Uncomplicated superficial vein thrombosis (SVT) within an axial superficial vein was once considered to be a benign and self-limiting condition. It is now known that even uncomplicated SVT is associated with venous thromboembolism (VTE) at the time of diagnosis and is associated with a future risk of propagation of thrombus, future VTE, and recurrent episodes of SVT.[17]van Langevelde K, Lijfering WM, Rosendaal FR, et al. Increased risk of venous thrombosis in persons with clinically diagnosed superficial vein thrombosis: results from the MEGA study. Blood. 2011 Oct 13;118(15):4239-41.
https://ashpublications.org/blood/article/118/15/4239/29051/Increased-risk-of-venous-thrombosis-in-persons
http://www.ncbi.nlm.nih.gov/pubmed/21849479?tool=bestpractice.com
[40]Di Minno MN, Ambrosino P, Ambrosini F, et al. Prevalence of deep vein thrombosis and pulmonary embolism in patients with superficial vein thrombosis: a systematic review and meta-analysis. J Thromb Haemost. 2016 May;14(5):964-72.
https://www.doi.org/10.1111/jth.13279
http://www.ncbi.nlm.nih.gov/pubmed/26845754?tool=bestpractice.com
Due to this fact, duplex ultrasound at the time of diagnosis is essential and treatment with prophylactic-dose anticoagulation for 45 days is warranted. Isolated thrombus within small tributary varicosities is considered more benign and may be treated without anticoagulation unless there is propagation.[44]Beyer-Westendorf J. Controversies in venous thromboembolism: to treat or not to treat superficial vein thrombosis. Hematology Am Soc Hematol Educ Program. 2017 Dec 8;2017(1):223-30.
https://ashpublications.org/hematology/article/2017/1/223/21080/Controversies-in-venous-thromboembolism-to-treat
http://www.ncbi.nlm.nih.gov/pubmed/29222259?tool=bestpractice.com
In uncomplicated SVT, symptoms generally subside in 1-2 weeks, though hardness of the vein may persist for longer.
Concomitant VTE, such as deep vein thrombosis (DVT) or pulmonary embolism (PE), may prolong the course and anticoagulation may be required for ≥3 months. Complications of DVT or PE include VTE recurrence, as well as chronic venous insufficiency and post-thrombotic syndrome in the case of DVT.
Risk of recurrence
Depending on the presence or absence of underlying risk factors such as varicose veins, malignancy, previous VTE, and/or family history of VTE, the risk of SVT recurrence ranges anywhere between 1.6% to 12.2% in treated patients and 3.3% to 36.7% in untreated patients.[85]Wichers IM, Di Nisio M, Büller HR, et al. Treatment of superficial vein thrombosis to prevent deep vein thrombosis and pulmonary embolism: a systematic review. Haematologica. 2005 May;90(5):672-7.
https://www.haematologica.org/content/haematol/90/5/672.full.pdf
http://www.ncbi.nlm.nih.gov/pubmed/15921382?tool=bestpractice.com
[86]Cosmi B, Filippini M, Campana F, et al; STEFLUX Investigators. Risk factors for recurrent events in subjects with superficial vein thrombosis in the randomized clinical trial SteFlux (Superficial Thromboembolism Fluxum). Thromb Res. 2014 Feb;133(2):196-202.
http://www.ncbi.nlm.nih.gov/pubmed/24365043?tool=bestpractice.com
The risk for subsequent VTE within the first 3 months following SVT is about 1.5% to 6.2%.[61]Kakkos SK, Gohel M, Baekgaard N, et al. Editor's Choice - European Society for Vascular Surgery (ESVS) 2021 clinical practice guidelines on the management of venous thrombosis. Eur J Vasc Endovasc Surg. 2021 Jan;61(1):9-82.
https://www.ejves.com/article/S1078-5884(20)30868-6/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/33334670?tool=bestpractice.com
[87]Barco S, Pomero F, Di Minno MND, et al. Clinical course of patients with symptomatic isolated superficial vein thrombosis: the ICARO follow-up study. J Thromb Haemost. 2017 Nov;15(11):2176-83.
https://www.jthjournal.org/article/S1538-7836(22)04391-4/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/28871623?tool=bestpractice.com
In the case of recurrent SVT in the setting of axial superficial venous insufficiency with or without varicose veins, interventions such as endovenous thermal or chemical ablation should be considered to decrease the risk of recurrence, after anticoagulation and once the acute thrombotic period has ended.