Total Bilirubin Level is Associated with the Risk of Left Atrial Appendage Thrombosis in Patients with Non-Valvular Atrial Fibrillation

OBJECTIVES: There are some evidence suggesting that total bilirubin (TBIL) appears to be associated with stroke in patients with nonvalvular atrial fibrillation (NVAF). The left atrial appendage (LAA) is the most common orgin of thrombus in patients with NVAF. The purpose of this study was to assess a possible relationship between plasma TBIL levels and LAA thrombus in NVAF patients. METHODS: We retrospectively screened 459 consecutive hospitalized patients with NVAF at three AF centers, who underwent transesophageal echocardiography or cardiac CT. According to the examination results, the patients were divided into either the LAA thrombosis group (41 cases) or the no LAA thrombosis group (418 cases). Independent sample t test, Mann-Whitney U-test and chi-square test were used to compare and analyze the general clinical data of the two groups. Multivariate Logistic regression was used to analyze whether TBIL was a risk factor for LAA thrombosis in patients with NVAF. Pearson correlation analysis was used to explore the correlation between TBIL and other influencing factors. The predictive value of TBIL for LAA thrombosis in patients with NVAF was evaluated by ROC curve. RESULTS: A total of 459 patients were enrolled in this study. Compared with the group without LAA thrombosis, the level of TBIL in LAA thrombosis group was significantly increased (21.34 ± 9.34 umol/L vs. 13.98 ± 4.25 umol/L, P < 0.001). Multivariate logistic regression showed that TBIL level was a risk factor for LAA thrombosis (OR, 1.229; 95% CI, 1.122~1.345; P < 0.001). The AUC of the ROC curve is 0.801 (95% CI, 0.725~0.877; P < 0.001). At 17.4 umol/L of TBIL, the patient may have LAA thrombosis (sensitivity 73.2%; specificity 82.1%). CONCLUSIONS: In patients with NVAF, TBIL level is positively associated with LAA thrombosis, and TBIL level may be an index reflecting LAA thrombosis.