AN ANIMAL-MODEL FOR THE EVALUATION OF GRAFT THROMBOSIS IN THE ACUTE-PHASE ON CARBON-LINED PTFE PROSTHESIS

Fortyfive carbon-lined (CL) and 45 standard (ST) 4 mm internal diameter polytetra-fluoroethylene (PTFE) grafts were implanted as aortic interposition in 90 rabbits. 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 New Zealand rabbits with lower morbidity. The two hours graft patency (Doppler and angiographic studies) showed better patency rate in CL group (93% versus 80%). In 10 animals, platelet accumulation was investigated in vivo using gammacamera imaging after injection of autologous platelets labeled with Indium(111) In vitro, radioactivity counting of the explanted midgraft sections at 2 hours revealed 6 times greater activity in ST grafts (6.60 +/- 1.98 x 10(3)platelets/mm(2) versus 0.82 +/- 0.25 x 10(3) platelets/mm(2); 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 (chi(2): 61.117, p<0.001). Carbon-lining decreases platelet accumulation on PTFE grafts in the acute phase of a new experimental model.