Correlation of Plasma Coagulation Parameters With Thromboprophylaxis, Patient Characteristics, and Outcome in the MEDENOX Study

Abstract Context.—Plasma anti-Xa and anti-IIa activities correlate with the dose of low-molecular-weight heparin, and D-dimer and thrombin-antithrombin complexes are markers of procoagulant activity. Objective.—To investigate the relationship between plasma coagulation parameters and patient characteristics, including renal function, thromboprophylaxis, and incidence of venous thromboembolism (VTE) in the MEDENOX study population. Design.—Controlled, multicenter, double-blind, randomized study. Patients.—Two hundred twenty-four acutely ill medical patients. Interventions.—Either 20 or 40 mg of enoxaparin administered subcutaneously or a placebo once daily for 10 (±4) days. Main Outcome Measures.—VTE and plasma anti-Xa and anti-IIa activities, D-dimer, and thrombin-antithrombin levels in blood collected before prophylaxis was given (day 0) and after the last injection of the study drug. Results and Conclusions.—Anti-Xa activity correlated with the dose of enoxaparin. In patients with mild or moderate renal...