Anticoagulation prevents the formation of blood clots, which have been linked to the underlying pathology of several forms of PH.  Anticoagulation is a conventional therapy prescribed for some people with pulmonary hypertension (PH). It will be prescribed life-long for patients who are at higher risk of developing blood clots, for example those with chronic thrombo-embolic pulmonary hypertension (CTEPH). It will also be recommended for patients suffering from problems of irregular heartbeats, for example atrial fibrillation (AF). The place in therapy of anticoagulation for other PH patients is decided on an individual basis. This clinical decision involves weighing up the potential benefits against risks.

Historically, the most commonly prescribed anticoagulant was warfarin. More recently alternatives have been approved and are increasingly used: rivaroxaban, apixaban, edoxaban and dabigatran, collectively known as either NOACs (Novel Oral Anticoagulants) or DOACs (Direct Oral Anticoagulants). These have also been shown to be safe and effective in preventing and treating blood clots. At this time, there are no large trials in PH. The 6th WSPH task force(Galiè et al., 2019) recognizes it remains unclear whether DOACs off sufficient anticoagulation in CTEPH.  Currently there is minimal evidence to suggest that one class of anticoagulant is better than another (i.e. warfarin vs. the newer NOACs/DOACs).

Other less commonly prescribed anticoagulants used include phenindione (used in patients who cannot tolerate warfarin), heparin and low-molecular weight heparin (LMWH) such as enoxaparin or dalteparin.