Elevated serum lipoprotein(a) is a risk factor for left atrial thrombus inpatients with chronic atrial fibrillation: A transesophageal echocardiographic study

Background Patients with chronic atrial fibrillation have an increased risk of thromboembolism. Apoprotein(a) has a structural homology with plasminog en, suggesting that lipoprotein(a) [Lp(a)] may produce thrombogenic effects by modulating the fibrinolytic system. However, the rote of Lp(a) level in the formation of left atrial thrombus has not been studied. We sought to e valuate whether Lp(a) is a risk factor for left atrial thrombus in patients with chronic atrial fibrillation. Methods and Results The consecutive series of 150 patients (mean age 67 +/- 8 years) with chronic atrial fibrillation underwent transesophageal echoca rdiography. Left atrial thrombus was diagnosed by transesophageal echocardi ography Clinical, biochemical, and echocardiographic variables were prospec tively collected. Univariate analysis showed that patients with left atrial thrombus (n = 29, 19%) had higher frequency of spontaneous echo contrast ( 93% vs 55%, P < .0001) than patients without left atrial thrombus (n = 121) . Patients with left atrial thrombus also had a significantly higher serum concentration of Ip(a) (34.5 +/- 24.7 vs 17.9 +/- 13.5 mg/dL, P < .0001), a larger left atrium (5.4 +/- 0.9 vs 4.8 +/- 0.7 cm, P < .001), and a tower left atrial appendage peak flow velocity (11.1 +/- 5.4 vs 23.5 +/- 14.6 cm/ s, P < .0001). Multivariate regression analysis showed that the Ip(a) conce ntration (P < .0001) was a significant positive predictor and the left atri al appendage peak flow velocity (P = .0125) was a significant negative pred ictor of left atrial thrombus. Left atrial thrombus was present in 16 (48%) of 33 patients with Lp(a) level greater than or equal to 30 mg/dL. Conclusions Elevated serum levels of Lp(a) are strongly associated with lef t atrial thrombus. These findings suggest that Lp(a) level may be a novel r isk factor for left atrial thrombus in patients with chronic atrial fibrill ation.