Reactivation of ischemic events in acute coronary syndromes: Results from GUSTO-IIb

OBJECTIVES We sought to determine the incidence of and risk factors for thr ombotic events early after discontinuing antithrombin therapy in patients w ith acute coronary syndromes. BACKGROUND Discontinuation of treatment with heparin and other thrombin inh ibitors in patients with unstable coronary syndromes has related to clinica l and biochemical evidence of early reactivation of thrombosis. METHODS We studied 8,943 of the 12,142 patients with acute coronary syndrom es enrolled in the Global Use of Strategies To Open occluded arteries in ac ute coronary syndromes trial of hirudin versus heparin. We excluded patient s who received no study drug, lacked timing data, died or had myocardial (r e)infarction [(re)MI] during study-drug infusion, or began heparin treatmen t within 2 h after treatment with the study drug was stopped. We assessed t he incidence and timing of (re)MI by type and timing of antithrombin treatm ent. RESULTS In all, 215 patients (2.4%) suffered (re)MI, 49 within 12 h of anti thrombin therapy discontinuation and 166 between hour 12 and hospital disch arge. The duration of infusion did not differ between the hirudin and hepar in groups. The rate of early re(MI) after drug therapy discontinuation was significantly higher in patients given heparin versus hirudin (0.8% vs. 0.3 %, p = 0.002). Patients with (re)MI had higher mortality at 30 days (23.6% vs. 2.4%, p = 0.001) and 1 year (35.2% vs. 6.7%, p = 0.001) compared with p atients without (re)MI. CONCLUSIONS The incidence of (re)MI was clustered within 12 h of heparin th erapy discontinuation, with the greatest risk within 4 h. There was no evid ence of early reactivation of thrombotic events after hirudin. Patients who had (re)infarction had worse outcomes. Better understanding of the mechani sm and possible prevention of recurrent thrombosis is needed. (J Am CoLl Ca rdiol 2001;37:1001-7) (C) 2001 by the American College of Cardiology.