Treatment

Carlos Martinez, MD, MSc, and Ben Freedman, OAM, MBBS, PhD, on VKA Oral Anticoagulation Therapy Cessation

Oral anticoagulation therapy is essential for preventing ischemic strokes and transient ischemic attacks among patients with nonvalvular atrial fibrillation (AF). However, only 20% to 50% of patients continue oral anticoagulation therapy with vitamin K antagonists (VKAs) at 1 year. This became the basis of a recent study, which examined the risk of ischemic strokes and transient ischemic attacks among patients who discontinued VKA therapy.1

Cardiology Consultant reached out to the lead authors of this study for more insight on their results. Carlos Martinez, MD, MSc, is from the Institute for Epidemiology, Statistics and Informatics in Frankfurt, Germany, and Ben Freedman, OAM, MBBS, PhD, is from the Heart Research Institute at the University of Sydney in Australia.

CARDIO CON: How does cessation of VKA therapy effect the risk of ischemic stroke and transient ischemic attack among patients newly diagnosed with AF?

Carlos Martinez, Ben Freedman: The risk of stroke is highest in the first year after AF diagnosis. Thus, the risk of cessation in terms of more strokes is higher in absolute terms if VKA is stopped within the first year after diagnosis. The implications are that we need to pay a lot of attention to persistence with oral anticoagulation therapy after prescription in the first year after diagnosis. If we do this through innovative methods, it may even mean that patients will be more likely to continue the drugs long term.

CARDIO CON: Specifically, you and your colleagues found that cessation of VKAs increased the risk of stroke and transient ischemic attacks within the first year after AF diagnosis, and even 3 years after discontinuation, the risk is still doubled. How can this risk be ameliorated for these patients?

CM, BF: We need to pay as much attention to persistence with oral anticoagulation therapy as we do to encouraging prescription of oral anticoagulation therapy according to guidelines. The issue is that persistence with both VKA and non-VKA oral anticoagulation therapy is far from ideal, and the best way to encourage very high persistence rates is unknown.

CARDIO CON: What is the key take-home message from your study for cardiologists?

CM: Because non-persistence with oral anticoagulation therapy is high, cardiologists need to be aware that there is a significant penalty of stopping oral anticoagulation therapy within the first year after diagnosis and that a significant penalty persists and remains constant even if stopping occurs at 3 years. Cardiologists need to be aware that non-persistence should be searched for and avoided in their patients.

 

Reference:

  1. Martinez C, Wallenhorst C, Rietbrock S, Freedman B. Ischemic stroke and transient ischemic attack risk following vitamin K antagonist cessation in newly diagnosed atrial fibrillation: a cohort study [published online January 15, 2020]. J Am Heart Assoc. https://doi.org/10.1161/JAHA.119.014376.