Anticoagulation is not effective at preventing pulmonary embolism (PE) for patients with isolated distal deep vein thrombosis (id-DVT), according to research published in the International Heart Journal.

Current guidelines from the American College of Chest Physicians state that patients with proximal DVT should receive anticoagulant therapy. However, recommendations for id-DVT are not backed by high-quality evidence.

The retrospective study looked at data from 151 patients diagnosed with id-DVT over a median observation period of 571 days. The study sought to determine the risk of PE in patients with id-DVT and whether anticoagulants were necessary.

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Patients were divided in an anticoagulation group, which consisted of 38 patients who had received any anticoagulant after id-DVT detection, and a no-anticoagulation group of 113 patients who never received anticoagulants.

Only 1 patient developed PE, a 79-year old female in the no-anticoagulation group. A total of 9 patients, all in the anticoagulation group, developed bleeding events, with 2 major and 7 minor events. The low occurrence of PE shows no significant difference between the 2 groups.

A total of 21.5% of patients who underwent follow up lower-extremity ultrasound (n=81) had recurrent venous thromboembolism, with 6 patients in the anticoagulation group and 11 in the no anticoagulation group. The difference between the groups was not significant. 

In this study, id-DVT had a low risk of PE, and anticoagulant use increased bleeding events. The authors noted that the hospital has a rigorous DVT screening process, allowing for early detection, as well as prevention measures for people at risk of DVT. These protocols may contribute to the low rate of PE.

Limitations of the study included the retrospective nature and small sample size from a single center. However, the results indicated that anticoagulation for id-DVT is not highly effective at preventing PE.


Ochiai Y, Yamaguchi T, Komiyama C, Kodama T. Impact of anticoagulation therapy on the risk of pulmonary embolism and bleeding events in patients with isolated distal deep-vein thrombosis. Int Heart J. Published online May 1, 2021. doi:10.1536/ihj.20-726