Prosthetic Mitral Valve Obstruction with Left Atrial Appendage Thrombus: A Therapeutic Dilemma

Abstract

Valvular obstruction is a rare but life-threatening complication of mechanical prosthetic valves that raises significant challenges in management. We describe a unique case of mechanical mitral valve obstruction with co-existing left atrial appendage (LAA) thrombus. A 48-year-old man with a past medical history of atrial fibrillation and mechanical mitral valve replacement 18 months prior, presented with symptoms of new onset heart failure for 10 days. INR on presentation was sub-therapeutic. Trans-thoracic and trans-esophageal echocardiography revealed prosthetic mitral valve obstruction with mobile, echogenic masses seen on the mechanical valve as well as LAA, suggestive of thrombus. His clinical course rapidly deteriorated and he developed cardiogenic shock. He was deemed to have prohibitive risk for emergent surgical intervention. He received trial of thrombolytic therapy, with partial improvement of hemodynamic parameters and a mild decrease in thrombus burden. He then underwent surgical intervention with a favorable outcome. Intra-operative visualization of the prosthetic valve revealed a combination of pannus and thrombus. Prosthetic valve function should be promptly assessed in patients presenting with heart failure symptoms, as clinical deterioration can be rapid. Acute presentation, history of inadequate anticoagulation and appearance of soft mass on an echocardiogram, are suggestive of thrombus as the etiology of valve obstruction. However, thrombus and pannus are known to frequently co-exist. Emergent surgery is the recommended management strategy in patients with left-sided prosthetic valve thrombosis with the New York Heart Association (NYHA) III or IV symptoms, due to a lower rate of thrombo-embolism, major bleeding, and recurrent prosthetic valve thrombosis when compared with thrombolytic therapy. Slow-infusion, low-dose thrombolytics were recently shown to have favorable outcomes and can be considered when surgery is not available or the patient is deemed to have prohibitive surgical risk.