Impact of anticoagulation therapy on the risk of pulmonary embolism and bleeding events in patients with isolated distal deep-vein thrombosis

Abstract

The efficacy of anticoagulation for isolated distal DVT (id-DVT) is still uncertain and controversial. The aim of this study was to elucidate the risk of pulmonary embolism (PE) from id-DVT and to investigate the need for anticoagulants. We identified hospitalized patients with id-DVT diagnosed by lower-extremity ultrasonography (LEUS) from January 2013 to December 2013 in our institute. The exclusion criteria were the simultaneous detection of PE, a history of PE and/or DVT, and administration of anticoagulants before DVT detection. We retrospectively investigated the patient characteristics, treatments, occurrence of PE, and bleeding events between the groups with and without anticoagulation. A total of 151 patients met the criteria. The median (IQR) age was 74 (67, 80) years old, and there were 60 (39.7%) men. The median (IQR) observation period was 571 (160, 721) days. Significant differences in patient characteristics were observed for hypertension, operation time, consultation with experts, and follow-up LEUS. During the observation period, only one patient in the no-anticoagulation group who had traumatic cerebral hemorrhaging and was bedridden developed PE (non-massive type). However, there was no statistically significant difference in the occurrence of PE between the groups (log-rank P = 0.569). Bleeding episodes were observed in 9 of 151 (6.0%) patients, and all patients with bleeding events were taking anticoagulants (log-rank P < 0.001). The present retrospective single center study suggests that anticoagulation for id-DVT in inpatients with various backgrounds has a low efficacy to prevent the occurrence of PE and may increase bleeding events.