Topical application of beta-radiation to reduce intimal hyperplasia after carotid artery balloon injury in rabbit. A possible application for brachytherapy in vascular surgery.
OBJECTIVE
Endovascular brachytherapy for the prevention of intimal hyperplasia (IH) and restenosis after balloon/stent angioplasty has proven effective both in animal preparations and clinical trials. A variety of beta-emitting isotopes and catheter-based devices have been developed for the delivery of low-dose radiation in clinical coronary and peripheral trials. No platform, however, has yet been developed for brachytherapy in concert with vascular surgical operations. The purpose of this study was to evaluate the vascular histopathologic response following balloon injury to rabbit carotid arteries with and without topically applied low-dose beta-radiation.


METHODS
The beta-emitting isotope strontium-90 (Sr-90) was conjugated onto the matrix of polypropylene (PLYP) mesh. Rabbit carotid arteries were balloon-injured with a #2 embolectomy catheter. Six carotid arteries were wrapped with nonradioactive PLYP mesh (controls) and Sr-90 ( approximately 90 microCi) PLYP mesh in order to deliver low-dose radiation to the vessel wall from the external (adventitial) surface. Tissue was harvested at 6 weeks and processed for histologic examination.


RESULTS
There was consistent blockade of fibrocellular neointima formation with virtually no neointima present in all treated segments, compared to moderate neointima formation in controls. Medial thinning and smooth muscle cell (SMC) necrosis were also associated with topical brachytherapy.


CONCLUSIONS
beta-Radiation applied by an externally wrapped PLYP mesh labeled with Sr-90 markedly suppressed neointima formation in an animal vascular surgical injury model. Further studies, however, are necessary to determine a suitable isotope and dosage for clinical application.
Rosenthal
David
D
Department of Vascular Surgery, Atlanta Medical Center, 315 Boulevard NE, Suite 412, Atlanta, GA 30312, USA. docro@mindspring.com
Stevens
Scott L
SL
Skillern
C S
CS
Wellons
Eric D
ED
Robinson
Keith
K
Matsuura
John H
JH
Gannon
Brian J
BJ
D000287:Administration, Topical; D000800:Angioplasty, Balloon / Q000009:adverse effects*; D000818:Animals; D001610:Beta Particles / Q000627:therapeutic use*; D001918:Brachytherapy; D002341:Carotid Artery Thrombosis / Q000209:etiology / Q000401:mortality / Q000532:radiotherapy; D017536:Carotid Artery, Common / Q000473:pathology* / Q000528:radiation effects*; D004195:Disease Models, Animal; D004307:Dose-Response Relationship, Radiation; D006965:Hyperplasia / Q000209:etiology* / Q000401:mortality / Q000532:radiotherapy*; D007249:Inflammation / Q000209:etiology / Q000532:radiotherapy; D009336:Necrosis; D011183:Postoperative Complications / Q000209:etiology / Q000401:mortality / Q000532:radiotherapy; D011817:Rabbits; D013326:Strontium Radioisotopes / Q000008:administration & dosage; D016019:Survival Analysis; D016896:Treatment Outcome; D017539:Tunica Intima / Q000293:injuries* / Q000528:radiation effects*; D014656:Vascular Surgical Procedures / Q000009:adverse effects*
D013326:Strontium Radioisotopes