Approach

Superficial vein thrombosis (SVT) has traditionally been considered a relatively benign condition, with conservative management recommended, mainly focusing on relief of local symptoms.

In patients with a high risk of thrombus progression into the deep venous system and embolisation, anticoagulation is recommended to prevent thrombus extension, thromboembolic complications, and recurrence.[60][61]​ Surgical treatment is considered an alternative for patients with a high risk and contraindications to anticoagulation; it involves ligation of the superficial vein at the junction with the deep vein and mechanically prohibits thrombus propagation. 

Oral non-steroidal anti-inflammatory drugs (NSAIDs), usually in combination with elastic bandages or compression stockings, can be considered as first-line therapy for SVT that only involves tributaries of varicose veins.[62]

NSAIDs may also be considered first-line if the thrombus in the affected saphenous vein is less than 5 cm in length and in the below-knee great saphenous vein; however, as many of these patients exhibit progression when followed clinically, prophylactic-dose anticoagulation may be warranted. Anticoagulation should also be considered for any patient with at least one risk factor for venous thromboembolism (VTE).

Most of the available evidence for treatment of SVT pertains to thrombosis in the lower extremities. There are insufficient data to assess the safety and efficacy of topical treatments, systemic anticoagulation, or NSAIDs for upper-extremity SVT.[63] Management of upper-extremity SVT is beyond the scope of this topic.

Anticoagulation

Prophylactic anticoagulation is recommended for all patients with a superficial thrombus ≥5 cm in length within the great saphenous (GSV), small saphenous (SSV), or anterior accessory great saphenous (AASV) veins and >3 cm from the saphenofemoral or saphenopopliteal junctions.​[44][62][64]​​​​​[65]​​​​​ Studies suggest SVT in axial superficial veins (GSV, SSV, AASV) is associated with a higher risk propagation and future VTE when compared with thrombus in the tributary varicosities alone.[66][67][68]​​​ Clear evidence is lacking, but prophylactic anticoagulation may also be warranted for patients SVT <5 cm in length within an axial superficial vein, or patients with thrombus within tributary varicose veins only if they have one or more risk factors for VTE.[62][65]

Thrombus within 3 cm or less of the saphenofemoral or saphenopopliteal junctions is managed with therapeutic, not prophylactic, anticoagulation due to the increased risk of propagation to deep vein thrombosis (DVT).[62] Therapeutic anticoagulation is also indicated for patients with concomitant DVT or pulmonary embolism (PE), and for SVT with extension into the femoral vein or popliteal vein.

A thorough assessment of bleeding risk should be undertaken before prescribing an anticoagulant. Direct oral anticoagulants (DOACs) should be used with caution in patients with renal insufficiency; a dose adjustment or an alternative treatment (e.g., heparin, warfarin) may be required.[69]​ Surveillance for heparin-induced thrombocytopenia may be necessary in some cases.

See section on pregnancy below for recommendations on anticoagulation during pregnancy.

Prophylactic anticoagulation

Guidelines recommend 45 days of anticoagulation, with prophylactic doses of fondaparinux as the preferred option.[60][62][65]​​ Recommended alternatives include prophylactic or intermediate-dose low molecular weight heparin (LMWH), or oral rivaroxaban for patients who decline or are unable to use parenteral anticoagulation.[60][62]​ Intermediate doses are larger than prophylactic doses, and smaller than treatment doses. The 2023 European Society for Vascular Surgery (ESVS) guideline on antithrombotic therapy recommends intermediate-dose LMWH, as data suggests it is more effective than prophylactic-dose LMWH at preventing recurrent events.[65]

One Cochrane review of treatment of lower-limb SVT found that most studies were small and of poor quality.[70]​ Based on moderate-quality evidence from one large randomised controlled trial (the CALISTO trial), fondaparinux significantly reduces symptomatic VTE, SVT extension, and SVT recurrence compared with placebo.[70][71]​ Low-quality evidence suggests LMWH reduces SVT extension and recurrence compared with placebo, but LMWH treatment is not associated with prevention of future VTE.[70][72]

Use of oral rivaroxaban is supported by an open-label randomised trial (the SURPRISE trial) of patients with SVT at high risk of VTE complications (above-knee SVT and age over 65 years, male sex, previous VTE, cancer, autoimmune disease, or SVT of non-varicose veins), which found that rivaroxaban was non-inferior to fondaparinux with respect to a composite outcome of symptomatic DVT or PE, progression or recurrence of superficial vein thrombosis, and all-cause mortality at 45 days.[73]

It is important to note the differences between the CALISTO trial, which excluded high-risk patients and enrolled low-risk patients, and the SURPRISE trial, which enrolled exclusively high-risk patients. The risk for subsequent VTE in patients in the SURPRISE trial was substantially higher after treatment for 45 days than for patients in the CALISTO trial.[71][73]​ This indicates that high-risk patients with SVT may require treatment for longer than 45 days, but data to support a specific duration are lacking. The ESVS guideline recommends considering treatment with intermediate-dose anticoagulation for 3 months in patients with high-risk features (e.g., extensive SVT involving both the calf and thigh, absence of local pain, axial SVT, multiple sites of thrombosis).[65]

Other options include unfractionated heparin (UFH) alone, or warfarin overlapped with 4 days of UFH or LMWH and continued for 45 days. These options are not commonly used in the US but may be indicated in rare circumstances (e.g., critically ill hospitalised patients). Use of UFH is supported by weak evidence.[70][74]​​ Warfarin has largely been replaced by alternative options because it requires frequent monitoring and is associated with an increased risk of bleeding.[69]

A repeat Doppler ultrasound following the start of anticoagulant therapy may be required to assess for SVT extension, especially for proximal greater saphenous vein SVT treated with intermediate or prophylactic doses of LMWH, prophylactic doses of fondaparinux, or intermediate doses of UFH.

Therapeutic anticoagulation

Patients with SVT and concomitant DVT or PE must be treated according to VTE practice guidelines, including therapeutic doses of anticoagulation.[62]​​[75]​ At least 3 months of therapeutic anticoagulation is also recommended for SVT with extension into the femoral vein or popliteal vein, or if the thrombus is located 3 cm or less from the saphenofemoral junction or saphenopopliteal junction.[62] It is important to note that these patients were excluded from the recent randomised controlled trials on SVT due to extremely high risk of thrombus propagation into the deep venous system.

First-line therapy includes treatment doses of a DOAC (e.g., apixaban, edoxaban, rivaroxaban, dabigatran); or LMWH, UFH, or fondaparinux, followed by warfarin to target INR 2.5. See Deep vein thrombosis.

Surgical intervention: ligation or inferior vena cava filter

Guidelines recommend medical treatment with anticoagulants over surgical treatment.[60][61] This recommendation is based on studies that compared surgical therapy with anticoagulation and showed similar rates of SVT progression but higher rates of complications with surgical therapy, such as wound infections.[76]

In patients with a contraindication to anticoagulation (active bleeding, severe thrombocytopenia) and a thrombus located 3 cm or less from the saphenofemoral or saphenopopliteal junction, ligation with or without thrombectomy may be indicated, where local expertise is available.

If the thrombus extends into the common femoral vein substantially, placement of an optional inferior vena cava (IVC) filter is appropriate, with retrieval as soon as the contraindication to anticoagulation has resolved.

In patients with a contraindication to anticoagulation and SVT ≥5 cm in length within an axial superficial vein and >3 cm from the saphenofemoral or saphenopopliteal junction, treat surgically with ligation of the saphenofemoral or saphenopopliteal junction (depending on where the SVT is located), with anticoagulation initiated when the reason for the contraindication has resolved.

Even in patients in whom therapeutic anticoagulation for treatment of SVT is contraindicated, prophylactic LMWH is nevertheless recommended postoperatively for at least 7-10 days to reduce postoperative VTE. Once there is no longer a contraindication to anticoagulation, LMWH or UFH should be started or resumed in order to prevent thromboembolic complications.

Non-steroidal anti-inflammatory drugs (NSAIDs)

If patients have a short segment SVT of less than 5 cm in length or SVT in a tributary varicose vein only, NSAIDS may be employed along with close clinical follow-up and serial ultrasound examinations as necessary.[62]

NSAIDs should not be prescribed in patients at higher risk of thromboembolism (e.g., extensive SVT with involvement above the knee, particularly if within 3 cm of the saphenofemoral junction; thrombus ≥5 cm in length; severe SVT symptoms; involvement of the greater saphenous vein; history of venous thrombosis or SVT; active cancer) and should not be given in combination with anticoagulants due to the increased risk of bleeding.[77]​ Contraindications to NSAIDs (such as peptic ulcer disease) should also be considered before they are prescribed.

Oral NSAIDs, when compared with placebo, have been shown to help with local symptoms and to prevent SVT extension or recurrence.[68][78][79]

However, one Cochrane review found that NSAIDs do not influence the rate of VTE or resolution of symptoms.[70]​​​

Compression therapy: elastic bandages and compression stockings

Compression therapy is important in the resolution of the SVT and helps relieve local symptoms such as swelling and pain. Compression therapy aims to control venous reflux and peripheral oedema by either active or passive options:

  • Compression stockings or long stretch bandages provide an active pressure on the limb both at rest and during muscle contraction

  • Inelastic bandages counteract the increase in muscle volume resulting from muscle contraction (i.e., exerts passive compression). At rest the bandages deliver little or no pressure.

In the acute phase of SVT, bandages may provide relief from symptoms such as itchiness, pain, and swelling, and compression stockings or long stretch bandages may help with resolution of the SVT and prevent chronic swelling.

Some data from the acute DVT literature supports this, but data on compression stockings for treatment of SVT are inconclusive.[72][80]​​​ One small randomised trial comparing LMWH plus compression stockings versus LMWH alone for patients with isolated leg SVT found no significant difference in clinical symptoms or quality of life after 3 weeks, despite faster thrombus regression in the compression stockings plus LMWH group after 7 days.[81]

Compression therapy has not been shown to prevent SVT extension or thromboembolic complications.

Compression stockings are usually prescribed for 10-14 days. They are put on in the morning before getting up and removed in the evening when going to bed.

Limitations and contraindications

The major limitations to compression therapy are usually poor patient compliance and, in the elderly, difficulty in applying.

An important contraindication to compression therapy includes a systolic arterial pressure at the ankle <80 mmHg or an ankle-brachial pressure index (ABPI) <0.8. An ABPI of 0.5 to 0.8 indicates that arterial disease may be present and that compression may further compromise arterial blood supply.

Other contraindications to the use of stockings include acute dermatitis, open wounds, and phlegmasia cerulea dolens. Caution is advised in patients with diabetes, neuropathy, skin sensitivities or allergies, and signs of infection.

Local ice/heat and leg elevation

Although there is no evidence for its therapeutic efficacy, local heat application and leg elevation can be used as an ancillary treatment for SVT. Ice may be used instead of heat initially to decrease inflammation.

Patients should be encouraged to ambulate and to elevate the affected leg when resting. These strategies have not been shown to prevent thromboembolic complications, but they are reasonable to recommend to all patients for symptom relief.

Varicose vein surgery

After the acute treatment of SVT of an incompetent saphenous vein with associated varicose veins or, and in the case of repeated episodes, consider referral for a varicose vein procedure, such as endovenous thermal or chemical ablation. In patients with associated saphenous vein insufficiency, treatment of the refluxing axial superficial vein serves to prevent recurrence of SVT.[61]​ The workup would include a venous insufficiency ultrasound to evaluate the deep and superficial veins for evidence of reflux once the patient is out of the prothrombotic period.

Varicose vein procedures should only be done after the acute SVT episode resolves to avoid thromboembolic complications induced by such procedures.[61]​ Guidelines for varicose surgery should be followed. Prophylactic LMWH therapy may be considered at the time of surgery.[82]

Pregnancy

Guidelines recommend anticoagulation for all pregnant women with SVT, due to the persistent increased thrombotic risk throughout pregnancy and for at least 6 weeks postnatal.[2][83]​​​ Prophylactic- or intermediate-dose LMWH is recommended, but optimum duration of treatment is uncertain.[62][83]​ Recommendations vary from a fixed period (1-6 weeks) to treatment for the remainder of pregnancy and 6 weeks postnatal for SVT that is bilateral, symptomatic, ≤5 cm from the deep venous system, or ≥5 cm in length.[62][83]

The American Society of Hematology guideline suggests that the benefit of anticoagulation may be less for SVT that is more distal or less symptomatic and for patients who are needle averse.[83] If no treatment is administered, guidelines recommend clinical follow-up and repeat ultrasound within 7-10 days.[62] 

Patients with extension into the femoral vein or popliteal vein, a thrombus ≤3 cm from the saphenofemoral or saphenopopliteal junction, or concomitant DVT or PE must be treated according to VTE practice guidelines, including therapeutic doses of anticoagulation for at least 3 months.[62][75]​ During pregnancy, LMWH is recommended. If anticoagulation is contraindicated, an IVC filter may be placed but typically in the suprarenal location due to the gravid uterus. Ligation of the saphenofemoral or saphenopopliteal junction (depending on where the SVT is located) is also an option during pregnancy, but may require general anesthesia. IVC ligation is not typically an option during pregnancy.

See Deep vein thrombosis.

NSAIDs should be avoided during pregnancy. Warfarin is contraindicated in pregnancy, and DOACs are not recommended during pregnancy as they may cross the placenta.

Varicose vein procedures would not be considered during pregnancy.

Supportive care for SVT during pregnancy includes increased hydration (pregnancy has higher blood volume), ambulation, compression stockings, and local ice (acute SVT) or heat (subacute SVT, after the initial inflammation is starting to decrease).

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