Venous blood clots in the deep veins (DVT) or lungs (PE) remain a medical emergency, killing one person every 37 seconds in the Western World.
Venous Thromboembolism (VTE) occurs when part of a clot formed in a deep vein, for example in the leg (known as deep vein thrombosis, or DVT), is carried to the lung, via the heart, preventing the uptake of oxygen. This is known as a pulmonary embolism (PE), an event which can be rapidly fatal.
VTE is the third most common cardiovascular illness, after acute coronary syndrome and stroke, responsible for approximately 780,000 deaths in the Europe and United States each year. In around 90% of fatal cases the embolism is undetected or untreatable prior to death, making VTE-prevention an essential task for every health care system.
In patients with PE, up to 25% of patients present with sudden death and a further 15-20% die within three months. In patients with DVT, 60% of patients develop post-thrombotic syndrome (PTS), the symptoms of which include pain, swelling, varicose veins and skin discolouration. 3-4% of patients develop venous ulcers, which are chronic wounds that require dressing and compression.
Both PTS and venous ulcers have a significant impact on a patient’s quality of life, and are associated with significant direct and indirect costs. The total cost of VTE treatment and management is estimated to be £640 million per year in the United Kingdom.
New oral anticoagulants have been developed to serve as a single-drug solution approved for the treatment and subsequent prevention of VTE, providing simplified patient management without the need for injections or routine coagulation monitoring. Xarelto (rivaroxaban) was the first such single-drug solution approved for the treatment of DVT and the prevention of recurrent DVT and PE in 2011.
As many as one in four VTEs occur in patients with a previous VTE. The estimated increasing risk of recurrence in unprovoked VTE is 10% at one year and 30% at 10 years. Both morbidity and mortality are increased with recurrent VTE.
The traditional standard of care for acute VTE treatment and long-term prevention of recurrence is a dual-drug approach of daily injections of a low molecular weight heparin (LMWH) followed by a transition to long-term oral anticoagulant therapy with a vitamin K antagonist (VKA), such as warfarin.