From the Guidelines
Warfarin should be used instead of direct oral anticoagulants (DOACs) in patients with mechanical heart valves or moderate-to-severe mitral stenosis, as stated in the 2024 ESC guidelines for the management of atrial fibrillation 1. The decision to use warfarin over DOACs is based on specific clinical scenarios where the benefits of warfarin outweigh those of DOACs. Some key scenarios include:
- Patients with mechanical heart valves, where warfarin is preferred due to the increased risk of thrombotic events with DOACs
- Patients with moderate to severe mitral stenosis, where warfarin is recommended over DOACs
- Patients who cannot afford DOACs, where warfarin is a more economical option, though it requires regular INR monitoring
- Patients with severe kidney disease, where warfarin may be preferred due to varying degrees of renal clearance with DOACs
- Pregnancy, where warfarin is the anticoagulant of choice as DOACs cross the placenta and are contraindicated It's essential to weigh the advantages and disadvantages of warfarin, including its numerous drug and food interactions, slower onset and offset of action, and the need for regular monitoring, against its specific benefits in these patient populations. The target INR for patients with atrial fibrillation prescribed warfarin for stroke prevention is 2.0-3.0, as recommended in the 2024 ESC guidelines 1.
From the Research
Indications for Warfarin Over DOACs
- Patients with prosthetic valves, as warfarin is still the preferred anticoagulant for this condition 2
- Antiphospholipid syndrome, where warfarin has been shown to be more effective 2, 3
- High risk of gastrointestinal bleeding, as warfarin may be preferred in these cases 2
- Mechanical heart valves, where DOACs have been associated with inferior efficacy or worse safety compared to warfarin 4, 3
- Thrombotic antiphospholipid syndrome, where warfarin is still the preferred treatment 3
Clinical Scenarios with Limited Evidence
- Mitral stenosis, where evidence is lacking but may eventually support the use of DOACs 2
- Obesity, altered gastrointestinal anatomy, pulmonary arterial hypertension, renal or hepatic impairment, and left ventricular thrombus, where more research is needed to determine the appropriateness of DOAC use 2
Comparison of DOACs and Warfarin in Specific Patient Populations
- In patients with atrial fibrillation and valve replacement or repair, DOACs were associated with lower risk of mortality, ischemic stroke, and bleeding compared to warfarin in some cases, but higher risk of ischemic stroke in others 5
- In patients with atrial fibrillation and valvular heart disease without mechanical valves, DOACs were associated with a lower rate of ischemic stroke or systemic embolism and bleeding compared to warfarin 6