Introduction: Atrial fibrillation (AF) is associated with increased thrombo-embolic events, with thrombi most frequently located in the left atrial appendage (LAA). Asymmetric dimethylarginine (ADMA), a potent endogenous inhibitor of nitric oxide synthase, is elevated in subjects with AF. We investigated the relationship between ADMA and risk of LAA thrombus in patients with non-valvular AF.
Methods and results: A total of 223 consecutive patients with non-valvular AF were enrolled (63 ± 10 years, 65% male). LAA thrombus was detected in 27 subjects by transesophageal echocardiography. Serum ADMA was significantly increased (2.5 ± 0.6 μmol/L vs 1.8 ± 0.4 μmol/L, p<0.001), while serum nitrite/nitrate was significantly reduced in patients with LAA thrombus (30.3 ± 7.1 μmol/L vs 48.4 ± 9.3 μmol/L, p<0.001). ADMA was positively correlated with age and left atrium diameter, and was negatively correlated with nitrite/nitrate and LAA peak flow velocity. The area under the receiver operating characteristic curve of ADMA predicting thrombus was 0.84. In multivariate logistic regression analysis, ADMA (OR 4.0, 95% CI 1.2-13.0; p=0.003) was one of independent risk factors for LAA thrombus.
Conclusions: Our study suggested that high ADMA was independently associated with the presence of LAA thrombus in patients with non-valvular AF.
Keywords: Asymmetric dimethylarginine; Atrial fibrillation; Left atrial appendage; Thrombus.
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