Heparin in the management of VTE

Dr Mark Crowther is a professor and chair of the Department of Medicine and the Leo Pharma Chair in Thromboembolism Research at McMaster University.

Is there still a place for unfractionated heparin and low-molecular-weight heparin (LMWH) in the current management of venous thromboembolism (VTE)? When to use them?

Mark Crowther, MD, MSc: In cancer-associated deep vein thrombosis (DVT) there is still a role for LMWH in 2 places. The first is, if you choose to use edoxaban as the direct oral anticoagulant (DOAC), you need to use 5 to 7 days of LMWH at the start of that treatment. Secondarily, the DOACs do appear to cause an increased risk of gastrointestinal bleeding and many guidance documents are being produced, or have been produced, which suggest that if the patient has a tumor of the gastrointestinal lumen, you should use a LMWH instead of a DOAC. So, DOACs are not the universal choice for cancer-associated thrombosis but are the choice in most patients. LMWH still has a role.

In other patients with VTE the role of LMWH and of unfractionated heparin diminishes every year, and the reason for this is that people are becoming more and more comfortable with up-front treatment with DOACs. In many centers, for example, a patient who is admitted to the hospital with an acute pulmonary embolism will be automatically treated with a LMWH and then transitioned to a DOAC at the time of hospital discharge. The safety of rivaroxaban or apixaban right from the start of pulmonary embolism treatment has been established by large studies, and people are becoming more comfortable with it. As they become more comfortable, the use of LMWH and unfractionated heparin will be reduced.

Finally, unfractionated heparin still has a role to play because there are some patients who are at very high risk of bleeding, and unfractionated heparin remains the only truly reversable anticoagulant that we have. And so, in selected hospitalized patients who have acute VTE and who are identified to have a high risk of bleeding, unfractionated heparin still has a role to play.