Effect of Metabolic Syndrome on Risk Stratification for Left Atrial or Left Atrial Appendage Thrombus Formation in Patients with Nonvalvular Atrial Fibrillation

BACKGROUND: Metabolic syndrome (MS) is a risk factor for stroke and thromboembolism event. Left atrial or LA appendage (LA/LAA) thrombus is a surrogate of potential stroke. The relationship between MS and atrial thrombus remains unclear. In this study, we sought to investigate the effect of MS on risk stratification of LA/LAA thrombus formation in patients with nonvalvular atrial fibrillation (NVAF). METHODS: This cross-sectional study enrolled 294 consecutive NVAF patients without prior anticoagulant and lipid-lowering therapies. LA/LAA thrombus was determined by transesophageal echocardiography. Risk assessment of LA/LAA thrombus was performed using the CHADS(2), CHA(2)DS(2)-VASc, MS, CHADS(2)-MS, and CHA(2)DS(2)-VASc-MS scores. Logistic regression analyses were performed to determine which factors were significantly related to LA/LAA thrombus. Odds ratio (OR) including 95% confidence interval was also calculated. The predictive powers of different scores for the risk of LA/LAA thrombus were represented by C-statistics and compared by receiver operating characteristic (ROC) analysis. RESULTS: LA/LAA thrombi were identified in 56 patients (19.0%). Logistic analysis showed that MS was the strongest risk factor for LA/LAA thrombus in NVAF patients (OR = 14.698, P < 0.001). ROC curve analyses revealed that the C-statistics of CHADS(2)-MS and CHA(2)DS(2)-VASc-MS was significantly higher than those of CHADS(2) and CHA(2)DS(2)-VASc scores (CHADS(2)-MS vs. CHADS(2), 0.807 vs. 0.726, P = 0.0019). Furthermore, MS was helpful for identifying individuals with a high risk of LA/LAA thrombus in the population with a low risk of stroke (CHADS(2) or CHA(2)DS(2)-VASc score = 0). CONCLUSIONS: MS is associated with LA/LAA thrombus risk in patients with NVAF. In addition to the CHADS(2) and CHA(2)DS(2)-VASc scores, the CHADS(2)-MS and CHA(2)DS(2)-VASc-MS scores provide additional information on stroke risk assessment.