Article Figures & Data
Figures
- Fig 1.
Stent surface reconstructions show the architecture of the OCD NF stent (top, A) and of the CCD Enterprise stent (top, C). Four platinum markers for improved visualization under fluoroscopy are attached at the ends of the stents. “Down the barrel” views of stent and wall reconstructions show the fully deployed NF (A) and Enterprise (C) stents inside PTFE tubes. Slight strut vertex misalignment is present along the NF stent (double arrows, A). Due to larger size markers, some struts are prolapsed into the lumen (arrows, C). Velocity (centimeter/second) contour plots on cross-sectional planes at peak systole are superimposed on the corresponding 3D reconstructions for NF (B) and Enterprise (D) stents. The struts and walls are shown in 3D projections (gray). The plane in B illustrates the flow near 8 vertices where strut vertex prolapse (arrow) and strut vertex misalignment (double arrows) are present. Low-speed flow under the prolapse and misalignment can be seen. Due to closed cell design, no strut prolapse is present with the Enterprise stent (D) except at the markers.
- Fig 2.
Overall WSS (dyne/square centimeter) distributions at peak systole for NF (A) and Enterprise (B) along the tube show that the peak WSS is generated at the luminal face of the struts and markers. Increased WSS is seen at the center of the cells of the NF stent (A). The WSS pattern in the Enterprise case is relatively uniform along the tube (B). Contour plots of z-component (longitudinal flow direction) WSS are clipped to indicate locations of negative WSS for the NF (C) and Enterprise (D) stents. Negative WSS is present at some strut vertices (arrow, C) and the markers. For the Enterprise stent, negative WSS is present distal to the markers (arrows, D). Also, the struts connected to the markers prolapse into the lumen (double arrows, D).
- Fig 3.
WSS (dyne/square centimeter) distributions at peak systole for a regularly apposed cell for NF (A) and for Enterprise (C) stents. Low WSS regions develop upstream and/or downstream to strut vertices (arrows, A and C) and markers (single arrows, B and D). The location where the markers are connected to the struts is also subjected to low-velocity flow (double arrows, B and D). The prolapsed strut vertices (double arrows, D) permit low-speed flow between the strut and the wall, creating a low WSS shadow under the raised strut.
- Fig 4.
Plot of WSS along a longitudinal line across a regularly apposed cell. The NF cell is longer than the Enterprise cell by about a factor of 2. High WSS is present on the luminal faces of the struts. WSS is low proximal and distal to the struts, whereas inside the cells, the WSS increases toward the middle. The average WSS for the NF stent is approximately 57 dyne/cm2, whereas for the Enterprise stent, it is approximately 46 dyne/cm2.
- Fig 5.
Plots of near-wall (10 μm) velocity vectors (centimeter/second) around imaging markers for the NF (A) and for the Enterprise (B) stent. Due to the size of the NF stent markers (∼180-μm height and 400-μm width), the flow is disturbed (A) in these regions. A similar perturbation occurs near the Enterprise markers (∼250-μm height and 350-μm width). The flared ends of the Enterprise stent keep the struts here away from the wall and permit near-wall flow under the strut (B), which does not occur with the NF (A).
Tables
Stent dimensions after deployment*
Sent Inlet (inner diameter) Outlet (inner diameter) Cross-Sectional Area Length Major Axis Minor Axis Major Axis Minor Axis Neuroform 4.0 mm 3.5 mm 3.8 mm 3.8 mm 11.11 mm2 3.0 cm Enterprise 4.0 mm 3.6 mm 4.0 mm 3.6 mm 11.21 mm2 3.0 cm * Note deviations from symmetry and longitudinal nonuniformity.
