Study protocol for a Prospective, Randomized controlled trial of stEnt graft and Drug-coated bAlloon Treatment for cephalic arch stenOsis in dysfunctional arteRio-venous fistulas (PREDATOR).

BACKGROUND: Treatment of cephalic arch stenosis (CAS) is associated with high risk of failure and complications. Although stent-graft (SG) placement has improved patency rates, stent edge restenosis has been raised as a potential limiting factor for SG usage in CAS. This study aims to evaluate the safety and efficacy of combining stent graft placement with paclitaxel-coated balloon (PCB) angioplasty versus PCB alone in the treatment of CAS. METHODS: This is an investigator-initiated, prospective, international, multicenter, open-label, randomized control clinical trial that plans to recruit 80 patients, who require fistuloplasty from dysfunctional arteriovenous fistula (AVF) from CAS. Eligible participants are randomly assigned to receive treatment with SG and PCB or PCB alone in a 1:1 ratio post-angioplasty (n = 40 in each arm). Randomization is stratified by de novo or recurrent lesion, and the participants are followed up for 1 year. The primary endpoints of the study are target lesion primary patency (TLPP) and access circuit primary patency (ACPP) rates at 6-months. The secondary endpoints are TLPP and ACPP at 3- and 12-month; target lesion and access circuit assisted primary and secondary patency rates at 3, 6, and 12-months and the total number of interventions; complication rate; and cost-effectiveness. DISCUSSION: This study will evaluate the clinical efficacy and safety of combination SG and PCB implantation compared to PCB alone in the treatment of CAS for hemodialysis patients.

Sirolimus-coated balloon angioplasty in maintaining the patency of thrombosed arteriovenous graft: 1-year results of a prospective study.

BACKGROUND: A prospective, pilot study was designed to test the feasibility of using sirolimus-coated balloon (SCB) to treat graft vein junction of thrombosed arteriovenous graft (AVG) following successful pharmacomechanical thrombectomy. The present report provides the 1-year results of this study. METHODS: This is a 1-year follow-up of a single, prospective, single-arm study that was conducted from 2018 to 2019 in 20 patients who presented to a tertiary institution with thrombosed AVG. The recruited patients received SCB angioplasty at the graft-vein junction following successful endovascular thrombectomy of a thrombosed AVG. One year after recruitment, there were three deaths, one AVG revision, and one AVG explantation among the participants recruited. The outcomes of 15 subjects at 1-year following the index procedure obtained from electronic medical records were re-examined. RESULTS: The 1-year access circuit primary patency rate was 40%, while assisted primary and secondary patency rates were 46.7% and 73.3%, respectively. A total of 16 interventions (4 angioplasties, 12 thrombectomies) were performed in 9 patients over the 12 months. Four AVGs were abandoned. The median number of interventions per patient was 1 (0-3) per year. Using Kaplan-Meier analysis, the mean estimated post-intervention access circuit primary patency was 230 (95% CI: 162-300) days, while access circuit assisted primary patency was 253 (95% CI: 187-320) days, and access circuit secondary patency was 292 (95% CI: 230-356) days. Sub-group analysis did not show a significant difference in the mean estimated primary patency between AVG with de novo and recurrent stenosis (245 days, 95% CI: 151-339 vs 210 days, 95% CI: 113-307; p = 0.29). CONCLUSIONS: SCB may help sustain the patency of thrombosed AVG following successful thrombectomy.

Single-Center Prospective Pilot Study of Sirolimus Drug-Coated Balloon Angioplasty in Maintaining the Patency of Thrombosed Arteriovenous Graft.

PURPOSE: To investigate the use of a sirolimus drug-coated balloon (DCB) in the management of a thrombosed arteriovenous graft (AVG). MATERIALS AND METHODS: A single-center prospective pilot study was conducted between October 2018 and October 2019. Twenty patients (age = 67.0 years ± 10; male = 35%; mean time on dialysis = 31 months) with thrombosed upper limb AVG were enrolled. After successful pharmacomechanical thrombectomy and adequate treatment of the graft vein junction, sirolimus DCB angioplasty was performed at the graft vein junction. The patients were followed-up for 6 months, and all adverse events occurring during the study period were recorded. RESULTS: The primary circuit patency rates at 3 and 6 months were 76% and 65%, respectively, while the assisted-primary circuit patency rates at 3 and 6 months were 82% and 65%, respectively. The 3- and 6-month secondary circuit patency rates were 88% and 76%, respectively. Using Kaplan-Meier analyses, the estimated mean primary, assisted-primary, and secondary patencies were 285 days (95% confidence interval (CI) = 194-376 days), 319 days (95% CI = 221-416 days), and 409 days (95% CI = 333-485 days). No adverse event directly related to sirolimus DCB use was observed. CONCLUSIONS: The results of this pilot study suggest that the application of sirolimus DCB at the graft vein junction after the successful thrombectomy of AVG may be a feasible option to improve patency outcomes.

Effect of short-term low molecular weight heparin on patency following successful salvage of arteriovenous access with recurrent thrombosis.

AIM: This study aims to investigate the effect of low molecular weight heparin (LMWH) in maintaining the patency of arteriovenous (AV) access with recurrent thrombosis. METHODS: Following successful thrombectomy, 66 patients with recurrent thrombosis were included in the study. The primary, assisted primary and secondary patency rates of patients who received LMWH (n = 24) were compared with those who did not receive anticoagulant (n = 42) using Kaplan-Meier analysis. Cox-regression analysis was performed to investigate potential predictors of patency rates. RESULTS: The mean dose of enoxaparin used was 40 ± 13.1 mg or 0.74 ± 0.2 mg/kg daily for a median duration of 14 (IQR 7,28) days. The mean trough anti-Xa concentrations measured after two doses of LMWH was 0.17 ± 0.13 IU/mL. Kaplan-Meier analyses for mean primary, assisted primary and secondary patency rates of LMWH vs no anticoagulation groups were 149 (95% CI: 91 - 207) vs 87 (95% CI: 42-132) days (P < .006), 230 (95% CI: 142-320) vs 107 (95% CI: 62-150) days (P = .01) and 438 (299-579) vs 294 (95% CI: 197-392) days (P = .08) respectively. LMWH remained a significant protective predictor of primary (HR: 0.49; 95% CI: 0.25-0.86; P = .02) and assisted primary patency rates (HR: 0.51; 95% CI: 0.27-0.98; P = .04) after adjusting for patient age, access age, type of AV access, presence of peripheral vascular disease and haemoglobin levels. CONCLUSION: LMWH may improve short and mid-term patency rates for AV accesses with recurrent thrombosis.

Validation of the failure to maturation equation and proposal for a novel scoring system for arteriovenous fistula maturation in multiethnic Asian haemodialysis patients.

INTRODUCTION: A successful arteriovenous fistula is essential for effective haemodialysis. We aim to validate the existing failure to maturation equation and to propose a new clinical scoring system by evaluating arteriovenous fistula success predictors. METHODS: Data of end-stage renal disease patients initiated on haemodialysis from January 2010 to December 2012 were retrospectively obtained from medical records with follow-up until 1 January 2014. Application of the failure to maturation equation was evaluated. A nomogram was developed using arteriovenous fistula success predictors and was calibrated with a bootstrapping technique. RESULTS: A total of 694 patients were included with mean duration of follow-up of 2.3 years. Arteriovenous fistula maturation was achieved by 542 patients (78%). Comparing our cohort with the failure to maturation cohort, there were statistically significant differences in mean age, ethnicity and presence of diabetes mellitus. The failure to maturation equation failed to predict arteriovenous fistula outcomes with area under the curve performance of 0.519 on a receiver operating characteristic curve. Multivariate logistic regression showed that Malay patients (odds ratio = 0.628; 95% confidence interval = 0.403-0.978; p < 0.05) and patients requiring preoperative vein mapping (odds ratio = 0.601; 95% confidence interval = 0.410-0.883; p < 0.01) had a lower chance of arteriovenous fistula success, whereas male gender (odds ratio = 1.526; 95% confidence interval = 1.040-2.241; p < 0.05) and presence of postoperative good thrill (odds ratio = 3.137; 95% confidence interval = 2.127-4.625; p < 0.0001) had a higher chance of arteriovenous fistula success. The derived nomogram predicted arteriovenous fistula success (odds ratio = 1.030; 95% confidence interval = 1.022-1.038; p < 0.0001) with the area under the curve of 0.695 on a receiver operating characteristic curve and an adequacy index of 99.86% (p < 0.0001). CONCLUSION: The failure to maturation equation was not validated in our cohort. The clinical utility of our proposed arteriovenous fistula scoring system requires external validation in larger studies.

A prospective study of clinical characteristics and outcomes of acute kidney injury in a tertiary care Centre.

BACKGROUND: Acute kidney injury (AKI) is a major global health problem. We aim to evaluate the epidemiology, risk factors and outcomes of AKI episodes in our single centre. METHODOLOGY: We prospectively identified 422 AKI and acute on chronic kidney disease episodes in 404 patients meeting KDIGO definitions using electronic medical records and clinical data from 15th July to 22nd October 2016, excluding patients with baseline estimated GFR (eGFR) of < 15 mL/min. Patients were followed up till 6 months after AKI diagnosis. RESULTS: The mean age was 65.8 ± 14.1. Majority of patients were male (58.2%) of Chinese ethnicity (68.8%). One hundred and thirty-two patients (32.6%) were diagnosed in acute care units. Seventy-five percent of patients developed AKI during admission in a non-Renal specialty. Mean baseline eGFR was 50.2 ± 27.7 mL/min. Mean creatinine at AKI diagnosis was 297 ± 161 µmol/L. Renal consultations were initiated at KDIGO Stages 1, 2 and 3 in 58.9, 24.5 and 16.6% of patients, respectively. Three hundred and ten (76.7%) patients had a single etiology of AKI with the 3 most common etiologies of AKI being pre-renal (27.7%), sepsis-associated (25.5%) and ischemic acute tubular necrosis (15.3%). One hundred and nine (27%) patients received acute renal replacement therapy. In-hospital mortality was 20.3%. Six-month mortality post-AKI event was 9.4%. On survival analysis, patients with KDIGO Stage 3 AKI had significantly shorter survival than other stages. CONCLUSION: AKI is associated with significant in-hospital to 6-month mortality. This signifies the pressing need for AKI prevention, early detection and intervention in mitigating reversible risk factors in order to optimize clinical outcomes.

Role of platelets in thrombin generation amongst patients with non-transfusion-dependent thalassaemia.

Non-transfusion-dependent thalassaemia (NTDT) is associated with a hypercoagulable state with thrombotic risk highest after splenectomy. Various mechanisms have been proposed. Although an antiplatelet agent is commonly recommended as thromboprophylaxis in NTDT, the role of platelets contributing to this hypercoagulable state is not well-defined. This study aims to evaluate the role of platelets contributing to hypercoagulability in NTDT patients using thrombin generation (TG). Platelet-rich (PRP) and platelet-poor plasma (PPP) were collected from NTDT patients (n = 30) and normal controls (n = 20) for TG measurement and compared. Controls had higher endogenous thrombin potential (ETP) in PPP (1204.97 nM.min vs 911.62 nM.min, p < 0.001) and PRP (1424.23 nM.min vs 983.99 nM.min, p < 0.001) than patients. Patients' mean normalized ETP ratio [{PRP ETP (patient)/PPP ETP (patient)}/{mean PPP ETP (controls)/mean PPP ETP (controls)}], demonstrated that the presence of platelet does not alter ETP (mean ratio 0.97, 95% CI 0.93-1.02, equivalence defined as 10%). Types of thalassaemia, splenectomy, and severity of liver iron overload did not significantly influence patients' ETP in PPP and PRP by multivariate analysis. Platelets did not increase the TG potential of NTDT patients. Instead of being hypercoagulable, our NTDT patients were hypocoagulable by ETP measurement, although this could not be conclusively demonstrated to correlate with their iron overloading state giving rise to reduced synthesis of coagulation factors. The guideline recommendations for thromboprophylaxis with antiplatelet agents in similar NTDT patients should be re-examined.

A Case of Relapsing Peritoneal Dialysis-Associated Peritonitis by Dokdonella koreensis.

Peritonitis is a common and serious complication of peritoneal dialysis (PD) with significant morbidity. We report the first case of relapsing Dokdonella koreensis peritonitis in a patient on peritoneal dialysis. A 63-year-old Chinese man, with history of renal failure on continuous ambulatory peritoneal dialysis, presented with cloudy peritoneal effluent and abdominal pain. There was no sign or symptom suggestive of exit-site/tunnel tract infection. Peritoneal effluent cultures yielded Dokdonella koreensis which was initially misidentified as Weeksella virosa and Brevundimonas species by the API® 20 NE and VITEK® 2 GN ID card, respectively. He was treated with intraperitoneal amikacin, but the infection relapsed within a few days upon completing each antibiotic course. He eventually required removal of catheter and was transferred to hemodialysis. Infections due to unusual organisms may pose a diagnostic issue as currently available commercial tests will not be able to identify them. There is a role for using 16S rRNA sequencing to help identify these organisms and guide patient management.