Increased Mortality With Long-Term Platelet Glycoprotein IIb/IIIa Antagonists: An Explanation?

To the Editor:The increased mortality during long-term administration of oral glycoprotein IIb/IIIa antagonists as secondary prevention reported by Chew et al1 is indeed unexpected and perplexing. A possible hint may be given by the recent in vitro observations of Li et al.2 When platelets are activated with collagen in hirudinized whole blood in the presence of a glycoprotein IIb/IIIa antagonist, more platelet-leukocyte conjugates are formed. Conjugate formation is a consequence of P-selectin expression on the activated platelets and interaction of P-selectin with P-selectin glycoprotein ligand-1 and CD15 on leukocytes. Presumably because of the inhibition of platelet-platelet aggregation by glycoprotein IIb/IIIa antagonists, more activated platelets are …