This study was designed to assess the time course and nature of the vascular procoagulant response after 1.5-fold balloon overstretch injury of the coronary arteries in pigs. Arteries were excised for chromogenic assay of bound factor (F)Xa and thrombin at 24 h, 3 days, 1 week, or 2 weeks after injury. FXa at the site of injury remained elevated for 1 week (4.9±5.9 μg cm -2, n=10), compared with non-injured control arteries (0.4±0.2 μg cm -2, n=18, P=0.00025), while thrombin was increased only at 24 h. Tissue factor protein was abundant in non-injured coronaries (10±6ngp μg -1 total protein, n=9) and levels were unchanged by injury (13±11 ng μg -1, n=6) or 24-h administration of tissue factor pathway inhibitor (16±6ng μg -1, n=6). Persistent tissue factor-mediated procoagulant activity may explain the need for prolonged anticoagulation to attenuate neointimal formation after balloon-induced coronary injury.
- Tissue factor