Abstract Body (Do not enter title and authors here): Background: Pulmonary vein thrombi (PVTs) are common, and their prevalence is underestimated. Neutrophil extracellular traps (NETs) may initiate the formation of PVTs, and NETs are associated with many diseases, such as type 2 diabetes mellitus (T2DM), atherosclerosis and heart diseases. A study of the retrieved thrombi revealed that they had calcification, indicating that they were old. PVTs can release several types of particles, potentially ranging from microclots including NETs to large clots. We reported that standard-dose heparin-warfarin treatment ameliorated mild to moderate T2DM. Heparin might improve blood flow in the microvessels of most organs by destroying histones in NETs. Other NET-associated diseases might be ameliorated, so it is important to understand the traits of PVTs.
We reported several cases in which right lower pulmonary vein (RLPV) thrombi extended into the left atrium (LA). The reported shape of these extended thrombi is rod-like in many cases, as estimated using transesophageal echocardiography (TEE). Most of these thrombi cannot be detected using enhanced computed tomography (ECT). Whether LA thrombi extending from the right upper pulmonary vein (RUPV) are rod-like remains unclear.
Methods: We examined thrombi in the RUPV in thirty-one patients with and type 2 diabetes mellitus (24 men and 7 women; age = 73.5 (+/- 8.9)-year-old; range: 50- to 88-year-old) using TEE and ECT.
Results: None of the patients had rod-like LA thrombi extending from the RUPV in the LA. When we checked using TEE, six patients clearly had PVTs in the RUPV, in which thrombi were attached to the vessel wall and could not be detected using ECT. Thrombi extended into the LA, contacting the wall of the RUPV and the wall of the LA. Thrombi are difficult to visualize directly and are recognized as lacking in pulmonary vein blood flow. This study had two limitations. First, only thirty-one patients were included. If we check more patients, rod-like extending LA thrombi might exceptionally exist. The second was that there were several small white spot-like areas around the RUPV; however, we diagnosed them as having no thrombi. These spot-like areas might be thrombi.
Conclusions: PVTs in the RUPV did not have rod-like extending thrombi in the LA. Attachments to the vessel wall were not rare, and they were detectable when using TEE but not ECT. The thrombi depicted by TEE were different from the thrombi depicted by ECT in some cases.