Retrospective review on isolated distal deep vein thrombosis (IDDVT) - A benign entity or not?

- IDDVT patients in this review had a non-inferior rate of thrombosis recurrence compared to major VTE.
- IDDVT patients had a non-inferior rate of prospective malignancy detection compared to major VTE.
- Similar rates of long-term complications show that the IDDVT significance should not be understated.

IntroductionIsolated distal deep venous thrombosis (IDDVT) is traditionally associated with less severe clinical sequelae, with ongoing debate on multiple aspects of its management. Despite numerous studies evaluating its acute management, there remains a paucity of data evaluating long-term complications such as recurrence and subsequent malignancy. We aim to evaluate the characteristics of IDDVT in institutions that routinely perform whole leg ultrasonography, and the risks of recurrence and complications in comparison to major venous thromboembolism (major VTE; defined as above-knee or proximal DVT and pulmonary embolism (PE)).MethodsRetrospective evaluation of consecutive IDDVT and major VTE from July 2011 to December 2012 in a hospital network in Melbourne, Australia. Patients were followed up for a minimum of 24 months. Patients with active malignancy were excluded.ResultsOf 1024 VTE cases, there were 164 non-cancer patients (92 males, 72 females, median age of 61 years) with IDDVT. Compared to major VTE, IDDVT was more likely to be provoked (73% vs 59%, p < 0.01), has shorter duration of anticoagulation (median 3.5 months vs 6.0 months, p < 0.01) and less clinically significant bleeding (2.4% vs 6.7%, p = 0.05), independent of duration of therapy. Recurrence was non-inferior compared to major VTE (10% vs 7%, p = 0.36) and 60% recurred with major VTE. Three (1.8%) were subsequently diagnosed with cancer (vs 1.9% in major VTE, p = 0.97).ConclusionsIDDVT has non-inferior rates of recurrence and subsequent cancer detection compared to major VTE and hence, its clinical significance should not differ from major VTE. Further studies are required to determine the adequate length of anticoagulation.