Post-stenting intravascular brachytherapy trials on hypercholesterolemic rabbits using 32P liquid sources: implications for prevention of in-stent restenosis.
OBJECTIVE
Liquid sources of radiation delivered in angioplasty balloons may be a convenient self-centering device used for prevention of in-stent restenosis. To test the effectiveness of this method an intravascular brachytherapy study was performed using 32P liquid sources in an animal model.


METHODS
The radial dose distribution around angioplasty balloons filled with solutions of Na 2H 32PO 4 was calibrated by thermoluminescence dosimetry. The animal experiments were performed in rabbits with induced hypercholesterolemia. The balloons containing 32P were introduced into iliac arteries immediately after stent implantation. Estimated 7-49 Gy doses required 30-100 min irradiations. Radiation effects were evaluated by comparing the thickness of various components of the artery wall.


RESULTS
Doses of 7, 12, 16 or 49 Gy on the internal artery surface required 30-100 min of irradiation. The dose of 49 Gy at "zero" distance corresponding to 16 Gy at 1.0 mm from the balloon surface reduced hypertrophy in every layer of the arterial wall: in the intima the cross-sectional areas were 0.13 versus 0.91 mm 2, in the media were 0.5 versus 0.46 mm 2 and in the adventitia were 0.04 versus 0.3 mm 2 (p <0.05). A dose of 7 Gy at the balloon surface produced adverse irradiation effects: the intimal area of the artery was 2.087 versus 0.857 mm 2, the medial area was 0.59 versus 0.282 mm 2 and the adventitial area was 0.033 versus 0.209 mm 2 in treated and control arteries, respectively.


CONCLUSIONS
Application of a 49 Gy irradiation dose to the internal arterial surface effectively prevented in-stent restenosis.
Wilczek
Krzysztof
K
III rd Department of Cardiology, Silesian School of Medicine, 2 Szpitalna str., 41-800 Zabrze, Poland. scchs@infomed.slam.katowice.pl
Walichiewicz
Piotr
P
Petelenz
Barbara
B
Jache
Wojciech
W
Jochem
Jerzy
J
Tomasik
Andrzej
A
Bilski
Pawel
P
Snietura
Miroslaw
M
Wodniecki
Jan
J
D000792:Angiography; D000800:Angioplasty, Balloon / Q000379:methods*; D000818:Animals; D001918:Brachytherapy / Q000379:methods*; D006083:Graft Occlusion, Vascular / Q000517:prevention & control* / Q000532:radiotherapy*; D006937:Hypercholesterolemia / Q000139:chemically induced*; D007083:Iliac Artery / Q000000981:diagnostic imaging / Q000601:surgery*; D066298:In Vitro Techniques; D019047:Phantoms, Imaging; D010761:Phosphorus Radioisotopes / Q000627:therapeutic use*; D011817:Rabbits; D011829:Radiation Dosage; D015607:Stents / Q000009:adverse effects*; D013819:Thermoluminescent Dosimetry
D010761:Phosphorus Radioisotopes