Serum YKL-40 as a Marker of Left Atrial Fibrosis Assessed by Delayed Enhancement MRI in Lone Atrial Fibrillation.

Abstract

Assessment of the left atrial (LA) fibrosis by using delayed-enhanced magnetic resonance imaging (DE-MRI) in atrial fibrillation (AF) patients is a pioneering noninvasive method. Serum YKL-40 is a novel marker for inflammation and known to play a role in ongoing tissue fibrosis. However, its role in LA fibrosis is unclear. We aimed to investigate the association of serum YKL-40 with the presence and extent of LA fibrosis. A total of 50 patients with lone paroxysmal AF (62% male; age: 47.2 ± 7.0 years) underwent cardiac DE-MRI according to study protocol. Cardiac DE-MRI at 1.5 Tesla scanner was used to quantify LA fibrosis. Serum YKL-40 levels and clinical and echocardiographic data were recorded in all participants. DE-MRI revealed any degree of LA fibrosis in 31 (62%) patients. Median serum YKL-40 was significantly higher (P = 0.008) and left venticular ejection fraction was lower (P = 0.047) in patients with LA fibrosis as compared to patients without LA fibrosis. Extent of LA fibrosis was significantly correlated with age, duration of AF history, serum C-reactive protein, and serum YKL-40 levels. Only log (YKL-40) level was found as independent predictor for the presence of LA fibrosis (odds ratio: 1.626, P = 0.022). Multivariate linear regression analysis pointed out that duration of AF history (β = 0.330, P = 0.003) and serum log (YKL-40) levels (β = 0.546, P < 0.001) were significantly and independently associated with the extent of LA fibrosis. Higher levels of serum YKL-40 are associated with the presence and more extensive LA fibrosis in patients with lone AF. As a marker of inflammation, serum YKL-40 may also be used as an indicator for the degree of LA fibrosis.