Relation of left atrial blood stasis to clinical risk factors in atrial fibrillation

Abstract

Background The present study was conducted to investigate whether an accumulation of clinical risk factors for thromboembolism would correlate with severity of blood stasis in the left atrium (LA) and aortic atherosclerosis in patients with nonvalvular atrial fibrillation (NVAF). Methods Risk levels of thromboembolism were assessed in 515 (mean age 67.5 years) NVAF patients using CHADS 2 score (an acronym for Congestive heart failure, Hypertension, Age ≥ 75, Diabetes mellitus, and prior Stroke or transient ischemic attack) to estimate the thromboembolic risk. Spontaneous echocardiographic contrast in the LA (LASEC), left atrial appendage (LAA) peak flow velocity, and severity of atherosclerosis in the descending aorta were determined with transesophageal echocardiography. Results LASEC was significantly increased, and LAA flow velocity significantly decreased in correlation with an increase in the risk levels, as evaluated by CHADS 2 score ( p < 0.001). Severity of aortic atherosclerosis also increased in correlation with an increase in the risk levels ( p < 0.001). Even at the comparable risk level, patients with chronic atrial fibrillation (AF) ( n = 268) had higher LASEC ( p < 0.001) and lower LAA flow velocity ( p < 0.001) than those with paroxysmal AF ( n = 52) who were in AF rhythm at the time of echocardiographic investigation. Conclusion Severity of blood stasis in the LA and aortic atherosclerosis correlates with an accumulation of clinical risk factors for thromboembolism in NVAF patients. Additionally, the severity of blood stasis in the LA was greater in chronic AF patients than in paroxysmal AF patients at the comparable risk level.