Irradiation inhibits vascular anastomotic stenosis in a canine model.
OBJECTIVE
The graft patency rate after coronary artery bypass grafting (CABG) correlates with anastomotic stenosis. Intracoronary radiation therapy is effective for preventing restenosis after percutaneous coronary intervention (PCI). We postulated that intracoronary radiation therapy could prevent anastomotic stenosis and tested this hypothesis in an animal model.


METHODS
Femoral arteries and veins of beagle dogs were harvested, and composite arterioarterial and arteriovenous grafts were prepared. After external irradiation of the anastomotic sites, these composite grafts were transplanted into femoral arteries. Histomorphometric and immunohistological analyses of the anastomotic sites were performed. The study groups consisted of controls and animals exposed to 10 Gy, 20 Gy, and 30 Gy (n = 5, in each group).


RESULTS
In the artery graft model, the ratio of negative remodeling was significantly increased in all groups exposed to >or=10 Gy. The ratio of neointimal hyperplasia was significantly decreased in all groups exposed to >or=10 Gy. Cell density of anti-alpha-actin antibody-positive cells and anti-proliferating cell nuclear antigen (PCNA) antibody-positive cells was highest in the adventitial layer, and the density decreased as the dosage increased. Experimental results were almost the same in the vein graft models as in the artery graft models. With double immunohistostaining, the anti-PCNA antibody-positive cells expressed alpha-actin.


CONCLUSIONS
Irradiation can inhibit anastomotic stenosis in a canine model. Adventitia is a factor in the creation of stenosis, and irradiation appears to target the adventitia. We speculate that there might be a possible role for intracoronary irradiation in the future to prevent anastomotic stenosis.
Saito
Takeshi
T
Department of Cardiovascular Surgery, Sendai Open Hospital, Tsurugaya 5-22-1, Miyagino-ku, Sendai, 983-0824, Japan. stakeshi@mail.tains.tohoku.ac.jp
Iguchi
Atsushi
A
Tabayashi
Koichi
K
D000199:Actins / Q000378:metabolism; D000818:Animals; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects*; D049109:Cell Proliferation / Q000528:radiation effects; D003251:Constriction, Pathologic; D004285:Dogs; D005263:Femoral Artery / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects* / Q000601:surgery; D005268:Femoral Vein / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects* / Q000601:surgery; D006083:Graft Occlusion, Vascular / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D006965:Hyperplasia; D023421:Models, Animal; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011829:Radiation Dosage; D017539:Tunica Intima / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects* / Q000601:surgery
D000199:Actins; D018809:Proliferating Cell Nuclear Antigen