Antiplatelet treatment in patients with thrombosis and MPNs

Dr Chris Hillis is an assistant professor in the Division of Oncology at McMaster University and hematologist at the Juravinski Hospital and Cancer Centre.

What antithrombotic treatment should be used in a patient with thrombosis and myeloproliferative neoplasms (MPNs)? Should antiplatelet treatment be continued?

Chris Hillis, MD, MSc: We would generally stop antiplatelet treatment in patients who have a venous thromboembolic (VTE) event as they will require anticoagulation. What anticoagulant to use is a matter of discussion. More and more we are using direct oral anticoagulants (DOACs) in patients with MPNs to treat their VTE events. However, this is not based on particularly strong evidence.

What we do know is that there is a high failure rate on warfarin. Up to 20% or 30% of patients with MPNs who are treated with warfarin following a VTE will have recurrence despite being on warfarin. There are only 2 guidelines that I am aware of in this area and 1 actually recommends indefinite low-molecular-weight heparin, which I think is a big challenge for patients moving forward, as an MPN is a nonmodifiable risk factor. This person will have the MPN for the rest of their life, so they could end up on injected anticoagulants for a very long time.

Our clinical practice has really shifted to DOACs for venous thromboembolic disease and stopping the aspirin unless there is a very compelling indication to continue aspirin, such as a recent coronary artery event.