Plasma Asymmetric Dimethylarginine and Adverse Events in Patients with Atrial Fibrillation Referred for Coronary Angiogram

OBJECTIVES: Elevated plasma levels of asymmetric dimethylarginine (ADMA) have been reported to be associated with endothelial dysfunction, inflammation, and oxidative stress in multiple cardiovascular diseases. This study aimed to investigate whether ADMA was a predictor of clinical outcomes in atrial fibrillation (AF). METHODS AND RESULTS: From 2006-2009, 990 individuals were referred to our institution for coronary angiography. Among these patients, 141 subjects with a diagnosis of AF, including 52 paroxysmal AF (PAF) and 89 non-paroxysmal AF (non-PAF) patients, were identified as the study population. Plasma ADMA levels were measured. An adverse event was defined as the occurrence of ischemic stroke or cardiovascular death. The ADMA levels were higher in AF than non-AF patients (0.50±0.13 versus 0.45±0.07 µmol/L; p<0.001). Besides, non-PAF patients had higher ADMA levels than PAF patients (0.52±0.15 versus 0.48±0.08 µmol/L; p<0.001). During the follow-up of 30.7±14.4 months, 21 patients (14.9%) experienced adverse events, including cardiovascular death in 7 patients and ischemic stroke in 14. ADMA level, CHA(2)DS(2)-VASc score, and left atrial diameter were independent predictors of adverse events in the multivariate analysis. At a cutoff-value of 0.55 µmol/L, the Kaplan-Meier survival analysis showed that patients with a high ADMA level had a higher event rate during the follow-up period. CONCLUSIONS: A higher level of ADMA was a risk factor of adverse events in AF patients, which was independent from the CHA(2)DS(2)-VASc score. It deserves to further study whether ADMA could potentially refine the clinical risk stratification in AF.