Anticoagulation for rheumatic mitral stenosis, INVICTUS in perspective

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.

Oral Anticoagulants Beyond Warfarin

Direct oral anticoagulants (DOACs) have largely replaced vitamin K antagonists, mostly warfarin, for the main indications for oral anticoagulation, prevention and treatment of venous thromboembolism, and prevention of embolic stroke in atrial fibrillation. While DOACs offer practical, fixed-dose anticoagulation in many patients, specific restrictions or contraindications may apply. DOACs are not sufficiently effective in high-thrombotic risk conditions such as antiphospholipid syndrome and mechanical heart valves. Patients with cancer-associated thrombosis may benefit from DOACs, but the bleeding risk, particularly in those with gastrointestinal or urogenital tumors, must be carefully weighed. In patients with frailty, excess body weight, and/or moderate-to-severe chronic kidney disease, DOACs must be cautiously administered and may require laboratory monitoring. Reversal agents have been developed and approved for life-threatening bleeding. In addition, the clinical testing of potentially safer anticoagulants such as factor XI(a) inhibitors is important to further optimize anticoagulant therapy in an increasingly elderly and frail population worldwide.