Fibrin-mediated αIIbβ3-independent aggregation in viable versus fixed platelets. A suspension of washed (A) or fixed platelets (B) was incubated with dRGDW (200 μM) for 5 minutes, and subsequently fibrinogen (0.5 mg/mL) and different concentrations of thrombin (0-0.5 U/mL) were added. Platelet aggregation was monitored using standard suspension aggregometry at 37°C using a stir speed of 900 rpm. A representative aggregation tracing of 3 independent experiments is shown.