1. Knitted nitinol represents a new generation of constrictive external vein graft meshes 
Peter Zilla, MD, PhD, Loven Moodley, FCS(SA), Michael F. Wolf, BS, Deon Bezuidenhout, PhD, Mazin S. Sirry, MSc, Nasser Rafiee, BS, Wilhelm Lichtenberg, FCS(SA), Melanie Black, MSc, Thomas Franz, PhD 
Journal of Vascular Surgery 
Volume 54, Issue 5, Pages (November 2011)
DOI: /j.jvs
Copyright © 2011 Society for Vascular Surgery Terms and Conditions

2. Fig 1
Macrophotograph compares (left) a braided mesh and (right) a knitted mesh. The knitting pattern is uneven with large loops alternating with narrow ones.
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2011 Society for Vascular Surgery Terms and Conditions

3. Fig 2
Tensile force and radial contraction (narrowing) are shown vs longitudinal strain (stretch) of the braided and knitted mesh samples. The error bars show the standard deviation.
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2011 Society for Vascular Surgery Terms and Conditions

4. Fig 3
Compression force vs compression displacement is shown for braided and knitted meshes. The error bars show the standard deviation.
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2011 Society for Vascular Surgery Terms and Conditions

5. Fig 4
Anastomotic region of a control graft and a mesh-supported vein graft are shown at implantation. Although the control graft shows the typical size mismatch of the femoral model between the vein graft and the target artery, the mesh graft shows that a vein constriction was chosen that reduced the graft diameter even mildly below that of the artery. One can clearly see that the contractility of the vein allows such a distinct diameter constriction without wall folding.
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2011 Society for Vascular Surgery Terms and Conditions

6. Fig 5
The cross-sectional discrepancies between vein grafts (blue interrupted lines) and their target arteries (red circles) at the time of implantation and at explant are shown in this illustration. In the control group, the only mildly increased cross-sectional quotients (Qc from 0.20 to 0.18) betray the degree of intimal hyperplasia, because a 25% subintimal dilatation was compensated by neointimal tissue. In the controls sprayed with fibrin sealant (FS), the typically stronger wall fibrosis led to a 26.1% decrease in subintimal diameter, exaggerated by distinct neointimal proliferation (Qc from 0.16 to 0.30). In both mesh groups, an almost perfect size match was obtained after 6 months of implantation resulting from mild dilatation of the initially slightly overconstricted meshes.
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2011 Society for Vascular Surgery Terms and Conditions

7. Fig 6
Macroscopic appearance of vein grafts after 6 months of implantation. Top, The control grafts showed a thickened, whitish vessel wall and a distinctly larger diameter. Bottom, The mesh-supported grafts had a delicate, translucent wall, with the mesh visible throughout.
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2011 Society for Vascular Surgery Terms and Conditions

8. Fig 7
Histologic cross-sections of midgrafts at identical magnification (stitched at original magnification ×40; Azan stain) show the marked diameter difference between (top) control grafts and (bottom) mesh-supported grafts. The methacrylate-embedded, tungsten-cut section of the mesh graft shows the nitinol wires demarcating the delicate vessel wall from the surrounding tissue. A distinct layer of diffuse neointimal tissue narrows the lumen of the control grafts by almost a millimeter (see length bar).
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2011 Society for Vascular Surgery Terms and Conditions

9. Fig 8
Comparison of (top) intimal thickness and (bottom) intimal area between the groups. Nonmesh-supported control grafts showed an 8.5-times higher intimal thickness and 14.3-times higher intimal area than mesh grafts. In both groups, spraying with fibrin sealant (FS), as a means to firmly attach the mesh to the vein wall, led to more pronounced neointimal proliferation.
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2011 Society for Vascular Surgery Terms and Conditions

10. Fig 9
Double-stain (CD31, α-actin, and 4',6-diamidino-2-phenylindole [DAPI]) of methacrylate-embedded and tungsten-cut mesh graft. A monolayer of CD31+ endothelial cells lies loosely on the autofluorescing, yellow internal elastic lamella that separates it from the media. The strongly α-actin+ media consists of densely compacted smooth muscle cells with elastin fibers interspersed. The longitudinal orientation of the DAPI+ nuclei underlines the circumferential orientation of the smooth muscle cells of the cross-section. The insert shows a well-preserved wire loop of the nitinol mesh on a saw-ground section. Although the hematoxylin and eosin stains of such sections do not allow the color distinction between structures, one can still recognize the thin intima, the well-developed, aligned media, and the pinker, collagen-rich adventitia underneath the nitinol struts compared with the looser outside tissue.
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2011 Society for Vascular Surgery Terms and Conditions

11. Fig 10
Faxitron picture of (top) an occluded graft and (bottom) a patent graft. The clip indicates the proximal side. In the patent graft, wire breakages are visible in the proximal third, closer to the area affected by hip bending. Breakages are exclusively found at the interlocking angles of the wire loops of the knitted mesh structure. Breakages are absent in all occluded grafts, which indicates that graft occlusions occur early and that hemodynamic strain also contributes to the tiring of struts.
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2011 Society for Vascular Surgery Terms and Conditions