Acute Profound Thrombocytopenia following Abciximab Therapy

OBJECTIVE: To report a case of acute, profound thrombocytopenia (APT), defined as an abrupt drop in platelet count to <20,000/mm3 that occurred within 24 hours of administration of an abciximab bolus, to summarize other abciximab-associated APT cases reported in the literature, to review the postulated mechanisms behind this reaction, and to emphasize the importance of periodically monitoring platelet counts after initiating abciximab therapy. DATA SOURCES: MEDLINE and Index Medicus searches restricted to English-language literature from 1993 through June 1999 were conducted. MeSH headings included abciximab, ReoPro, thrombocytopenia, and glycoprotein IIb-IIIa (GP IIb-IIIa) inhibitors. References of the articles obtained were also reviewed. DATA EXTRACTION: Search and evaluation were focused on published case reports and reviews of abciximab-induced APT, as well as the incidence of thrombocytopenia from the drug compared with that from other GP IIb-IIIa inhibitors. DATA SYNTHESIS: Platelet aggregation has been identified as the structural basis for coronary thrombosis. This may lead to ischemic complications during acute coronary syndromes or following coronary intervention procedures. The use of GP IIb-IIIa inhibitors such as abciximab as antiplatelet agents has been effective in reducing these ischemic complications. We summarize 15 published cases of abciximab-associated APT gathered from data on 2,482 patients treated with the drug. Prior to suspecting abciximab, other potential causes of thrombocytopenia should be evaluated. It is important to monitor the platelet count at baseline, two hours after initiating abciximab, and 24 hours after initiation of therapy or prior to discharge, whichever comes first, to identify patients at risk for developing APT. If APT occurs and is left untreated, it can produce excessive hemorrhage and ischemia, potentially leading to death. Platelet transfusions have been more effective than immunoglobulin in the management of APT. CONCLUSIONS: Abciximab-induced APT has a low incidence of occurrence. If it does develop and is not recognized or treated promptly, it can lead to serious hemorrhagic complications. Consequently, monitoring the platelet count two hours after initiation of the infusion is essential. If APT develops, abciximab should be discontinued and a platelet transfusion should be considered.