Preclinical Evaluation of the Temporary Drug-Coated Spur Stent System in Porcine Peripheral Arteries

Abstract

Background: Drug penetration into the deeper arterial wall of heavily calcified lesions is one of the limitations of drug-coated balloons and drug-eluting stents in vascular interventions. The Temporary Spur Stent (TSS) system is characterized by a self-expanding nitinol stent that is uniformly covered in radialspikes, which, when coated, should allow a deeper penetration and longer retention of the drug into the diseased artery walls by penetrating through the calcified plaques. Materials and Methods and Results: Uncoated TSS and paclitaxel (PTX)-coated TSS systems have been deployed in porcine peripheral arteries. Four weeks after the deployment of uncoated TSS systems, no adverse vascular remodeling or neointimal formation in the treated vessel segments were noticed. PTX-coated TSS systems transferred 9%±7% of the drug that was on the device to the targeted vessel area (196±163 ng PTX/mg arterial tissue) and the addition of the fluorescent dye Nile red to the coating showed that the spikes promote the transfer of the coating to the deeper layers of the vessel wall. The PTX-coated TSS systems showed a significant reduction in neointimal proliferation compared to the uncoated TSS systems: quantitative angiography showed a vessel diameter stenosis of 37.2%±11.0% and 16.4%±8.8% 4 weeks after the treatment with uncoated and PTX-coated TSS systems, respectively. Conclusion: The treatment with the TSS system was well tolerated and the spikesfacilitate the transfer of the coating into deeper layers of the vessel wall. Moreover, the PTX-coated TSS systems effectively inhibit neointimal proliferation.