Venous thrombosis

The initial treatment for venous thromboembolism is typically with either low molecular weight heparin (LMWH) or unfractionated heparin, or increasingly with directly acting oral anticoagulants (DOAC). USA recommendations for those without cancer include anticoagulation (medication that prevents further blood clots from forming) with the DOACs dabigatran, rivaroxaban, apixaban, or edoxaban rather than warfarin or low molecular weight heparin (LMWH).

They are used in the prevention of blood clots and treatment of venous thromboembolism (deep vein thrombosis and pulmonary embolism) and in the treatment of myocardial infarction.

A common type of venous thrombosis is a deep vein thrombosis (DVT), which is a blood clot in the deep veins of the leg.

Together, DVT and pulmonary embolism are known as venous thromboembolism (VTE).

If the thrombus breaks off (embolizes) and flows towards the lungs, it can become a pulmonary embolism (PE), a blood clot in the lungs.

Together, deep vein thrombosis and PE are known as venous thromboembolism (VTE).

Portal vein thrombosis is a form of venous thrombosis affecting the hepatic portal vein, which can lead to portal hypertension and reduction in the blood supply to the liver.

A piece of thrombus that is transported in this way is an embolus: the process of forming a thrombus that becomes embolic is called a thromboembolism.

In thromboembolism, the thrombus (blood clot) from a blood vessel is completely or partially detached from the site of thrombosis (clot).

Venous thrombi are caused mainly by a combination of venous stasis and hypercoagulability—but to a lesser extent endothelial damage and activation.

The most common conditions associated with thrombophilia are deep vein thrombosis (DVT) and pulmonary embolism (PE), which are referred to collectively as venous thromboembolism (VTE).

Protein S deficiency is a disorder associated with increased risk of venous thrombosis.

Venous thrombi are caused mainly by a combination of venous stasis and hypercoagulability—but to a lesser extent endothelial damage and activation.

Venous stasis is a risk factor for forming blood clots in veins (venous thrombosis), as with the deep veins of the legs (deep vein thrombosis or DVT).

The splenic vein can be affected by thrombosis, presenting some of the characteristics of portal vein thrombosis and portal hypertension, but localized to part of the territory drained by the splenic vein.

Hereditary antithrombin deficiency results in a state of increased coagulation which may lead to venous thrombosis.

The overall absolute risk of venous thrombosis per 100,000 woman years in current use of combined oral contraceptives is approximately 60, compared to 30 in non-users.

Combined oral contraceptives increase the risk of venous thromboembolism (including deep vein thrombosis (DVT) and pulmonary embolism (PE)).

The risk of thromboembolism varies with different types of birth control pills; Compared with combined oral contraceptives containing levonorgestrel (LNG), and with the same dose of estrogen and duration of use, the rate ratio of deep vein thrombosis for combined oral contraceptives with norethisterone is 0.98, with norgestimate 1.19, with desogestrel (DSG) 1.82, with gestodene 1.86, with drospirenone (DRSP) 1.64, and with cyproterone acetate 1.88.

It has been suggested that very high dosages (e.g., 40 mg/day, which are sometimes used in clinical practice for various indications) of NETA (and by extension norethisterone) may result in an increased risk of venous thromboembolism (VTE) analogously to high dosages (above 50 μg/day) of EE, and that even dosages of NETA of 10 to 20 mg, which correspond to EE dosages of approximately 20 to 30 μg/day, may in certain women be associated with increased risk.

The risk of thromboembolism varies with different types of birth control pills; Compared with combined oral contraceptives containing levonorgestrel (LNG), and with the same dose of estrogen and duration of use, the rate ratio of deep vein thrombosis for combined oral contraceptives with norethisterone is 0.98, with norgestimate 1.19, with desogestrel (DSG) 1.82, with gestodene 1.86, with drospirenone (DRSP) 1.64, and with cyproterone acetate 1.88.

Serious side effects of combined oral contraceptives containing desogestrel may include venous thromboembolism, arterial thromboembolism, hormone-dependent tumors (e.g., liver tumors, breast cancer), and melasma.

The risk of thromboembolism varies with different types of birth control pills; Compared with combined oral contraceptives containing levonorgestrel (LNG), and with the same dose of estrogen and duration of use, the rate ratio of deep vein thrombosis for combined oral contraceptives with norethisterone is 0.98, with norgestimate 1.19, with desogestrel (DSG) 1.82, with gestodene 1.86, with drospirenone (DRSP) 1.64, and with cyproterone acetate 1.88.

Women who take oral contraceptives containing gestodene are 5.6 times as likely to develop venous thromboembolism than women who do not take any contraceptive pill, and 1.6 times as likely to develop venous thromboembolism compared to women taking oral contraceptives containing levonorgestrel.

Platelets in venous thrombi attach to downstream fibrin, while in arterial thrombi, they compose the core.

This type of thrombosis arises by mechanisms different from those of a normal clot: namely, extending the fibrin of venous thrombosis; extending an unstable or ruptured arterial plaque, causing arterial thrombosis; and microcirculatory thrombosis.

The risk of thromboembolism varies with different types of birth control pills; Compared with combined oral contraceptives containing levonorgestrel (LNG), and with the same dose of estrogen and duration of use, the rate ratio of deep vein thrombosis for combined oral contraceptives with norethisterone is 0.98, with norgestimate 1.19, with desogestrel (DSG) 1.82, with gestodene 1.86, with drospirenone (DRSP) 1.64, and with cyproterone acetate 1.88.

While all oral contraceptives can increase the risk for venous thromboembolic events, including fatal blood clots, several studies have reported a greater risk for women taking contraceptives containing drospirenone.

This results in an increased risk of venous thrombosis, which can cause problems with circulation, such as pulmonary embolism.

USA recommendations for those without cancer include anticoagulation (medication that prevents further blood clots from forming) with the DOACs dabigatran, rivaroxaban, apixaban, or edoxaban rather than warfarin or low molecular weight heparin (LMWH).

Dabigatran, sold under the brand name Pradaxa among others, is an anticoagulant used to treat and prevent blood clots and to prevent stroke in people with atrial fibrillation.

The risk of thromboembolism varies with different types of birth control pills; Compared with combined oral contraceptives containing levonorgestrel (LNG), and with the same dose of estrogen and duration of use, the rate ratio of deep vein thrombosis for combined oral contraceptives with norethisterone is 0.98, with norgestimate 1.19, with desogestrel (DSG) 1.82, with gestodene 1.86, with drospirenone (DRSP) 1.64, and with cyproterone acetate 1.88.

USA recommendations for those without cancer include anticoagulation (medication that prevents further blood clots from forming) with the DOACs dabigatran, rivaroxaban, apixaban, or edoxaban rather than warfarin or low molecular weight heparin (LMWH).

Apixaban, sold under the trade name Eliquis among others, is an anticoagulant used to treat and prevent blood clots and to prevent stroke in people with atrial fibrillation.

When this affects the blood vessels of the brain it can cause stroke. In hospitalized people who have had a stroke and not had surgery, mechanical measures (compression stockings) resulted in skin damage and no clinical improvement.

Rudolf Virchow first described the mechanism of thromboembolism as a major factor.

USA recommendations for those without cancer include anticoagulation (medication that prevents further blood clots from forming) with the DOACs dabigatran, rivaroxaban, apixaban, or edoxaban rather than warfarin or low molecular weight heparin (LMWH).

It was developed by Daiichi Sankyo and approved in July 2011 in Japan for prevention of venous thromboembolisms following lower-limb orthopedic surgery.

No differences have been detected in the route of administration of UFH (subcutaneous or intravenous).

Central IV lines carry risks of bleeding, infection, gangrene, thromboembolism and gas embolism (see Risks below).

In hospitalized people who have had a stroke and not had surgery, mechanical measures (compression stockings) resulted in skin damage and no clinical improvement.

Pharmacological (warfarin, unfractionated heparin, low molecular weight heparin) and mechanical measures (graded compression stockings, intermittent pneumatic compression devices, and venous foot pumps) are used to prevent venous thromboembolism (VTE) in clinical practice.

Thrombosis is a term for a blood clot occurring inside a blood vessel.

Thrombosis may occur in veins (venous thrombosis) or in arteries (arterial thrombosis).