Associations among serum trimethylamine-N-oxide (TMAO) levels, kidney function and infarcted coronary artery number in patients undergoing cardiovascular surgery: a cross-sectional study

BACKGROUND: Trimethylamine-N-oxide (TMAO) is a metabolite of phosphatidylcholine generated by gut microbiota and liver enzymes, and has recently been recognized as contributing to atherosclerosis. Elevated serum TMAO levels have been shown to increase the risk of cardiovascular disease (sudden death, myocardial infarction, or stroke) in patients undergoing elective coronary angiography. We aimed to clarify whether TMAO levels are associated with the number of infarcted coronary arteries as a measure of the severity of atherosclerosis, with adjustment using a priori-defined covariates such as kidney function. METHODS: By conducting a cross-sectional study of 227 patients who underwent cardiovascular surgery for coronary artery disease, valvular heart disease, or aortic disease, the association between serum TMAO levels as measured by HPLC-APCI-MS/MS and the number of infarcted coronary arteries was evaluated using ordered logistic regression models with adjustment of 10 covariates, including chronic kidney disease (CKD) stage. Unadjusted and adjusted odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were determined. RESULTS: Significantly higher TMAO levels were observed in advanced-stage CKD (p ≤ 0.001). In fully adjusted models with the 10 covariates, a significantly increased number of infarcted coronary arteries was identified in the highest quartile and quintile of TMAO compared to the lowest quartile (OR 11.9; 95 % CI 3.88–36.7, p ≤ 0.001) and quintile (OR 14.1; 95 % CI 3.88–51.2; p ≤ 0.001), respectively, independent of dyslipidemia. CONCLUSIONS: Higher serum TMAO levels may be associated with advanced CKD stages and with an increased number of infarcted coronary arteries in patients who undergo cardiovascular surgery.