The role of thyroid hormones in acute coronary syndromes: Prognostic value of alterations in thyroid hormones

A Rare Encounter: Unstable Vasospastic Angina Induced by Thyrotoxicosis

Coronary artery vasospasm plays a crucial role in the prevalence of unstable angina. Despite common misdiagnosis, there is limited evidence on this topic. Here, we present a rare case of unstable vasospastic angina in a female with severe thyrotoxicosis. Case Report: A 62-year-old female patient was admitted to the cardiac intensive care unit due to crushing chest pain at rest. The patient exhibited ischemic changes on the ECG with a normal troponin I level. Recurrent chest pain prompted urgent coronary angiography, revealing generalized vasospasm of all coronary artery branches including the left main coronary artery. Intracoronary nitroglycerin injection partially alleviated the vasospasm; however, there was a persistent stenosis in the left main artery. Subsequent intravascular ultrasound demonstrated an anatomically normal left main artery. Post-procedure, laboratory tests revealed undetectable levels of thyroid-stimulating hormone and thyroid hormones above the detectable level. The patient was initiated on methimazole and discharged symptom-free, expecting a good prognosis under conservative management. Conclusions: Clinically significant coronary vasospasm triggered by thyrotoxicosis remains a rarity in clinical practice, often posing diagnostic challenges. This case emphasizes the significance of intracoronary nitroglycerin and intravascular ultrasound in discerning the etiology of coronary lesions seen on angiography. We advocate for these techniques to optimize invasive coronary artery diagnostics, enabling the selection of the appropriate treatment strategies and improving long-term prognosis.

Artificial intelligence based prediction model of in-hospital mortality among females with acute coronary syndrome: for the Jerusalem Platelets Thrombosis and Intervention in Cardiology (JUPITER-12) Study Group

Introduction

Despite ongoing efforts to minimize sex bias in diagnosis and treatment of acute coronary syndrome (ACS), data still shows outcomes differences between sexes including higher risk of all-cause mortality rate among females. Hence, the aim of the current study was to examine sex differences in ACS in-hospital mortality, and to implement artificial intelligence (AI) models for prediction of in-hospital mortality among females with ACS.

Methods

All ACS patients admitted to a tertiary care center intensive cardiac care unit (ICCU) between July 2019 and July 2023 were prospectively enrolled. The primary outcome was in-hospital mortality. Three prediction algorithms, including gradient boosting classifier (GBC) random forest classifier (RFC), and logistic regression (LR) were used to develop and validate prediction models for in-hospital mortality among females with ACS, using only available features at presentation.

Results

A total of 2,346 ACS patients with a median age of 64 (IQR: 56-74) were included. Of them, 453 (19.3%) were female. Female patients had higher prevalence of NSTEMI (49.2% vs. 39.8%, p < 0.001), less urgent PCI (<2 h) rates (40.2% vs. 50.6%, p < 0.001), and more complications during admission (17.7% vs. 12.3%, p = 0.01). In-hospital mortality occurred in 58 (2.5%) patients [21/453 (5%) females vs. 37/1,893 (2%) males, HR = 2.28, 95% CI: 1.33-3.91, p = 0.003]. GBC algorithm outscored the RFC and LR models, with area under receiver operating characteristic curve (AUROC) of 0.91 with proposed working point of 83.3% sensitivity and 82.4% specificity, and area under precision recall curve (AUPRC) of 0.92. Analysis of feature importance indicated that older age, STEMI, and inflammatory markers were the most important contributing variables.

Conclusions

Mortality and complications rates among females with ACS are significantly higher than in males. Machine learning algorithms for prediction of ACS outcomes among females can be used to help mitigate sex bias.

Prognostic implications of thyroid disease in patients with atrial fibrillation

Atrial fibrillation (AF) is often accompanied by thyroid disease (THD). This study aimed to explore the relationship between THD and the occurrence of significant clinical outcomes in patients with AF. This post hoc analysis utilized data from the MISOAC-AF trial (NCT02941978), which enrolled hospitalized patients with AF. Patients were categorized based on their THD history into hyperthyroidism, hypothyroidism, or euthyroidism. Cox regression models were employed to calculate unadjusted and adjusted hazard ratios (aHRs). The primary outcomes of interest included all-cause mortality, cardiovascular death, and hospitalizations during the follow-up period. The study included 496 AF patients (mean age 73.09 ± 11.10 years) with available THD data, who were followed-up for a median duration of 31 months. Among them, 16 patients (3.2%) had hyperthyroidism, 141 (28.4%) had hypothyroidism, and 339 (68.4%) had no thyroid disease. Patients with hypothyroidism exhibited higher rates of hospitalization during follow-up (aHR: 1.57, 95% CI 1.12 to 2.20, p = 0.025) compared to the euthyroid group. Elevated levels of thyroid-stimulating hormone (TSH) were correlated with an increased risk of cardiovascular mortality (aHR: 1.03, 95% CI 1.01 to 1.05, p = 0.007) and hospitalizations (aHR: 1.06, 95% CI 1.01 to 1.12, p = 0.03). Conversely, lower levels of triiodothyronine (T3) were associated with higher risks of all-cause mortality (aHR: 0.51, 95% CI 0.31 to 0.82, p = 0.006) and cardiovascular mortality (aHR: 0.42, 95% CI 0.23 to 0.77, p = 0.005). Among patients with AF, hypothyroidism was associated with increased hospitalizations. Furthermore, elevated TSH levels and decreased T3 levels were linked to higher cardiovascular and all-cause mortality risks, respectively.

Association between thyroid function and regorafenib efficacy in patients with relapsed wild-type IDH glioblastoma: a large multicenter study

PURPOSE

Regorafenib demonstrated encouraging results in recurrent glioblastoma patients. Some studies showed that changes in circulating thyroid hormones (fT3, fT4, fT3/fT4 ratio) can be considered as prognostic factors in patients with various types of tumors. We designed this study to investigate the relationship between baseline thyroid variables and outcome in IDH-wild type GBM patients who were treated with regorafenib.

METHODS

This multicenter retrospective study included recurrent IDH-wild-type glioblastoma patients treated with regorafenib. Only patients with baseline thyroid function values (TSH, fT3, fT4, fT3/fT4 ratio) available were evaluated. RANO criteria were used to analyze neuroradiological response. Survival curves were estimated using the Kaplan-Meier method. The relationships between baseline thyroid variables (TSH, fT3, fT4, fT3/fT4) and survival (PFS, OS) were investigated with Cox regression models.

RESULTS

From November 2015 to April 2022, 134 recurrent IDH-wildtype GBM patients were treated with regorafenib and 128 of these had information on baseline thyroid function value. Median follow-up was 8 months (IQR 4.7-14.0). Objective Response Rate was 9% and Disease Control Rate was 40.9%. Median PFS was 2.7 months (95%CI 2.2-3.6) and median OS was 10.0 months (95%CI 7.0-13.0). Lower baseline TSH value in the blood was correlated with a higher rate of disease progression to regorafenib (p = 0.04). Multivariable analyses suggested a non-linear relationship between PFS (p = 0.01) and OS (p = 0.03) with baseline fT3/fT4 ratio.

CONCLUSION

In recurrent wild-type IDH glioblastoma patients, baseline fT3/fT4 ratio showed a non-linear relationship with survival, with different impacts across the spectrum of fT3/fT4 ratio. Moreover, baseline TSH may be a predictor of regorafenib activity.

Is there an association between thyroid function tests and 18F FDG PET/CT parameters in untreated cancer patients?

Objectives: We aimed to investigate the association between the extent of disease, 18F FDG PET/CT parameters (SUVmax and the highest SUVmax) and thyroid function tests (TFT) (TSH, FT4, FT3, FT3/FT4 ratio, AntiTG, and AntiTPO) in untreated cancer patients. Material and Method: One hundred and seventy-nine patients who underwent FDG PET/CT for metabolic characterization and staging in our clinic between May 2020 and November 2020 were included in the study. Patients were divided into two groups as malignant and benign according to histopathology findings. Thyroid function tests were ordered from all patients at the time of PET/CT imaging. The association between the presence of local lymph node metastasis, distant metastases and thyroid function tests as well as the association between PET/CT parameters and thyroid function tests in benign and malignant groups were statistically analyzed. Results: Thyroid function tests did not exhibit a significant difference between patients with malignant and benign disease (p> 0.05). Univariate logistic regression analysis revealed that age, FT4 value, and the FT3/F4 ratio were significant parameters in predicting distant metastases. These parameters were also significant in predicting mortality. Multivariate logistic regression analysis showed that age was an independent prognostic factor predicting mortality. Conclusion: Thyroid function tests are not decisive in differentiating malignant and benign lesions. While no statistically significant correlation was observed between thyroid function tests and PET/CT parameters, univariate analyses revealed that especially FT4 and FT3/FT4 ratio were significant in predicting disease extent and mortality in malignant disease. Age was found to be an independent prognostic factor in predicting mortality.

Triiodothyronine (T3), inflammation and mortality risk in patients with acute myocardial infarction

OBJECTIVES

To study the relationship between serum-free T3 (FT3), C-reactive protein (CRP) and all-cause mortality in patients with acute myocardial infarction (AMI).

DESIGN

Prospective multicentre longitudinal cohort study.

METHODS

Between December 2014 and December 2016, thyroid function and CRP were analysed in AMI (both ST-elevation (STEMI) and non-ST-elevation) patients from the Thyroxine in Acute Myocardial Infarction study. The relationship of FT3 and CRP at baseline with all-cause mortality up to June 2020 was assessed. Mediation analysis was performed to evaluate if CRP mediated the relationship between FT3 and mortality.

RESULTS

In 1919 AMI patients (29.2% women, mean (s.d.) age: 64.2 (12.1) years and 48.7% STEMI) followed over a median (interquartile range) period of 51 (46-58) months, there were 277 (14.4%) deaths. Overall, lower serum FT3 and higher CRP levels were associated with higher risk of mortality. When divided the patients into tertiles based on the levels of FT3 and CRP; the group with the lowest FT3 and highest CRP levels had a 2.5-fold increase in mortality risk (adjusted hazard ratio (95% CI) of 2.48 (1.82-3.16)) compared to the group with the highest FT3 and lowest CRP values. CRP mediated 9.8% (95% CI: 6.1-15.0%) of the relationship between FT3 and mortality.

CONCLUSIONS

In AMI patients, lower serum FT3 levels on admission are associated with a higher mortality risk, which is partly mediated by inflammation. Adequately designed trials to explore the potential benefits of T3 in AMI patients are required.

Impact of low triiodothyronine syndrome on long-term outcomes in patients with myocardial infarction with nonobstructive coronary arteries

BACKGROUND

Low triiodothyronine syndrome (LT3S), frequently seen in patients with acute myocardial infarction (AMI), has been regarded as a predictor of poor outcomes after AMI. However, little is known about the prognostic value of LT3S in euthyroid patients with myocardial infarction with nonobstructive coronary arteries (MINOCA).

METHODS

A total of 1162 MINOCA patients were enrolled and divided into LT3S and no-LT3S groups. LT3S was defined as decreased free T3 (fT3 < 2.36 pg/mL) with normal values of thyroid-stimulating hormone. The primary endpoint was a composite of major adverse cardiovascular events (MACE), including all-cause death, nonfatal MI, stroke, revascularization, and hospitalization for unstable angina or heart failure. Kaplan-Meier, Cox regression, propensity score matching (PSM), and receiver-operating characteristic analyses were performed.

RESULTS

Patients with LT3S (prevalence of 17.5%) had a significantly higher incidence of MACE (19.6% vs. 12.9%; p = .013) than patients without during the median follow-up of 41.7 months. LT3S was closely associated with an increased risk of MACE even after multivariable adjustment (HR 1.50, 95% CI: 1.03-2.18, p = .037). After PSM, 197 pairs of patients with or without LT3S were identified, and LT3S remained a robust risk factor of worse outcomes (HR 1.53, 95% CI: 1.02-2.65, p = .042). Moreover, LT3S had an area under the curve (AUC) of 0.60 for predicting MACE. When adding LT3S to the thrombolysis in myocardial infarction (TIMI) risk score, the combined model yielded a significant improvement in discrimination for MACE.

CONCLUSIONS

LT3S was independently associated with poor outcomes after MINOCA. Routine assessment of LT3S may provide valuable prognostic information in this specific population.

Clinical Significance of Low-Triiodothyronine Syndrome in Patients Requiring Non-Surgical Intensive Care - Triiodothyronine Is a Comprehensive Prognostic Marker for Critical Patients With Cardiovascular Disease

Background: Low-triiodothyronine (T₃) syndrome is a known complication in intensive care unit (ICU) patients, but the underlying mechanisms and prognostic impact are unclear.

Methods and Results: This study retrospectively enrolled 2,976 patients who required care in the ICU. Of these patients, 2,425 were euthyroid and were divided into normal (n=1,666; free T₃ [FT₃] ≥1.88 µIU/L) and low-FT₃ (n=759; FT₃ <1.88 µIU/L) groups. Multivariate logistic regression analysis revealed that prognostic nutritional index >46.03 (odds ratio [OR] 2.392; 95% confidence interval [CI] 1.904–3.005), age (per 1-year increase; OR 1.022; 95% CI 1.013–1.031), creatinine (per 0.1-mg/dL increase; OR 1.019; 95% CI 1.014–1.024), and C-reactive protein (per 1-mg/dL increase; OR 1.123; 95% CI 1.095–1.151) were independently associated with low FT₃. Survival rates (within 365 days) were significantly lower in the low-FT₃ group. A multivariate Cox regression model showed that low FT₃ was an independent predictor of 365-day mortality (hazard ratio 1.785; 95% CI 1.387–2.297). Low-T₃ syndrome was significantly more frequent in patients with non-cardiovascular than cardiovascular diseases (73.5% vs. 25.8%). Prognosis was significantly poorer in the low-FT₃ than normal group for patients with cardiovascular disease, particularly those with acute coronary syndrome and acute heart failure.

Conclusions: Low-T₃ syndrome was associated with aging, inflammatory reaction, malnutrition, and renal insufficiency and could lead to adverse outcomes in patients admitted to a non-surgical ICU.

Free Triiodothyronine Connected With Metabolic Changes in Patients With Coronary Artery Disease by Interacting With Other Functional Indicators

This study aims to evaluate the association between free triiodothyronine (FT3) and outcomes of coronary artery disease (CAD) patients, as well as to assess the predictive power of FT3 and related functional markers from the perspective of potential mechanism. A total of 5104 CAD patients with an average follow-up of three years were enrolled into our study. Multivariate Cox regression was used to evaluate the associations between FT3, FT4 (free thyroxin), FT3/FT4 and death, MACE. We developed and validated an age, biomarker, and clinical history (ABC) model based on FT3 indicators to predict the prognosis of patients with CAD. In the multivariable Cox proportional hazards model, FT3 and FT3/FT4 were independent predictors of mortality (Adjusted HR = 0.624, 95% CI = 0.486–0.801; adjusted HR = 0.011, 95% CI = 0.002–0.07, respectively). Meanwhile, emerging markers pre-brain natriuretic peptide, fibrinogen, and albumin levels are significantly associated with low FT3 (p < 0.001). The new risk death score based on biomarkers can be used to well predict the outcomes of CAD patients (C index of 0.764, 95% CI = 0.731–0.797). Overall, our findings suggest that low levels of FT3 and FT3/FT4 are independent predictors of death and MACE risk in CAD patients. Besides, the prognostic model based on FT3 provides a useful tool for the death risk stratification of CAD patients.

Serum total triiodothyronine (T3) as a predictor of mortality and morbidity in critically ill patients and its correlation of predictability with acute physiology and chronic health evaluation II score: A prospective observational study

Background:

The aim is to assess the prognostic value of total T3, total T4, and thyroid-stimulating hormone among critically ill patients admitted to the medical intensive care unit (ICU) in association with mortality and its correlation with the acute physiology and chronic health evaluation II (APACHE II) score.

METHODS

: Our prospective observational study consists of 257 patients without known thyroid diseases admitted to the medical ICU. The baseline characteristics of the patients were recorded, including the APACHE II score and thyroid hormone levels at ICU admission. Based on the primary outcome of mortality, we analyzed the data by appropriate statistical methods. A P < 0.05 was considered significant.

Results:

Of the 257 patients included in the study, 47 (18.28%) succumbed to their illnesses. A significant difference in T3 levels (P < 0.001), T4 levels (P < 0.001), and APACHE II score (P < 0.001) was found between the survivors and the nonsurvivors. There was negative correlation observed between T3 and APACHE II score (r = −0.448, P < 0.001) and T4 and APACHE II score (r = −0.221, P ≤ 0.001). Multivariate logistic regression analysis determined T3 to be the only independent predictor of ICU mortality among thyroid hormones. The area under the curve (AUC) for T3 (0.811 ± 0.04) was almost equal to that of the APACHE II score (0.858 ± 0.029). The duration of ICU stay and hospital stay in patients with low T3 was significantly higher compared to patients with normal T3.

Conclusion:

Serum T3 is a good indicator for predicting mortality and morbidity among critically ill patients.

Serum Free Triiodothyronine and the Responsiveness to Clopidogrel in Patients Undergoing Elective Percutaneous Coronary Intervention

INTRODUCTION

Both thyroid dysfunction and low responsiveness to clopidogrel have been reported to be associated with increased cardiovascular risk. Our study aims at determining the relationship between free triiodothyronine (FT3) and low responsiveness to clopidogrel in patients undergoing elective percutaneous coronary intervention (PCI).

METHODS

Consecutive patients undergoing elective PCI were enrolled. All patients received a loading dose of 300 mg clopidogrel, and platelet function was assessed by thromboelastography at least 12 h later. Low responsiveness to clopidogrel was defined by an adenosine diphosphate-induced platelet-fibrin clot strength > 47 mm and adenosine diphosphate-induced platelet inhibition rate < 50%. Major adverse cardiovascular events (MACEs) were defined as a composite of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and ischemia-driven revascularization.

RESULTS

Of 812 patients included in the study, 289 showed low responsiveness to clopidogrel. The FT3 level was significantly lower in low responders (4.61 ± 0.60 pmol/l versus 4.94 ± 4.66 pmol/l, p = 0.002). Moreover, the percentage of low responders was greater among patients with low FT3 level than among those without (56.1% versus 34.5%, p = 0.007). Logistic regression analysis showed that a FT3 level was independently associated with the risk of low responsiveness to clopidogrel (odds ratio 0.720, 95% confidence interval [CI] 0.533-0.973, p = 0.033). In patients with low responsiveness to clopidogrel, low FT3 was independently associated with increased risk of MACEs (adjusted hazard ratio 3.040, 95% CI 1.077-8.580, p = 0.036) at a median of 19-month follow-up.

CONCLUSIONS

Low FT3 was independently associated with increased risks of both low responsiveness to clopidogrel and cardiovascular events in patients undergoing elective PCI.

Prognostic value of free triiodothyronine and N-terminal pro-B-type natriuretic peptide for patients with acute myocardial infarction undergoing percutaneous coronary intervention: a prospective cohort study

Background

Altered thyroid function and increased N-terminal pro-B-type natriuretic peptide (NT-proBNP) are prognostic factors in acute myocardial infarction (AMI). The study aims to investigate whether free triiodothyronine (fT3) and NT-proBNP are prognostic factors for long-term outcomes in patients with AMI undergoing percutaneous coronary intervention (PCI).

Methods

This was an observational, prospective, single-center study of consecutive patients enrolled at Fuwai Hospital between January, 2013 and December, 2013. The patients were divided into two groups according to fT3 levels: low fT3 (<2.5 pg/mL) and normal fT3 (2.50–4.09 pg/mL). The primary outcome of this study was the incidence of major adverse cardiovascular events (MACEs).

Results

There were 252 patients with low fT3 and 561 patients with normal fT3. After >2 years of follow-up, patients with low fT3 levels had higher rates of MACEs than those with normal fT3 (27.0% vs. 7.8%, P<0.001). Univariable Cox proportional hazards regression analyses showed that NT-proBNP >802.7 pg/mL [hazard ratio (HR) =5.063, 95% confidence interval (CI): 3.176–8.071, P<0.001] and fT3 <2.5 pg/mL (HR =3.867, 95% CI: 2.646–5.651, P<0.001) were the strongest predictors of MACEs. After adjustment for traditional risk predictors, fT3 <2.5 pg/mL (HR =2.570, 95% CI: 1.653–3.993, P<0.001) was one of the most important independent predictors of MACEs. Patients with NT-proBNP ≤802.7 pg/mL and fT3 ≥2.5 pg/mL had the best prognosis, while patients with NT-proBNP >802.7 pg/mL and fT3 <2.5 pg/mL had the worst outcomes (P<0.001).

Conclusions

Low fT3 is a strong predictor of poor prognosis after AMI. The fT3+NT-proBNP combination might be a valuable predictor of the long-term outcomes of PCI after AMI.

Predictive Value of Free Triiodothyronine to Free Thyroxine Ratio in Euthyroid Patients With Myocardial Infarction With Nonobstructive Coronary Arteries

BACKGROUND

Thyroid function is closely involved in cardiovascular diseases. The free triiodothyronine (fT3) to free thyroxine (fT4) ratio has been reported as a risk factor for coronary artery disease, but its prognostic value in euthyroid patients with myocardial infarction with nonobstructive coronary arteries (MINOCA) remains unclear.

METHODS

A total of 1162 euthyroid patients with MINOCA were enrolled and divided according to decreased tertiles of fT3/fT4 ratio. The study endpoint was major adverse cardiovascular events (MACE), including all-cause death, nonfatal MI, nonfatal stroke, revascularization, and hospitalization for unstable angina or heart failure. Kaplan-Meier, Cox regression, and receiver-operating characteristic analyses were performed.

RESULTS

Patients with lower fT3/fT4 tertile levels had a significantly higher incidence of MACE (10.0%, 13.9%, 18.2%; p=0.005) over the median follow-up of 41.7 months. The risk of MACE increased with the decreasing fT3/fT4 tertiles even after multivariate adjustment (tertile1 as reference, tertile2: HR 1.58, 95% CI: 1.05-2.39, p=0.030; tertile3: HR 2.06, 95% CI: 1.17-3.11, p=0.006). Lower level of fT3/fT4 ratio remained a robust predictor of MACE in overall (HR 1.64, 95% CI: 1.18-2.29, p=0.003) and in subgroups. When adding fT3/fT4 ratio [area under the curve (AUC) 0.61] into the thrombolysis in myocardial infarction (TIMI) risk score (AUC 0.69), the combined model (AUC 0.74) yielded a significant improvement in discrimination for MACE (ΔAUC 0.05, p=0.023).

CONCLUSIONS

Low level of fT3/fT4 ratio was strongly associated with a poor prognosis in euthyroid patients with MINOCA. Routine assessment of fT3/fT4 ratio may facilitate risk stratification in this specific population.

Prognostic implications of thyroid hormone alterations in acute coronary syndrome-A systematic review

There is considerable association of thyroid function and the cardiovascular system during various acute systemic illnesses. It is well established that the normal thyroid homeostasis is known to alter in disease states including the acute coronary syndromes (ACS). Abnormal thyroid hormonal status has been shown to be related to worse outcomes and prognosis. This review focuses on the relationship of alterations in thyroid function and its influence on the pathophysiological mechanisms and cardiovascular hemodynamics in ACS and based upon the literature, summarises all the existing evidence to this date on this subject. The data largely points out that low levels of triiodothyronine (T3) levels seen in ACS might be useful in prognosticating the outcomes of ACS.

The Role of Thyroid Diseases and their Medications in Cardiovascular Disorders: A Review of the Literature

The association between thyroid disease and cardiovascular manifestations is significant and undeniable. Previous studies have explained several aspects of the effects of thyroid hormone on the heart and cardiovascular system. Accordingly, both hyper and hypothyroidism can cause important alterations in cardiac rhythm, output and contractility as well as vascular resistance and blood pressure. Since treating the thyroid abnormality, especially in its initial stages, could lead to a significant improvement in most of its resultant cardiovascular disturbances, early suspicion and recognition of thyroid dysfunction, is necessary in patients with cardiovascular manifestations. In this in-depth review, we discuss the physiological roles as well as the effects of abnormal levels of thyroid hormones on the cardiovascular system. We also review the effects of the medications used for the treatment of hyper and hypothyroidism on cardiac function. In the end, we discuss the association between thyroid function and amiodarone, an effective and frequently-used antiarrhythmic drug, because of its well-known effects on the thyroid.

The impact of thyroid hormone dysfunction on ischemic heart disease

Thyroid hormones have a central role in cardiovascular homeostasis. In myocardium, these hormones stimulate both diastolic myocardial relaxation and systolic myocardial contraction, have a pro-angiogenic effect and an important role in extracellular matrix maintenance. Thyroid hormones modulate cardiac mitochondrial function. Dysfunction of thyroid axis impairs myocardial bioenergetic status. Both overt and subclinical hypothyroidism are associated with a higher incidence of coronary events and an increased risk of heart failure progression. Endothelial function is also impaired in hypothyroid state, with decreased nitric oxide-mediated vascular relaxation. In heart disease, particularly in ischemic heart disease, abnormalities in thyroid hormone levels are common and are an important factor to be considered. In fact, low thyroid hormone levels should be interpreted as a cardiovascular risk factor. Regarding ischemic heart disease, during the late post-myocardial infarction period, thyroid hormones modulate left ventricular structure, function and geometry. Dysfunction of thyroid axis might even be more prevalent in the referred condition since there is an upregulation of type 3 deiodinase in myocardium, producing a state of local cardiac hypothyroidism. In this focused review, we summarize the central pathophysiological and clinical links between altered thyroid function and ischemic heart disease. Finally, we highlight the potential benefits of thyroid hormone supplementation as a therapeutic target in ischemic heart disease.

Thyroid stimulating hormone elevation as a predictor of long-term mortality in patients with acute myocardial infarction

BACKGROUND

Hypothyroidism has been known to be associated with hyperlipidemia, endothelial dysfunction and atherosclerosis. Elevation of thyroid-stimulation hormone (TSH) is a gold standard to detect these conditions. However, no large studies have investigated the association between TSH elevation and long-term clinical outcomes in patients with acute myocardial infarction (AMI).

HYPOTHESIS

Hypothyroidism is associated with higher mortality in patients with AMI.

METHODS

A total of 4748 AMI patients undergoing percutaneous coronary intervention (PCI) with drug-eluting stents were consecutively enrolled. We analyzed 1977 patients whose thyroid function data available after the exclusion of hyperthyroidism and possible central hypothyroidism. Patients were divided into two groups; euthyroid group (n = 1846) with normal TSH and normal free thyroxine (FT4); hypothyroidism group (n = 131) with elevated TSH and normal or low FT4. The two groups were subsequently compared with their all-cause and cardiac mortalities.

RESULTS

Median follow-up duration was 3.5 years. Hypothyroidism group were older, included in more females, and had higher incidences of atrial fibrillation, stroke, and renal dysfunction. Elevated TSH was associated with significantly higher all-cause mortality (26.0% vs 11.7%, P < 0.0001) and cardiac mortality (9.2% vs 4.6%, P = 0.014). The multivariate Cox proportional hazards model identified that TSH elevation was a significant predictor of all-cause mortality (adjusted hazard ratio 1.560, 95% confidence interval 1.017 to 2.392, P = 0.041).

CONCLUSIONS

Our data suggest that AMI patients with TSH elevation had worse clinical outcome. Moreover, TSH elevation was a predictor of all-cause mortality in patients with AMI.

Free triiodothyronine and global registry of acute coronary events risk score on predicting long-term major adverse cardiac events in STEMI patients undergoing primary PCI

Background

The aim of this study is to investigate the combined value of fT3 and GRACE risk score for cardiovascular prognosis in ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI).

Methods

Three hundred and thirty eight patients with STEMI who received successful primary PCI were enrolled in our study. All patients underwent (33.5 ± 7.1) month’s follow-up. Mace was defined as cardiac death and nonfatal myocardial infarction.

Results

Multivariate Cox analysis showed that both fT3 (HR = 0.462, 95%CI: 0.364–0.587, P < 0.001) and GRACE score (HR = 1.011, 95%CI: 1.004–1.018, P = 0.003) were independent predictors of Mace. Similarly, fT3 (HR = 0.495, 95%CI: 0.355–0.690, P < 0.001) and GRACE score (HR = 1.022, 95%CI: 1.011–1.034, P < 0.001) were the most important independent predictors of cardiac death. Kaplan-Meier analysis revealed that those patients with low fT3 and higher GRACE score had higher rates of Mace (Log-Rank χ2 = 25.087, P < 0.001). In ROC analysis, combining fT3 and GRACE risk score had a good area under the curve (AUC) value for Mace (AUC = 0.735, 95% CI: 0.680–0.790, P < 0.001), with net reclassification index of 11.1 and 5.3%, respectively.

Conclusion

The low fT3 level, a common phenomenon, is a strong predictor of long-term poor prognosis in STEMI patients who underwent primary PCI. The combination of GRACE score and fT3 may be a more valuable predictor of Mace as compared to each measure alone.

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.

The role of thyroid hormones in acute coronary syndromes: Prognostic value of alterations in thyroid hormones

The prognosis of acute coronary syndromes (ACS) is affected by many factors. Normal thyroid homeostasis is known to alter during various critical illnesses, a condition that has been shown to correlate with the severity of the disease and increased mortality. The purpose of this article is to review literature to emphasize the considerable association of thyroid function with the cardiovascular system and summarize all existing evidence with regard to the role of thyroid hormones alterations during ACS. The electronic databases of PubMed, Medline, Scopus, and Cochrane were searched for relevant literature and studies. Alterations in thyroid hormone plasma concentrations, especially low triiodothyronine (T3) levels, represent a hormonal imbalance that is not uncommon among patients suffering an acute coronary event. Many studies have identified this abnormal thyroid hormonal status to be related to worse prognosis. Although further large-scale clinical trials are needed, the low T3 syndrome manifesting in patients during ACS might be useful in prognostic stratification.