Development of an in vitro system to assess stent-induced smooth muscle cell proliferation: a feasibility study.

PURPOSE: To develop an in vitro system capable of rapidly evaluating how specific stent structures may stimulate smooth muscle cell proliferation in living isolated porcine carotid arteries. MATERIALS AND METHODS: A vascular bioreactor system was developed that housed a native porcine carotid artery under physiologic pulsatile flow and pressure conditions. The bioreactor system was designed to enable vascular stent deployment into a test section of vessel that was kept alive for 1 week. The three stents tested were a Wallstent, a Cordis Smart stent, and a balloon-expandable NIR Royal stent in three different arteries. RESULTS: Stents were successfully deployed in the native porcine arteries within the bioreactor system. Organ bath studies demonstrated that the explanted arteries maintained 40% of their contractility. Immunohistochemical staining of the stented vessel demonstrated that smooth muscle cell proliferation was related to stent design and strut location. Specifically, smooth muscle proliferation was shown to increase with stiffer (less compliant) vascular stents and in the edge region of the stents. CONCLUSIONS: The system could potentially be used to assess the influence of stent design and smooth muscle cell proliferation.