Background: Thrombocytopenia is infrequently associated with abciximab therapy but may contribute to hemorrhagic risk. Factors associated with development of thrombocytopenia, the role of weight-adjustment in concomitant heparin administration, and clinical outcomes in patients with thrombocytopenia are not well defined.
Methods and results: Pooled data from 3 placebo-controlled, randomized trials (EPIC, EPILOG, and EPISTENT) of abciximab therapy during percutaneous coronary intervention identified 178 patients (2. 4% of 7290 patients) in whom thrombocytopenia (platelet count <100 x 10(9)/L) developed after enrollment. Multivariate regression analysis identified age (>65 years; P <.001), weight (<90 kg; P =. 023), baseline platelet count (<200 x 10(9)/L; P <.001), abciximab therapy (P =.002), and enrollment into the EPIC trial (P <.001) to be associated with development of thrombocytopenia. Major and minor nonsurgical hemorrhage and transfusion were more frequent (all P <. 001) in thrombocytopenic patients. Although the primary composite clinical end point of these trials (death, myocardial infarction, or urgent revascularization to 30 days) was observed with similar frequency in patients with (11.2%) and those without (7.9%; P =.114) thrombocytopenia, 30-day mortality rate was higher in thrombocytopenic patients (8.4% vs 0.6%, respectively; P <.001). This excess mortality rate persisted after excluding patients in whom thrombocytopenia was first noted after the performance of coronary bypass surgery (4.8% vs 0.6%; P <.001). Among patients in whom thrombocytopenia developed during these trials, those who received prophylactic abciximab had fewer primary end point events (7.1% vs 23.1%; P =.056) and had a lower 30-day mortality rate (3.5% vs 15.4%; P =.048) than patients with thrombocytopenia who had received prophylactic placebo.
Conclusions: Thrombocytopenia associated with abciximab therapy for percutaneous coronary intervention was more frequent in older, lighter-weight patients, those with lower baseline platelet counts, and in those patients who were enrolled into the EPIC trial. Both bleeding and transfusion events occur more frequently in patients with thrombocytopenia. Patients in whom thrombocytopenia developed during these trials had increased mortality rates to 30 days not attributable to the performance of coronary bypass surgery. Among patients with thrombocytopenia, those who received prophylactic abciximab had better clinical outcomes including survival than those who did not.