Predictors for euthyroid sick syndrome and its impact on in-hospital clinical outcomes in high-risk patients undergoing coronary artery bypass grafting

The purpose of this cohort study was to investigate the independent relationship between euthyroid sick syndrome and in-hospital outcomes in high-risk patients undergoing isolated coronary artery bypass grafting, and we also examined the direct correlation between pre- or intra-operative variables and the incidence of coronary artery bypass grafting-associated euthyroid sick syndrome.The present study enrolled high-risk patients undergoing coronary artery bypass grafting from 1 January 2017 to 31 December 2017 in Beijing Anzhen hospital, including 387 (58.7%) patients with coronary artery bypass grafting-associated euthyroid sick syndrome and 272 (41.3%) patients without coronary artery bypass grafting-associated euthyroid sick syndrome.The mean age of euthyroid sick syndrome group was significantly older than that of no euthyroid sick syndrome group (65.9 ± 7.5 vs 60.9 ± 9.6, p < 0.0001). Compared with the control group, significantly higher proportions of patients with euthyroid sick syndrome had presented with the following clinical characteristics at hospital admission: moderate and poor left ventricular ejection fraction (42.9% vs 28.7%, p < 0.0001), higher euroscore II (9.2 ± 4.1 vs 8.0 ± 3.9, p < 0.0001). Multivariate logistic regression analysis on the total patients revealed that the independent risk factors for coronary artery bypass grafting-associated euthyroid sick syndrome were advanced age (odds ratio = 1.07, 95% confidence interval = 1.05-1.09, p < 0.0001), higher euroscore II (odds ratio = 1.06, 95% confidence interval = 1.01-1.11, p = 0.013), and moderate and poor left ventricular ejection fraction (odds ratio = 2.26, 95% confidence interval = 1.61-3.18, p < 0.0001). Furthermore, euthyroid sick syndrome was independently correlated with an increased risk of in-hospital major adverse cardiovascular and cerebral events (odds ratio = 3.40, 95% confidence interval = 1.64-7.02, p = 0.001) and post-infection (odds ratio = 8.11, 95% confidence interval = 3.97-16.57, p < 0.0001) Besides, we also confirmed coronary artery bypass grafting-associated euthyroid sick syndrome was associated with Sequential Organ Failure Assessment maximum greater than 11 (odds ratio = 2.98, 95% confidence interval = 1.90-4.65, p < 0.0001), which predicted an in-hospital death rate of 95%, independently.Coronary artery bypass grafting-associated euthyroid sick syndrome exerted detrimental effects on short-term clinical outcomes in high-risk patients undergoing isolated coronary artery bypass grafting. Advanced age, higher euroscore II, and moderate and poor left ventricular ejection fraction were independent risk factors for coronary artery bypass grafting-associated euthyroid sick syndrome.