[Morphological and histological studies of in-stent restenosis in seven types of stents implanted in porcine coronary arteries].
OBJECTIVE
Differences in the mechanism of restenosis after stenting between coil and tubular stents were examined in porcine coronary arteries using histological and immunohistochemical methods.


METHODS
Twenty-four pigs underwent balloon-induced injury in the left anterior descending coronary artery. Two weeks later, seven different stents clinically available in Japan (Coil stents: GR I, GR II, Wiktor, Cordis; Tubular stents: gfx, Multilink, Palmaz-Schatz) were implanted in the injured site. Four weeks after the stent implantation, the pigs were sacrificed for histological examination and for morphometrical analysis of the lumen, neointima, media and adventitia. Immunohistochemical studies using anti-proliferating cell nuclear antigen (PCNA), anti-alpha-smooth muscle actin and anti-macrophage antibody were also performed.


RESULTS
The coil stents formed eccentric, and the tubular stents formed concentric neointimal proliferation. Although there was no difference in the area of neointima between the stents, the area of lumen in the tubular stents was bigger than that in the coil stents (p < 0.01), because the vascular area was bigger in the tubular stents (p < 0.05). Immunohistochemical examination found many PCNA-positive cells in the proliferated neointima, especially in the area around the stent strut. Many of these cells around the stent strut were positively stained by anti-macrophage antibody. Other cells positively stained for PCNA were confirmed as smooth muscle cells.


CONCLUSIONS
Tubular stents maintained a wider lumen than coil stents, because negative remodeling after stenting was less in the tubular stents. Implantation of stents with less negative remodeling is very important to prevent restenosis after stenting.
Yorozuya
M
M
Third Department of Internal Medicine, Showa University School of Medicine, Hatanodai 1-5-8, Shinagawa-ku, Tokyo 142-8666.
Takeyama
Y
Y
Iso
Y
Y
Shibata
M
M
Nakatani
M
M
Koba
S
S
Suzuki
H
H
Murakami
M
M
Katagiri
T
T
D000199:Actins / Q000032:analysis; D015906:Angioplasty, Balloon, Coronary; D000818:Animals; D023903:Coronary Restenosis / Q000473:pathology*; D003331:Coronary Vessels / Q000473:pathology*; D007150:Immunohistochemistry; D008264:Macrophages / Q000276:immunology; D008297:Male; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D015607:Stents; D013552:Swine
D000199:Actins; D018809:Proliferating Cell Nuclear Antigen