Superficial Venous Thrombosis

“SUPERFICIAL VENOUS THROMBOSIS (SVT) –BEWARE THE PITFALLS!”

The meeting of the IUA (International Union of Angiology) recently held in Sydney (10-14 August 2014) highlighted recent international research regarding the significance of superficial venous thrombosis.

An exhaustive review by an international committee found that rather than being the benign condition we learnt about in medical school, SVT should be considered part of a spectrum of thromboembolic disease that includes DVT & PE. The topic has been summarised in a consensus document (1) that forms the basis of much of the material discussed below. It should be noted that these recommendations apply to cases of “spontaneous” thrombosis and would not apply to iatrogenic thrombosis secondary to cannulation, intravenous lines etc.

Importantly in patients with spontaneous SVT almost 20-25% have either co-existing DVT or PE at the time of diagnosis, hence simple reassurance and anti-inflammatory drugs alone (as is widely practiced) would place a number of patients at risk for preventable subsequent DVT & PE. These complications being more common in patients with thrombus in the great and short saphenous veins close to their junction with the deep system.

SVT occurs in two forms, with varicose veins (V-SVT, comprising 75% of cases) and without varicose veins (NV-SVT, comprising 25% of cases). NV-SVT has much more serious implications if occurring spontaneously and was found to be associated with thrombophilia(i.e. Factor V Leiden mutation, protein C/S deficiency, anti-thrombin III deficiency etc.) in 48%, neoplasm in 4.8%, and non-neoplastic systemic disease such as Buerger’s and Behcets disease in 9.5%.

A condensed form of the 9 main recommendations are:

  • In cases of spontaneous NV-SVT or recurrent V-SVT, investigate for SVT risk factors, especially cancer and thrombophilia.
  • Ultrasound of the deep and superficial system of both limbs is recommended in all cases of SVT due to the high % of co-existing DVT and to assess the extent and location of SVT which cannot be fully determined clinically.
  • Immediate mobilisation and elastic compression is recommended (to prevent propagation and for patient comfort).
  • Anticoagulation with low molecular weight heparin (LMWH) is recommended for 4 weeks if the thrombus is >5cm in length to prevent propagation and DVT/PE. LMWH was said to give greater symptomatic improvement than warfarin or novel anticoagulants.
  • In cases of V-SVT, treatment of the underlying venous insufficiency and varicose veins following the acute event may prevent further problems.

Terminology Recommendations

Superficial Venous Thrombosis (SVT) should replace “superficial thrombophlebitis” as it is primarily a thrombotic rather than inflammatory condition with the old term having connotations of a benign inflammatory condition.

Superficial femoral vein – Readers are reminded that this term is incorrect and refers to a deep vein and thrombus in this location indicates a significant DVT requiring anticoagulation. Radiologists and sonographers have been cautioned not to use this term as confusion has led to at least one death as the clinician believed this was a superficial vein thrombosis not requiring anticoagulation.

Superficial vein thrombosis: a consensus statement
[Int Angiol 2012;31:203-16]

  • University of Melbourne