[Value of carbon in the thrombogenicity of cardiovascular prostheses]

Forty five Carbon-lined (CL) and 45 Standard (ST) 4 mm internal diameter polytetrafluoroethylene (PTFE) grafts were implanted as aortic interpositions 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-hour graft patency (Doppler study, Transonic flow probe and 8 mHZ) showed a better patency rate in the CL group (93% versus 80%). In 10 animals, platelet accumulation was investigated in vivo using scintigraphy after injection of autologous platelets labeled with Indium111. 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 103 platelets/mm2 versus 0.82 +/- 0.25 x 103 platelets/mm2; p < 0.05). Light microscopy found platelet and fibrin deposition (PFD) in nearly all ST grafts, whereas PFD were found in only 13% of the CL grafts corresponding to those thrombosed grafts (chi2:61.117; 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.