Venous thromboembolism (VTE) is the term used to describe a condition in which a blood clot (a thrombus) forms in a vein and then dislodges to travel in the blood (an embolus). A venous thrombus most commonly occurs in the deep veins of the legs or pelvis; this is called deep vein thrombosis (DVT). Blood flow through the affected vein can be limited by the clot, and it can cause swelling and pain in the leg. If the thrombus dislodges and travels to the lungs, this can lead to a potentially fatal pulmonary embolism (PE) when the clot blocks the blood supply to the lungs. Other complications of DVT include post-thrombotic syndrome, a chronic disorder that may include symptoms such as pain, heaviness, swelling, cramps, itching or tingling, increased skin pigmentation and ulceration in the affected limb.
Risk factors for VTE include a history of DVT, recent surgery, immobility, active cancer or cancer treatment, age over 60 years, obesity, hormone replacement therapy or oestrogen containing contraceptive therapy and the presence of co-morbidities such as heart disease. It is estimated that there will be over 46,000 cases of acute DVT in England and Wales during 2012, rising to nearly 50,000 by 2016 due in large part to the aging population.
Treatments for VTE include initiation with injectable anticoagulants such as low-molecular-weight heparin or fondaparinux sodium. Treatment is then overlapped with a vitamin-K antagonist, such as warfarin, until effective anticoagulation with the oral agent is achieved.
Rivaroxaban is an orally administered drug that helps to prevent blood from clotting. It does this by stopping a substance called Factor Xa from working. Factor Xa is necessary in the formation of thrombin and fibrin, the key components in blood clot formation. Duration of treatment with rivaroxaban is based on an assessment of the benefit of anticoagulation compared with the risk of bleeding and usually ranges from 3 to 12 months. Some people with ongoing risk factors for recurrence of VTE need ongoing treatment, possibly for many years or lifelong.
Professor Carole Longson, NICE Health Technology Evaluation Centre Director, said: “For many people, using warfarin is difficult because of the need for regular monitoring with blood tests, dosing adjustments, and the need to be careful about their diet because of warfarin’s interaction with certain foods. Because rivaroxaban does not require frequent blood tests to monitor treatment it represents a potential benefit for many people who have had a DVT, particularly those who have risk factors for recurrence of VTE and who therefore need longer term treatment. We are pleased, therefore, to be able to recommend rivaroxaban as a cost-effective option for treating DVT and preventing recurrent VTE in adults.”
The guidance is available (from 25 July) on the NICE website at http://guidance.nice.org.uk/TA261