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Computational Flow Dynamics and Preclinical Assessment of a Novel Hemodialysis Catheter

Authors


Address correspondence to: Timothy W.I. Clark, M.D., University of Pennsylvania School of Medicine, Penn Presbyterian Medical Center, 39th and Market Street, Philadelphia, PA 19104, Tel.: (215) 662-9182, Fax: (215) 243-4608, or e-mail: timothy.clark@uphs.upenn.edu.

Abstract

We examined flow characteristics and recirculation of a novel dialysis catheter with helically contoured lumens, which optimize the vectors of blood entering and leaving the device. Computational flow dynamics were used to measure shear stress, residence time (RT), Platelet Lysis Index (PLI), and recirculation of the study catheter, termed the VectorFlow catheter, compared with the Palindrome catheter. Bench and animal models were used to measure recirculation compared with other dialysis catheter designs. The VectorFlow catheter was associated with an 18% reduction in mean shear stress compared with the Palindrome catheter, at 13.6 and 16.6 Pa, respectively. Low PLI was seen with the VectorFlow (PLI = 0.019) and Palindrome (PLI = 0.015) catheters. The VectorFlow catheter was associated with a % RT >0.030  seconds of 1.2%, compared to 0.9% for the Palindrome. Calculated recirculation of the VectorFlow, Palindrome, and step-tip catheter designs in reversed position were 1.2 × 10−4%, 0.039%, and 13.6%, respectively. In vitro, the VectorFlow catheter had no detectable recirculation (0%) compared to 7.3–9.5% with the Palindrome at flow rates of 400–600  ml/minute. In vivo, the VectorFlow catheter had no detectable recirculation, compared to 6.7–12% for the Palindrome. The VectorFlow catheter was associated with an absence of detectable recirculation with favorable flow dynamics.

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