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Objective: Although observational cohort studies report that interventions to achieve functionality are clinically successful in 85% of patients, the proportion of newly created autologous arteriovenous fistulas that result in functional vascular access typically is only 70 -80%. To address this discrepancy, the selection and outcomes of interventions to achieve functionality in a multicentre prospective cohort study were analysed. Methods: The Shunt Simulation Study enrolled 222 patients who needed a first arteriovenous fistula in nine dialysis units in The Netherlands from 2015 to 2018 and followed these patients until one year after access creation. In this observational study, the technical and clinical success rates of interventions to achieve functionality based on lesion and intervention characteristics were analysed and the clinical outcomes of arteriovenous fistulas with assisted and unassisted functionality were compared. Results: For patients who were on dialysis treatment at the end of the study, unassisted fistula functionality was 54% and overall fistula functionality was 78%. Thirty-four per cent of arteriovenous fistulas required an intervention to achieve functionality, 68% of which eventually became functional. Seventy-five per cent of these interventions were percutaneous balloon angioplasties of vascular access stenoses. Patients with clinically successful interventions to achieve functionality had larger pre-operative vein diameters (2.8 + 1.0 mm vs. 2.3 + 0.6 mm, p = .036) and less often presented with thrombosed fistulas than patients with unsuccessful interventions (7% vs. 43%, p = .006). Arteriovenous fistulas with assisted functionality had similar secondary patency as fistulas with unassisted functionality (100% and 98% at six months, p = .44), although they required more interventions to maintain function (2.6 vs. 1.7 per year; rate ratio 1.52, 95% CI 1.04 -2.18, p = .032). Conclusion: Interventions to achieve functionality were needed in about a third of newly created arteriovenous fistulas. Most thrombosed fistulas were abandoned, and when selected for thrombectomy rarely reached clinical success. On the other hand, interventions to achieve functionality of patent fistulas had high clinical success rates and therefore can be done repeatedly until the fistula has become functional.

Objective. An arteriovenous fistula (AVF) needs to mature before it becomes suitable to cannulate for haemodialysis treatment. Maturation importantly depends on the post-operative flow increase. Unfortunately, 20-40% of AVFs fail to mature (FTM). A patient specific computational model that predicts immediate postoperative flow was developed, and it was hypothesised that providing information from this model for planning of fistula creation might reduce FTM rates.Methods: A multicentre, randomised controlled trial in nine Dutch hospitals was conducted in which patients with renal failure who were referred for AVF creation, were recruited. Patients were randomly assigned (1:1) to the control or computer simulation group. Both groups underwent a work up, with physical and duplex ultrasonography (DUS) examination. In the simulation group the data from the DUS examination were used for model simulations, and based on the immediate post-operative flow prediction, the ideal AVF configuration was recommended. The primary endpoint was AVF maturation defined as an AVF flow >= 500 mL/min and a vein inner diameter of >= 4 mm six weeks post-operatively. The secondary endpoint was model performance (i.e. comparisons between measured and predicted flows, and (multivariable) regression analysis for maturation probability with accompanying area under the receiver operator characteristic curve [AUC]).Results: A total of 236 patients were randomly assigned (116 in the control and 120 in the simulation group), of whom 205 (100 and 105 respectively) were analysed for the primary endpoint. There was no difference in FTM rates between the groups (29% and 32% respectively). Immediate post-operative flow prediction had an OR of 1.15 (1.06-1.26; p Conclusion: Providing pre-operative patient specific flow simulations during surgical planning does not result in improved maturation rates. Further study is needed to improve the predictive power of these simulations in order to render the computational model an adjunct to surgical planning.

Introduction. As the mean age of haemodialysis patients is increasing, fewer patients will have suitable blood vessels for the creation of a Brescia-Cimino fistula and an increased use of graft implants is to be expected. Methods. To assess the change in vascular access and the use of surveillance techniques, all haemodialysis centres in The Netherlands received a questionnaire regarding the types of vascular accesses and surveillance techniques used in their department on 31 December, 1996. The results were related to a comparable study done in 1987, shown between brackets. Results. The response of the haemodialysis staff was 96%, of the vascular surgeons this was 91%. Sixty-two per cent (70%) of the patients had Brescia-Cimino fistulas, 21% (13%) Polytetrafluoroethylene (PTFE) graft fistulas, 17% (17%) other vascular accesses. Scheduled surveillance for stenosis detection was done by recirculation measurements in 6%, venous pressure measurements in 31%, Duplex scanning in 11% and angiography in 11% of the centres. When access problems occurred, 79% of the physicians performed recirculation measurements, 38% venous pressure measurements, 79% Duplex scanning and 100% angiography. In 46% of the centres PTA was done occasionally, and in 46% routinely for the treatment of stenotic complications in arteriovenous fistulas. Conclusions. The use of PTFE grafts and other types of vascular accesses has increased at the expense of BC fistulas. Recirculation and venous pressure measurements are primarily done when problems occur and not according to a standard surveillance schedule. For visualization of failing fistulas, 79% of the centres uses Duplex ultrasound analysis and 100% angiography. The popularity of PTA has increased from 46 to 92% of the centres.

Contains fulltext : 133876.pdf (Publisher’s version ) (Open Access) BACKGROUND: Despite the increasing use of pre- and posthydration protocols and low-osmolar instead of high-osmolar iodine-containing contrast media, the incidence of contrast-induced nephropathy (CIN) is still significant. There is evidence that contrast media cause ischemia-reperfusion injury of the medulla. Remote ischemic preconditioning (RIPC) is a non-invasive, safe, and low-cost method to reduce ischemia-reperfusion injury. METHODS: The RIPCIN study is a multicenter, single-blinded, randomized controlled trial in which 76 patients at risk of CIN will receive standard hydration combined with RIPC or hydration with sham preconditioning. RIPC will be applied by four cycles of 5 min ischemia and 5 min reperfusion of the forearm by inflating a blood pressure cuff at 50 mmHg above the actual systolic pressure. The primary outcome measure will be the change in serum creatinine from baseline to 48 to 72 h after contrast administration. DISCUSSION: A recent pilot study reported that RIPC reduced the incidence of CIN after coronary angioplasty. The unusual high incidence of CIN in this study is of concern and limits its generalizability. Therefore, we propose a randomized controlled trial to study whether RIPC reduces contrast-induced kidney injury in patients at risk for CIN according to the Dutch guidelines. TRIAL REGISTRATION: Current Controlled Trials ISRCTN76496973.

Purpose: The durability of prosthetic arteriovenous fistulas (AVF) for hemodialysis is jeopardized by thrombotic occlusions due to intimal hyperplastic stenoses. In arterial reconstructive surgery, peripheral arterial bypasses with prosthetic material benefit from a venous cuff at the distal anastomosis. Therefore, a study was performed to assess the effect of a venous cuff at the venous anastomosis of PTFE graft AVFs in terms of stenosis development, hemodynamics and patency rates. Methods: A subset of 40 patients from a multicenter study were enrolled into the study, of which 20 patients were randomized for venous cuff interposition. Duplex measurements to detect stenoses and volume flows were performed at 6, 12, 26 and 52 weeks postoperatively. Relative distension (RD) and wall shear rate (WSR) were calculated by means of vessel wall Doppler tracking (VWDT). Results: The total number of stenoses was significantly less in the cuff group (21 vs. 33; p = 0.045). This feature was found at the site of the venous anastomosis (cuff 5; no cuff 12). Volume flow, graft and efferent vein diameters, RD and WSR in the graft and efferent vein were comparable for both groups. WSR in the venous anastomosis tended to be lower in the cuff group (768 vs. 1,448 s–1, p = 0.068).Volume flows and WSR were significantly lower in failing grafts. Patency rates were similar in both groups (primary patency 13 vs. 29%; secondary patency 78 vs. 67%). Conclusions: A venous cuff at the venous anastomosis of PTFE graft AVFs results in less stenoses, but improved patency rates could not be demonstrated.