Usefulness of Serum Triiodothyronine (T3) to Predict Outcomes in Patients Hospitalized With Acute Heart Failure

Radioactive Iodine-131 Therapy Reduced the Risk of MACEs and All-Cause Mortality in Elderly with Hyperthyroidism Combined with Type 2 Diabetes

Aim

This study aimed to assess the efficacy of antithyroid drugs (ATDs) and radioactive iodine-131 (RAI) therapies in reducing the risk of major adverse cardiovascular events (MACEs) and all-cause mortality in patients with hyperthyroidism complicated with type 2 diabetes mellitus (T2DM).

Methods

Between January 2013 and December 2021, 540 subjects were included in the analysis. All participants were followed up for 9 years, with a median of 54 months (2451 person-years). The subjects were categorized into two groups: the ATDs group (n = 414) and the RAI group (n = 126). According to the free triiodothyronine (FT3) tertiles, the patients receiving RAI were further grouped as follows: low-level (≤ 4.70 pmol/L, n = 42), moderate-level (4.70-12.98 pmol/L, n = 42), and high-level (≥ 12.98 pmol/L, n = 42). The efficacy of ATDs and RAI therapies in reducing the risk of MACEs and all-cause mortality was assessed.

Results

Of the 540 participants, 163 experienced MACEs (30.19%), 25 (15.34%) of whom died. Multivariate Cox regression analyses revealed that RAI was associated with a 38.5% lower risk of MACEs (P = 0.016) and a 77.1% lower risk of all-cause mortality (P = 0.046). Stratified analyses indicated that RAI had a protective effect on MACEs in patients aged ≥ 60 years (P = 0.001, P for interaction = 0.031) and patients with a duration of diabetes mellitus ≥ 6 years (P = 0.013, P for interaction = 0.002). Kaplan‒Meier analysis revealed a lower cumulative incidence of MACEs and all-cause mortality in the RAI group (log-rank, all P < 0.05). Moreover, the ROC curve suggested an optimal FT3 cut-off value of 5.4 pmol/mL for MACE (P < 0.001).

Conclusion

Our findings suggested that RAI therapy effectively reduced the risk of MACEs and all-cause mortality in elderly patients with hyperthyroidism combined with T2DM.

Long-term prognostic value of thyroid hormones in left ventricular noncompaction

PURPOSE

Thyroid function is closely related to the prognosis of cardiovascular diseases. This study aimed to explore the predictive value of thyroid hormones for adverse cardiovascular outcomes in left ventricular noncompaction (LVNC).

METHODS

This longitudinal cohort study enrolled 388 consecutive LVNC patients with complete thyroid function profiles and comprehensive cardiovascular assessment. Potential predictors for adverse outcomes were thoroughly evaluated.

RESULTS

Over a median follow-up of 5.22 years, primary outcome (the combination of cardiovascular mortality and heart transplantation) occurred in 98 (25.3%) patients. For secondary outcomes, 75 (19.3%) patients died and 130 (33.5%) patients experienced major adverse cardiovascular events (MACE). Multivariable Cox analysis identified that free triiodothyronine (FT3) was independently associated with both primary (HR 0.455, 95%CI 0.313-0.664) and secondary (HR 0.547, 95%CI 0.349-0.858; HR 0.663, 95%CI 0.475-0.925) outcomes. Restricted cubic spline analysis illustrated that the risk for adverse outcomes increased significantly with the decline of serum FT3. The LVNC cohort was further stratified according to tertiles of FT3 levels. Individuals with lower FT3 levels in the tertile 1 group suffered from severe cardiac dysfunction and remodeling, resulting in higher incidence of mortality and MACE (Log-rank P < 0.001). Subgroup analysis revealed that lower concentration of FT3 was linked to worse prognosis, particularly for patients with left atrial diameter ≥ 40 mm or left ventricular ejection fraction ≤ 35%. Adding FT3 to the pre-existing risk score for MACE in LVNC improved its predictive performance.

CONCLUSION

Through the long-term investigation on a large LVNC cohort, we demonstrated that low FT3 level was an independent predictor for adverse cardiovascular outcomes.

Predictive Value of Serum Inflammatory Factors and FT3 for Stroke-Associated Pneumonia in Patients With Acute Ischemic Stroke

OBJECTIVE

The ability of serum inflammatory factors and free triiodothyronine (FT3) in predicting the occurrence of stroke-associated pneumonia (SAP) in patients with acute ischemic stroke (AIS) was assessed in this study.

METHODS

A retrospective analysis was conducted on 285 consecutive patients with AIS initially diagnosed and admitted to our hospital from January to December 2022. Patients were categorized into SAP and non-SAP groups based on the presence of SAP. Both groups were compared in terms of baseline characteristics, including National Institute of Health Stroke Scale (NIHSS) score, SAP risk assessment (A2DS2), TOAST classification. Independent risk factors for SAP were identified using multivariate logistic regression analysis, and the predictive value of inflammatory markers was evaluated through ROC curves.

RESULTS

Among 285 patients with AIS, 40 (14.03%) were found to have developed SAP. Higher NIHSS and A2DS2 scores, elevated serum IL-1β, IL-8, and IL-33 levels, increased age, atrial fibrillation, swallowing difficulties, and a higher proportion of patients with low FT3 levels were observed in the SAP group compared with the non-SAP group (all P<0.05). Significant risk factors for SAP in patients with AIS were identified through multivariate logistic regression analysis, including age, swallowing difficulties, NIHSS, A2DS2 , IL-1β , IL-8 , IL-33, and FT3 (P<0.05). The highest predictive values were observed for A2DS2, FT3, and IL-8 with AUC values of 0.854, 0.844, and 0.823, respectively.

CONCLUSION

SAP can be highly predicted by A2DS2, FT3, and IL-8, enabling the early identification of patients with high-risk SAP and facilitating timely intervention and treatment.

Low TSH and low T3 hormone levels as a prognostic for mortality in COVID-19 intensive care patients

Introduction

Coronavirus diasease 2019 (COVID-19) can cause both pulmonary and systemic inflammation, potentially determining multi-organ dysfunction. The thyroid gland is a neuroendocrine organ that plays an important role in regulating immunity and metabolism. Low serum levels of thyroid hormones are common in critical disease situations. The association between low thyroid hormone levels and mortality in COVID-19 intensive care patients has yet to be studied.

Aim

The aim of this study is to compare thyroid hormone levels between patients in the general intensive care unit (ICU) to patients in the COVID-19 ICU.

Methods

This was a retrospective comparative study of 210 patients who were hospitalized at Ziv Medical Center in the general ICU and in the COVID-19 ICU. Clinical and demographic data were collected from patient's electronic medical records.

Results

Serum thyroid hormone levels of Thyroid Simulating Hormone (TSH), T4, and T3 were significantly lower in COVID-19 intensive care unit patients compared to the patients from the general intensive care unit (p < 0.05). The mortality rate in the COVID-19 ICU (44.4%) was higher compared to that in the general ICU (27.3%) (p < 0.05). No significant statistical difference was observed between the two groups in terms of gender and recorded comorbidities of diabetes mellitus, cerebral vascular accident, kidney disease, and cancer.

Conclusions

Low serum thyroid hormone levels-T3, T4, and TSH-in COVID-19 ICU patients are associated with higher mortality and could possibly be used as a prognostic factor for mortality among COVID-19 ICU patients. Thyroid hormone levels should be a part in the routine evaluation of COVID-19 ICU patients.

Analyzing predictors of in-hospital mortality in patients with acute ST-segment elevation myocardial infarction using an evolved machine learning approach

Acute ST-segment elevation myocardial infarction (STEMI) is a severe cardiac ailment characterized by the sudden complete blockage of a portion of the coronary artery, leading to the interruption of blood supply to the myocardium. This study examines the medical records of 3205 STEMI patients admitted to the coronary care unit of the First Affiliated Hospital of Wenzhou Medical University from January 2014 to December 2021. In this research, a novel predictive framework for STEMI is proposed, incorporating evolutionary computational methods and machine learning techniques. A variant algorithm, AGCOSCA, is introduced by integrating crossover operation and observation bee strategy into the original Sine Cosine Algorithm (SCA). The effectiveness of AGCOSCA is initially validated using IEEE CEC 2017 benchmark functions, demonstrating its ability to mitigate the deficiency in local mining after SCA random perturbation. Building upon this foundation, the AGCOSCA approach has been paired with Support Vector Machine (SVM) to forge the predictive framework referred to as AGCOSCA-SVM. Specifically, AGCOSCA is employed to refine the selection of predictors from a substantial feature set before SVM is utilized to forecast the occurrence of STEMI. In our analysis, we observed that SVM excels at managing nonlinear data relationships, a strength that becomes particularly prominent in smaller datasets of STEMI patients. To assess the effectiveness of AGCOSCA-SVM, diagnostic experiments were conducted based on the STEMI sample data. Results indicate that AGCOSCA-SVM outperforms traditional machine learning methods, achieving superior Accuracy, Sensitivity, and Specificity values of 97.83 %, 93.75 %, and 96.67 %, respectively. The selected features, such as acute kidney injury (AKI) stage, fibrinogen, mean platelet volume (MPV), free triiodothyronine (FT3), diuretics, and Killip class during hospitalization, are identified as crucial for predicting STEMI. In conclusion, AGCOSCA-SVM emerges as a promising model framework for supporting the diagnostic process of STEMI, showcasing potential applications in clinical settings.

Thyroid Autoimmunity and SARS-CoV-2 Infection

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological culprit of COronaVIrus Disease 19 (COVID-19), can enter the cells via the angiotensin-converting enzyme 2 (ACE2) receptor, which has been found in several tissues including in endocrine organs, such as the ovaries, testes, pancreas, and thyroid. Several thyroid disorders have been associated with SARS-CoV-2 infection [subacute thyroiditis (SAT), thyrotoxicosis, and non-thyroidal illness syndrome (NTIS)] and, in part, they are believed to be secondary to the local virus replication within the gland cells. However, as documented for other viruses, SARS-CoV-2 seems to interfere with several aspects of the immune system, inducing the synthesis of autoantibodies and triggering latent or new onset autoimmune disease (AID), including autoimmune thyroid disease (AITD), such as Hashimoto Thyroiditis (HT) and Graves' disease (GD). Several mechanisms have been hypothesized to explain this induction of autoimmunity by SARS-CoV-2 infection: the immune system hyper-stimulation, the molecular mimicry between the self-antigens of the host and the virus, neutrophils extracellular traps, and finally, the virus induced transcriptional changes in the immune genes; nonetheless, more evidence is needed especially from large, long-term cohort studies involving COVID-19 patients, to establish or reject this pathogenetic relationship.

Thyroid Hormone and Heart Failure: Charting Known Pathways for Cardiac Repair/Regeneration

Heart failure affects more than 64 million people worldwide, having a serious impact on their survival and quality of life. Exploring its pathophysiology and molecular bases is an urgent need in order to develop new therapeutic approaches. Thyroid hormone signaling, evolutionarily conserved, controls fundamental biological processes and has a crucial role in development and metabolism. Its active form is L-triiodothyronine, which not only regulates important gene expression by binding to its nuclear receptors, but also has nongenomic actions, controlling crucial intracellular signalings. Stressful stimuli, such as acute myocardial infarction, lead to changes in thyroid hormone signaling, and especially in the relation of the thyroid hormone and its nuclear receptor, which are associated with the reactivation of fetal development programmes, with structural remodeling and phenotypical changes in the cardiomyocytes. The recapitulation of fetal-like features of the signaling may be partially an incomplete effort of the myocardium to recapitulate its developmental program and enable cardiomyocytes to proliferate and finally to regenerate. In this review, we will discuss the experimental and clinical evidence about the role of the thyroid hormone in the recovery of the myocardium in the setting of heart failure with reduced and preserved ejection fraction and its future therapeutic implications.

Low T3 syndrome upon admission and response to nutritional support in malnourished medical inpatients

INTRODUCTION

During illness, deiodination of thyroxine (T4) to triiodothyronine (T3) is down regulated. This is called "low T3 syndrome", an adaptive metabolic mechanism to reduce energy expenditure and prevent catabolism. We investigated the prognostic role of low T3 syndrome in patients at nutritional risk regarding mortality, clinical outcomes and response to nutritional support.

METHODS

This is a secondary analysis of the Effect of Early Nutritional Support on Frailty, Functional Outcomes, and Recovery of Malnourished Medical Inpatients Trial (EFFORT), a randomized-controlled Swiss multicenter trial comparing effects of individualized nutritional support with usual care in adult medical inpatients at nutritional risk. The primary endpoint was all-cause mortality over 30-,180-days and 5-years.

RESULTS

We had complete data including fT3 concentration of 801/2028 (39.5%) patients from the initial trial. Of these 492 (61.4%) had low T3 syndrome (fT3 < 3.2 pmol/l). Low T3 syndrome was associated with higher mortality over 30 days (adjusted hazard ratio 1.97 [95%CI 1.17 to 3.31], p 0.011) and other adverse clinical outcomes. Nutritional support only lowered mortality in the group of patients with but not in those without low T3 syndrome (adjusted odds ratio of nutritional support of 0.82 [95%CI 0.47 to 1.41] vs. 1.47 [95%CI 0.55 to 3.94]). This finding, however, was not significant in interaction analysis (p for interaction = 0.401).

CONCLUSIONS

Our secondary analysis of a randomized trial suggests that medical inpatients at nutritional risk with low T3 syndrome have a substantial increase in mortality and may show a more pronounced beneficial response to nutritional support interventions.

Suppression of the hypothalamic-pituitary-thyroid axis is associated with the severity of prognosis in hospitalized patients with COVID-19

BACKGROUND

The outbreak of severe acute respiratory syndrome novel coronavirus 2 (SARS-CoV-2) has spread rapidly worldwide. SARS-CoV-2 has been found to cause multiple organ damage; however, little attention has been paid to the damage to the endocrine system caused by this virus, and the subsequent impact on prognosis. This may be the first research on the hypothalamic-pituitary-thyroid (HPT) axis and prognosis in coronavirus disease 2019 (COVID-19).

METHODS

In this retrospective observational study, 235 patients were admitted to the hospital with laboratory-confirmed SARS-CoV-2 infection from 22 January to 17 March 2020. Clinical characteristics, laboratory findings, and treatments were obtained from electronic medical records with standard data collection forms and compared among patients with different thyroid function status.

RESULTS

Among 235 patients, 17 (7.23%) had subclinical hypothyroidism, 11 (4.68%) severe non-thyroidal illness syndrome (NTIS), and 23 (9.79%) mild to moderate NTIS. Composite endpoint events of each group, including mortality, admission to the ICU, and using IMV were observed. Compared with normal thyroid function, the hazard ratios (HRs) of composite endpoint events for mild to moderate NTIS, severe NTIS, subclinical hypothyroidism were 27.3 (95% confidence interval [CI] 7.07-105.7), 23.1 (95% CI 5.75-92.8), and 4.04 (95% CI 0.69-23.8) respectively. The multivariate-adjusted HRs for acute cardiac injury among patients with NTF, subclinical hypothyroidism, severe NTIS, and mild to moderate NTIS were 1.00, 1.68 (95% CI 0.56-5.05), 4.68 (95% CI 1.76-12.4), and 2.63 (95% CI 1.09-6.36) respectively.

CONCLUSIONS

Our study shows that the suppression of the HPT axis could be a common complication in COVID-19 patients and an indicator of the severity of prognosis. Among the three different types of thyroid dysfunction with COVID-19, mild to moderate NTIS and severe NTIS have a higher risk of severe outcomes compared with subclinical hypothyroidism.

Prognostic role of hypothyroidism and low free-triiodothyronine levels in patients hospitalized with acute heart failure

Low thyroid function has been widely recognized as a potential cause of heart failure (HF), but the evidence about a possible association with in-hospital, all-cause mortality in patients with acute HF (AHF) is not consistent. This study sought to investigate the prevalence and prognostic role of hypothyroidism, overt and subclinical, and of low free-triiodothyronine (fT3) levels in patients hospitalized with AHF. We retrospectively analyzed consecutive 1018 patients who were hospitalized for AHF in a single academic medical center [Fondazione Policlinico A.Gemelli IRCCS, Rome, Italy] between January 1st 2016, and December 31st 2018. Patients were divided into three groups: normal thyroid function (n = 798), subclinical hypothyroidism (n = 105), and overt hypothyroidism (n = 115). The outcome was in-hospital, all-cause mortality. Patients were 81 years of age, 55% were females and nearly two-thirds of the patients were on New York Heart Association functional class III. The three most common cardiovascular comorbidities were coronary artery disease, hypertension, and atrial fibrillation with no differences across the three groups. Overall, 138 patients (14%) died during the hospital stay. The mortality rate was 27% among patients with overt hypothyroid, 17% among those with subclinical hypothyroidism, and 11% among euthyroid patients (p < 0.001). At a multivariate Cox regression model, overt hypothyroidism (HR 2.1, 95% CI 1.4-3.2) and fT3 levels < 1.8 pg/mL (HR 3.4, 95% CI 2.3-5.1) were associated with an increased likelihood of in-hospital death. No association was found with subclinical hypothyroidism. Among patients hospitalized with AHF, overt hypothyroidism and low fT3 levels are independent predictors of all-cause mortality during the hospital stay.

Combined use of low T3 syndrome and NT-proBNP as predictors for death in patients with acute decompensated heart failure

BACKGROUND

In patients with established HF, low triiodothyronine syndrome (LT3S) is commonly present, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a useful marker for predicting death. This study was aimed to evaluate the prognostic value of LT3S in combination with NT-proBNP for risk of death in patients with heart failure (HF).

METHODS

A total of 594 euthyroid patients hospitalized with acute decompensated HF were enrolled by design. Of these patients, 27 patients died during hospitalization and 100 deaths were identified in patients discharged alive during one year follow-up. Patients were divided into 2 groups on the base of the reference ranges of free T3 (FT3) levels: LT3S group (FT3 < 2.3pg/mL, n = 168) and non-LT3S group (FT3 ≥ 2.3pg/mL, n = 426).

RESULTS

In multivariable Cox regression, LT3S was significantly associated with 1 year all-cause mortality (adjusted hazard ratio, 1.85; 95 % confidence interval [CI], 1.21 to 2.82; P = 0.005), but not significant for in-hospital mortality (adjusted hazard ratio, 1.58; 95 % CI, 1.58 to 2.82; P = 0.290) after adjustment for clinical variables and NT-proBNP. Addition of LT3S and NT-proBNP to the prediction model with clinical variables significantly improved the C statistic for predicting 1 year all-cause mortality.

CONCLUSIONS

In patients with acute decompensated HF, the combination of LT3S and NT-proBNP improved prediction for 1 year all-cause mortality beyond established risk factors, but was not strong enough for in-hospital mortality.

Evaluation of Thyroid Function in Patients Hospitalized for Acute Heart Failure

BACKGROUND

Thyroid hormones (TH) are crucial for cardiovascular homeostasis. Recent evidence suggests that acute cardiovascular conditions, particularly acute heart failure (AHF), significantly impair the thyroid axis. Our aim was to evaluate the association of thyroid function with cardiovascular parameters and short- and long-term clinical outcomes in AHF patients.

METHODS

We performed a single-centre retrospective cohort study including patients hospitalized for AHF between January 2012 and December 2017. We used linear, logistic, and Cox proportional hazard regression models to analyse the association of thyroid-stimulating hormone (TSH) and free thyroxine (FT4) with inpatient cardiovascular parameters, in-hospital mortality, short-term adverse clinical outcomes, and long-term mortality. Two models were used: (1) unadjusted, and (2) adjusted for age and sex.

RESULTS

Of the 235 patients included, 59% were female, and the mean age was 77.5 (SD 10.4) years. In the adjusted model, diastolic blood pressure was positively associated with TSH [β = 2.68 (0.27 to 5.09); p = 0.030]; left ventricle ejection fraction (LVEF) was negatively associated with FT4 [β = -24.85 (-47.87 to -1.82); p = 0.035]; and a nonsignificant trend for a positive association was found between 30-day all-cause mortality and FT4 [OR = 3.40 (0.90 to 12.83); p = 0.071]. Among euthyroid participants, higher FT4 levels were significantly associated with a higher odds of 30-day all-cause death [OR = 4.40 (1.06 to 18.16); p = 0.041]. Neither TSH nor FT4 levels were relevant predictors of long-term mortality in the adjusted model.

CONCLUSIONS

Thyroid function in AHF patients is associated with blood pressure and LVEF during hospitalization. FT4 might be useful as a biomarker of short-term adverse outcomes in these patients.

Thyroid Dysfunction in Patients Admitted in Cardiac Care Unit: Prevalence, Characteristic and Hospitalization Outcomes

Introduction

Cardiovascular disease is one of the main causes of hospital admission and mortality, and thyroid dysfunction increases the risk of developing acute or exacerbation of chronic cardiac conditions. The aim of this study is to investigate the prevalence of thyroid hormone abnormality among patients in the cardiac care unit (CCU) patients and its relation to admission diagnosis, clinical, biochemical data, and hospital-related outcomes.

Methods

We conducted a retrospective cohort observational that included adult patients who were admitted to the CCU. We excluded those with known thyroid dysfunction and those who received amiodarone or IV contrast.

Results

A total of 374 patients with a mean age of 62.7+14.7 years old were included. Ischemic changes were observed in 70.6% of the patients based on the admission diagnosis. In comparison to the non-ischemic group, the ischemic group was more likely to be male (P=0.010), to be active/former smokers (P=0.011), to have diabetes (P=0.009), to have diastolic dysfunction (P=<0.001), to have undergone thrombolysis (P=<0.001), and to have been referred to a tertiary center (P=<0.001). Euthyroidism was observed in 57.8% of the patients based on the thyroid function test at admission. Compared to patients with thyroid dysfunction, those with Euthyroidism were more likely to be active/former smokers (P=0.002), to have lower heart rates (P=0.018), to not have chronic kidney disease (P=0.016), to not have heart failure (P=0.006), to have lower thyroid-stimulating hormone (TSH) levels (P=<0.001), and to have lower tricuspid regurgitation (P=0.042).

Conclusion

Thyroid dysfunction is common among patients admitted to the CCU. Non-significant positive correlations between TSH and hospitalization length, tertiary center referral, 30-day readmission, and in-hospital mortality when adjusting for potential confounders.

Low Free Triiodothyronine as a Predictor of Poor Prognosis in Patients With Myocardial Infarction With Non-Obstructive Coronary Arteries

BACKGROUND

Low free triiodothyronine (fT3) level is strongly associated with poor prognosis in various patient populations. However, the role of fT3 in the risk of clinical outcomes in myocardial infarction with non-obstructive coronary arteries (MINOCA) has not been studied. Our study aimed to evaluate the association between low fT3 levels and the clinical outcomes of MINOCA patients.

METHODS

A total of 218 MINOCA patients without a history of thyroid disease were enrolled in the study. Demographic, baseline clinical data, thyroid hormones, and other biochemical parameters were assessed in all patients. According to the fT3 levels, the present study was classified into two groups: the low fT3 group (fT3<3.5 pmol/L) and the normal fT3 group (fT3 3.5-6.5 pmol/L). The endpoint of the study was major adverse cardiac events (MACE).

RESULTS

Fifty-nine patients were in the low fT3 group and 159 patients were in the normal fT3 group. Over the two years of follow-up, 36 MACE have occurred. The occurrence of MACE was higher in the low fT3 group compared with normal fT3 group (25.4% vs 13.2%; P=0.031). Kaplan-Meier survival curves showed a significantly increased risk of MACE in patients with low fT3 (log-rank P=0.027). Multivariable logistic regression analysis stated that high fT3 was independently associated with lower risk of MACE after two years of follow up (OR, 0.623; 95% CI, 0.399- 0.972; P=0.037).

CONCLUSION

Low fT3 levels were significantly associated with increased risk of MACE in patients with MINOCA. This finding suggests that the fT3 levels may serve as a potential biomarker in risk stratification of MINOCA patients.

Association Between Low T3 Syndrome and Poor Prognosis in Adult Patients With Acute Myocarditis

BACKGROUND

This study aims to investigate the role of free triiodothyronine (fT3) in predicting poor prognosis of adult patients with acute myocarditis.

METHODS

A total of 173 consecutive adult patients with acute myocarditis completed thyroid function evaluations. They were divided into two groups according to fT3 levels: low fT3 group (n = 54, fT3 < 3.54 pmol/liter) and normal fT3 group (n = 119, fT3 ≥ 3.54 pmol/liter). The primary endpoint was major adverse cardiac events (MACE).

RESULTS

During the 3.5 ± 2.8 years follow-up, the rate of MACE was 29.6% versus 3.5% in low fT3 group versus normal fT3 group, respectively (P < 0.0001). Long-term at 8 years MACE-free survival were lower in low fT3 group versus normal fT3 group (52.9% versus 92.3%, log-rank P < 0.0001), respectively. Univariate Cox analysis showed that left ventricular ejection fraction (LVEF) < 50% [hazard ratio (HR) 10.231, 95% confidence interval (CI): 3.418-30.624, P < 0.0001) and low fT3 level (HR 0.360, 95% CI: 0.223-0.582, P < 0.0001) were strongest two predictors of MACE. After adjustment for traditional risk predictors, the prognostic value of fT3 status was still significant (HR 0.540, 95% CI: 0.316-0.922, P = 0.024). Compared with normal fT3 group, those in low fT3 group were at a much higher risk of MACE (HR 5.074, 95% CI: 1.518-16.964, P = 0.008).

CONCLUSIONS

Low T3 syndrome was a strong predictor of poor prognosis in adult patients with acute myocarditis. These findings suggest that fT3 level could serve as a biomarker for risk stratification in acute myocarditis patients.

Modification of cardiac thyroid hormone deiodinases expression in an ischemia/reperfusion rat model after T3 infusion

The deiodinases regulate the activation and inactivation of Thyroid hormones (TH), in both physiological and pathological conditions. The three deiodinases, DIO1, DIO2 and DIO3, have different catalytic role and cellular and tissue distribution. Aim of this study is to evaluate a rat model of regional ischemia/reperfusion (I/R), the modification of cardiac main function after the administration of 6 µg/kg/day of triiodothyronine (T3), and the associated to DIO1, DIO2 and DIO3 gene expression. We also aim to study DIO1 and DIO2 protein levels in different left ventricular regions after an ischemic event. Four groups of rats were studied: sham-operated, sham-operated + T3, I/R rats and I/R rats + T3. DIO1, DIO2 and DIO3 expression were evaluated in I/R region (AAR: area-at-risk) and in a more distant region from ischemic wound (RZ: remote zone). In I/R group, circulating free-T3 (FT3) levels were significantly decreased with respect to basal values, whereas in I/R + T3 rats, FT3 levels were comparable to basal values. In AAR of I/R + T3 rats, DIO1 and DIO2 gene expression significantly increased with respect to sham. In RZ, DIO1 and DIO3 gene expression was significantly lower in sham and I/R rats when compared to I/R + T3. In sham + T3 group, DIO1 and DIO2 gene expression was not detectable, whereas DIO3 was significantly higher than in the other three groups. The present study gives interesting new insights on DIO1, DIO2 and DIO3 in the ischemic heart and their role in relation to T3-mediated amelioration of cardiac function and structure.

Congestive Heart Failure and Thyroid Dysfunction: The Role of the Low T3 Syndrome and Therapeutic Aspects

Background:

Both the morbidity and mortality rates from congestive heart failure (CHF) remain elevated despite the medical and non-medical management of the disease, thus suggesting the existence of residual risk factors such as thyroid dysfunction. Particularly, the 15-30% of patients with CHF, especially those with severe ventricular dysfunction, display the so-called low T3 syndrome (LT3S), which seems to negatively affect the cardiovascular prognosis.

Objective:

Only a few clinical trials have been carried out to verify both the safety and the efficacy of thyroid replacement in the LT3S, aiming to ameliorate the prognosis of CHF, and most of the results were controversial.

Methods:

Since the aim of the present review was to briefly overview both the indication and contraindication of triiodothyronine replacement in CHF and LT3S, the authors searched PubMed using the medical subject headings (MeSH) related to the following terms: “congestive heart failure” and “low T3 syndrome” or “euthyroid sick syndrome” or “non-thyroidal sick syndrome”. The research study only focused on the narrative and systematic reviews, randomized clinical trials and meta-analysis studies which were conducted before June 2019.

Results:

Studies conducted in both animal models and humans provided controversial information about the effectiveness and safety of the T3 replacement for improving ventricular dysfunction, particularly in the long-term.

Conclusion:

Further clinical trials are needed to better explore the role of LT3S in patients with CHF and its consequent therapeutic strategy in this clinical setting.

Non-thyroidal illness syndrome, the hidden player in the septic shock induced myocardial contractile depression

Septic shock causes high mortality in hospitalized patients, especially in those that develop myocardial dysfunction as an early complication. The myocardial dysfunction of septic shock is characterized by a decrease in ventricular relaxation (diastolic dysfunction) and reduced ventricular ejection fraction (systolic dysfunction). Most patients with septic shock have low serum thyroid hormone levels, a condition known as non-thyroidal illness syndrome. Thyroid hormones sustain myocardial contractility and energy metabolism. Septic shock non-thyroidal illness syndrome causes myocardial hypothyroidism, and hypothyroidism causes myocardial dysfunction that resembles the myocardial depression of septic shock. We hypothesize that the myocardial hypothyroidism that occurs during septic shock has a causal role in the pathogenesis of septic shock-induced myocardial dysfunction. Thyroid hormones regulate the calcium cycle, the phenotype of contractile proteins, adrenergic response, and fatty acid transport and oxidation in the cardiomyocytes. Therefore, the administration of levothyroxine and liothyronine to normalize thyroid hormones level within the myocardium will improve the myocardial function. The hypothesis will be tested in humans with septic shock by performing a prospective, randomized, placebo-controlled study to compare the effect of thyroid hormone administration with placebo on myocardial function. The proposed hypothesis challenges the idea that non-thyroidal illness syndrome is a beneficial response of the thyroid hormone axis to illness and that thyroid hormone replacement is detrimental. The administration of thyroid hormone in order to prevent and reverse myocardial hypothyroidism during septic shock is a new theoretical concept on thyroid hormone metabolism and action at the tissue level during non-thyroidal illness syndrome. If the hypothesis is correct, clinicians should consider cardiac hypothyroidism as a central player in myocardial dysfunction caused by sepsis. Thyroid hormone replacement should be incorporated into the armamentarium of septic shock treatment.

Relation of Low Triiodothyronine Syndrome Associated With Aging and Malnutrition to Adverse Outcome in Patients With Acute Heart Failure

Low triiodothyronine (T3) syndrome has recently been evaluated as a prognostic marker of acute heart failure (AHF). However, in which cases low T3 syndrome typically leads to adverse outcomes remain unclear. Of 1,432 AHF patients screened, 1,190 were enrolled. Euthyroidism was present in 956 patients (80.3%), who were divided into 2 groups: the normal group (n = 445, FT3 ≥1.88 µIU/L) and low-FT3 group (n = 511, FT3 <1.88 µIU/L). The survival rates and event-free rates within 365 days were significantly lower in the low-FT3 group than in the normal group. A multivariate Cox regression model showed that the low-FT3 group was an independent predictor of 365-day mortality (hazard ratio [HR] 1.429, 95% confidence interval [CI] 1.013 to 2.015) and HF events (HR 1.349, 95% CI 1.047 to 1.739). The multivariate logistic regression analysis revealed that age (per 10-year old increase, odds ratio [OR]: 1.186, 95% CI: 1.046 to 1.345) and prognostic nutritional index (PNI; per 1-point increase, OR: 1.067, 95% CI: 1.046 to 1.089) were independently associated with the low-FT3 group. The prognosis in patients with a low PNI and over 75 years old, including all-cause death within 365 days, was significantly poorer in the low-FT3 group than in the normal group. In conclusion, adverse outcomes were predicted by the presence of low T3. AHF patients with low T3 syndrome are strongly associated with aging and malnutrition. Low T3 syndrome complicated with older age and malnutrition is likely to lead to adverse outcomes in patients with AHF.

Adverse transverse-tubule remodeling in a rat model of heart failure is attenuated with low-dose triiodothyronine treatment

Abstract

Pre-clinical animal studies have shown that triiodothyronine (T3) replacement therapy improves cardiac contractile function after myocardial infarction (MI). We hypothesized that T3 treatment could prevent adverse post-infarction cardiomyocyte remodeling by maintaining transverse-tubule (TT) structures, thus improving calcium dynamics and contractility.

Methods

Myocardial infarction (MI) or sham surgeries were performed on female Sprague-Dawley rats (aged 12 wks), followed by treatment with T3 (5μg/kg/d) or vehicle in drinking water for 16 wks (n = 10–11/group). After in vivo echocardiographic and hemodynamic analyses, left ventricular myocytes were isolated by collagenase digestion and simultaneous calcium and contractile transients in single cardiomyocytes were recorded using IonOptix imaging. Live cardiomyocytes were stained with AlexaFluor-488 conjugated wheat germ agglutinin (WGA-488) or di-8-ANEPPS, and multiple z-stack images per cell were captured by confocal microscopy for analysis of TT organization. RTqPCR and immunoblot approaches determined expression of TT proteins.

Results

Echocardiography and in vivo hemodynamic measurements showed significant improvements in systolic and diastolic function in T3- vs vehicle-treated MI rats. Isolated cardiomyocyte analysis showed significant dysfunction in measurements of myocyte relengthening in MI hearts, and improvements with T3 treatment: max relengthening velocity (Vmax, um/s), 2.984 ± 1.410 vs 1.593 ± 0.325, p < 0.05 and time to Vmax (sec), 0.233 ± 0.037 vs 0.314 ± 0.019, p < 0.001; MI + T3 vs MI + Veh, respectively. Time to peak contraction was shortened by T3 treatment (0.161 ± 0.021 vs 0.197 ± 0.011 s., p < 0.01; MI + T3 vs MI + Veh, respectively). Analysis of TT periodicity of WGA- or ANEPPS-stained cardiomyocytes indicated significant TT disorganization in MI myocytes and improvement with T3 treatment (transverse-oriented tubules (TE%): 9.07 ± 0.39 sham, 6.94 ± 0.67 MI + Veh and 8.99 ± 0.38 MI + T3; sham vs MI + Veh, p < 0.001; MI + Veh vs MI + T3, p < 0.01). Quantitative RT-PCR showed that reduced expression of BIN1 (Bridging integrator-1), Jph2 (junctophilin-2), RyR2 (ryanodine receptor) and Ca_v1.2 (L-type calcium channel) in the failing myocardium were increased by T3 and immunoblot analysis further supporting a potential T3 effect on the TT-associated proteins, BIN1 and Jph2.

In conclusion, low dose T3 treatment initiated immediately after myocardial infarction attenuated adverse TT remodeling, improved calcium dynamics and contractility, thus supporting the potential therapeutic utility of T3 treatment in heart failure.

Low Free T3 Is Associated With Worse Outcomes in Patients in the ICU Requiring Invasive Mechanical Ventilation

OBJECTIVE

Critical illness causes a decrease in serum free triiodothyronine (T₃) levels. This condition, known as nonthyroidal illness syndrome (NTIS), is associated with poor outcomes. The association of NTIS and outcomes in patients in the intensive care unit (ICU) requiring mechanical ventilation has not been well studied. This study aimed to determine the impact of NTIS on the outcomes of these patients.

METHODS

This prospective study included 162 patients in the ICU who underwent mechanical ventilation. Serum free T₃ levels were tested on the day of initiation of mechanical ventilation. The rates of in-hospital mortality and ventilator-free days (VFDs) at day 28 after the initiation of mechanical ventilation were compared between patients with low (<2.3 pg/mL) and normal (≥2.3 pg/mL) free T₃ levels. Patients who died while on mechanical ventilation were assigned a VFD of 0.

RESULTS

Low T₃ was present in 60% of study patients. The in-hospital mortality rate of the entire cohort was 39%, and the mean and median VFDs at day 28 were 13.5 and 21 days, respectively. Compared to patients with normal free T₃, patients with low free T₃ had higher in-hospital mortality (52% vs 19%, P < .001) and less mean and median VFDs at day 28 (10.7 vs 18 and 0 vs 23, respectively. P < .001 for both mean and median VFDs).

CONCLUSIONS

The presence of low T₃ due to NTIS in patients in the ICU requiring mechanical ventilation is associated with poor outcomes.

Thyroid Hormones and Cardiovascular Function and Diseases

Thyroid hormone (TH) receptors are present in the myocardium and vascular tissue, and minor alterations in TH concentration can affect cardiovascular (CV) physiology. The potential mechanisms that link CV disease with thyroid dysfunction are endothelial dysfunction, changes in blood pressure, myocardial systolic and diastolic dysfunction, and dyslipidemia. In addition, cardiac disease itself may lead to alterations in TH concentrations (notably, low triiodothyronine syndrome) that are associated with higher morbidity and mortality. Experimental data and small clinical trials have suggested a beneficial role of TH in ameliorating CV disease. The aim of this review is to provide clinicians dealing with CV conditions with an overview of the current knowledge of TH perturbations in CV disease.

Low triiodothyronine syndrome and selenium deficiency - undervalued players in advanced heart failure? A single center pilot study

Background

The function of deiodinases – selenoproteins converting thyroid hormones may be disturbed by oxidative stress accompanying heart failure. Selenium (Se) may be used by glutathione peroxidase, leading to a lack of deiodinase and triiodothyronine (T3). The aim of the study was the evaluation of the prevalence and clinical significance of low T3 syndrome in heart failure and the assessment of the association of low fT3 and Se deficiency.

Methods

The study group consisted of 59 consecutive patients hospitalized due to decompensated HFrEF NYHA III or IV. Exclusion criteria were: thyroid dysfunction, severe systemic disease, treatment with amiodarone, steroids or propranolol. Group A included 9 patients with low free T3 (fT3) concentration below 3.1 pmol/L. Group B consisted of the remaining 50 patients with normal fT3 levels.

Results

The prevalence of low T3 syndrome was 15.3%. The prevalence of Se deficiency was 74.6%. We demonstrated correlations between fT3 and main clinical variables (i.e. NT-proBNP, LVEF, hsCRP), but we did not find correlation between fT3 and the Se level. Kaplan-Meier survival analysis showed lower survival probability in patients with low fT3 (p < 0.001).

Conclusions

Low T3 syndrome is frequently found in patients with HFrEF and is associated with a poor outcome. We did not identify any significant correlation between Se and fT3 level.

Cardioprotection and Thyroid Hormones in the Clinical Setting of Heart Failure

Ischemic heart disease is the main cause of morbidity and mortality worldwide and is becoming more widespread with population aging. Cardioprotection is a dynamic process characterized by mechanisms related to myocardial damage and activation of protective factors. Targeting these processes could be attractive as a new therapeutic strategy in the evolution of post-ischemic heart failure (HF). In this context, the role of thyroid hormone (TH)-mediated cardioprotection is supported by a number of findings regarding the modulation of neuroendocrine systems, inflammatory and oxidative stress status, pro-survival intracellular pathways, and epigenetic factors, its effects on cardiac angiogenesis, structure, and function and on the preservation of mitochondrial function and morphology, and its beneficial effects on cell growth and redifferentiation. Moreover, the numerous effects of TH on the heart involve genomic mechanisms, which include cardiac differentiation during the perinatal period and non-genomic action, directed toward the maintenance of cardiovascular homeostasis. This evidence suggests that there is an opportunity to treat HF patients with TH. This review is mainly focused on the clinical evidence of the role of the thyroid system in the complex setting of HF.

Hypothyroidism: Cardiovascular Endpoints of Thyroid Hormone Replacement

Thyroid dysfunction, either thyrotoxicosis or hypothyroidism, represents an important cardiovascular risk factor. Heart disease is the leading cause of death for men and women in the United States. Cardiovascular disease is multifactorial and many efforts have been made to assess precipitants for optimal guideline-based, primary, and secondary prevention. Thyroid hormone receptors are present in the myocardium and endothelium, and small alterations in its levels could have significant effects in cardiac function. Specifically, overt hypothyroidism is associated with an increased risk for atherosclerotic cardiovascular disease due to metabolic and hemodynamic effects. Several concomitant factors like impaired lipid profile, low-grade chronic inflammatory state, increased oxidative stress and increased insulin resistance enforce this relationship. The last decade has seen a renewed interest on the impact of subclinical hypothyroidism on the cardiovascular system and whether or not it should be treated. The aim of this review is to provide current evidence of the effect of thyroid hormone replacement, either with levothyroxine mono-therapy or in combination with liothyronine, on specific cardiovascular parameters.

Correlation of Triiodothyronine Level with In-Hospital Cardiac Function and Long-Term Prognosis in Patients with Acute Myocardial Infarction

Objective

The pathophysiologic mechanism of how thyroid function is related to the development and prognosis of acute myocardial infarction (AMI) remains under explored, and there has been a lack of clinical investigations. In this study, we investigate the relationship between triiodothyronine (T3) level and cardiac ejection fraction (EF) as well as probrain natriuretic peptide (NT-proBNP) on admission and subsequent prognosis in AMI patients.

Methods

We measured admission thyroid function, NT-proBNP, and EF by echocardiography in 345 patients diagnosed with AMI. Simple and multiregression analyses were performed to investigate the correlation between T3 level and EF as well as NT-proBNP. Major adverse cardiovascular events (MACE), including new-onset myocardial infarction, acute heart failure, and cardiac death, were documented during the follow-up. 248 participants were separated into three groups based on T3 and free triiodothyronine (FT3) levels for survival analysis during a 2-year follow-up.

Results

345 patients diagnosed with AMI were included in the initial observational analysis. 248 AMI patients were included in the follow-up survival analysis. The T3 levels were found to be significantly positively correlated with EF (R square = 0.042, P < 0.001) and negatively correlated with admission NT-proBNP levels (R square = 0.059, P < 0.001), which is the same with the correlation between FT3 and EF (R square = 0.053, P < 0.001) and admission NT-proBNP levels (R square = 0.108, P < 0.001). Kaplan-Meier survival analysis revealed no significant difference with regard to different T3 or FT3 levels at the end of follow-up.

Conclusions

T3 and FT3 levels are moderately positively correlated with cardiac function on admission in AMI patients but did not predict a long-time survival rate. Further studies are needed to explain whether longer-term follow-up would further identify the prognosis effect of T3 on MACE and all-cause mortality.

Association between Low Free Triiodothyronine Levels and Poor Prognosis in Patients with Acute ST-Elevation Myocardial Infarction

Background

Low free triiodothyronine (fT3) levels are generally associated with poor prognosis in patients with heart diseases, but this is controversial and there is a lack of data about ST-elevation myocardial infarction (STEMI) in Chinese patients.

Objective

To assess the association between fT3 levels and the prognosis of patients with STEMI.

Methods

This was a prospective observational study of 699 consecutive patients with STEMI treated at the Xinqiao Hospital between January 1, 2013, and December 31, 2014. The patients were divided into the low fT3 (fT3 < 3.1 pmol/L; n = 179, 27.5%) and normal fT3 (fT3 ≥ 3.1 pmol/L; n = 473, 72.5%) groups according to fT3 levels at admission. Patients were followed up at 1, 3, 6, and 12 months for all-cause death and major adverse cardiac events (MACE).

Results

During the 1-year follow-up, there were 70 all-cause deaths (39.1%) in the low fT3 group and 40 (8.5%) in the normal fT3 group (P < 0.001). MACE occurred in 105 patients (58.7%) in the low fT3 group and 74 (15.6%) in the normal fT3 group (P < 0.001). Multivariate Cox proportional hazards regression analysis indicated that fT3 levels were independently associated with 30-day and 1-year all-cause death [30-day: hazard ratio (HR) = 0.702, 95% confidence interval (95% CI): 0.501–0.983, P = 0.04; 1-year: HR = 0.557, 95% CI: 0.411–0.755, P < 0.001] and MACE (30-day: HR = 0.719, 95% CI: 0.528–0.979, P = 0.036; 1-year: HR = 0.557, 95% CI: 0.445–0.698, P < 0.001).

Conclusion

Low fT3 levels were strongly associated with poor prognosis in patients with STEMI. Measurement of fT3 levels may be a valuable and simple way to identify high-risk STEMI patients.

Low T3 syndrome improves risk prediction of in-hospital cardiovascular death in patients with acute myocardial infarction

BACKGROUND

Low triiodothyronine (T3) syndrome (LT3S) is frequently seen in patients with acute myocardial infarction (AMI). We examined the association between LT3S and severity of myocardial injury and determined whether LT3S adds predictive value over thrombolysis in myocardial infarction (TIMI) risk score for in-hospital cardiovascular (CV) death.

METHODS

Of 2459 AMI patients, 529 pairs of euthyroid and LT3S individuals with similar baseline characteristics were identified using 1:1 propensity score matching. LT3S was defined as free T3 (fT3) <2.36pg/mL, normal values of thyroid-stimulating hormone and free thyroxin. Primary outcome was in-hospital CV death. Receiver operating characteristic curves were generated to assess the predictive effects of fT3, TIMI risk score, and TIMI-LT3S risk score on in-hospital CV death.

RESULTS

LT3S was found in 23.3% of patients with AMI. The peak values of cardiac troponin I in ng/mL and N-terminal pro-brain natriuretic peptide in ng/mL were significantly higher in LT3S: 6.6 (1.3-19.6) vs. 3.5 (0.8-12.1), p<0.001 and 3625 (1046-12,776) vs. 2158 (774-6759), p<0.001. Patients with LT3S had significantly higher rate of in-hospital CV death than those without (4.7% vs. 1.7%, p=0.005). Lower levels of fT3 yielded an area under the curve (AUC) of 0.741 for predicting CV death. LT3S, when added to the TIMI risk score, significantly increased AUC for in-hospital CV death than TIMI risk score alone (0.775 vs. 0.738, p=0.005).

CONCLUSIONS

LT3S was associated with more severe myocardial injury and increased in-hospital CV mortality in patients with AMI. Furthermore, it improved risk prediction of in-hospital CV death post-AMI when it was added to the TIMI risk score.