Characterisation and validity of inflammatory biomarkers in the prediction of post-operative atrial fibrillation in coronary artery disease patients

Atrial fibrillation (AF) is a common complication of coronary artery bypass grafting (CABG). We sought to determine the diagnostic validity of plasma biomarkers of i) inflammation (marked by interleukin-6 IL-6 and high-sensitivity C-reactive protein hs-CRP), ii) extracellular matrix remodelling (matrix metalloproteinase MMP-9, tissue inhibitor of matrix metalloproteinase TIMP-1) and iii) the prothrombotic state (tissue factor and von Willebrand factor vWF) in the risk prediction of post-operative AF. Samples were obtained preoperatively from peripheral/femoral vein and from intracardiac chambers (right atrium RA, the right atrial appendage RAA, the left atrium LA and the left atrial appendage LAA) amongst 100 consecutive patients free of AF and inflammatory disease undergoing elective CABG. Biomarker concentrations were related to incident AF (30 days). At 30 days post CABG, 30 patients were proven to have had AF. Concentrations of tissue factor (TF) and vWF were unrelated to postoperative AF. Peripheral (p=0.018), and intracardiac levels (RAA (p=0.029) and LA (p=0.026)) of hs-CRP were associated with the presence of AF after CABG. Intracardiac levels of IL-6 in samples from the RAA (p=0.031), LA (p=0.042) and LAA (p=0.006), and MMP-9 in the LAA sample were also associated with AF (p=0.007). Our data suggest that an intra-cardiac inflammatory environment that is manifest peri-operatively may predispose to the development of post-operative AF. This intracardiac inflammatory state was reflected by increased peripheral hs-CRP levels. These differences may indicate local substrate abnormalities contributing to the development of AF post-operatively.