Impact of anticoagulation levels on outcomes in patients undergoing elective percutaneous coronary intervention: insights from the STEEPLE trial

Aims To determine the relationship between anticoagulation levels during percutaneous coronary intervention, and ischaemic events and bleeding. Methods and results A sub-analysis from the STEEPLE trial was conducted. Pre-defined target anticoagulation levels were achieved in 86% of patients receiving enoxaparin, compared with 20% receiving unfractionated heparin (UFH) (P < 0.001). A significant relationship was observed between anti-Xa levels > 0.9 IU/mL and covariate-adjusted rate of non-coronary artery bypass graft-related major and minor bleeding [odds ratio (OR) 1.6, 95% CI 1.0-2.5 for each unit of anti-Xa; P = 0.03]; anti-Xa levels and covariate-adjusted incidence of death, myocardial infarction, or revascularization showed no significance (P = 0.47). Major bleeding increased significantly with an activated clotting time (ACT) > 325 s (OR 1.6, 95% CI 1.1-2.2 per 100 s; P = 0.04). A significant relationship with increasing ischaemic events was observed when ACT was < 325 s (OR 0.7, 95% CI 0.2-0.8 per 100 s; P = 0.006) indicating a narrow therapeutic window. Conclusion Target anticoagulation levels were achieved more readily in patients receiving enoxaparin. An anti-Xa level of up to 0.9 IU/mL has a good safety and efficacy profile; poor achievement of target ACT with UFH makes assessing the optimal range difficult.