Placement of self-expanding stents with different diameters in the porcine venous system: an experimental study.
OBJECTIVE
To study the vascular histologic response after placement of oversized self-expanding stents in the porcine venous system.


METHODS
Twenty-four oversized stents (range of oversizing, 119.5%-216.0%) were deployed in jugular and iliac veins of six miniature pigs divided into two groups with follow-up times of 1 and 3 months. Necropsy with histologic evaluation of each stent was performed, and the areas of neointimal proliferation were calculated with slices obtained during follow-up from each stent at 5 mm from the proximal and distal edges and at the midpoint.


RESULTS
Neointimal proliferation was observed inside the stent lumen. All segments were patent in both groups. However, one jugular stent in the 1-month group and one jugular stent in the 3-month group had migrated at follow-up and were excluded from analysis. There were no significant differences in neointimal growth between the stent edges (proximal and distal) and middle segments of the stents at follow-up in the 1-month group (P = .970) or in the 3-month group (P = .694). Simple linear regression showed strong positive correlation between stent oversizing and neointimal proliferation in the 1-month model (r = 0.791; P < .001) and the 3-month model (r = 0.718; P < .001). There were no significant differences between 1-month and 3-month groups in the degree of neointimal proliferation (P = .072). Also, branched vessels showed no neointimal proliferation at their intersections with the stent-implanted segments.


CONCLUSIONS
Stent oversizing showed a strong positive correlation with neointimal growth in each follow-up model in this study.
Yamaguchi
Masato
M
Department of Radiology, Kobe Red Cross Hospital, Kobe, Japan. m-yamaguchi@hemc.jp
Sugimoto
Koji
K
Zamora
Carlos A
CA
Takahashi
Takuya
T
Hayashi
Yoshitake
Y
Sugimura
Kazuro
K
D015901:Angiography, Digital Subtraction; D000818:Animals; D049109:Cell Proliferation; D004867:Equipment Design; D007084:Iliac Vein / Q000473:pathology*; D007601:Jugular Veins / Q000000981:diagnostic imaging / Q000473:pathology*; D016014:Linear Models; D008297:Male; D015607:Stents / Q000009:adverse effects*; D013552:Swine; D013556:Swine, Miniature; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000473:pathology*; D018084:Ultrasonography, Interventional