Recurrence of venous thromboembolism at one, five and 10 years was common following isolated distal deep venous thrombosis.

In patients who are given anticoagulation for distal deep venous thrombosis (DVT) of the lower extremity (i.e. calf DVT), a three-month course is recommended (Chest 2021; 160: 2247-2259). Investigators assessed long-term risk for venous thromboembolism (VTE) recurrence and initial bleeding risk in 475 Norwegian patients who presented with first calf DVT and received three months of anticoagulation.

During average follow up of five years (maximum, 15 years), one-, five- and 10-year risk for VTE recurrence was 6%, 15% and 27%, respectively; nearly two-thirds of recurrences were pulmonary embolism or proximal DVTs. Unprovoked calf DVT (compared with provoked calf DVT) was associated with a higher rate of recurrent VTE (40% vs 20% at 10 years). When the provoking factor was considered ‘minor’ (e.g. use of estrogen-containing products, pregnancy-related, after long flights), VTE recurrence was similar to that in patients with unprovoked calf DVT (36% vs 40% at 10 years). Incidence of major bleeding during the first three months – while receiving anticoagulation – was only 0.8% in patients who received direct-acting oral anticoagulants (DOACs).

Comment: This study demonstrates isolated calf DVTs are associated with a high rate of VTE recurrence over time. Although most patients with calf DVTs receive short-term anticoagulation, this study raises the question of whether anticoagulation should be extended, especially in patients with unprovoked – and possibly minor provoked – calf DVTs. International guidance suggests extended anticoagulation for VTEs when recurrence risk is high (5% or more at one year and 15% or more at five years; J Thromb Haemost 2010; 8: 2313-2315). Based on these data, patients with calf DVTs meet that threshold, but patients and clinicians would need to balance potential benefit against cumulative bleeding risk during extended anticoagulation.

Daniel D. Dressler, MD, MSc, MHM, FACP, Professor of Medicine, Emory University School of Medicine, Atlanta, USA.

Jørgensen CT, et al. Incidence of bleeding and recurrence in isolated distal deep vein thrombosis: findings from the Venous Thrombosis Registry in Østfold Hospital. J Thromb Haemost 2023; 21: 2824-2832.

This summary is taken from the following Journal Watch titles: General Medicine, Cardiology, Ambulatory Medicine, Hospital Medicine.