Browsing by Subject "stent"

The purpose of this research is to introduce a novel device to intracranial flow-diverting stent delivery in endovascular neurosurgery to limit, and potentially eliminate, issues associated with instability upon stent delivery. Precisely, the goal of the device is to initiate a friction force between the delivery system and the arterial vessel wall to both assure immediate stent deployment and prevent axial advancement of the stent-anchoring wire. A prototype was constructed and its effectiveness of applying a friction force to a vessel wall was tested ex vivo using an LRX Plus Materials Testing Machine. Afterwards, the experimental performance of the device was compared to that of a finite element simulated model. The device demonstrated the ability to apply a friction force to the vessel wall to meet its objective. However, experimental values were consistently greater than those gathered from the simulation. Since the force prescribed by the device is minimal, future work includes increasing the force capabilities of the device and defining force requirements. Upon further development and testing, this device can be implemented into endovascular neurosurgery to improve occlusion rates of intracranial aneurysms and reduce patient risk during these operations.

Covering the metal surface of blood-contacting cardiovascular implants (stents, ventricular assist devices) with functional endothelium may reduce the incidence of clotting and restenosis complications and also reduce the need for risky anticoagulation therapy following implantation of such devices. We developed a novel cell therapy for seeding autologous endothelium onto blood-contacting vascular stents at the point of care to reduce thrombosis and stent restenosis. The proposed research tested the following hypotheses: (1) autologous endothelial cells (ECs) can spread on titanium (Ti) tubes and reduce thrombosis on the Ti surface in vivo; (2) shear stresses on the surfaces of an implanted carotid artery stent will be conducive to EC retention and function under arterial flow; and (3) nitinol stents seeded with ECs at the point of care will remain adherent and functional after stent deployment and arterial fluid shear stress conditions in vitro and in vivo. Based on the experiments reported herein, the primary conclusions of the dissertation are as follows: (1) autologous ECs significantly reduce thrombosis on Ti surfaces implanted into the bloodstream in vivo; (2) shear stresses on stent surfaces under carotid artery flow conditions are sufficiently low to be compatible with EC retention and function; (3) ECs seeded onto nitinol stents by infusion at the point of care are retained and spread to form a functional layer following deployment and arterial flow conditions both in vitro and in vivo.