In Vitro Measurement and Calculation of Drag Force on Aortic Stentgraft in a Compliant Arterial Wall Model

by Rontala Raghunathan, Ravi Shankar

Abstract (Summary)
Interventional treatment of aortic aneurysms using endovascular stent grafting is a minimally invasive technique. Following device implantation, continuous hemodynamic forces are exerted (drag force) on the stentgraft. When the drag force exceeds the fixation force, complications like stentgraft migration, endoleaks and stentgraft failure occur. In such a scenario the device becomes unstable, causing concern over the long-term durability of endovascular repairs. The objective of this study is: 1) to measure the drag force on a stentgraft in an in vitro experiment; 2) to calculate the drag force using blood flow–compliant arterial wall interaction model and compare it with the measured values on the stentgraft for the in vitro experiment; 3) to calculate drag force on the stentgraft using physiological flow conditions. Experimental data for a stentgraft within a silicon tubing, representing a compliant artery, shows a peak drag force of 2.79 N whereas the calculation predicts a peak drag force of 2.57 N; thus a percentage difference of 7.8 % is observed. When physiological flow and pressure pulse are used for the blood flow-compliant arterial wall computations, a peak drag force of 0.59 N is obtained for the same stentgraft that was used in the experiment. Compared to previous studies of constant iliac limb diameter for the abdominal aortic aneurysm stentgraft, the proposed model, where the distal end is not fixed to the arterial wall and is approximately half of its proximal diameter, the drag force is reduced by 47 % for the in vitro experiment and 81 % for the physiologic flow conditions. These forces can be used as design guidelines for the fixation force needed at the proximal end of the stentgraft under physiological pulsatile flow.
Bibliographical Information:


School:University of Cincinnati

School Location:USA - Ohio

Source Type:Master's Thesis

Keywords:abdominal aortic aneursym drag force stentgraft


Date of Publication:01/01/2006

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