Left Atrium Thrombi Extending From Pulmonary Vein Thrombi Are Heterogeneous, Exhibit Calcifications, and Can Cause Acute Myocardial Infarction

Previous studies have shown that thrombi, upon retrieval, sometimes exhibit calcification and endothelialization, indicating that they are old, and they can be classified as red clots, white clots, or mixed clots according to the degree of heterogeneity of the thrombus. These findings suggest that, prior to the occurrence of acute myocardial infarction (AMI) and acute ischemic stroke (AIS), such large and heterogeneous thrombi may already be present. Pulmonary vein thrombi (PVTs) are common in patients with age-related diseases. During lung infection, neutrophil extracellular traps (NETs) are generated and have the potential to form thrombi. We previously reported that warfarin and novel oral anticoagulants (NOACs) can partially resolve PVTs, indicating that PVTs are heterogeneous. However, it is unclear whether PVTs contain areas of calcification. In the present case, we describe a patient with left atrium (LA) thrombi extending from PVTs that contained calcifications according to cardiac computed tomography (CT) and transesophageal echocardiography (TEE). On these imaging modalities, the calcifications of the extended LA thrombi appeared as white areas and white areas with white shadows, respectively. Some thrombi, including calcifications, can be resolved with dabigatran, whereas others cannot, indicating that thrombi, including calcifications, are heterogeneous. The effects of microclots, including NETs released from PVTs, have been well studied, and NETs have been reported to be related to many diseases. Treatments for PVTs also produce beneficial effects against these diseases; however, the direct effects of PVTs on the heart and lungs are not well known.