Heparin coupling in inhibition of calcification of vascular bioprostheses

Inhibitory effect of heparin coupling on calcification of bioprosthetic vascular grafts of different origin was studied. Heparinbonded (Hep) and 0.625% glutaraldehyde-cross-linked (GA) segments of porcine thoracic aorta (AO), pulmonary artery (PA), jugular vein (JV) and rabbit aorta (RA) were implanted subcutaneously in weanling rats for 5 months. Heparin bonding is ineffective in prevention of calcification of JV (Hep: Ca, 159±32.26 mg g−1; GA: Ca, 193.55±17.81; p=0.075) and RA (Hep: Ca, 150.17±14.78; GA: Ca, 192.12±26.61; p=0.015). Calcium content of heparin-coupled PA and AO was significantly less when compared with their GA-treated counterparts. Calcification inhibition was achieved to a greater extent in heparin-bonded PA (Hep: Ca=22.62±5.72, GA: Ca=115.99±21.91, p<0.0001) than in the AO coupled to heparin (Hep: Ca=63.77±22.75, GA: Ca=150.40±35.21, p<0.0001). Elastin fibers were the predominant site of calcification in all explanted vascular grafts. Heparin-bonded porcine pulmonary artery is seemed to be the best among all vascular bioprostheses in this study.