Hemodynamic optimization of a novel single-puncture dual-lumen coaxial catheter for arteriovenous fistula access: A computational fluid dynamics study.

Arteriovenous fistula (AVF) is the gold standard for hemodialysis access, but traditional dual-needle cannulation is limited by a restricted cannulation area and progressive stenosis; single-puncture systems may reduce these risks if hemodynamics can be optimized to prevent recirculation. This study aimed to design a novel single-puncture dual-lumen coaxial catheter and to evaluate its hemodynamic performance, flow efficiency, and recirculation rate using high-resolution computational fluid dynamics (CFD). In this CFD and design-optimization study, a dual-lumen coaxial catheter with a unique fenestration geometry was designed and analyzed using SolidWorks Flow Simulation at a physiological temperature of 37°C. Boundary conditions included an AVF flow rate of 1000 mL/min and a dialysis pump speed of 300 mL/min. The primary endpoints were flow velocity, shear stress, and recirculation control. CFD simulation (1,030,641 cells) showed a maximum flow velocity of 12.69 m/s and a peak calculated shear stress of 2,602.45 Pa at the narrowest lumen section; because blood damage depends on both stress magnitude and exposure time, these computational data alone do not establish blood compatibility. Thermodilution analysis yielded a theoretical recirculation rate of 0.007% under the modeled conditions, and flow trajectories showed spatial separation of the venous jet from the arterial intake. Under the modeled steady-state conditions (AVF flow, 1000 mL/min; dialysis pump flow, 300 mL/min), CFD predicted stable separation of the return and aspiration streams and a theoretical recirculation rate of 0.007%. These proof-of-concept findings support further geometric optimization and physical testing; they do not establish clinical safety, efficacy, or superiority over standard dual-needle cannulation.