Pulmonary vein thrombus;64-MDCT;Left atrial thrombus;Stroke
Ischemic stroke is a serious clinical problem  ; . To prevent ischemic stroke, it is crucial to identify clinical targets. Left atrial thrombus is a known cause of ischemic stroke  ; ; however, the cause of left atrial thrombus remains unknown.
Pulmonary vein thrombosis (PVT) is thought to be rare; however, I have published several cases of PVT in elderly patients with chest pain using a 64-slice multidetector CT (64-MDCT) since 2012 ; ; ; ; ;  ; . In 2014, I reported that 61% (35 patients) of 57 elderly patients with chest pain had PVT, as assessed using 64-MDCT, which suggests that PVT is common in elderly patients with chest pain . Although I have reported that a thrombus in the pulmonary vein extends into the left atrium ; ;  ; , the relationship between PVT and a left atrial thrombus remains unknown.
I reviewed the images of 64-MDCT scans obtained from 35 patients with PVT. Seventeen patients (49%) had a thrombus in the left atrium, which was extended from pulmonary vein thrombi, indicating that approximately half of patients with PVT had a left atrial thrombus. In addition, among the 22 patients without PVT, only three patients (14%) had a left atrial thrombus. These three patients may have a fine pulmonary vein thrombus, which could not be clearly visualized using 64-MDCT. Thus, there is a possibility that nearly all left atrial thrombi are extended from pulmonary vein thrombi. Nearly all left atrial thrombi may use pulmonary vein thrombi as a root, which may provide a strong structure in the thrombi. In addition, I reported that some of the thrombi were partially dissolved within three months following warfarin  and dabigatran ;  ;  treatment, indicating that warfarin and dabigatran could prevent ischemic stroke by dissolving the pulmonary vein thrombus and the connected left atrial thrombus. However, not all thrombi were dissolved upon warfarin  and dabigatran  treatment, and thus, more efficient anti-coagulants are needed to prevent ischemic stroke.
The authors report no relationships that could be construed as a conflict of interest.