BB-EVAR Flow Studies
In the 2 pictures on the left the AneuFill procedure is demonstrated with one “Full Dogbone” balloon with a large proximal “bulb” and a small distal bulb filled with red dye, and a Half Dogbone balloon with only a small distal bulb filled with blue dye. The “skirt” is mounted on the red Full Dogbone balloon and positioned just under the large proximal bulb, such that the blue Half Dogbone balloon forms a large 8-shaped opening under the proximal balloon, and thus a nice gradual change in diameter which is needed is create a blood flow without pertubations.
To confirm that this configuration is the most optimal from a flow perspective, University Twente was asked to conduct a series of flow studies using a custom-made windkessel setup with pulsatile flow (60 beats/min, 90-120mmHg, mean flow 1.6L/min, range 0,0-5,0 L/min). A blood mimicking fluid (BMF) based on water, glycerol and sodium iodide (47.4%, 36.9%, 15.7%) with a viscosity of 4.3 cP and a refractive index of 1.4, equal to PDMS, was used during the flow experiments.
Small fluorescent particles of 1-20 μm (density 1190 kg/m³) were added. A continuous wave laser was used to create a parallel beam that illuminated a streak of fluid. Perpendicular to the laser beam, a high speed camera (1000-3000 frames/second) captured the fluorescent signal emitted by the particles. An optical filter was mounted at the camera lens to block reflections other than those of the particles. A window of approximately 30x30 mm was captured by the camera with a resolution of 1024x1024 pixels.
The resulting flow pattern is a near perfect laminar flow without pertubations, as is witnessed by the systolic and diastolic flow patters shown in the pictures below: