We investigated the acute thrombogenicity of synthetic arterial prostheses compared to biological arterial surfaces in contact with flowing nonanticoagulated blood. The acute events following blood/surface interactions were quantified using 51Cr-platelet deposition, 111In-neutrophil adhesion, and 125I-fibrin(ogen) adsorption on expanded polytetrafluoroethylene (ePTFE) synthetic arterial surfaces (Goretex and Impra) and on intact and injured biological arterial surfaces in ex vivo superfusion flow chambers at low (424/sec) and high (3397/sec) shear rates for 5 min at 37 degrees C. The hematological parameters were determined, and surface analysis was assessed by scanning electron microscopy. At low shear rate, the retention on intact arterial surfaces averaged 3.7 +/- 0.7 x 10(6) platelets/cm2, 26.5 +/- 4.2 x 10(3) neutrophils/cm2, and 10.7 +/- 2.2 cpm of fibrin(ogen)/cm2; retention remained statistically similar at the high shear rate on both Goretex and Impra ePTFE surfaces. In contrast, the deposition of platelets and neutrophils on injured arterial surfaces was significantly higher and increased with shear rate, although the significant increase in fibrin(ogen) adsorption was not influenced by the shear rate. At shear rates characterized by patent and stenosed arteries, ePTFE arterial prostheses demonstrated a low level of thrombogenicity compared to injured arteries. This favorable comparison can be considered as the first requirement for their successful use in arterial substitution.