Inhibition of platelet deposition in the thrombus chamber. The number of deposited platelets was determined using gamma camera imaging in 5-minute intervals during thrombus formation in order to obtain kinetic information. The total doses of antithrombotic agents (μg/kg for 70 minutes) are displayed after the symbols and labels in the inset in panel B. (A) The effect on the net platelet accumulation rates (NPARs) of the intermediate doses of PCA (4.2 μg/kg) and LMWH (650 μg/kg), and the standard dose of APC (28 μg/kg) is shown. NPARs increased throughout the experiment in vehicle-treated controls. Treatment with PCA, APC, or LMWH slowed down the NPAR increase and, about 30 minutes after the start of thrombosis, decelerated the NPAR. The R2 for the polynomial regression of each displayed curve was above 0.85. (B) The absolute number of platelets residing in the thrombus is displayed every 5 minutes from deployment of the thrombogenic device at 10 minutes after start of treatment. The highest doses of PCA (8.3 μg/kg) and LMWH (1300 μg/kg and above) terminated platelet accumulation early, while the antithrombotic effect of the lowest doses of PCA and LMWH as well as of APC manifested the later. The means are shown with error bars.
