General information about anticoagulant therapy

Thrombosis is the most common pathology underlying acute coronary syndromes, stroke and venous thromboembolism, which are major causes of death and disability worldwideISTH Steering Committee for World Thrombosis Day, 2014. Venous thromboembolism is a leading preventable cause of hospital deaths, and up to 60% of cases of venous thromboembolism occur during or within 90 days of hospitalisationJha, 2013. The prevention and treatment of thromboembolism have significant potential to reduce the global burden of disease; see Venous thromboembolism: prophylaxis or Venous thromboembolism: treatment for more information.

Anticoagulant therapy prevents thrombus formation by indirectly or directly targeting coagulation proteins. Anticoagulants are most effective when the predominant pathophysiology is coagulation activation leading to fibrin formation, such as within veins or within the left atrial appendage in atrial fibrillation. However, anticoagulants can also prevent and treat arterial thrombus formation, where platelet activation is the primary pathophysiology; they have an additive effect with antiplatelet drugs.

Anticoagulants are effective and extensively used in clinical practice, but for all indications the harm–benefit balance for anticoagulant therapy must be weighed for each patient. Direct-acting oral anticoagulants (DOACs) (eg apixaban, rivaroxaban, dabigatran) do not need anticoagulation monitoring and are dosed according to the specific indication. Warfarin and unfractionated heparin (UFH) have significant pharmacokinetic variability necessitating frequent monitoring and/or dose adjustment. Despite this, warfarin and UFH remain the first-line options for some indications, such as patients with rheumatic mitral stenosis and/or a mechanical heart valve, and for patients with impaired kidney function.

Anticoagulant use in patients with palliative care needs can be complex. The decision to continue, change or stop the drug is based on assessing the benefit of anticoagulation for stroke risk reduction or secondary prevention of thromboembolism, compared to the elevated bleeding risk, and alongside the potential burden to the patient; see Principles of rationalising anticoagulants in palliative care in the Palliative care guidelines for more information.