Lipoprotein(a), left atrial appendage function and thromboembolic risk in patients with chronic nonvalvular atrial fibrillation

Lipoprotein(a) (Lp(a)) has a prothrombotic effect by modulating the fibrino lytic system. The purpose of the present study was to determine whether ser um Lp(a) levels are associated with an increased risk of thromboembolism in chronic nonvalvular atrial fibrillation (NVAF). Clinical, laboratory and t ransesophageal echocardiographic data were collected in 172 consecutive, no n-anticoagulated patients with chronic NVAF. Thirty-four patients (thromboe mbolic group) had a recent (<1 month) embolic event and/or a left atrial th rombus on transesophageal echocardiography. The thromboembolic group had a higher frequency of spontaneous echo contrast (94 vs 58%, p<0.0001), increa sed concentrations of Lp(a) (median: 31.5 vs 15.5 mg/dl, p<0.0001) and fibr inogen (median: 352 vs 314 mg/dl, p=0.0015), larger left atrial dimensions (median, 5.1 vs 4.8 cm, p=0.0078), and reduced left atrial appendage (LAA) flow velocities (median: 9.5 vs 21.2 cm/s, p<0.0001) than the nonthromboemb olic group. Multivariate analysis identified 3 independent predictors of th romboembolism: Lp(a) level greater than or equal to 30 mg/dl (odds ratio (O R) 9.5, 95% confidence interval (CI) 4.4-20.4, p<0.0001), LAA flow velocity of <20 cm/s (OR 8.7, 95% CI 3.3-23.0, p=0.0003) and a fibrinogen concentra tion of <377 mg/dl (OR 3.2, 95% CI 1.5-6.9, p=0.0201). The Lp(a) elevations and reduced LAA flow velocities are independently associated with thromboe mbolism in chronic NVAF.