Optimizing Anticoagulation Strategies in Patients With Atrial Fibrillation and Valvular Heart Disease: A Comprehensive Evidence-Based Review

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, significantly increases the risk of thromboembolism and stroke. Its coexistence with valvular heart disease (VHD) further complicates management due to elevated risks of thromboembolism, bleeding, and mortality. This review explores the pathophysiology of AF and its interaction with VHD, focusing on diagnostic tools like echocardiography and risk stratification scores such as CHA2DS2-VASc and HAS-BLED. Vitamin K antagonists (VKAs) remain the cornerstone of anticoagulation therapy in high-risk VHD populations, particularly in patients with mechanical heart valves or moderate-to-severe mitral stenosis (MS). VKAs have demonstrated proven efficacy in reducing thromboembolic events in these subgroups, supported by decades of clinical evidence. However, their use requires frequent international normalized ratio (INR) monitoring and is associated with higher bleeding risks, posing challenges in long-term management. Despite these limitations, VKAs are indispensable in these populations due to the lack of robust evidence supporting the safety and efficacy of direct oral anticoagulants (DOACs) in these high-risk groups. Ongoing clinical trials, such as the RIVER trial, aim to evaluate the role of DOACs in VHD. However, current guidelines continue to recommend VKAs as the standard of care for these patients. In contrast, DOACs offer significant advantages in non-valvular AF and selected VHD populations. Their predictable pharmacokinetics, fewer dietary restrictions, and lower risks of intracranial hemorrhage make them a preferred choice for many patients. Landmark trials and meta-analyses, including RE-LY, ROCKET-AF, and ARISTOTLE, have demonstrated the safety and efficacy of DOACs in non-valvular AF and certain VHD subgroups. However, DOACs are contraindicated in high-risk VHD populations, such as those with mechanical valves or moderate-to-severe MS, due to insufficient evidence and potential risks of thromboembolic events. Evolving guidelines from leading societies emphasize individualized approaches and collaborative decision-making in anticoagulation therapy. While DOACs are preferred for most AF patients, VKAs remain essential for high-risk VHD patients. Future advancements, such as factor XIa inhibitors, hold promise for improving outcomes and safety in these complex populations. This review provides a comprehensive framework for clinicians to navigate the complexities of anticoagulation in AF and VHD, ensuring evidence-based, patient-centered care.