INFLUENCE OF CARBON-LINING IN THE THROMBO GENICITY OF VASCULAR PROSTHESES

Forty five Carbon-lined (CL) and 45 Standard (ST) 4 mm internal diamet er polytetrafluoroethylene (PTFE) grafts were implanted as aortic inte rpositions in 90 New Zealand rabbits. In a pilot study of 20 animals, 10 CL and 10 ST grafts were used to develop microsurgical techniques, then 60 grafts were placed in 60 rabbits with lower morbidity. The 2-h our graft patency (Doppler study, Transonic flow probe and 8 mHZ) sho wed a better patency rate in the CL group (93 % versus 80 %). In 10 an imals, platelet accumulation was investigated in vivo using scintigrap hy after injection of autologous platelets labeled with Indium(111) In vitro, radioactivity counting of the explanted midgrafts sections at 2 hours revealed a 6-fold higher activity in ST grafts (6.60 +/- 1.98 x 10(3) platelets/mm(2) versus 0.82 +/- 0.25 x 103 platelets/mm(2); p< 0.05). Light microscopy found platelet and fibrin deposition(PFD) in n early all ST grafts, whereas PFD were found in only 13 % of the CL gra fts corresponding to those thrombosed grafts (chi(2): 61.117; p<0.001) . Carbon-lining decreases platelet accumulation on PTFE grafts and the rabbit aortic interposition appears to constitute a quantitative and reproducible model for investigation of antithrombotic drugs.