: We analyzed 280 primary fistulas (59% radiocephalic, 33% brachiocephalic, and 8% brachiobasilic) in this cohort consisting of 31.8% aged ≥65 years, 50% Chinese, 39% Malay, 42% women, and 70% diabetic. One- and 2-year primary and secondary patency in patients aged <65 vs ≥65 years were comparable: 41.3% vs 36.7% and 28.7% vs 24.4% (P = .547) and 57.7% vs 56.8% and 47.1% vs 47.2% (P = .990). On multivariate analysis, only non-Chinese, dialysis initiation with tunneled catheters, and surgical/endovascular interventions affected fistula survival hazard ratios (HR): 0.622 (95% confidence interval [CI], 0.43-1.00), 0.549 (95% CI, 0.297-0.841), and 2.503 (95% CI, 1.695-3.697), respectively. Nonmaturation and intervention rates were also similar at 56.7% vs 61.8% and 34% vs 32.2% at 3 and 6 months and 0.31 vs 0.36 per access year, respectively (P > .05). Females and tunneled catheters were the only risk factors for nonmaturation (HR, 1.568; 95% CI, 1.148-1.608, and HR, 1.623; 95% CI, 1.400-1.881, respectively). CONCLUSIONS: A primary fistula strategy in incident elderly ESRD is feasible and does not result in inferior outcomes. Age should therefore not be a determinant for primary fistula creation.

Comparative outcomes of treated symptomatic versus non-treated asymptomatic high-grade central vein stenoses in the outflow of predominantly dialysis fistulas.

BACKGROUND: Witholding treatment in asymptomatic/pauci-symptomatic high-grade central vein stenosis (CVS), i.e. those not causing debilitating painful extremity oedema, the benefits of which have been shown in only one study in grafts, is debatable. The aim of our study was to assess the short- and long-term benefits of such a strategy in mainly autogenous fistulas. METHODS: We retrospectively compared the outcomes of 53 untreated asymptomatic/pauci-symptomatic and 50 symptomatic high-grade CVS treated by dilation with or without stenting between January 1998 and August 2010 at a single center. Central vein and access patency was estimated by Kaplan-Meier analysis. RESULTS: Mean age, central catheter use and location of stenosis (brachiocephalic vein) in asymptomatic/pauci-symptomatic and symptomatic CVS were significantly different at 69 versus 75 years, 28 versus 48% and 74 versus 56%, respectively. Ninety percent of the cases had an autogenous fistula. The mean degree of stenosis was >80%. Fourty percent of asymptomatic/pauci-symptomatic CVS became severely symptomatic after 4 years. Primary central vein patency at 3, 12, 24 and 36 months in asymptomatic/pauci-symptomatic and symptomatic CVS were 87±5 versus 82±6, 77±6 versus 55±9, 71±7 versus 35±9 and 67±7 versus 18±9%, respectively (P=0.002). Primary access circuit patency rate was not significantly different between the two groups with 66±5 versus 50±4% at 1 year. Secondary central vein and access circuit patency rates at 1 and 3 years were 100 and 93±7 versus 89±5 and 84±7% (P=0.014). CONCLUSIONS: Withholding treatment in asymptomatic/pauci-symptomatic CVS in dialysis fistulas yielded significantly better short- and long-term central vein patency than treatment of symptomatic cases without detrimental effects on overall dialysis circuit.

The clinical course of rapidly growing nontuberculous mycobacterial peritoneal dialysis infections in Asians: A case series and literature review.

INTRODUCTION: Peritoneal dialysis (PD)-related infections due to rapidly growing nontuberculous mycobacterium (RGNTM) are rare in Asians and have variable clinical outcomes. METHODS: We analysed retrospectively a series of RGNTM infections in a single-centre multi-ethnic Asian population over a 5-year period. Clinical features, treatment, risk factors and outcomes are discussed. RESULTS: Ten infections are described. They constituted 3% of all culture-positive exit site infection (ESI) and PD peritonitis. Seventy percent were due to Mycobacterium abscessus (three ESI and four peritonitis). There were two Mycobacterim fortuitum and one Mycobacterium chelonei peritonitis. No specific findings differentiated RGNTM infections from those caused by traditional organisms. Six cases had received prior antibiotics, two being topical gentamicin. Initial routine culture and alcohol acid fast bacillus were negative except for one case of M. abscessus. A confirmatory diagnosis was made a median 9 days post culture. No infection responded to routine antibiotics. Antibiotic resistance was variable but M. abscessus was universally sensitive to clarithromycin. Combined antibiotics based on sensitivity profile were successfully used in 70% of the cases. PD catheter loss was 80%. Three-month mortality was 40% (vs. 8.5% and 12% in non-RGNTM ESI and peritonitis, respectively). This may be related to the cohort high mean Charlson score of 7.5. CONCLUSION: RGNTM PD infections are commoner in Asians than previously reported. Their early diagnosis requires a high index of suspicion and appropriate treatment started promptly. They are associated with prior antibiotic use and refractory culture-negative infections, delayed diagnosis and lead to significant catheter loss and death.

Outcomes of a nephrologist-driven tunnelled dialysis catheter insertion service in South East Asia.

INTRODUCTION: Tunnelled dialysis catheters (TDCs) are being increasingly inserted by nephrologists globally but there is limited experience and paucity of published outcomes data from South-East Asia (SEA). This study was conducted to analyse the outcomes of TDC insertion by nephrologists from a single centre in SEA. METHODS: All patients who underwent TDC insertion by nephrologists from October 2013 to June 2016 were included. TDC survival was calculated using Kaplan-Meier survival method. Impact of variables was assessed using Cox proportional hazards model. RESULTS: A total of 344 TDCs were inserted in 274 patients. The most common indication was haemodialysis initiation (60.2%) followed by existing catheter dysfunction (CD) (12.2%), failed vascular access (10.2%) and catheter-related bacteraemia (CRB) (9.9%). Insertion was successful in 97% patients. The most common location was the right internal jugular vein (87%). The cumulative survival for all TDCs inserted, as defined by the time to non-elective removal of a TDC, at 3, 6 and 9 months was 83%, 61%, and 44%, respectively. Median catheter survival was 231 days. Common indications for removal were CD (13.4%) and CRB or suspected infection (12.5%). Common complications were bleeding (8.72%), infection (13.7%) and CD (16.5%). Median time to infection was 103 days. In multivariate analysis, male gender was associated with poor catheter survival, for primary insertions (p = 0.015, HR 0.62) and diabetes was associated with TDC infection (p = 0.024, OR 1.1). CONCLUSIONS: This is one of the first reports of TDC insertion by nephrologists from SEA. Our outcomes compare favourably with those reported in the literature.

Post-hemodialysis dosing of 1 vs. 2 g of ceftazidime in anuric end-stage renal disease patients on low-flux dialysis and its pharmacodynamic implications on clinical use.

Ceftazidime is a cost-effective antimicrobial against Gram-negative pathogens associated with sepsis in end-stage renal disease (ESRD) hemodialysis patients with potential for wider use with the advent of ceftazidime-avibactam. Dosing ceftazidime post-hemodialysis appears attractive and convenient, but limited in vivo data on pharmacodynamic efficacy (PE) attainment, defined as >70% of the interdialytic period drug concentrations exceed susceptible pathogens minimal inhibitory concentrations (MICs) (%TMIC), warrants further assessment. We therefore evaluated PE and tolerability of 1 against 2 g regime in anuric ESRD patients on low-flux hemodialysis. Two doses of 1 or 2 g ceftazidime were administered post-hemodialysis prior to 48- and 72-hour interdialytic intervals in ESRD inpatients without active infections. Peak and trough concentrations (mg/L) were assayed using a validated liquid chromatography-tandem mass spectrometry method. Proportion of patients achieving PE for known pathogens with MICs ≤ 8 mg/L and adverse effects were assessed. Six (43%) and eight (57%) adult patients received 1 and 2 g dose, respectively. Median (25th-75th percentile), peak, 48- and 72-hour trough ceftazidime concentrations were 78 (60-98) vs. 158 (128-196), 37 (23-37) vs. 49 (39-71), and 13 (12-20) vs. 26 (21-41) mg/L, respectively, resulting in 100% TMIC for both doses. One patient on the 1-g dose experienced mild pruritus. Reliable and safe PE attainment over both 48- and 72-hour interdialytic interval was achievable with 1 g of ceftazidime dosed post-hemodialysis. The 2 g dose was equally effective and well tolerated but may not be necessary. These findings need validation in non-anuric patients, high-flux hemodialysis, and during avibactam co-administration.

Transjugular tunnelled dialysis catheter tip placement into the inferior vena cava upper segment after length overestimation.

PURPOSE: The right atrium is preferred over the superior vena cava (SVC) for tunnelled dialysis catheter (TDC) tip placement as it offers the best compromise between optimal catheter performance and complications. However, clinical practice guidelines are not all unanimous on this as a universal recommendation. Right atrial tip placement may also fail due to variations in body surface area, venous anatomy or TDC designs and lengths. Moreover, the presence of recurrent long intra-cardiac fibrin sheath or cardiac rhythm management device leads serves as contraindications. Extra-cardiac tip placement in the azygous, hepatic veins and lower segment of the inferior vena cava (IVC) is an alternative but is invariably associated with poor blood flow and shortened patency. METHODS: We report the concept of extra-cardiac tip placement into the larger calibre hepatic segment IVC via a transjugular approach in two diabetic haemodialysis patients with overestimated TDC length out of 380 insertions. RESULTS: Blood flow was maintained above 250 ml/min for 5-6 months and no tip migration ensued. CONCLUSIONS: The IVC upper segment is a reliable site for extra-cardiac tip placement in select cases but its safety and efficacy need to be further studied in larger clinical trials.

High-dose cefazolin on consecutive hemodialysis in anuric patients with Staphylococcal bacteremia.

Methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia is a leading cause of infection in hemodialysis (HD) patients. Cloxacillin, cefazolin, and vancomycin are the mainstay antimicrobials. Cloxacillin administration leads to frequent drug dosing, longer length of stay (LOS), and higher cost, while resistance and poorer outcomes are associated with vancomycin use. Dosing cefazolin during HD allows for prolonged blood therapeutic levels. We assessed the outcomes and safety of a strategy of treating MSSA bacteremia with 2-3 g cefazolin on HD only. All HD patients with MSSA bacteremia admitted in June-December 2009 at our center and receiving this regime were compared with historical controls who received cloxacillin. Demographic characteristics and outcome measures like mortality, LOS, cost, recrudescence, and adverse drug reactions were assessed. Of 27 consecutive episodes reviewed, 14 and 13 patients received cefazolin and cloxacillin, respectively. Baseline demographics were comparable between the 2 treatment groups. More than one-third of the bacteremia was related to tunneled catheter infection. The 30-day mortality of cloxacillin- and cefazolin-treated patients was 15% and 7%, respectively (P=0.14). Two of the 11 survivors treated with cloxacillin (18%) had recrudescent bacteremia while none was observed in cefazolin-treated survivors. Cefazolin was associated with shorter LOS (10 vs. 20 days, P<0.05) and lower cost (US$8262.00 vs. US$15,367.00, P<0.05). Cefazolin use resulted in 3 idiosyncratic adverse drug reactions. Cefazolin dosed on each HD in MSSA bacteremia leads to earlier discharge and less cost. Larger prospective studies are, however, warranted to fully assess its safety and efficacy.