Experimental Application of Polyvinyl Alcohol-Silica for Small Artificial Vessels

Abstract

Polyvinyl alcohol-silica (PVA-SiO₂) composite and heparinized PVA-SiO₂ were examined in vitro and in vivo as materials to coat artificial vessels to be used for the replacement of small arteries.

PVA-SiO₂ was observed to prolong coagulation time and on heparinized PVA-SiO₂ surfaces no blood coagulation was noticed after a period of two days using the Lee-White and plasma recalcification methods.

After placing non-coated and coated surfaces in contact with blood components in vitro and in vivo, the degree of blood component adhesion was greater in non-coated woven Dacron than in PVA-SiO₂ coated Dacron. The degree of adhesion was even less in heparinized PVA-SiO₂ coated Dacron.

Furthermore, artificial vessels made of these 3 types of materials were used to replace parts of the canine abdominal aorta and were removed one and a half years later. Patency rates were as follows: non-coated 2/7, PVA-SiO₂-coated 4/7, heparinized PVA-SiO₂-coated 8/12. The inner surfaces of these prosthese were observed with light microscopy and scanning electron microscopy.

Intima formation was thinner on the PVA-SiO₂ composite surfaces than on the control surfaces. Heparin acted as a local anticoagulant and PVA-SiO₂ limited intima formation. This report showed that PVA-SiO₂ composite coated surfaces can be effective for small artery replacement due to good tissue affinity and anticoagulability.