Triiodothyronine acutely increases blood flow in the ventricles and kidneys of anesthesized rabbits

Low Triiodothyronine Syndrome Increased the Incidence of Acute Kidney Injury After Cardiac Surgery

Background

Acute kidney injury (AKI) is a severe complication of cardiac surgery. This study was designed to explore the association between the preoperative low T3 syndrome and cardiac surgery-associated acute kidney injury (CSA-AKI).

Methods

This was a retrospective single-center study. Data on 784 patients undergoing elective coronary artery bypass grafting (CABG) or valve surgery were collected from January 2016 to July 2019. AKI was defined according to Kidney Disease: Improving Global Outcomes guidelines. The effect of preoperative low T3 syndrome (fT3 < 3.5pmol/L) on the risk of the postoperative AKI was analyzed in a logistic regression model.

Results

There were 171 (21.8%) patients developing AKI. Preoperative T3 and FT3 levels were lower in patients with AKI than in those without AKI (P < 0.001). The incidence of postoperative AKI was higher in patients with low T3 syndrome than in those without (31.0% vs 19.8%; P = 0.003). Multivariate logistic regression analysis showed that low T3 syndrome was an independent risk factor for CSA-AKI patients (OR = 1.609, 95% CI: 1.033–2.504; P = 0.035), after adjusting for confounding factors, such as age, albumin, and uric acid. Subgroup analyses showed that preoperative low T3 syndrome also increased incidence of CSA-AKI in those with high risk factors, such as age ≧60 yrs (OR: 1.891, 95% CI: 1.183–3.022, P = 0.008), hypertension (OR: 2.104, 95% CI: 1.218–3.3.635, P = 0.008), and hyperuricemia (OR: 2.052, 95% CI: 1.037–4.06, P = 0.039).

Conclusion

Low T3 syndrome independently increases the risk of CSA-AKI. Patients with low T3 syndrome should be considered at higher risk and be evaluated before cardiac surgery.

Association of low T3 level with increased in-hospital mortality in patients with stress cardiomyopathy

BACKGROUND

Stress cardiomyopathy (SCMP) is an acute but reversible heart failure syndrome with varying clinical outcomes. Although low triiodothyronine (T3) levels are closely associated with heart failure, it is uncertain whether total T3 levels on admission might be correlated with clinical outcomes in patients with SCMP. The aim of this study was to investigate the prognostic value of total T3 level for in-hospital mortality in patients with SCMP.

METHODS

Patients presenting with SCMP at a single tertiary hospital between January 2013 and May 2019 were retrospectively reviewed. The diagnosis of SCMP was confirmed using the International Takotsubo Diagnostic Criteria and echocardiography was performed at least twice at the time of admission. Comorbidities, antecedent triggers, and other cardiac and metabolic parameters were measured in the survivor group compared with the non-survivor group. We evaluated the correlation between these parameters, especially total T3 and the prevalence of in-hospital mortality and the predictive values of total T3.

RESULTS

Of the 134 SCMP patients (69.4 ± 15.5 years old, 94 women), 29 (21.6%) died during hospitalisation. The median follow-up period (interquartile range) was 480 days (63.25-1052.50). Total T3 levels were significantly lower in the non-survival group than in the survival group (33.38 ± 22.58 ng/dL vs. 65.72 ± 34.68 ng/dL, p < 0.0001). Receiver operating characteristic curve analysis showed the cut-offs of total T3 levels (≤64.37 ng/dL) for in-hospital mortality (area under curve [AUC] = 0.764, p < 0.001). In multivariable analysis, the T3 level (odds ratio [OR], 0.957; 95% confidential interval [CI], 0.934 to 0.982; p < 0.001), left ventricular ejection in follow-up echocardiography (OR, 0.935; 95% CI, 0.889-0.983; p = 0.008), and shock at initial presentation (OR, 3.389; 95% CI, 1.076-10.669; p = 0.037) were independent predictors for in-hospital mortality in SCMP patients. In patients with low T3 (<64.37 ng/dL), the 30-day survival rate was also significantly lower (81.58 vs. 100%, Log rank p = 0.001).

CONCLUSIONS

Lower levels of total T3 were strongly correlated with in-hospital mortality in patients with SCMP. A low T3 level might suggest poor prognosis in patients with SCMP.