ABSTRACT
During the last three decades, polyester arterial grafts have been widely accepted as substitutes for large- and medium-caliber arteries. Because of their handling characteristics and their healing properties, knitted polyester grafts are preferred for peripheral surgery. On the other hand, the woven grafts are the substitute of choice in surgery of the thoracic aorta and ruptured abdominal aortic aneurysms, owing to their mechanical stability. Moreover, they are capable of preventing blood seepage through the wall even in patients who are heparinized, and consequently the graft need not require preclotting. However, because of their tight structure, poor handling characteristics and limited encapsulation, the woven grafts are infrequently implanted for other vascular repairs.
In an attempt to overcome these deficiencies, new prototypes of woven polyester grafts have been developed with two novel design features: a velour effect on the outer surface to promote tissue infiltration, and a polypropylene spiral filament wrap thermally bonded on the outside of the graft to prevent fraying at cut ends. Two prototypes of this device with nominal water permeability of 200 ml/cm2/min (LP, low-porosity prototype) and 1000 ml/cm2/min (HP, high-porosity prototype) were developed.
These two prototypes have been evaluated as thoraco-abdominal bypass grafts in the dog for preestablished durations of 4 hours to 6 months in order to investigate their healing characteristics and their mechanical stability. The new textile design appears to offer significantly improved tissue infiltration and intimai attachment properties in both devices. Woven grafts of such design compare favorably to any knitted graft commercially available. The LP prototype appears to be more stable and resistant to fraying. It is preferred to the HP prototype, which proved to be less resistant to suture pullout.
