Fig. 4. EDTA-quenching is necessary to observe the anti-thrombotic effect of eptifibatide (a) platelets (and leukocytes) and fibrin were visualised using confocal microscopy over a 30 min time-course. The images are representative of n = 6 donors. Mean platelet and fibrin accumulation ± S.D. is shown in the graphs (n = 6). (b) The platelet and fibrin integrated density values at 30 min. Treatment with eptifibatide had a significant effect on platelet accumulation in both devices (unquenched P = 0.0128(*); EDTA-quenched P = 0.0027(**)). Treating blood with eptifibatide had a significantly different effect on fibrin accumulation depending on which device was used (P = 0.0456(*)). (c) Mean blood flow rate in each condition with S.D. shown in the shaded area (n = 6). (d) Time to occlude for each experiment is shown in the graph. Treating with eptifibatide had a significant effect when using EDTA-quenched devices (P = 0.0219(*)) but no significant effect in unquenched devices.