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

Abstract

Objective: 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. Methods: 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. Results: 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. Conclusion: 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.