What are the effects of heparin on platelet function?
Heparin binds to platelets and can either induce or inhibit platelet aggregation depending on the experimental conditions. High-molecular-weight heparin fractions with low affinity for antithrombin have a greater effect on platelet function than low-molecular-weight fractions with high antithrombin affinity. Heparin can also prolong the bleeding time in humans and enhance blood loss from the microvasculature in rabbits, which may contribute to heparin-induced bleeding by mechanisms independent of its anticoagulant effect. In addition, Heparin-induced thrombocytopenia (HIT) is the most important nonhemorrhagic side effect of heparin.