Trough anticoagulant levels of high-dose versus standard-dose intravenous enoxaparin in patients undergoing trans-radial coronary angiography alone

It was presumed that enoxaparin 0.5 mg/kg, the guideline-recommended anticoagulant regimen for percutaneous coronary intervention (PCI), could achieve target anticoagulation for 90 min, which, however, was based on the results of pharmacokinetic simulation. This study aimed to directly assess the trough anticoagulant levels (anti-Xa activities at 90 min after administration) of enoxaparin 0.75 mg/kg versus 0.5 mg/kg in patients undergoing trans-radial coronary angiography (CAG) alone. Before CAG, eligible patients were randomly assigned to receive enoxaparin 0.75 mg/kg (High-dose group) or 0.5 mg/kg (Standard-dose group). After CAG, patients undergoing both CAG and PCI were excluded from each group according to the study protocol. Anti-Xa activities were assessed at 0 min, 10 min, and 90 min after enoxaparin was administered. The primary endpoint was anti-Xa activity at 90 min. Target anticoagulation was defined as anti-Xa activities of 0.5-1.8 IU/ml. A total of 177 patients underwent randomization, 96 of which underwent CAG alone (48 in each group). The baseline characteristics were well balanced between the two groups. In the High-dose compared to the Standard-dose group, (1) the anti-Xa activities were higher at both 90 min (0.80 [0.68, 0.90] IU/ml vs. 0.57 [0.49, 0.69] IU/ml, p < 0.001) and 10 min (1.37 [1.16, 1.50] IU/ml vs. 0.94 [0.83, 1.13] IU/ml, p < 0.001); (2) the rates of target anticoagulation were higher at 90 min (100.0% [38/38] vs. 72.7% [32/44], p < 0.001), although similar at 10 min (100.0% [41/41] vs. 97.9% [46/47], p = 1.000). Enoxaparin 0.75 mg/kg achieved higher anticoagulant levels and higher rates of target anticoagulation at 90 min after administration in patients undergoing trans-radial CAG alone compared to enoxaparin 0.5 mg/kg. This trial was registered on ClinicalTrials.gov (NCT03145675) on May 21, 2017.