According to the 2019 AHA/ACC Guideline Update for the Management of Patients with Atrial Fibrillation, the evaluation of atrial fibrillation (AF) includes a distinction between 2 categories: valvular and nonvalvular.
- Valvular AF refers to AF in the setting of moderate-to-severe mitral stenosis or in the presence of an artificial/mechanical heart valve.
- In contrast, nonvalvular AF refers to AF in the absence of moderate-to-severe mitral stenosis or an artificial/mechanical heart valve; however, nonvalvular AF does not imply the absence of other forms of valvular heart disease. In fact, 20% of patients with nonvalvular AF have some degree of valvular heart disease that does not otherwise fit into the valvular AF category, as defined above.
Patients with valvular AF carry a 3‐fold increased risk of stroke and nearly 7‐fold increased risk of peripheral embolization compared to those with nonvalvular AF.
As such, valvular AF requires long-term anticoagulation with warfarin—not a NOAC/DOAC. The INR target range for these patients depends on the valve abnormality (mitral stenosis, mitral valve prosthesis, aortic valve prosthesis, etc.)
“NOACs (dabigatran, rivaroxaban, apixaban, and edoxaban) are recommended over warfarin in NOAC-eligible patients with AF (except with moderate-to-severe mitral stenosis or a mechanical heart valve) (S4.1.1-8–S4.1.1-11). NEW: Exclusion criteria are now defined as moderate-to-severe mitral stenosis or a mechanical heart valve. When the NOAC trials are considered as a group, the direct thrombin inhibitor and factor Xa inhibitors were at least noninferior and, in some trials, superior to warfarin for preventing stroke and systemic embolism and were associated with lower risks of serious bleeding.” [I, A]
Source: January et al. J Am Coll Cardiol. 2019
Additionally, the CHA2DS2‐VASc risk calculator should only be used for patients with nonvalvular AF regarding anticoagulation decision-making.
“In patients with AF (except with moderate-to-severe mitral stenosis or a mechanical heart valve), the CHA2DS2-VASc score is recommended for assessment of stroke risk (S4.1.1-5–S4.1.1-7). MODIFIED: Exclusion criteria are now defined as moderate-to-severe mitral stenosis or a mechanical heart valve.” [I, B]
Source: January et al. J Am Coll Cardiol. 2019