Neointimal hyperplasia after stent placement across size-discrepant vessels in an animal study.
OBJECTIVE
To examine differences in neointimal hyperplasia (NIH) after placing a self-expanding (SE) stent across size-discrepant vessels.


METHODS
The subjects were 6 beagles, and the target vessels were the abdominal aorta and the external iliac artery (EIA). A nitinol SE stent was placed which was normal-sized in the aorta and oversized in the EIA. Angiography and intravascular ultrasound (IVUS) were performed immediately and after 1 and 3 months; histopathologic examinations were then performed. Furthermore, the chronic outward force (COF) on the same type of stent was investigated in vitro.


RESULTS
On IVUS, thickened intima was seen on the EIA at 1 month (5.1 ± 4.2 mm(2)) and at 3 months (7.8 ± 2.5 mm(2)). For the aorta, thickening of the intima was negligible at any time. Histopathologically, the percentage of the vessel obliterated by NIH was significantly greater on the iliac side than on the aortic side (33.2 ± 10.4 vs. 13.4 ± 4.4 %). The COF exerted when stent diameter reached that of the EIA and the aorta was 0.73 and 0.17 N/mm(2), respectively.


CONCLUSIONS
When a non-tapered stent is placed in vessels with a large discrepancy in diameter, attention must be paid to increased NIH in the oversized side.
Department of Radiology, Japan Community Health care Organization Osaka Hospital, 4-2-78 Fukushima, Fukushima-ku, Osaka, 553-0003, Japan.
Hisayuki
H
Cho
Mineyoshi
M
Nango
Yukimasa
Y
Sakai
Etsuji
E
Sohgawa
Ken
K
Kageyama
Shinichi
S
Hamamoto
Toshiaki
T
Kitayama
Akira
A
Yamamoto
Yukio
Y
Miki
D000818:Animals; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects*; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D005500:Follow-Up Studies; D006965:Hyperplasia / Q000209:etiology; D007083:Iliac Artery / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D058426:Neointima / Q000000981:diagnostic imaging / Q000473:pathology*; D011859:Radiography; D015607:Stents / Q000009:adverse effects*; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000473:pathology*; D018084:Ultrasonography, Interventional / Q000379:methods