Rapamycin potentiates the procoagulant activity of HUVECs in the presence of VEGF. The procoagulant activity of HUVECs was determined in a one-stage clotting assay in response to VEGF (20 ng/mL; ▨) or rapamycin (5 ng/mL; ▩) or both (▦). □ indicates control. Results show the mean coagulation time ± SEM in 3 independent experiments performed in quadruplicate. ^*P < .001 versus control; +, P < .05 versus VEGF.