Risk factors for left atrial thrombus or spontaneous echo contrast in non-valvular atrial fibrillation patients with low CHA2DS2-VASc score

Risk factors of left atrial thrombus (LAT) or spontaneous echo contrast (LASEC) in non-valvular atrial fibrillation (NVAF) had been reported. However, information in the subgroup of NVAF patients with low CHA2DS2-VASc scores was limited. Here, we evaluated the risk factors of LAT/LASEC in NVAF patients with low CHA2DS2-VASc scores. Transesophageal echocardiography (TEE) file of NVAF patients with low CHA2DS2-VASc scores was reviewed (between June 2009 and Feb 2019) in this retrospective observational study. Binary logistic regression analysis was performed to identify risk factors other than the CHA2DS2-VASc score. Propensity score matching (PSM) was used to further evaluate independent risk markers for LAT/LASEC. The newly discovered factors were added to the CHA2DS2-VASc score, and receiver operating characteristic analysis was used to evaluate the ability of the model to predict LAT/LASEC. TEE files of 3056 NVAF patients with low CHA2DS2-VASc scores were reviewed. Regression analysis revealed elevated fibrinogen and enlarged left atrium (LA) were risk factors for LAT/LASEC. Further PSM analysis confirmed that elevated fibrinogen and enlarged LA were independent risk factors for LAT/LASEC. After including fibrinogen and left atrial diameter (LAD), the CHA2DS2-VASc score was more accurate for LAT/LASEC prediction in NVAF patients with low CHA2DS2-VASc scores (area under the curve difference is 0.241, 95% confidence interval (CI) 0.188–0.294, Z = 8.890, P < 0.0001). Elevated fibrinogen and enlarged LA were independent risk factors for LAT/LASEC in NVAF patients with low CHA2DS2-VASc scores. Taking fibrinogen and LAD into consideration may help improve LAT/LASEC risk evaluation, which warrants further validation studies.