Is the antithrombotic activity of "antiplatelet" drugs based on protection of endothelium?

In only five "antiplatelet" agents has the antithrombotic activity been confirmed both clinically and experimentally. These include acetylsalicylic acid, dipyridamole, clofibrate, hydroxychloroquine and sulfinpyrazone. Whereas only acetylsalicylic acid has a demonstrable effect on platelet aggregation in doses usually applied, the effects of all remaining drugs are more easily explained by their influence on the vessel wall. This assumption is supported by the finding that all five drugs possess a stabilizing effect on endothelium in doses corresponding closely to the clinical dose range. The method based on counting detached endothelial cells in blood after a standard stimulus was used to demonstrate this effect.