Thrombocytopenia in Patients Treated with Heparin, Combination Antiplatelet Therapy, and Intra‐Aortic Balloon Pump Counterpulsation

OBJECTIVES: Determine the incidence and timing of intra-aortic balloon pump (IABP)-associated thrombocytopenia, if concomitant antiplatelet agents increase the incidence of thrombocytopenia, and the incidence of heparin-induced thrombocytopenia (HIT) in a contemporary IABP population. BACKGROUND: Previous studies predate the current practice of treating acute coronary syndrome patients with heparin and aspirin plus thienopyridines and glycoprotein IIb/IIIa receptor antagonists such that data are unavailable to determine if their co-administration worsens IABP-associated thrombocytopenia. METHODS: A retrospective cohort study of adult IABP patients (n = 107) from 2002 to 2006 was performed to determine the indication for and duration of counterpulsation, platelet counts during and for 7 days postcounterpulsation, medications potentially contributing to thrombocytopenia, and HIT antibody results if obtained. RESULTS: Thrombocytopenia, defined as platelets <150,000/mL or >50% decrease from baseline, occurred in 57.9% of patients. Overall, platelets declined to 60.2 +/- 22.8% of baseline with the mean (+/- standard deviation) nadir on day 2.8 +/- 2.0. Comparing patients who received heparin, aspirin, thienopyridines, and glycoprotein IIb/IIIa antagonists (n = 44) versus heparinized patients +/- aspirin (n = 45), platelet nadirs were 62.7 +/- 20.9% versus 58.3 +/- 23.9% of baseline levels, respectively (P = 0.42). The incidence of HIT was 2.8% in the entire cohort. CONCLUSIONS: IABP-associated thrombocytopenia occurred in 57.9% of this cohort. HIT was diagnosed in 2.8% and should be considered as a diagnosis if platelet counts do not stabilize or continue to fall after 3-4 days of counterpulsation. Increased use of antiplatelet therapy does not impact the degree of thrombocytopenia although the current practice of prompt IABP removal may offset this effect.