Mechanical valve thrombosis: Current management and differences between guidelines

All foreign bodies inserted in the circulatory system are thrombogenic and require temporary or lifelong antithrombotic therapies to prevent thrombosis. The adequate level of anticoagulation during the first few months determines the long-term durability, particularly for mechanical prostheses, and also for biological valves. Suboptimal anticoagulation is the most frequent source of mechanical valve thrombosis (MVT). The patient's clinical presentation decides how mechanical prosthetic valve obstruction is managed. If the mechanical valve thrombosis is obstructive and the patient is in a critical condition with hemodynamic instability, an immediate surgical intervention should be performed. The thrombolytic treatment is an option for left mechanical valve thrombosis in patients who have high surgical risk and no contraindications and also for right heart valve thrombosis. In non-obstructive thrombosis on the mechanical valve, patients can be asymptomatic, requiring optimization of the anticoagulant treatment. Both obstructive and non-obstructive thrombus formed on the mechanical prosthesis can result in embolic events. If the thrombus persists following anticoagulant treatment, the recommended options include thrombolytic treatment or redo surgery. Pannus can also cause obstruction of the prosthesis for which surgical treatment is the only option. While these clinical scenarios may initially appear to have straightforward solutions in terms of surgery, thrombolysis, or effective anticoagulation, real-world clinical experience often proves more complex. For instance, a patient with some usual comorbidities and non-obstructive mechanical valve thrombosis, experiencing symptoms solely by repeated systemic embolizations, might undergo all three therapeutic options due to the unpredictable nature of MVT. Therefore, treatment indications can intersect both on the time axis and depending on the patient's clinical status and the expertise of the center where he is hospitalized. Moreover, the European and American guidelines show subtle but important differences. The aim of this review was to compare these differences, comment on recent studies and evidence gaps, propose a more pragmatic algorithm combining all current recommendations, and highlight important research directions for this disease that has dominated the cardiovascular landscape for more than five decades, but for which there have been no significant recent changes in management.