SBIR-STTR Award

A new, highly compliant vascular graft fabricated from a unique polyurethane material will be developed and tested. The bulk and surface properties required of this material have been decoupled and developed independently intwo separate materials. The final polymer will possess overall optimized characteristics by blending optimized surface active copolymers into the optimized bulk material.Using a patented process for fabrication of multilayered tubing, 4 mm diameter vascular grafts will be produced. These grafts will be tested both in vivo and in vitro.In vitro testing will include compliance, burst strength, kink radius, elongation, and suture pullout strength. In vivo evaluation will be accomplished by implanting 8 cm lengths in the carotid arteries of mature goats. These will be checked for patency every 30 days using 99mTechnetium scanning. After 60 days of observation, grafts will be explanted and resubjected to the in vitro test protocol. Additionally, both SEM and standard microscopic examinations will be performed.National Heart, Lung, and Blood Institute (NHLBI)

A new, highly compliant vascular graft has been fabricated from a unique polyurethane material. Prototype grafts have demonstrated excellent blood compatibility and no perigraft reaction. The maximum thickness of endothelial and subintimal tissues bridging the anastomoses have been 15 to 20 microns, and in some cases, only a continuous monolayer of endothelial cells has been found.Bulk and surface properties required of this material have been decoupled and developed independently in two separate materials. The final polymer consists of a blend of surface active copolymers and bulk material to produce a formulation optimized for this specific use.Four-mm diameter vascular grafts will be produced using Thoratec Laboratories Corporation's patented process for fabrication of multilayered tubing. These grafts will be tested both in vivo and in vitro. In vitro testing will include compliance, burst strength, kink radius, elongation, and suture pullout strength. Grafts will be tested before and after sterilization. Life-testing will also be accomplished.In vivo evaluation will be accomplished by implanting 8-cm lengths in the carotid arteries of mature goats and as aorto-coronary bypasses in calves. 99mTechnetium scanning will be used to determine patency. Explanted grafts will be resubjected to the in vitro test protocol, as well as SEM and standard microscopic examination.National Heart, Lung, and Blood Institute (NHLBI)