© 2014 Wichtig Publishing - ISSN 1129-7298 J Vasc Access ( 2014; 5): 409 414 15 - 409 ORIGINAL ARTICLE management guidelines for stenosis recommend angio- plasty for stenosis >50% (1). There are no reliable tools that can assess the hemodynamic significance of a specific vascular access stenosis at a given location with a given severity in an individual vascular access circuit. Duplex Doppler Ultrasound (DDUS) has evolved as an effective tool which can provide structural definition of stenosis in the peripheral veins in the fistula outflow circuit (2). It also provides very reliable information on the functional impact of the stenosis (3). Recently, ultrasound assessment of the AVF has been validated with compu- tational fluid dynamics (CFD) analysis (4, 5). However, hemodynamic evaluation of an AVF using ultrasound is neither routinely practiced nor is available in most inter- ventional suites. CFD analysis has been used extensively to evaluate blood flow pattern and hemodynamic parameters in AVF INTRODUCTION Stenoses are the major cause for access dysfunc- tion necessitating repeated interventions and often result in access failure. The stenoses in arteriovenous fistulae (AVFs) can be present days, months or years after their creation. The effect of stenosis on access flow depends on their location within the access circuit (in arterial, juxta- anastomotic, outflow vein or central vein), the percent- age of luminal diameter affected and their length. While stenoses closer to the anastomosis tend to be flow limit- ing, stenoses in the outflow vein result in increased intra- access pressure and pressure-related problems. Based on their hemodynamic significance, stenosis may manifest as varied clinical symptoms and may interfere with dialysis delivery. While not all stenoses interfere with the deliv- ery of dialysis prescription, the current vascular access DOI: 10.5301/jva.5000226 Validation of computational fluid dynamics-based analysis to evaluate hemodynamic significance of access stenosis David M. Hoganson 1,2 , Cameron J. Hinkel 2 , Xiaomin Chen 3 , Ramesh K. Agarwal 3 , Surendra Shenoy 4 1 Division of Cardiothoracic Surgery, Department of Surgery, Washington University in St. Louis, St. Louis, MO - USA 2 Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO - USA 3 Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO - USA 4 Division of Abdominal Transplantation, Department of Surgery, Washington University in St. Louis, St. Louis, MO - USA Accepted: February 12, 2014 ABSTRACT Purpose: Stenosis in a vascular access circuit is the predominant cause of access dysfunction. Hemodynamic significance of a stenosis identified by angiography in an access circuit is uncertain. This study utilizes computational fluid dynamics (CFD) to model flow through arteriovenous fistula to predict the functional significance of stenosis in vascular access circuits. Methods: Three-dimensional models of fistulas were created with a range of clinically relevant stenoses using SolidWorks. Stenoses diameters ranged from 1.0 to 3.0 mm and lengths from 5 to 60 mm within a fistula diameter of 7 mm. CFD analyses were performed using a blood model over a range of blood pressures. Eight patient-specific stenoses were also modeled and analyzed with CFD and the resulting blood flow calculations were validated by comparison with brachial artery flow measured by duplex ultrasound. Results: Predicted flow rates were derived from CFD analysis of a range of stenoses. These stenoses were modeled by CFD and correlated with the ultrasound measured flow rate through the fistula of eight patients. The calculated flow rate using CFD correlated within 20% of ultrasound measured flow for five of eight patients. The mean difference was 17.2% (ranged from 1.3% to 30.1%). Conclusions: CFD analysis-generated flow rate tables provide valuable information to assess the functional significance of stenosis detected during imaging studies. The CFD study can help in determining the clinical relevance of a stenosis in access dysfunction and guide the need for intervention. Key words: Arteriovenous fistula, Computational fluid dynamics, Stenosis