RESUMO
BACKGROUND: Low-molecular-weight heparins are attractive alternatives to unfractionated heparin (UFH) for management of unstable angina/non-Q-wave myocardial infarction (UA/NQMI). METHODS AND RESULTS: Patients (n=3910) with UA/NQMI were randomized to intravenous UFH for >/=3 days followed by subcutaneous placebo injections or uninterrupted antithrombin therapy with enoxaparin during both the acute phase (initial 30 mg intravenous bolus followed by injections of 1.0 mg/kg every 12 hours) and outpatient phase (injections every 12 hours of 40 mg for patients weighing <65 kg and 60 mg for those weighing >/=65 kg). The primary end point (death, myocardial infarction, or urgent revascularization) occurred by 8 days in 14.5% of patients in the UFH group and 12.4% of patients in the enoxaparin group (OR 0.83; 95% CI 0.69 to 1.00; P=0. 048) and by 43 days in 19.7% of the UFH group and 17.3% of the enoxaparin group (OR 0.85; 95% CI 0.72 to 1.00; P=0.048). During the first 72 hours and also throughout the entire initial hospitalization, there was no difference in the rate of major hemorrhage in the treatment groups. During the outpatient phase, major hemorrhage occurred in 1.5% of the group treated with placebo and 2.9% of the group treated with enoxaparin (P=0.021). CONCLUSIONS: Enoxaparin is superior to UFH for reducing a composite of death and serious cardiac ischemic events during the acute management of UA/NQMI patients without causing a significant increase in the rate of major hemorrhage. No further relative decrease in events occurred with outpatient enoxaparin treatment, but there was an increase in the rate of major hemorrhage.
Assuntos
Angina Instável/tratamento farmacológico , Enoxaparina/uso terapêutico , Fibrinolíticos/uso terapêutico , Heparina/uso terapêutico , Infarto do Miocárdio/tratamento farmacológico , Terapia Trombolítica , Doença Aguda , Idoso , Angina Instável/complicações , Angina Instável/cirurgia , Anticoagulantes/administração & dosagem , Anticoagulantes/efeitos adversos , Anticoagulantes/uso terapêutico , Creatina Quinase/sangue , Método Duplo-Cego , Eletrocardiografia , Emergências , Enoxaparina/administração & dosagem , Enoxaparina/efeitos adversos , Europa (Continente)/epidemiologia , Inibidores do Fator Xa , Feminino , Fibrinolíticos/administração & dosagem , Fibrinolíticos/efeitos adversos , Hemorragia/induzido quimicamente , Heparina/administração & dosagem , Heparina/efeitos adversos , Humanos , Isoenzimas , Tábuas de Vida , Masculino , Pessoa de Meia-Idade , Mortalidade , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/etiologia , Infarto do Miocárdio/prevenção & controle , Infarto do Miocárdio/cirurgia , Revascularização Miocárdica/estatística & dados numéricos , América do Norte/epidemiologia , Tempo de Tromboplastina Parcial , Recidiva , Segurança , América do Sul/epidemiologia , Terapia Trombolítica/efeitos adversos , Resultado do TratamentoRESUMO
BACKGROUND: There are no reported studies on the safety and efficacy of low-dose aspirin with low-intensity oral anticoagulation in patients with heart valve replacement. In this study, we compared the use of 100 mg/d aspirin with 650 mg/d aspirin in the prevention of systemic embolism and vascular death in patients with heart valve replacement who were being treated with oral anticoagulants with a target international normalized ratio (INR) of 2.0 to 3.0. METHODS AND RESULTS: Four hundred nine of 416 consecutive patients who had cardiac valve replacement were randomized in open allocation into one of two groups; both groups were treated with oral anticoagulant therapy with a target INR of 2.0 to 3.0. Two hundred seven patients who received 100 mg/d aspirin for an average of 24.1 months were compared with 202 patients who received 650 mg/d aspirin for an average of 21.7 months in a randomized-treatment, open-allocation study. There were no significant differences in systemic embolism, vascular death, or total death rates between the low- and high-dose aspirin treatment groups (0.5 and 1.1, 1.2 and 0.5, and 4.6 and 2.5 per 100 patients/y, respectively). The total number of hemorrhagic events was 13.4 per 100 patients/y in the high-dose aspirin group and 7.9 per 100 patients/y in the low-dose aspirin group (P = .035), but the rate of bleeding was influenced by dipyridamole in the 650-mg aspirin group. CONCLUSIONS: In patients with mechanical heart valve replacements, low-dose aspirin (100 mg/d) in conjunction with oral anticoagulants at an INR of 2.0 to 3.0 is as effective as the use of high-dose aspirin (650 mg/d) in the prevention of systemic embolism.