External beam irradiation in angioplasted arteries of hypercholesterolemic rabbits. The dose and time effect.
OBJECTIVE
To study the dose and time effect of external beam irradiation on the morphometry of both angioplasted and nonangioplasted arteries in a hypercholesterolemic rabbit model.


METHODS
Eight groups of rabbit femoral arteries were studied: arteries (a) with no intervention, (b) irradiated with a 12-Gy 6 MV X-ray dose, (c) with a 18-Gy, (d) treated with balloon angioplasty, (e) dosed with 12-Gy half an hour post-angioplasty, (f) dosed with 18-Gy half an hour post-angioplasty, (g) dosed with 12-Gy 48 h post angioplasty, (g) dosed with 18-Gy 48 h post angioplasty.


RESULTS
External irradiation at either 12 or 18 Gy was not found to change vessel morphometry in noninjured arteries. The 12-Gy dose given soon after angioplasty further increased percentage stenosis (63% on the average), despite the preservation of the lumen cross-sectional area. Positive remodeling was not observed in arteries given 18-Gy half an hour post angioplasty to counterbalance the increased neointimal formation. Therefore, this treatment resulted in a drastic reduction in lumen area and in enhancement of percentage stenosis (84% on the average). On the contrary, the delayed irradiation of the angioplasted arteries at either 12 or 18 Gy was not found to influence any of the studied morphometric parameters 5 weeks after angioplasty.


CONCLUSIONS
Uniform external beam irradiation up to 18 Gy was well tolerated by intact femoral arteries. Prompt 12- or 18-Gy irradiations accentuated percentage stenosis. However the lumen cross-sectional area was preserved only at the lower dose point. Delayed irradiation at any dose did not influence the restenosis process.
Kalef-Ezra
J
J
Department of Medical Physics, Medical School, University of Ioannina, 451-10, Ioannina, Greece. jkalef@cc.uoi.gr
Michalis
L K
LK
Malamou-Mitsi
V
V
Tsekeris
P
P
Katsouras
C
C
Boziari
A
A
Toumpoulis
I
I
Bozios
G
G
Charchanti
A
A
Sideris
D A
DA
D000800:Angioplasty, Balloon; D000818:Animals; D001157:Arterial Occlusive Diseases / Q000209:etiology; D004195:Disease Models, Animal; D004307:Dose-Response Relationship, Radiation; D005263:Femoral Artery / Q000528:radiation effects* / Q000601:surgery*; D006937:Hypercholesterolemia / Q000150:complications / Q000628:therapy*; D008297:Male; D011183:Postoperative Complications / Q000209:etiology; D011817:Rabbits; D011879:Radiotherapy Dosage; D013997:Time Factors; D016896:Treatment Outcome; D017539:Tunica Intima / Q000528:radiation effects / Q000601:surgery; D017540:Tunica Media / Q000528:radiation effects / Q000601:surgery; D014964:X-Ray Therapy