Regional Citrate Anticoagulation during Double-Filtration Plasmapheresis in Kidney Transplant Recipients: A Single-Center Retrospective Cohort Study.

INTRODUCTION: Double-filtration plasmapheresis (DFPP) may be used for immunomodulation in kidney transplant (KTx). While DFPP reduces plasma product exposure, risk of circuit clotting merits adequate anticoagulation. Regional citrate anticoagulation (RCA) avoids the risks of systemic anticoagulation, but a protocol for RCA-DFPP is not previously widely described. METHODS: We conducted a single-center retrospective cohort study involving adult (≥21 years old) KTx recipients who underwent RCA-DFPP from 2018 to 2020 to investigate efficacy and safety for an RCA protocol during DFPP in KTx recipients. RESULTS: Fifty-one (85%) of 60 RCA-DFPP sessions in 17 patients completed without circuit clotting. Circuit clotting was associated with high post-filter ionized calcium (28 vs. 3.7%, odds ratio 10.1, 95% CI 1.1-89.4, p = 0.037). Hypo- and hypercalcemia developed in 5 (8.3%) and 8 (13.3%) sessions, respectively, but no adverse effects were noted despite severe hypocalcemia in one. There was no significant change in pre- and post-RCA-DFPP sodium, bicarbonate, albumin, and platelet levels. With regards DFPP procedure, prolongation of prothrombin time (PT) and activated partial thromboplastin time (aPTT) was observed following 38 (64.4%) and 12 (20.3%) sessions, respectively. Severely prolonged (>1.5 × upper limit normal) PT and aPTT were recorded in 2 sessions each. Expectedly, hypofibrinogenemia developed after 31 (51.7%) sessions: including 4 (6.7%) severe hypofibrinogenemia (<0.5 g/L). Two patients developed bleeding requiring blood product transfusion. The median total volume of fluids administered per session was 1.495 (1.373-1.612) L; post-RCA-DFPP significant weight gain of 0.5 (0-1.25) kg was noted. Diuretic was commenced or dose increased following 20 (33.3%) sessions for fluid balance management. DISCUSSION/CONCLUSION: Protocol-based RCA for DFPP is feasible and safe in KTx recipients. However, DFPP-related coagulopathy can develop consequent to treatment; caution should be exercised for patients with bleeding risk. Close monitoring and management of the patients' electrolytes, especially hypocalcemia and hypomagnesemia, and fluid status is recommended.

Peritoneal dialysis: Status report in South and South East Asia.

BACKGROUND: Peritoneal dialysis (PD) as a modality of kidney replacement therapy (KRT) is largely underutilized globally. We analyzed PD utilization, impact of economic status, projected growth and impact of state policy(s) on PD growth in South Asia and Southeast Asia (SA&SEA) region. METHODS: The National Nephrology Societies of the region responded to a questionnaire on KRT practices. The responses were based on the latest registry data, acceptable community-based studies and societal perceptions. The representative countries were divided into high income and higher-middle income (HI & HMI) and low income and lower-middle income (LI & LMI) groups. RESULTS: Data provided by 15 countries showed almost similar percentage of GDP as health expenditure (4%-7%). But there was a significant difference in per capita income (HI & HMI -US$ 28 129 vs. LI & LMI - US$ 1710.2) between the groups. Even after having no significant difference in monthly cost of haemodialysis (HD) and PD in LI & LMI countries, they have poorer PD utilization as compared to HI & HMI countries (3.4% vs. 10.1%); the reason being lack of formal training/incentives and time constraints for the nephrologist while lack of reimbursement and poor general awareness of modalities has been a snag for the patients. The region expects ≥10% PD growth in the near future. Hong Kong and Thailand with 'PD first' policy have the highest PD utilization. CONCLUSION: Important deterrents to PD underutilization were lack of PD centric policies, lackadaisical patient/physician's attitude, lack of structured patient awareness programs, formal training programs and affordability.

Aetiology, practice patterns and burden of end-stage kidney disease in South Asia and South-East Asia: A questionnaire-based survey.

AIM: There is paucity of data on the epidemiology of end-stage kidney disease (ESKD) from South Asia and South-East Asia. The objective of this study was to assess the aetiology, practice patterns and disease burden and growth of ESKD in the region comparing the economies. METHODS: The national nephrology societies of the region; responded to the questionnaire; based on latest registries, acceptable community-based studies and society perceptions. The countries in the region were classified into Group 1 (High|higher-middle-income) and Group 2 (lower|lowermiddle income). Student t-test, Mann-Whitney U test and Fisher's exact test were used for comparison. RESULTS: Fifteen countries provided the data. The average incidence of ESKD was estimated at 226.7 per million population (pmp), (Group 1 vs. Group 2, 305.8 vs. 167.8 pmp) and average prevalence at 940.8 pmp (Group 1 vs. Group 2, 1306 vs. 321 pmp). Group 1 countries had a higher incidence and prevalence of ESKD. Diabetes, hypertension and chronic glomerulonephritis were most common causes. The mean age in Group 2 was lower by a decade (Group 1 vs. Group 2-59.45 vs 47.7 years). CONCLUSION: Haemodialysis was the most common kidney replacement therapy in both groups and conservative management of ESKD was the second commonest available treatment option within Group 2. The disease burden was expected to grow >20% in 50% of Group 1 countries and 78% of Group 2 countries along with the parallel growth in haemodialysis and peritoneal dialysis.

Ensuring Sustainability of Continuous Kidney Replacement Therapy in the Face of Extraordinary Demand: Lessons From the COVID-19 Pandemic.

With the exponential surge in patients with coronavirus disease 2019 (COVID-19) worldwide, the resources needed to provide continuous kidney replacement therapy (CKRT) for patients with acute kidney injury or kidney failure may be threatened. This article summarizes subsisting strategies that can be implemented immediately. Pre-emptive weekly multicenter projections of CKRT demand based on evolving COVID-19 epidemiology and routine workload should be made. Corresponding consumables should be quantified and acquired, with diversification of sources from multiple vendors. Supply procurement should be stepped up accordingly so that a several-week stock is amassed, with administrative oversight to prevent disproportionate hoarding by institutions. Consumption of CKRT resources can be made more efficient by optimizing circuit anticoagulation to preserve filters, extending use of each vascular access, lowering blood flows to reduce citrate consumption, moderating the CKRT intensity to conserve fluids, or running accelerated KRT at higher clearance to treat more patients per machine. If logistically feasible, earlier transition to intermittent hemodialysis with online-generated dialysate, or urgent peritoneal dialysis in selected patients, may help reduce CKRT dependency. These measures, coupled to multicenter collaboration and a corresponding increase in trained medical and nursing staffing levels, may avoid downstream rationing of care and save lives during the peak of the pandemic.

Augmented Adsorptive Blood Purification during Continuous Veno-Venous Haemodiafiltration in a Severe Septic, Acute Kidney Injury Patient: Use of oXiris®: A Single Centre Case Report.

The use of the oXiris® haemofilter during continuous veno-venous haemodiafiltration (CVVHDF) for acute kidney injury (AKI) and severe sepsis is not completely understood. Although this filter has in vitro adsorptive properties for blood-borne cytokines and other humoural mediators of sepsis, its clinical usefulness is uncertain. Given its inherent adsorptive limitation for septic mediators, we developed a CVVHDF protocol in which the oXiris haemofilter was electively changed every 12 h even though there was no clotting or adverse circuit pressures. Augmented filter membrane adsorption was conducted for 3 consecutive days. We treated a critically ill patient with severe sepsis secondary to a gram-negative bacterial infection and sepsis-associated acute kidney injury (SA- AKI) in this way. The patient required high-dose vasopressor support, required mechanical ventilation, had received 12 h of CVVHDF with conventional M100 haemofilter, was on broad spectrum antibiotics and other conventional intensive care unit (ICU) care, prior to institution of the frequent oXiris haemofilter change protocol. Following the start of elective 12 hourly oXiris filter change, the patient showed reduction in the need for vasopressor and by Day 4 of this SA- AKI frequent filter change protocol, vasopressor requirement ceased, he was extubated. He survived ICU and but not hospital stay. To this end, more clinical studies are needed.

Family dynamics in a multi-ethnic Asian society: comparison of elderly CKD patients and their family caregivers experience with medical decision making for managing end stage kidney disease.

BACKGROUND: Elderly end stage kidney patients face a decision concerning whether or not to initiate dialysis. In Asia, this decision is highly influenced by family caregivers. The objective of this paper was to understand patients' experience with and preferences for family involvement in treatment decisions, and via a series of hypothetical vignettes, to identify whether there was discordance in treatment preferences between patients and their caregivers, and how any potential conflicts were reconciled. METHODS: We conducted a survey with 151 elderly (aged ≥65) chronic kidney disease patients and their caregivers at outpatient renal clinics. The survey asked, when making treatment decisions, whom they wish makes the final decisions (i.e., preference) and who usually makes the final decisions (i.e., experience). The survey also presented a series of choice vignettes for managing patient's condition and asked respondents to choose between two hypothetical treatment profiles in each vignette. Patients and caregivers were first interviewed separately in tandem, and then were brought together to choose a treatment jointly for vignettes where the initial treatment choice differed within the dyad. We used multivariate regressions to investigate the predictors of discordance and reconciliation. RESULTS: We found that most (51%) patients preferred and experienced (64%) significant involvement from caregivers. However, 38% of patients preferred to make final decisions alone but only 27% of patients did. In the hypothetical vignettes, caregivers chose the more intensive option (i.e., dialysis) more than patients did (26% vs 19%; p < 0.01). Overall, 44% of the dyads had discordance in at least 3 vignettes, and the odds of discordance within patient-caregiver dyads was higher when caregivers chose dialysis or treatment with the higher cost (p < 0.01). In half the cases, discordance resolved in the patients' favor, and this was more likely to be the case if the patient was employed and wanted to be in charge of final decisions (p < 0.01). CONCLUSIONS: Our results highlight the important role of caregivers in decision-making but also the potential for them to overstep. Clinicians should be aware of this challenge and identify strategies that minimize the chances that patients may receive treatments not consistent with their preferences.

Impact of simulation-based learning on immediate outcomes of temporary haemodialysis catheter placements by nephrology fellows.

AIM: Traditional apprenticeship model (AM) of teaching in invasive procedures such as temporary haemodialysis catheter (THDC) insertion can result in propagation of errors and complications. Simulation-based learning (SBL) offers standardization of skills and allows trainees to repeatedly practice invasive procedures prior to performing them on actual patient. METHODS: Retrospective cohort study of first-, second- and third-year Nephrology Fellows from a tertiary teaching hospital from September 2008 to September 2015. The intervention group (n = 9) received simulation training in ultrasound-guided THDC placement. The historical control group (n = 12) received training through traditional AM. The primary and secondary outcomes were the immediate complications and success rates of THDC insertion. RESULTS: A total of 2481 THDCs were placed in 1787 patients. Success rate of internal jugular THDC placement for AM vs. SBL Fellow was 99.8% versus 100% (P = 0.90), while the success rate for femoral THDC placement was 99.6% versus 99.2% (P = 0.53). SBL Fellows reported fewer overall peri-procedure complications (8.3% vs. 11.2%, P = 0.02) and mechanical complications (1% vs. 2.4%, P = 0.02) compared to AM Fellows. The rate of reported technical difficulty was similar (7.5% vs. 9.2%, P = 0.17). After adjusting for side and site of THDC placement, body mass index and laboratory indices, THDC inserted by AM Fellows were independently associated with increased overall peri-procedure complications (OR = 1.396, 95% CI: 1.052-1.854, P = 0.02) and mechanical complications (OR = 2.481, 95% CI: 1.178-4.810, P = 0.02). CONCLUSIONS: Simulation-based learning was associated with lower procedure related complications and should be an integral component in the teaching of procedural skills in Nephrology.

30-year follow-up study of IgA nephritis in a Southeast Asian population: an evaluation of the Oxford histological classification
.

BACKGROUND: In 1985 we reported that 11% of a cohort of 151 patients with IgA nephritis (IgAN) had developed end-stage renal disease (ESRD) after a follow-up period of 5 years. 15 years later, 35% had developed ESRD. METHODS: We retrieved 125 stored renal biopsy paraffin blocks of the original cohort. From these, 102 patients were included in the present study and scored according to the Oxford classification as 21 specimens with less than 8 glomeruli were excluded and in 2 others, tissue samples were too tiny for a re-block. ESRD was ascertained by linking the study cohort to the Singapore Renal Registry at the National Registry of Diseases Office. RESULTS: Renal survival curves for each of the Oxford MEST lesions: endocapillary proliferation (E) (p < 0.04), segmental glomerulosclerosis (S) (p < 0.05), tubular atrophy/interstitial fibrosis (p < 0.0001) were significantly associated with ESRD. Mesangial hypercellularity, less commonly associated with progressive chronic kidney disease (CKD) in the study, was independently associated with ESRD at 30 years (p < 0.03). In this cohort, E and S were associated with lower eGFR at presentation and doubling of serum creatinine in the first 5 years. This study's initial 5 years was representative of the "natural history" of IgAN since no renin-angiotensin system (RAS) blockers or immunosuppression were administered. This represents the early phase of disease progression. E and S may be considered "early disease activity predictors". CONCLUSION: Mesangial hypercellularity and tubular atrophy/interstitial fibrosis (M1 and T1/T2 lesion) of the Oxford classification independently predicted long term ESRD.
.

Epstein-Barr virus-associated smooth muscle tumors after kidney transplantation: treatment and outcomes in a single center.

BACKGROUND: Epstein-Barr virus-associated smooth muscle tumors (EBV SMT) in adult kidney transplant recipients (KTR) are rare. The aims of this study are to document the clinical features, types of treatment given, and outcomes of KTR with EBV SMT in our institution. METHODS: Sixteen patients were identified from our institution's databases. Patients' survival, tumor outcome, and graft survival were compared between patients who remained on cyclosporine-based immunosuppressant and those who converted to sirolimus-based therapy. RESULTS: The median time of diagnosis was 9.4 yr after kidney transplantation, and majority of the patients had multifocal disease at the time of diagnosis. Overall, the patient survival rate was 75% over a mean follow-up period of five yr. Two patients with non-functioning allograft at the time of diagnosis of EBV SMT were excluded from the treatment outcome analysis. Comparing the sirolimus (n = 7) vs. cyclosporine groups (n = 7), patient survival rate was 100% vs. 42.9% (p = 0.08), graft survival 71.4% vs. 28.7% (p = 0.53), and disease-free status 42.9% vs. 14.3% (p = 0.73), respectively. CONCLUSION: Surgical resection in combination with decreasing immunosuppression or conversion to sirolimus appears to be effective in the treatment of EBV SMT in KTR.

Development and validation of an interpretable clinical score for early identification of acute kidney injury at the emergency department.

Acute kidney injury (AKI) in hospitalised patients is a common syndrome associated with poorer patient outcomes. Clinical risk scores can be used for the early identification of patients at risk of AKI. We conducted a retrospective study using electronic health records of Singapore General Hospital emergency department patients who were admitted from 2008 to 2016. The primary outcome was inpatient AKI of any stage within 7 days of admission based on the Kidney Disease Improving Global Outcome (KDIGO) 2012 guidelines. A machine learning-based framework AutoScore was used to generate clinical scores from the study sample which was randomly divided into training, validation and testing cohorts. Model performance was evaluated using area under the curve (AUC). Among the 119,468 admissions, 10,693 (9.0%) developed AKI. 8491 were stage 1 (79.4%), 906 stage 2 (8.5%) and 1296 stage 3 (12.1%). The AKI Risk Score (AKI-RiSc) was a summation of the integer scores of 6 variables: serum creatinine, serum bicarbonate, pulse, systolic blood pressure, diastolic blood pressure, and age. AUC of AKI-RiSc was 0.730 (95% CI 0.714-0.747), outperforming an existing AKI Prediction Score model which achieved AUC of 0.665 (95% CI 0.646-0.679) on the testing cohort. At a cut-off of 4 points, AKI-RiSc had a sensitivity of 82.6% and specificity of 46.7%. AKI-RiSc is a simple clinical score that can be easily implemented on the ground for early identification of AKI and potentially be applied in international settings.

Interventional nephrology and vascular access practice: A perspective from South and Southeast Asia.

South and Southeast Asia is the most populated, heterogeneous part of the world. The Association of Vascular Access and InTerventionAl Renal physicians (AVATAR Foundation), India, gathered trends on epidemiology and Interventional Nephrology (IN) for this region. The countries were divided as upper-middle- and higher-income countries as Group-1 and lower and lower-middle-income countries as Group-2. Forty-three percent and 70% patients in the Group 1 and 2 countries had unplanned hemodialysis (HD) initiation. Among the incident HD patients, the dominant Vascular Access (VA) was non-tunneled central catheter (non-TCC) in 70% of Group 2 and tunneled central catheter (TCC) in 32.5% in Group 1 countries. Arterio-Venous Fistula (AVF) in the incident HD patients was observed in 24.5% and 35% of patients in Group-2 and Group-1, respectively. Eight percent and 68.7% of the prevalent HD patients in Group-2 and Group-1 received HD through an AVF respectively. Nephrologists performing any IN procedure were 90% and 60% in Group-2 and Group 1, respectively. The common procedures performed by nephrologists include renal biopsy (93.3%), peritoneal dialysis (PD) catheter insertion (80%), TCC (66.7%) and non-TCC (100%). Constraints for IN include lack of time (73.3%), lack of back-up (40%), lack of training (73.3%), economic issues (33.3%), medico-legal problems (46.6%), no incentive (20%), other interests (46.6%) and institution not supportive (26%). Routine VA surveillance is performed in 12.5% and 83.3% of Group-2 and Group-1, respectively. To conclude, non-TCC and TCC are the most common vascular access in incident HD patients in Group-2 and Group-1, respectively. Lack of training, back-up support and economic constraints were main constraints for IN growth in Group-2 countries.

Patient Decision Aid Development for Older Adults With End-Stage Kidney Disease in Singapore.

INTRODUCTION: In managing end-stage kidney disease (ESKD), older adults face a decision regarding whether to undergo dialysis or manage symptoms through kidney supportive care (KSC). This article describes the development of a patient decision aid (PDA) that is designed specifically for older adults with ESKD. METHODS: The decision context of the PDA was to choose a treatment between hemodialysis, peritoneal dialysis, and KSC. The development process used insights obtained from qualitative interviews with patients, informal caregivers, and health care providers. The PDA was then developed in English and Mandarin and was pilot-tested with patients, caregivers, and health care providers. We finalized the PDA based on feedback from pilot testing and performed a preliminary evaluation based on the International Patient Decision Aid Standards (IPDASi v4.0) criteria. RESULTS: The final PDA consists of 2 booklets and a video. During pilot testing, patients and caregivers reported high levels of ease of understanding and usefulness with ≥92.5% providing agree/strongly agree responses for the "Content"-related criteria, and ≥75% providing agree/strongly agree responses for the "Development Process and Effectiveness"-related criteria. The final PDA met 10 of 12 IPDASi v4.0 criteria. CONCLUSIONS: This PDA was found useful during pilot-testing. It will be used during renal counseling in Singapore to help older adults with ESKD and their caregivers make informed decisions on which treatment option is best for the patients.

Age and diabetes mellitus associated with worse outcomes after percutaneous coronary intervention in a multi-ethnic Asian dialysis patient population.

INTRODUCTION: There is limited literature on clinical outcomes following percutaneous coronary intervention (PCI) in Asian dialysis patients. We evaluated the angiographic characteristics and clinical outcomes of dialysis patients treated with PCI in an Asian society. METHODS: A retrospective analysis was performed of 274 dialysis patients who underwent PCI in a tertiary care institution from January 2007 to December 2012. Data on clinical and angiographic characteristics was collected. The primary endpoint was major adverse cardiac events (MACE), defined as a composite of cardiac death, acute myocardial infarction (AMI) and stroke at two years. RESULTS: 274 patients (65.0% male, median age 62.0 years) with 336 lesions (81.8% Type B2) were treated. 431 stents (35.0% drug-eluting stents) with a mean diameter of 2.96 mm and mean length of 21.30 mm were implanted. The MACE rate was 55.8% (n = 153) at two years, from death (36.5%) and AMI (35.0%). In multivariable analysis, age and diabetes mellitus were significant predictors of both mortality (odds ratio [OR] 1.09, 95% confidence interval [CI] 1.05-1.12, p < 0.001; OR 2.65, 95% CI 1.46-4.82, p = 0.001, respectively) and MACE (OR 1.06, 95% CI 1.03-1.08, p < 0.001; OR 1.84, 95% CI 1.07-3.15, p = 0.027, respectively). Left ventricular ejection fraction (LVEF) (OR 0.97, 95% CI 0.95-0.99, p = 0.006) was a significant predictor of mortality but not MACE. CONCLUSION: Asian dialysis patients who underwent PCI had a two-year MACE rate of 55.8% due to death and AMI. Age, LVEF and diabetes mellitus were significant predictors of mortality at two years.

Impact of National Economy and Policies on End-Stage Kidney Care in South Asia and Southeast Asia.

BACKGROUND: The association between economic status and kidney disease is incompletely explored even in countries with higher economy (HE); the situation is complex in lower economies (LE) of South Asia and Southeast Asia (SA and SEA). METHODS: Fifteen countries of SA and SEA categorized as HE and LE, represented by the representatives of the national nephrology societies, participated in this questionnaire and interview-based assessment of the impact of economic status on renal care. RESULTS: Average incidence and prevalence of end-stage kidney disease (ESKD) per million population (pmp) are 1.8 times and 3.3 times higher in HE. Hemodialysis is the main renal replacement therapy (RRT) (HE-68%, LE-63%). Funding of dialysis in HE is mainly by state (65%) or insurance bodies (30%); out of pocket expenses (OOPE) are high in LE (41%). Highest cost for hemodialysis is in Brunei and Singapore, and lowest in Myanmar and Nepal. Median number of dialysis machines/1000 ESKD population is 110 in HE and 53 in LE. Average number of machines/dialysis units in HE is 2.7 times higher than LE. The HE countries have 9 times more dialysis centers pmp (median HE-17, LE-02) and 16 times more nephrologist density (median HE-14.8 ppm, LE-0.94 ppm). Dialysis sessions >2/week is frequently followed in HE (84%) and <2/week in LE (64%). "On-demand" hemodialysis (<2 sessions/week) is prevalent in LE. Hemodialysis dropout rates at one year are lower in HE (12.3%; LE 53.4%), death being the major cause (HE-93.6%; LE-43.8%); renal transplants constitute 4% (Brunei) to 39% (Hong Kong) of the RRT in HE. ESKD burden is expected to increase >10% in all the HE countries except Taiwan, 10%-20% in the majority of LE countries. CONCLUSION: Economic disparity in SA and SEA is reflected by poor dialysis infrastructure and penetration, inadequate manpower, higher OOPE, higher dialysis dropout rates, and lesser renal transplantations in LE countries. Utility of RRT can be improved by state funding and better insurance coverage.

Current state of vascular access in Singapore.

This article described the current state of vascular access management for patients with end-stage renal disease in Singapore. Over the past 10 years, there has been a change in the demographics of end-stage renal disease patients. Aging population and the increase in prevalence of diabetes mellitus has led to the acceleration of chronic kidney disease and increase in incidence and prevalence of end-stage renal disease. Vascular access care has, therefore, been more complicated, with the physical, psychological, and social challenges that occur with increased frequency in elderly patients and patients with multiple co-morbidities. Arteriovenous fistula and arteriovenous graft are created by vascular surgeons, while maintenance of patency of vascular access through endovascular intervention has been a shared responsibility between surgeons, interventional radiologists, and interventional nephrologists. Pre-emptive access creation among end-stage renal disease patients has been low, with up to 80% of new end-stage renal disease patients being commenced on hemodialysis via a dialysis catheter. Access creation is exclusively performed by a dedicated vascular surgeon with arteriovenous fistula success rate up to 78%. The primary and cumulative patency rates of arteriovenous fistula and arteriovenous graft were consistent with the results from many international centers. Vascular access surveillance is not universally practiced in all dialysis centers due to its controversies, in addition to the cost and the limited availability of equipment for surveillance. Timely permanent access placement, with reduced dependence on dialysis catheters, and improved vascular access surveillance are the main areas for potential intervention to improve vascular access management.

Non-randomized safety and performance evaluation of the av-Guardian vascular access system.

INTRODUCTION: The ability to successfully cannulate the arteriovenous fistula reliably is a critical step in the delivery of hemodialysis therapy. The av-Guardian vascular access system (Advent Access, Singapore) is designed to overcome the technical barrier to establishing reliable blunt needle access in patients with mature arteriovenous fistula. METHODS: This was a first-in-man, prospective, non-randomized trial (registered on the Australian New Zealand Clinical Trial Registry (ACTRN12617000501347)) performed to assess the safety and feasibility of achieving repeatable successful cannulation via av-Guardian vascular access system to facilitate blunt needling in patients with mature arteriovenous fistula. The primary endpoints of the study included rate of successful hemodialysis sessions via av-Guardian vascular access system cannulation over 3 months and safety of the implants. RESULTS: A total of six patients (four patients with brachiocephalic and two with radiocephalic arteriovenous fistula) were enrolled in the study. A pair of av-Guardian vascular access system were implanted, one each at the arterial and venous cannulation sites, under local anesthesia. Overall, the rate of successful cannulation through the av-Guardian vascular access system over 3 months in 216 hemodialysis sessions was 98.1% (212/216) at the arterial site and 94.4% (204/216) at the venous site. Significantly, 90% and 85.5% of the cannulations at the arterial and venous site, respectively, were successful at first attempt. Blood flow rates within the arteriovenous fistula were unaffected by the devices. CONCLUSION: The results demonstrated the safety and feasibility of a subcutaneously implanted, extravascular device in achieving repeatable successful cannulation via a constant site, to facilitate blunt needling in matured arteriovenous fistula in limited number of patients.

Mid-Term Outcomes of Patients with Central Venous Occlusive Disease Undergoing Surveillance Venography and Intervention.

INTRODUCTION: To evaluate the mid-term outcomes of regular surveillance venography with or without percutaneous transluminal angioplasty (PTA) in haemodialysis patients presenting with central venous occlusive disease. MATERIALS AND METHODS: A single-centre retrospective analysis of haemodialysis patients who presented with central vein occlusion (CVO) and central vein stenosis (CVS) between January 2008 and December 2011 was performed. CVO and significant CVS were defined as 100% and >50% luminal narrowing, respectively. Upon successful angioplasty on first presentation, patients were followed up with regular surveillance venography within 3-6 months of the intervention and were re-treated when a significant stenosis or occlusion was demonstrated. Data on patient's demographics, comorbidities, presenting symptoms, type of upper limb dialysis access, lesion characteristics and complications were collected. Technical success, primary patency and primary assisted patency were analysed. RESULTS: Thirty-five patients with CVO and 77 patients with CVS were enrolled. The technical success of initial PTA was 77% and 73% for the CVO and CVS groups, respectively. The primary patency at 3 months was 65% and 55% for the CVO group and CVS group, respectively (P = 0.32). The primary assisted patency at 1 year was 88% and 99% for the CVO group and CVS group, respectively (P = 0.009). At 2 years, the primary assisted patency were 77% and 90%, respectively (P = 0.07). There was significant difference in the overall primary assisted patency (P = 0.048) between the CVO and CVS groups. CONCLUSION: CVOs are more difficult to treat than CVS. High primary assisted patency rates can be achieved with surveillance venography, albeit at the expense of increased number of interventions. Further cost effectiveness studies need to be performed to study the true benefit of our surveillance programme.

Prevalence of hepatitis C virus infection and the IL28B genotype polymorphism among blood donors and high-risk populations.

INTRODUCTION: To study the prevalence of hepatitis C virus (HCV) infection in blood donor (BD), haemodialysis (HD) and intravenous drug user (IVDU) populations in Singapore and assess the IL28B polymorphism if HCV positive. METHODS: The BD population were healthy volunteers, the HD population were patients who were on haemodialysis for at least six months of follow-up between January 2009 and December 2014. IVDU population was from inmates at halfway houses who consented. RESULTS: Between 2011 and 2014, of 161,658 individuals who underwent screening prior to blood donation, 95 (0.059%) were positive for HCV. Of the 42 sera available, common genotypes (GTs) were GT-3 (47.6%) and GT-1 (31.0%). Of 1,575 HD patients, 2.2% were anti-HCV positive. The HCV GT distribution was HCV GT-1 (32.4%), HCV GT-3 (20.5%) and GT-6 (8.8%). 83 halfway house inmates were screened. Of the 47 IVDUs, 36.2% were anti-HCV positive with predominant GT-3 (%). IL28B polymorphism was noted to be CC predominantly 85.3%. CONCLUSION: Prevalence of HCV infection has decreased in both the BD and HD populations. However, it remains high in the IVDU population. GT-1 remains the most common in the HD population; however, GT-3 infection is now more common among the BD population in Singapore. IL28B - CC is the predominant variant among the HCV-infected individuals in Singapore.