The safety of empiric anticoagulation during the diagnostic work-up for deep vein thrombosis: a post hoc analysis and a systematic review

Abstract

Background: This project thesis is based on a manuscript for the article “The safety of empiric anticoagulation during the diagnostic work-up for deep vein thrombosis: a post hoc analysis and a systematic review” that is ready for submission to Thrombosis Research. Empiric anticoagulation is frequently used in patients with suspected deep vein thrombosis (DVT) until the work-up is completed to prevent complications such as proximal extension and pulmonary embolism. However, the safety of such a strategy is not fully established. Therefore, we aimed to evaluate the safety of empiric anticoagulation during the diagnostic work-up for DVT and to explore the use of this practice both in a local and international setting. Methods: We conducted a post hoc analysis of a previous prospective study which included patients referred to the emergency department at Østfold Hospital, Norway, with suspected DVT who had received empiric low-molecular-weight heparin (LMWH). Outcome measures were major bleeding events and/or death, clinically relevant non-major and minor bleeding events, as well as worsening of symptoms, assessed 48 hours after study enrolment. We also performed a systematic review of the literature assessing complications of empiric anticoagulation, such as major bleeding events and death. In addition, the pattern of use of empiric anticoagulation in the reviewed studies was elucidated. Results: Three-hundred twenty-eight patients had received therapeutic or prophylactic doses of LMWH. Of these, 303 patients (92.4%, 95% CI, 89.0-95.0) received enoxaparin while 25 patients (7.6%, 95% CI, 5.0-11.0) received dalteparin. None of these patients (0%, 95% CI, 0.0-0.1) experienced major bleeding events. Our systematic review included six prospective and four retrospective studies. No major bleeding events were observed in any of the reviewed studies (0%, 95% CI, 0.0-0.1). Conclusions: Our findings support the practice of providing empiric anticoagulation to patients with suspected DVT until completion of the work-up.