Prevention of intimal hyperplasia; Initial results with low-dose beta-radiation applied by an external vascular polymer wrap.
OBJECTIVE
Endovascular brachytherapy, delivered by a variety of catheter-based devices, has proven clinically effective for the inhibition of neointimal hyperplasia (NIH) after coronary and peripheral balloon/stent angioplasty. No platform, however, has been developed to deliver low-dose radiation in concert with vascular surgical operations. The purpose of this study was to evaluate the vascular response following balloon injury to the rabbit carotid artery, with and without topical low-dose 45Ca, applied by an external vascular "wrap".


METHODS
Twelve rabbit carotid arteries were subjected to balloon injury by embolectomy catheter. The common carotid artery was then "wrapped" circumferentially with a biostable polyurethane membrane (Nanoskin Secant Medical, Perkasie, PA), without radiation (n = 6), or with radiation (n = 6) (45Ca approximately 50 microCi). The animals were sacrificed at 4 weeks for histologic assessment of the treated vessels.


RESULTS
The 45Ca wrap inhibited NIH evidenced by trends towards reduction of intimal area (0.46 +/- 0.19 control carotid vs. 0.35 +/- 0.15 (45)Ca-treated carotid arteries; P = .11), maximal intimal thickness (0.21 +/- 0.08 vs. 0.16 +/- 0.05; P = .12), average intimal thickness (0.12 +/- 0.06 vs. 0.08 +/- 0.03; P = .08), marginally significant reduction in percent area stenosis (33 +/- 15% vs. 21 +/- 9%; P = .06) and marked neointima suppression in areas immediately adjacent to 45Ca wrap remnants. Medial necrosis (P = .003), however, was observed slightly more for 45Ca-treated carotid arteries versus control arteries.


CONCLUSIONS
Low-dose 45Ca beta-radiation labeled onto a polyurethane membrane appears to inhibit NIH in an animal model.
Levitt
Adam B
AB
Department of Vascular Surgery, Atlanta Medical Center, 315 Boulevard NE, Suite 412, Atlanta, GA 30312, USA.
Robinson
Keith
K
Wellons
Eric
E
Lai
Kin Man
KM
Cui
Jian Hua
JH
Gannon
Brian
B
Rosenthal
David
D
D000800:Angioplasty, Balloon / Q000009:adverse effects; D000818:Animals; D001157:Arterial Occlusive Diseases / Q000517:prevention & control; D001610:Beta Particles / Q000627:therapeutic use*; D001707:Biopsy, Needle; D002339:Carotid Arteries / Q000473:pathology* / Q000528:radiation effects*; D004195:Disease Models, Animal; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006965:Hyperplasia / Q000517:prevention & control; D007150:Immunohistochemistry; D008297:Male; D011817:Rabbits; D011829:Radiation Dosage; D012016:Reference Values; D012307:Risk Factors; D012680:Sensitivity and Specificity; D017539:Tunica Intima / Q000473:pathology*