In this prospective, randomized and controlled study, we compare complications in 2 groups of patients: group 1, enoxaparin 0.8 mg/kg, subcutaneous every 12 hours during 5 days, and group 2, intravenous unfractionated heparin during 5 days, by infusion treated to activate partial tromboplastin time 1.5-2 the upper limit of normal. Blood samples were obtained at 4, 12, 24 hours and at day 5 of treatment, to measure anti-Xa levels, and also, evaluated end points at 30 days, between groups. Univariate and multivariate logistic regression analyses were performed with clinical and angiographic variables between groups, with p < 0.05.
Results: 203 consecutive patients, average age of 60.5 +/- 11.2 years, and 80% men, were included. There were no differences in clinical and angiographic characteristics. All patients with enoxaparin had therapeutic levels of anti-Xa, of 0.5 to 0.67 U/mL. There was increasing risk of total bleeding in group 2 (18.7%) than in group 1 (5.6%), with RR = 1.72 (95% CI 1.29, 2.29), p = .003. Also, there was 33.3% of MACE in group 2, and only 17.8% in group 1, with RR = 1.88 (CI 95% 1.29, 2.29), p = .011.
Conclusions: 1) Low doses of enoxaparine achieve therapeutic levels, since the first 4 hours of treatment. 2) A significant reduction of total bleeding occurred with the low doses of enoxaparin, with the same efficacy to reduce MACE during follow-up.