Effect of supplemental CTI, heparin, or bivalirudin on the capacity of fondaparinux to attenuate catheter-induced clotting. PCI catheter segments were incubated for 10 minutes at 37°C in plasma containing the indicated concentration of fondaparinux and (A) 0 (closed circles) or 100 (open circles) μg/mL CTI, (B) 0 (closed circles), 0.05 (open circles), or 0.1 (triangles) anti-Xa U/mL heparin, or (C) 0 (closed circles), 12.5 (open circles), or 50 (triangles) μg/mL bivalirudin. After initiating clotting by addition of CaCl2 to 20mM, absorbance was monitored up to a maximum of 14 000 seconds, and time to clot was determined. The symbols represent the mean and the lines above and below the symbols reflect the SD.