VPB0023 - Inhibition of restenosis after orbital atherectomy of severely calcified artery using combined electrohydraulic low level shock wave therapy and 125I- mediated gamma-intravascular brachytherapy

Background: Three mechanisms are responsible for the development of restenosis: elastic recoil, intimal hyperplasia and late vascular constriction, all grouped under the catch phrase “negative remodeling”. Neointimal hyperplasia is usually defined in an artery as thickening of the intimal layer after an injury such as angioplasty, mechanical atherectomy or surgical repair. The orbital atherectomy method that are currently in use, cause to inflammation and subsequent restenosis.

Aims: The aim of this study was to evaluate the effect of combined electrohydraulic shock wave therapy and 125I- mediated gamma-intravascular brachytherapy on inflammation and restenosis reduction after mechanical atherectomy of the animal model of severely calcified common carotid artery, wherein diagnostic ultrasound is adjuncted with atherectomy and combination therapy system, with a goal of increased safety.

Methods: Briefly, New Zealand white rabbits were submitted to common carotid artery severely calcified atherosclerotic stenosis. Then treatment group underwent B- mode ultrasound- guided orbital atherectomy followed by combined shock wave (V= 20 Kv, F= 0.5 Hz, Impulses= 120) therapy and gamma-intravascular brachytherapy (125I-, 23 Gy).

Results: Results from histopathology and ultrasonography showed a significant reduction in the mean value for macrophages and smooth muscle hyperplasia cells density after orbital atherectomy in the treated group compared with the other groups (p < 0.05).

Conclusion(s): Anti- inflammatory effect of shock waves accompanied by apoptotic effect of gamma- mediated brachytherapy, can cause to reduce the inflammation and smooth muscle hyperplasia cells in the intimal layer. These findings provide the basis for developing of combined low level electrohydraulic focused shock wave therapy and 125I- mediated gamma-intravascular brachytherapy for a successful clinical application in the treatment of restenosis after orbital atherectomy.