Thrombus on Mitral Annular Calcification: A Systematic Review of Management and Outcomes.

Background: Mitral annular calcification (MAC) is a common chronic degenerative process of the mitral valve. Thrombus formation on MAC is a rare complication that likely contributes to the increased risk of thromboembolic events. Outcomes and management strategies for this condition are unknown. The aim of this study was to perform a systematic review to describe the management and outcomes of patients who have thrombus on MAC. Methods: The MEDLINE, Embase, and Cochrane databases were searched. Patients with a prior mitral valve intervention or prosthesis were excluded. The primary outcomes were treatment, mortality, and thromboembolic events. Results: Fifteen studies, with a total of 22 cases (patients aged 69.1 ± 14.8 years; n = 18 [82%] female) were included. Most patients presented with stroke or a transient ischemic event (n = 15; 68%) or myocardial infarction (n = 4; 18%). All patients were diagnosed with either transthoracic (n = 18; 82%) or transesophageal (n = 4; 18%) echocardiography. Seventeen patients (77%) were treated with anticoagulation therapy alone, and 5 (23%) required surgery. The most common surgical indication was prevention of recurrent embolization (n = 3; 14%). No mortality was reported. Six patients (27%) had thromboembolic events after diagnosis. For those treated with anticoagulation therapy alone, 5 (23%) had persistent thrombus with or without embolization. Conclusions: In this systematic review, patients with MAC who present with a thromboembolic event require careful echocardiographic assessment of the MAC, to exclude the presence of thrombus. Although most patients can be managed with anticoagulation therapy alone, a significant number will require surgery. Persistent thrombus, despite anticoagulation therapy, and recurrent embolization are common. Larger studies are needed to elucidate what constitutes the optimal long-term care for these patients.