Anticoagulation in critically ill patients with isolated distal deep vein thrombosis: a retrospective cohort study

Anticoagulation for isolated distal deep vein thrombosis (IDDVT) in critically ill patients remains controversial. The aim of our study was to assess whether anticoagulation could benefit critically ill patients with IDDVT.

We identified critically ill patients with IDDVT diagnosed by ultrasound from June 2022 to June 2023 and divided them into anticoagulation and non-anticoagulation groups retrospectively. The primary outcome was thrombus propagation, defined as a composite of pulmonary embolism (PE) and proximal deep vein thrombosis (PDVT). The secondary outcomes included PE, PDVT, thrombus resolution, major bleeding, clinically relevant non-major bleeding and all-cause mortality. The follow-up period was from the day of IDDVT diagnosis to the time of discharge/death. After propensity score matching (PSM), the incidence of outcomes was compared and risk factors for thrombus propagation/bleeding were analyzed.

A total of 261 patients were included for analysis, 115 in the non-anticoagulation group and 146 in the anticoagulation group. After PSM, 53 pairs of patients were well-matched. The incidence of thrombus propagation was significantly lower in the anticoagulation group than in the non-anticoagulation group (5.7% vs. 18.9%, P = 0.038). However, there was no statistical difference in the incidence of secondary outcomes between the two groups. Subgroup analysis revealed that over 70% of patients received low-dose rather than standard-dose anticoagulation, particularly those with coagulopathy and deep vein catheterization, and no significant differences were observed in any outcomes between the two subgroups. Finally, surgery (OR 3.959, 95% CI 1.101-14.233, P = 0.035) was an independent risk factor for thrombus propagation, while early anticoagulation (OR 0.243, 95% CI 0.061-0.966, P = 0.045) was a protective factor. Active malignant tumor (OR 10.257, 95% CI 1.883-55.870, P = 0.007), trauma (OR 9.766, 95% CI 1.193-79.948, P = 0.034), and an IMPROVE score ≥ 7 (OR 5.279, 95% CI 1.146-24.321, P = 0.033) were all independent risk factors for bleeding.

Early low-dose anticoagulation can reduce the risk of thrombus propagation in critically ill patients with IDDVT without increasing bleeding risk, but caution should be exercised in those with active malignant tumor, trauma or an IMPROVE score ≥ 7, given their inherently high bleeding risk.