Influence of Antiplatelet Drugs on Platelet-Surface Interactions

Abstract

Platelet aggregates are important in the thromboembolic complications of prosthetic devices, and drugs that alter platelet function have shown promise in clinical trials. Results with these drugs have increased insight into the interaction of platelets with artificial materials, particularly when the clinical experience has been correlated with the results of in vitro models. In a bead column/surface contact model, the characteristic interactions of platelets with artificial surfaces resemble effects of adding thrombin or ADP to platelet-rich plasma. Anti-inflammatory agents and other antiplatelet drugs inhibit these reactions. Results in an in vivo model, survival of ⁵¹Cr-labeled platelets in sheep bearing arteriovenous shunts of test materials, correlate well with results in the in vitro model. Findings in these model systems indicate that the initial events upon contact of a surface with plasma proteins persistently influence the long-term behavior of that surface toward blood. A review of clinical studies discusses the effect of antiplatelet drugs on platelet survival and also on thrombotic complications of heart valve replacement and other conditions employing prosthetic devices.