Preoperative Arteriovenous Fistula Simulation Study (ShuntSimulationStudy)
Preoperative Arteriovenous Fistula Simulation Study (ShuntSimulationStudy)
Patients suffering from end-stage renal disease (ESRD) are dependent on renal replacement
 therapy (dialysis). The majority of dialysis is facilitated by hemodialysis. For hemodialysis
 a vascular access is necessary, preferable an arteriovenous fistula (AVF) in which a vein is
 directly anastomosed to an artery. In order to use the AVF for hemodialysis three criteria
 have to be met; the minimal flow over the AVF is 600 mL/min, the diameter is at least 6 mm,
 and the AVF is located less than 6 mm under the skin. Unfortunately, approximately half of
 the patients (50%) are confronted with an AVF that does not meet these criteria; the so
 called non-maturation or primary failure. In case of non-maturation the AVF is not only
 unusable for dialysis, but also requires reinterventions on short- and long-term. Firstly to
 mature the AVF, and secondly, when the AVF is matured, to keep the vascular access. Using a
 computational simulation postoperative flow can be predicted. Based on patient-specific
 duplex measurements, the model can calculate the flow that can be expected following vascular
 access surgery for all AVF configurations; fore- or upper arm. These calculations lead to an
 advice which configuration is indicated; a flow that exceeds 600 mL/min, leading to
 maturation. Potentially the aforementioned 50% of non-maturation can be reduced. The patient
 then has an adequate vascular access and reinterventions are adverted, resulting in a
 decrease of costs, hospital demand, and an increase of the patients' quality of life. When
 the expected reduction of non-maturation is confirmed, the computational tool can be offered
 to other hospitals.
End-stage renal disease (ESRD) is a major and growing healthcare problem associated with
 substantial costs. By the end of 2010 the global patient population requiring chronic renal
 replacement therapy (RRT) exceeds 2 million, of which approximately 90% relies on
 hemodialysis (HD). The number of patients dependent on RRT are expected to annually increase
 with 8%. Based on this figure, it is expected that in 2030, 7.3 million ESRD patients need HD
 treatment. To facilitate adequate HD therapy a reliable vascular access (VA) is mandatory and
 can be provided by either creation of an autologous arteriovenous fistula (AVF), a prosthetic
 arteriovenous graft (AVG) or a central venous catheter (CVC). Guidelines by the National
 Kidney Foundation (NKF K/DOQI Guidelines), the Vascular Access Society (Good Nephrological
 Practice Guidelines) and the European Dialysis and Transplant Association (European Best
 Practice Guidelines on vascular access) advocate the implementation of an all-autologous
 fistula policy to maximize the use of AVF over AVG and CVC because AVF have the best
 long-term patency, fewer complications and require less interventions once fully maturated.
 Although the implementation of preoperative ultrasonography examination for vessel assessment
 has reduced the number of early AVF failure by improving the selection of the most suitable
 vessels and site for AVF creation, short- and long-term AVF dysfunction remains the major
 cause of morbidity and hospitalisation in HD patients, and is therefore the major limitation
 for HD treatment. This dysfunction is usually associated with non-maturation of the newly
 created AVF or the formation of neo-intimal hyperplasia (NIH) which potentially results in
 decreased access flow and eventual fistula thrombosis in up to 50% of AVFs. On the other
 hand, the low resistance vascular traject via the AVF may lead to impeded perfusion of the
 extremity distally of the AV anastomosis resulting in hand ischemia (HAIDI = Hemodialysis
 Access Induced Distal Ischemia), while an abundant AVF flow may lead to the development of
 left ventricular hypertrophy, both with potentially severe consequences. These high-flow
 complications occur in approximately 20% of fistulae. Numerous studies have investigated
 alternative preoperative mapping tools and criteria for reduction of AVF related
 complications. However, current clinical use of these individual tools and parameters does
 not take into account their potential interplay at a systemic level. Therefore one might
 consider that multiple prognostic parameters within a single patient are likely more valuable
 to improve outcome and therefore it is obvious to tailor the type of AVF to the individual
 patient. A possible solution to deal with multiple independent prognostic factors is
 implementation of a predictive patient-specific computational tool that relates geometrical,
 mechanical and hemodynamical parameters by means of physical laws. As a result, the
 computational tool takes the complex interplay between different prognostic parameters into
 consideration and accounts for individual differences in anatomy, physiology, demography and
 hemodynamics. Such an innovative computational tool opens new opportunities. By predicting
 postoperative flow abovementioned deleterious events can possibly be prevented. High-flow
 (>1500ml/min) and low-flow (<600ml/min) vascular access can then be predicted and
 consequently be rejected and a more suitable AVF-configuration chosen.

 Consequently, simulation of outcome after AVF creation is at hand. Recently, the feasibility
 of VA computational simulation has been investigated and proven in the ARCH FP7 ICT-224390
 project (ARCH; patient-specific image-based computational modeling for improvement of short-
 and long- term outcome of vascular access in patients on hemodialysis therapy). Within this
 technological and clinical study, longitudinal collection of cardiovascular data was
 performed with the intention to develop, calibrate and validate patient-specific modelling
 tools for surgical planning and assistance in the management of complications arising from
 AVF creation. Given the difficult and heterogeneous patient population, the study protocol
 was designed in such way that pre- and postoperative imaging could be performed strictly,
 aiming at complete datasets of structural, functional and demographical data. Although the
 computational simulation model has been validated in a small patient group, larger randomized
 observational patient studies, aiming at evaluating the potential beneficial effect of the
 use of computational tools in reducing AVF-related clinical problems, are needed.
Inclusion Criteria:

 -  Incident patients that enter the pre-dialysis program because of end-stage renal
 failure and need for vascular access.

 -  Permanent dialysis patients in need of a new VA in the contralateral arm because of a
 previous failed access.

 -  Patients in which treatment of first choice is the creation of an autologous AVF.

 -  Patients with adequate arteries and veins (duplex) for creation of RC-, BC- or BBAVF.

 -  Patients that signed the written informed consent.

 Exclusion Criteria:

 -  Patients with contraindications for creation of an autologous AVF (skin infection,
 ischemia, heart failure)

 -  Patients with a previous vascular access in the ipsilateral arm.