Biotolerant and haemodynamic effects of copolymerization with acrylic acid on Dacron arterial prostheses

The biotolerant and haemodynamic effects of three types of woven polyethylene terephthalate (Dacron) arterial prostheses were compared. Two of these were unmodified, one low, one high porosity; and the third was the latter type radiation graft copolymerized with 5% acrylic acid. The prostheses were implanted as aorto-aortic bypass grafts, in dogs, for periods ranging from three to seventeen months. The copolymerized prosthesis exhibited the smallest rise in circumferential elastance from the 'as supplied' state, as well as a significantly slower pulse wave velocity, a significantly thinner internal lining, and a markedly lower longitudinal impedance. Of the unmodified prostheses, the low porosity graft had a significantly greater circumferential elastance, the poorest handling characteristics, and a tendency for pseudo intimal detachment. It was concluded that, although there was little difference between the two unmodified prostheses, the low porosity one had little to recommend it for use in small calibre bypass grafting. Copolymerization with acrylic acid produced better haemotolerant and haemodynamic results as well as surface properties which appeared to discourage fibrin and platelet adherence, and promote a more complete and organised pseudointima.