Effects of triflusal and its main metabolite HTB on platelet interaction with subendothelium in healthy volunteers.

The ex vivo effect of triflusal and acetylsalicylic acid (ASA) on platelet interaction with the subendothelium using the Baumgartner perfusion system (wall shear rate 350 s-1) was assessed in blood from 10 healthy volunteers who given a 15-day course of triflusal 600 mg per day and ASA 400 mg per day in a cross-over trial. The percentage of platelets on the subendothelium showed a decrease of 62% in samples from subjects on ASA and a decrease of 93% in those from subjects on triflusal (P < 0.005). The percentage of the subendothelial surface covered by platelets was reduced by 23.3% after treatment with ASA, mainly due to inhibition of aggregates (75.2%), and by 29.9% after treatment with triflusal, mainly due to inhibition of aggregates (89.6%) and of adhesion (25%). The subendothelial surface covered by activated platelets (adhesions and thrombi) showed 32.5% inhibition after treatment with triflusal and 11.6% after treatment with ASA (P < 0.043 vs. triflusal). In the in vitro experiments, 10 mumol.l-1 triflusal did not modify the percentage of the subendothelium covered by platelets. HTB 1 mmol.l-1 inhibited adhesion (26%) and aggregates (18%). We conclude that HTB participates in the ex vivo effects of triflusal on the platelet-subendothelium interaction.