The 2012 ACCP guidelines offered weak recommendations. For at-risk long-haul travelers—those with "previous VTE, recent surgery or trauma, active malignancy, pregnancy, estrogen use, advanced age, limited mobility, severe obesity, or known thrombophilic disorder"—suggestions included calf exercises, frequent walking, and aisle seating in airplanes to ease walking. The use of graduated compression stockings that fit below the knee and give 15–30 mm Hg of pressure to the ankle was suggested, while aspirin or anticoagulants were not. Compression stockings have sharply reduced the levels of asymptomatic DVT in airline passengers, but the effect on symptomatic VTE is unknown, as none of the individuals studied developed symptomatic VTE.

The risk of VTE is increased in pregnancy by about five times because of a more hypercoagulable state, a likely adaptation against fatal postpartum hemorrhage. Additionally, pregnant women with genetic risk factors are subject to a roughly three to 30 times increased risk for VTE. Preventative treatments for pregnancy-related VTE in hypercoagulable women were suggested by the ACCP. Homozygous carriers of factor V Leiden or prothrombin G20210A with a family history of VTE were suggested for antepartum LMWH and either LMWH or a vitamin K antagonist (VKA) for the six weeks following childbirth. Those with another thrombophilia and a family history but no previous VTE were suggested for watchful waiting during pregnancy and LMWH or—for those without protein C or S deficiency—a VKA. Homozygous carriers of factor V Leiden or prothrombin G20210A with no personal or family history of VTE were suggested for watchful waiting during pregnancy and LMWH or a VKA for six weeks after childbirth. Those with another thrombophilia but no family or personal history of VTE were suggested for watchful waiting only. Warfarin, a common VKA, can cause harm to the fetus and is not used for VTE prevention during pregnancy.

Treatment with compression stockings should be offered to patients with lower extremity superficial phlebitis, if not contraindicated (e.g., peripheral artery disease). Patients may find them helpful for reducing swelling and pain once the acute inflammation subsides.

Nonsteroidal anti-inflammatory drugs (NSAID) are effective in relieving the pain associated with venous inflammation and were found in a randomized trial to significantly decrease extension and/or recurrence of superficial vein thrombosis.

Anticoagulation for patients with lower extremity superficial thrombophlebitis at increased risk for thromboembolism (affected venous segment of ≥5 cm, in proximity to deep venous system, positive medical risk factors).

Treatment with fondaparinux reduces the risk of subsequent venous thromboembolism.

Surgery reserved for extension of the clot to within 1 cm of the saphenofemoral junction in patients deemed unreliable for anticoagulation, failure of anticoagulation and patients with intense pain. Surgical therapy with ligation of saphenofemoral junction or stripping of thrombosed superficial veins appears to be associated higher rates of venous thromboembolism compared with treatment with anitcoagulants.

Treatment can be either conservative or active. Active treatments can be divided into surgical and non-surgical treatments. Newer methods including endovenous laser treatment, radiofrequency ablation and foam sclerotherapy appear to work as well as surgery for varices of the greater saphenous vein.

The National Institute for Health and Clinical Excellence (NICE) produced clinical guidelines in July 2013 recommending that all people with symptomatic varicose veins (C2S) and worse should be referred to a vascular service for treatment. Conservative treatments such as support stockings should not be used unless treatment was not possible.

The symptoms of varicose veins can be controlled to an extent with the following:

- Elevating the legs often provides temporary symptomatic relief.

- Advice about regular exercise sounds sensible but is not supported by any evidence.

- The wearing of graduated compression stockings with variable pressure gradients (Class II or III) has been shown to correct the swelling, nutritional exchange, and improve the microcirculation in legs affected by varicose veins. They also often provide relief from the discomfort associated with this disease. Caution should be exercised in their use in patients with concurrent peripheral arterial disease.

- The wearing of intermittent pneumatic compression devices have been shown to reduce swelling and increase circulation

- Diosmin/hesperidin and other flavonoids.

- Anti-inflammatory medication such as ibuprofen or aspirin can be used as part of treatment for superficial thrombophlebitis along with graduated compression hosiery – but there is a risk of intestinal bleeding. In extensive superficial thrombophlebitis, consideration should be given to anti-coagulation, thrombectomy, or sclerotherapy of the involved vein.

- Topical gel application helps in managing symptoms related to varicose veins such as inflammation, pain, swelling, itching, and dryness.

The field of PTS still holds many unanswered questions that are important targets for more research. Those include

- Fully defining the pathophysiology of PTS, including the role of inflammation and residual thrombus after completion of an appropriate duration of anticoagulant therapy

- Developing a PTS risk prediction model

- Role of thrombolytic ("clot-busting") drugs in PTS prevention

- Defining the true efficacy of elastic compression stockings for PTS prevention (and if effective, elucidating the minimum compression strength necessary and the optimal timing and duration of compression therapy)

- Whether PTS prevention methods are necessary for patients with asymptomatic or distal DVT

- Additional treatment options for PTS with demonstrated safety and efficacy (compression and pharmacologic therapies)

Prevention of PTS begins with prevention of initial and recurrent DVT. For people hospitalized at high-risk of DVT, prevention methods may include early ambulation, use of compression stockings or electrostimulation devices, and/or anticoagulant medications.

Increasingly, catheter-directed thrombolysis has been employed. This is a procedure in which interventional radiology will break up a clot using a variety of methods.

For people who have already had a single DVT event, the best way to prevent a second DVT is appropriate anticoagulation therapy.

A second prevention approach may be weight loss for those who are overweight or obese. Increased weight can put more stress and pressure on leg veins, and can predispose patients to developing PTS.

Some 125,000 cases a year have been reported in the United States, but actual incidence of spontaneous thrombophlebitis is unknown.

A fourfold increased incidence from the third to the eight decade in men and a preponderance among women of approximately 55-70%.

The average mean age of affected patients is 60 years.

Thrombophlebitis can develop along the arm, back, or neck veins, the leg is by far the most common site. When it occurs in the leg, the great saphenous vein is usually involved, although other locations are possible.

Evidence supports the use of heparin in people following surgery who have a high risk of thrombosis to reduce the risk of DVTs; however, the effect on PEs or overall mortality is not known. In hospitalized non-surgical patients, mortality decreased but not statistically significant. It does not appear however to decrease the rate of symptomatic DVTs. Using both heparin and compression stockings appears better than either one alone in reducing the rate of DVT.

In hospitalized people who have had a stroke and not had surgery, mechanical measures (compression stockings) resulted in skin damage and no clinical improvement. Data on the effectiveness of compression stockings among hospitalized non-surgical patients without stroke is scarce.

The American College of Physicians (ACP) gave three strong recommendations with moderate quality evidence on VTE prevention in non-surgical patients: that hospitalized patients be assessed for their risk of thromboembolism and bleeding before prophylaxis (prevention); that heparin or a related drug is used if potential benefits are thought to outweigh potential harms; and that graduated compression stockings not be used. As an ACP policy implication, the guideline stated a lack of support for any performance measures that incentivize physicians to apply universal prophylaxis without regard to the risks. Goldhaber recommends that people should be assessed at their hospital discharge for persistent high-risk of venous thrombosis, and that people who adopt a heart-healthy lifestyle might lower their risk of venous thrombosis.

In those with cancer who are still walking about yet receiving chemotherapy, LMWH decreases the risk of VTE. Due to potential concerns of bleeding its routine use is not recommended. For people who are having surgery for cancer, it is recommended that they receive anticoagulation therapy (preferably LMWH) in order to prevent a VTE. LMWH is recommended for at least 7–10 days following cancer surgery, and for one month following surgery for people who have a high risk of VTEs.

In adults who have had their lower leg casted or placed in a brace for more than a week, LMWH decreased the risk of VTEs. LMWH is recommended for adults not in hospital with an above-knee cast and a below-knee cast, and is safe for this indication.

Following the completion of warfarin in those with prior VTE, long term aspirin is beneficial.

Evidence-based clinical guidelines were published in 2016 for the treatment of VTE.

Warfarin and vitamin K antagonists are anticoagulants that can be taken orally to reduce thromboembolic occurrence. Where a more effective response is required, heparin can be given (by injection) concomitantly. As a side effect of any anticoagulant, the risk of bleeding is increased, so the international normalized ratio of blood is monitored. Self-monitoring and self-management are safe options for competent patients, though their practice varies. In Germany, about 20% of patients were self-managed while only 1% of U.S. patients did home self-testing (according to one 2012 study). Other medications such as direct thrombin inhibitors and direct Xa inhibitors are increasingly being used instead of warfarin.

The treatment for thrombosis depends on whether it is in a vein or an artery, the impact on the person, and the risk of complications from treatment.

Superficial vein thrombosis (SVT) is a type of venous thrombosis, or a blood clot in a vein, which forms in a superficial vein near the surface of the body. Usually there is thrombophlebitis, which is an inflammatory reaction around a thrombosed vein, presenting as a painful induration with erythema. SVT has a limited clinical significance (in terms of morbidity and mortality) when compared to a deep vein thrombosis (DVT), which occurs deeper in the body, at the deep venous system level. If the blood clot is too near from the sapheno-femoral junction there is a bigger risk of pulmonary embolism.

The current ‘best’ practice in the UK is to treat the underlying venous reflux once an ulcer has healed. It is questionable as to whether endovenous treatment should be offered before ulcer healing, as current evidence would not support this approach as standard care. EVRA (Early Venous Reflux Ablation) ulcer trial - A UK NIHR HTA funded randomised clinical trial to compare early versus delayed endovenous treatment of superficial venous reflux in patients with chronic venous ulceration opened for recruitment in October 2013. The study hopes to show an increase in healing rates from 60% to 75% at 24 weeks.

Research from the University of Surrey and funded by the Leg Ulcer Charity is currently looking at the psychological impact of having a leg ulcer, on the relatives and friends of the affected person, and the influence of treatment.

The main aim of the treatment is to create such an environment that allows skin to grow across an ulcer. In the majority of cases this requires finding and treating underlying venous reflux and National Institute for Health and Care Excellence (NICE) recommends referral to a vascular service for anyone with a leg ulcer that has not healed within 2 weeks or anyone with a healed leg ulcer.

Most venous ulcers respond to patient education, elevation of foot, elastic compression and evaluation, called the Bisgaard regimen. There is no evidence for intravenous or by mouth antibiotics for venous leg ulcers. Silver products are also not typically useful while there is some evidence for cadexomer iodine creams. There is a lack of quality evidence regarding the use of medical grade honey for venous leg ulcers.

There is no specific treatment for thrombophilia, unless it is caused by an underlying medical illness (such as nephrotic syndrome), where the treatment of the underlying disease is needed. In those with unprovoked and/or recurrent thrombosis, or those with a high-risk form of thrombophilia, the most important decision is whether to use anticoagulation medications, such as warfarin, on a long-term basis to reduce the risk of further episodes. This risk needs to weighed against the risk that the treatment will cause significant bleeding, as the reported risk of major bleeding is over 3% per year, and 11% of those with major bleeding may die as a result.

Apart from the abovementioned forms of thrombophilia, the risk of recurrence after an episode of thrombosis is determined by factors such as the extent and severity of the original thrombosis, whether it was provoked (such as by immobilization or pregnancy), the number of previous thrombotic events, male sex, the presence of an inferior vena cava filter, the presence of cancer, symptoms of post-thrombotic syndrome, and obesity. These factors tend to be more important in the decision than the presence or absence of a detectable thrombophilia.

Those with antiphospholipid syndrome may be offered long-term anticoagulation after a first unprovoked episode of thrombosis. The risk is determined by the subtype of antibody detected, by the antibody titer (amount of antibodies), whether multiple antibodies are detected, and whether it is detected repeatedly or only on a single occasion.

Women with a thrombophilia who are contemplating pregnancy or are pregnant usually require alternatives to warfarin during pregnancy, especially in the first 13 weeks, when it may produce abnormalities in the unborn child. Low molecular weight heparin (LMWH, such as enoxaparin) is generally used as an alternative. Warfarin and LMWH may safely be used in breastfeeding.

When women experience recurrent pregnancy loss secondary to thrombophilia, some studies have suggested that low molecular weight heparin reduces the risk of miscarriage. When the results of all studies are analysed together, no statistically signifiant benefit could be demonstrated.

Conservative treatment of CVI in the leg involves symptomatic treatment and efforts to prevent the condition from getting worse instead of effecting a cure. This may include

- Manual compression lymphatic massage therapy

- Skin lubrication

- Sequential compression pump

- Ankle pump

- Compression stockings

- Blood pressure medicine

- Frequent periods of rest elevating the legs above the heart level

- Tilting the bed so that the feet are above the heart. This may be achieved by using a 20 cm (7-inch) bed wedge or sleeping in a 6 degree Trendelenburg position. Obese or pregnant patients might be advised by their physicians to forgo the tilted bed.

A vein disorder is a class of disease involving veins of the circulatory system.

Common vein disorders include:

- Varicose veins

- Deep vein thrombosis

Treatments include anticoagulants, shunts, bypass surgery, and transplants.

In people without a detectable thrombophilia, the cumulative risk of developing thrombosis by the age of 60 is about 12%. About 60% of people who are deficient in antithrombin will have experienced thrombosis at least once by age 60, as will about 50% of people with protein C deficiency and about a third of those with protein S deficiency. People with activated protein C resistance (usually resulting from factor V Leiden), in contrast, have a slightly raised absolute risk of thrombosis, with 15% having had at least one thrombotic event by the age of sixty. In general, men are more likely than women to experience repeated episodes of venous thrombosis.

People with factor V Leiden are at a relatively low risk of thrombosis, but may develop thrombosis in the presence of an additional risk factor, such as immobilization. Most people with the prothrombin mutation (G20210A) never develop thrombosis.

Venous Insufficiency Conservative, Hemodynamic and Ambulatory treatment" is an ultrasound guided, minimally invasive surgery strategic for the treatment of varicose veins, performed under local anaesthetic. CHIVA is an abbreviation from the French "Cure Conservatrice et Hemodynamique de l'Insufficience Veineuse en Ambulatoire".

It is known that diabetes causes changes to factors associated with coagulation and clotting, however not much is known of the risk of thromboembolism, or clots, in diabetic patients. There are some studies that show that diabetes increases the risk of thromboembolism; other studies show that diabetes does not increase the risk of thromboembolism. A study conducted in the Umea University Hospital, in Sweden, observed patients that were hospitalized due to an thromboembolism from 1997 to 1999. The researchers had access to patient information including age, sex, vein thromboembolism diagnosis, diagnostic methods, diabetes type and medical history. This study concluded that there is, in fact, an increased risk of thromboembolism development in diabetic patients, possibly due to factors associated with diabetes or diabetes itself. Diabetic patients are twice as likely to develop a thromboembolism than are non-diabetic patient. The exact mechanism of how diabetes increases the risk of clot formation remains unclear and could possibly be a future direction for study.

From previous studies, it is known that long distance air travel is associated with high risk of venous thrombosis. Long periods of inactivity in a limited amount of space may be a reason for the increased risk of blood clot formation. In addition, bent knees compresses the vein behind the knee (the popliteal vein) and the low humidity, low oxygen, high cabin pressure and consumption of alcohol concentrate the blood. A recent study, published in the British Journal of Haematology in 2014, determined which groups of people, are most at risk for developing a clot during or after a long flight. The study focused on 8755 frequent flying employees from international companies and organizations. It found that travelers who have recently undergone a surgical procedure or who have a malignant disease such as cancer or who are pregnant are most at risk. Preventative measures before flying may be taken in these at-risk groups as a solution.

Patients who have undergone kidney transplant have a high risk of developing RVT (about 0.4% to 6%). RVT is known to account for a large proportion of transplanted kidney failures due to technical problems (damage to the renal vein), clotting disorders, diabetes, consumption of ciclosporin or an unknown problem. Patients who have undergone a kidney transplant are commonly prescribed ciclosporin, an immunosuppressant drug which is known to reduce renal blood flow, increase platelet aggregation in the blood and cause damage to the endothelial tissue of the veins. In a clinical study conducted by the Nuffield Department of Surgery at the Oxford Transplant Centre, UK, transplant patients were given low doses of aspirin, which has a some anti-platelet activity. There is risk of bleeding in transplant patients when using anticoagulants like warfarin and herapin. Low dosage of aspirin was used as an alternative. The study concluded that a routine low-dose of aspirin in kidney transplant patients who are also taking ciclosporin significantly reduces the risk of RVT development.

Treatment may consist of topical applications of steroid based creams and the use of compression stockings to help force the underlying buildup of fluids back out of the lower leg or intermittent pneumatic compression pumps.

Management of the underlying defect is proportional to the severity of the clinical presentation. Leg swelling and pain is best evaluated by vascular specialists (vascular surgeons, interventional cardiologists, interventional radiologists) who both diagnose and treat arterial and venous diseases to ensure that the cause of the extremity pain is evaluated. The diagnosis needs to be confirmed with some sort of imaging that may include magnetic resonance venography, venogram and usually confirmed with intravascular ultrasound because the flattened vein may not be noticed on conventional venography. In order to prevent prolonged swelling or pain from the consequences of the backed up blood from the compressed iliac vein, flow needs to be improved out of the leg. Uncomplicated cases may be managed with compression stockings.

Severe May-Thurner syndrome may require thrombolysis if there is a recent onset of thrombosis, followed by angioplasty and stenting of the iliac vein after confirming the diagnosis with a venogram or an intravascular ultrasound. A stent may be used to support the area from further compression following angioplasty. As the name implies, there classically is not a thrombotic component in these cases, but thrombosis may occur at any time.

If the patient has extensive thrombosis, it may be appropriate to consider pharmacologic and/or mechanical (also known as pharmacomechanical) thrombectomy. This is currently being studied to determine whether this will decrease the incidence of post-thrombotic syndrome.

In ideal circumstances, patients with known varices should receive treatment to reduce their risk of bleeding. The non-selective β-blockers (e.g., propranolol, timolol or nadolol) and nitrates (e.g., isosorbide mononitrate (IMN) have been evaluated for secondary prophylaxis. Non-selective β-blockers (but not cardioselective β-blockers like atenolol) are preferred because they decrease both cardiac output by β blockade and splanchnic blood flow by blocking vasodilating β receptors at splanchnic vasculature. The effectiveness of this treatment has been shown by a number of different studies.

However, non-selective β-blockers do not prevent the "formation" of esophageal varices.

When medical contraindications to beta-blockers exist, such as significant reactive airway disease, then treatment with prophylactic endoscopic variceal ligation is often performed.