ABCIXIMAB-INDUCED THROMBOCYTOPENIA IN THE TREATMENT OF ACUTE CORONARYSYNDROMES BY ANGIOPLASTY

ReoPro(R) (abciximab) is the Fab fragment of a chimeric monoclonal ant ibody directed against platelet glycoprotein IIb-IIIa. Its efficacy to prevent ischaemic complications after PTCA has been demonstrated in 3 studies: EPIC, EPILOG, UPTAKE. One hundred and sixty five cases of th rombocytopenia (< 100000/mu l) were reported in a series of 5461 patie nts randomized in these 3 studies (i.e. 3.0%), including 46 (2.03%) wi th placebo and 119 (3.73% with abciximab. Among the 2270 patients rand omized to receive placebo, 11 (0.48%) cases of severe thrombocytopenia (< 50000/mu l) were observed versus 34 (1.07%) with abciximab. Major acute thrombocytopenia (< 20000/mu l and < 24 hours) occurred in 0.60% (20 patients) of cases with abciximab. Their mechanism remains unknow n. A therapeutic challenge did not modify either their incidence, or t heir severity. The development of thrombocytopenia did not worsen the patient's prognosis and course was always favourable. Twenty five case s of thrombocytopenia (0.60%), including 3 cases of acute major thromb ocytopenia (0.08%) were spontaneously reported in France among the fir st 4000 patients treated with abciximab postmarketing. All patients tr eated with abciximab must be monitored by platelet count, 2 to 4 hours after the bolus administration, then 12 and 24 hours later. These pla telet counts should be performed on 3 tubes (EDTA, citrate, heparin) i n order to eliminate pseudothrombocytopenia and a differential diagnos is. In the case of true thrombocytopenia (< 10000/l), treatment should be suspended and the platelet count should be repeated daily until re turn to normal. In the case of thrombocytopenia less than 60000/mu l, heparin and aspirin should also be systematically discontinued and, be low 50000/mu l, platelet transfusion is justified.