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

Hypothyroidism in Older Adults: A Narrative Review

INTRODUCTION

The prevalence of hypothyroidism increases along with aging, resulting in one of the most common comorbidities among patients over 75 years. The leading causes of hypothyroidism in older adults are iatrogenic, Hashimoto's thyroiditis, and medications. The narrative review aimed to discuss the clinical characteristics of hypothyroidism in older adults and the impact of hormonal replacement therapy on survival rates. Thyroid function declines over time due to physiological changes in the thyroid stimulating hormone signaling, iodine absorption and metabolism, thyroid hormone metabolism, and activity at peripheral sites. A serum TSH value over the upper limit of the normal reference range is not necessarily attributable to hypothyroidism. However, an appropriate diagnostic work-up is required to rule out true hypothyroidism and discriminate the etiology (i.e., thyroid autoimmune diseases, iodine deficiency, drug-induced hypothyroidism). Levothyroxine treatment should be considered in cases of overt hypothyroidism. A complete risk-to-benefit assessment, particularly considering the overall health status, life expectancy, cognitive function, mood, and cardiovascular and neurological background, should be considered before treating subclinical hypothyroidism with more potential benefits in patients under 75 years old. Levothyroxine formulations facilitating hormone absorption and increasing compliance to long-term treatment should be preferred. TSH target should usually be set over 3 mIU/ml. Defining optimal diagnostic approaches and targeted therapeutic strategies should be considered in the personalized management of aged patients with hypothyroidism.

Chinese Medicine Supplementing Qi and Activating Blood Circulation Relieves the Progression of Diabetic Cardiomyopathy

BACKGROUND

Diabetic cardiomyopathy (DCM) is the leading cause of diabetic death as the final occurrence of heart failure and arrhythmia. Traditional Chinese medicine is usually used to treat various diseases including diabetes.

OBJECTIVE

This study sought to investigate the effects of Traditional Chinese medicine supplementing Qi and activating blood circulation (SAC) in DCM.

METHODS

After the construction of the DCM model by streptozotocin (STZ) injection and high glucose/fat diet feeding, rats were administered intragastrically with SAC. Then, cardiac systolic/diastolic function was evaluated by detecting left ventricular systolic pressure (LVSP), maximal rate of left ventricular pressure rise (+LVdp/dtmax), and fall (-LVdp/dtmax), heart rate (HR), left ventricular ejection fraction (EF), LV fractional shortening (FS) and left ventricular end-diastolic pressure (LVEDP). Masson’s and TUNEL staining were used to assess fibrosis and cardiomyocyte apoptosis.

RESULTS

DCM rats exhibited impaired cardiac systolic/diastolic function manifested by decreasing LVSP, + LVdp/dtmax, -LVdp/dtmax, HR, EF and FS, and increasing LVEDP. Intriguingly, traditional Chinese medicine SAC alleviated the above-mentioned symptoms, indicating a potential role in improving cardiac function. Masson’s staining substantiated that SAC antagonized the increased collagen deposition and interstitial fibrosis area and the elevations in protein expression of fibrosis-related collagen I and fibronectin in heart tissues of DCM rats. Furthermore, TUNEL staining confirmed that traditional Chinese medicine SAC also attenuated cardiomyocyte apoptosis in DCM rats. Mechanically, DCM rats showed the aberrant activation of the TGF-β/Smad signaling, which was inhibited after SAC.

CONCLUSION

SAC may exert cardiac protective efficacy in DCM rats via the TGF-β/Smad signaling, indicating a new promising therapeutic approach for DCM.

Low T3 syndrome is associated with poor prognosis in patients with hepatitis B virus-related acute-on-chronic liver failure

BACKGROUND

Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is a critical disease with high mortality risk. Low triiodothyronine syndrome (LT3S) is associated with various severe acute and chronic diseases. We investigated the relationship between LT3S and poor prognosis in patients with HBV-ACLF.

RESEARCH DESIGN AND METHODS

A total of 198 patients with HBV-ACLF were enrolled between January 2018 and March 2019. We screened for independent risk factors for 28-day mortality using univariate and multivariate logistic regression analyses. Spearman's correlation analysis was used to evaluate the correlation between LT3S and the poor prognostic parameters of HBV-ACLF.

RESULTS

LT3S was an independent risk factor for 28-day mortality in HBV-ACLF patients (odds ratio: 4.035, 95% confidence interval 1.117-14.579; p = 0.033). The death group had a lower serum FT3 level (Z-value = 2639.000, p < 0.001). Serum FT3 levels were negatively correlated with age, C-reactive protein, international normalized ratio, and neutrophil count but positively correlated with lymphocyte count. A negative correlation between FT3 and various prognostic scores was observed, indicating that a low FT3 level was closely related to a poor prognosis.

CONCLUSIONS

LT3S was an independent risk factor for 28-day mortality and was correlated with poor prognosis in patients with HBV-ACLF.

Endocrine system dysfunction and chronic heart failure: a clinical perspective

Chronic heart failure (CHF) leads to an excess of urgent ambulatory visits, recurrent hospital admissions, morbidity, and mortality regardless of medical and non-medical management of the disease. This excess of risk may be attributable, at least in part, to comorbid conditions influencing the development and progression of CHF. In this perspective, the authors examined and described the most common endocrine disorders observed in patients with CHF, particularly in individuals with reduced ejection fraction, aiming to qualify the risks, quantify the epidemiological burden and discuss about the potential role of endocrine treatment. Thyroid dysfunction is commonly observed in patients with CHF, and sometimes it could be the consequence of certain medications (e.g., amiodarone). Male and female hypogonadism may also coexist in this clinical context, contributing to deteriorating the prognosis of these patients. Furthermore, growth hormone deficiency may affect the development of adult myocardium and predispose to CHF. Limited recommendation suggests to screen endocrine disorders in CHF patients, but it could be interesting to evaluate possible endocrine dysfunction in this setting, especially when a high suspicion coexists. Data referring to long-term safety and effectiveness of endocrine treatments in patients with CHF are limited, and their impact on several "hard" endpoints (such as hospital admission, all-cause, and cardiovascular mortality) are still poorly understood.

Effect of levothyroxine replacement therapy in patients with subclinical hypothyroidism and chronic heart failure: A systematic review

BACKGROUND

Chronic heart failure (CHF) affects the health care system with high social and economic costs due to recurrent hospital admissions or frequent ambulatory reassessments. Subclinical hypothyroidism (SCH) is commonly observed in patients with CHF and negatively affects myocardial function and remodeling and, ultimately, increases the risk of hospitalizations and all-cause and cardiovascular (CV) mortality. The role of levothyroxine replacement on relevant CV outcomes in patients with SCH and CHF is unclear.

OBJECTIVE

To assess the effect of levothyroxine (compared to placebo or no treatment) on the incidence of all-cause and CV mortality, major adverse CV events, and heart failure in patients with SCH and CHF.

METHODS

PubMed/MEDLINE, Cochrane Library, and ClinicalTrial.gov were searched for randomized clinical trials, non-randomized observational, multicentric, and comparative studies. No language restrictions were included. After duplicate removal, articles were screened and extracted for the synthesis according to a hierarchical strategy that included title, abstract, and full-text appraisal. The risk of bias was assessed by RoB2 and ROBIN-I tools. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was applied to rate the quality of evidence and grade the strength of recommendations.

RESULTS

Two trials were included in the systematic review with considerable indirectness and inaccuracy that down-graded the level of evidence.

DISCUSSION

No evidence supports the use of levothyroxine for treating SCH in CHF due to the lack of reliable and well-designed clinical trials.

CONCLUSION

CV outcome and dose-response trials are needed to understand better the role of levothyroxine replacement treatment for a safer prescription in this clinical setting.

Commentary to the article "Multiple hormonal and metabolic deficiency syndrome predicts outcome in heart failure: the T.O.S.CA. Registry", Antonio Cittadini et al. Eur J Prev Cardiol. 2021

Chronic heart failure represents a relevant concern for public health. The endocrine system is heavily involved in the induction and progression of chronic heart failure. Among endocrine dysfunction, the most relevant alterations are related to the growth hormone-insulin like growth factor 1 axis, serum testosterone, dehydroepiandrosterone sulfate, triiodothyronine levels, insulin resistance, and type 2 diabetes mellitus. It is currently debated whether these changes might be simple adaptive mechanisms or, instead, they may deteriorate myocardial pump function over time. Medical management of patients exhibiting one or more hormonal deficiencies or metabolic disorders, including insulin resistance and diabetes mellitus, may have a therapeutic role.

Thyroid Hormone Plays an Important Role in Cardiac Function: From Bench to Bedside

Thyroid hormones (THs) are synthesized in the thyroid gland, and they circulate in the blood to regulate cells, tissues, and organs in the body. In particular, they exert several effects on the cardiovascular system. It is well known that THs raise the heart rate and cardiac contractility, improve the systolic and diastolic function of the heart, and decrease systemic vascular resistance. In the past 30 years, some researchers have studied the molecular pathways that mediate the role of TH in the cardiovascular system, to better understand its mechanisms of action. Two types of mechanisms, which are genomic and non-genomic pathways, underlie the effects of THs on cardiomyocytes. In this review, we summarize the current knowledge of the action of THs in the cardiac function, the clinical manifestation and parameters of their hemodynamics, and treatment principles for patients with hyperthyroid- or hypothyroid-associated heart disease. We also describe the cardiovascular drugs that induce thyroid dysfunction and explain the mechanism underlying the thyroid toxicity of amiodarone, which is considered the most effective antiarrhythmic agent. Finally, we discuss the recent reports on the involvement of thyroid hormones in the regulation of myocardial regeneration and metabolism in the adult heart.

Thyroid and COVID-19: a review on pathophysiological, clinical and organizational aspects

BACKGROUND

Thyroid dysfunction has been observed in patients with COVID-19, and endocrinologists are requested to understand this clinical issue. Pandemic-related restrictions and reorganization of healthcare services may affect thyroid disease management.

OBJECTIVE AND METHODS

To analyze and discuss the relationship between COVID-19 and thyroid diseases from several perspectives. PubMed/MEDLINE, Google Scholar, Scopus, ClinicalTrial.gov were searched for this purpose by using free text words and medical subject headings as follows: "sars cov 2", "covid 19", "subacute thyroiditis", "atypical thyroiditis", "chronic thyroiditis", "hashimoto's thyroiditis", "graves' disease", "thyroid nodule", "differentiated thyroid cancer", "medullary thyroid cancer", "methimazole", "levothyroxine", "multikinase inhibitor", "remdesivir", "tocilizumab". Data were collected, analyzed, and discussed to answer the following clinical questions: "What evidence suggests that COVID-19 may induce detrimental consequences on thyroid function?"; "Could previous or concomitant thyroid diseases deteriorate the prognosis of COVID-19 once the infection has occurred?"; "Could medical management of thyroid diseases influence the clinical course of COVID-19?"; "Does medical management of COVID-19 interfere with thyroid function?"; "Are there defined strategies to better manage endocrine diseases despite restrictive measures and in-hospital and ambulatory activities reorganizations?".

RESULTS

SARS-CoV-2 may induce thyroid dysfunction that is usually reversible, including subclinical and atypical thyroiditis. Patients with baseline thyroid diseases are not at higher risk of contracting or transmitting SARS-CoV-2, and baseline thyroid dysfunction does not foster a worse progression of COVID-19. However, it is unclear whether low levels of free triiodothyronine, observed in seriously ill patients with COVID-19, may worsen the disease's clinical progression and, consequently, if triiodothyronine supplementation could be a tool for reducing this burden. Glucocorticoids and heparin may affect thyroid hormone secretion and measurement, respectively, leading to possible misdiagnosis of thyroid dysfunction in severe cases of COVID-19. High-risk thyroid nodules require a fine-needle aspiration without relevant delay, whereas other non-urgent diagnostic procedures and therapeutic interventions should be postponed.

DISCUSSION

Currently, we know that SARS-CoV-2 could lead to short-term and reversible thyroid dysfunction, but thyroid diseases seem not to affect the progression of COVID-19. Adequate management of patients with thyroid diseases remains essential during the pandemic, but it could be compromised because of healthcare service restrictions. Endocrine care centers should continuously recognize and classify priority cases for in-person visits and therapeutic procedures. Telemedicine may be a useful tool for managing patients not requiring in-person visits.

COVID-19 and the Endocrine System: A Comprehensive Review on the Theme

Background and aim. The review aimed to summarize advances in the topic of endocrine diseases and coronavirus disease 2019 (COVID-19). Methods. Scientific and institutional websites and databases were searched and data were collected and organized, when plausible, to angle the discussion toward the following clinical issues. (1) Are patients with COVID-19 at higher risk of developing acute or late-onset endocrine diseases or dysfunction? (2) May the underlying endocrine diseases or dysfunctions be considered risk factors for poor prognosis once the infection has occurred? (3) Are there defined strategies to manage endocrine diseases despite pandemic-related constraints? Herein, the authors considered only relevant and more frequently observed endocrine diseases and disorders related to the hypothalamic-pituitary region, thyroid and parathyroid glands, calcium-phosphorus homeostasis and osteoporosis, adrenal glands, and gonads. Main. Data highlight the basis of some pathophysiological mechanisms and anatomical alterations of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)-induced endocrine dysfunctions. Some conditions, such as adrenal insufficiency and cortisol excess, may be risk factors of worse clinical progression once the infection has occurred. These at-risk populations may require adequate education to avoid the SARS-CoV-2 infection and adequately manage medical therapy during the pandemic, even in emergencies. Endocrine disease management underwent a palpable restraint, especially procedures requiring obligate access to healthcare facilities for diagnostic and therapeutic purposes. Strategies of clinical triage to prioritize medical consultations, laboratory, instrumental evaluations, and digital telehealth solutions should be implemented to better deal with this probably long-term situation.

Thyroid Dysfunction in COVID-19

OBJECTIVE

The aim of this study was to evaluate thyroid dysfunction in COVID-19 and study its association with disease severity in COVID-19.

METHODS

Patients with confirmed COVID-19 infection who were admitted to dedicated COVID hospital were recruited over 3 months period. Those with pre-existing thyroid disease were excluded. The thyroid function tests were performed and correlated with interleukin-6 levels.

RESULTS

A total of 164 patients (14 children) with mean(SD) age 53.85 (19.54) years were recruited. The proportion of patients with mild, moderate and severe disease were 22 (13.4%), 78 (47.6%) and 64 (39.0%), respectively, among which 12 (54.5%), 56 (71.8%) and 43 (67.2%) patients had thyroid dysfunction, respectively; P = 0.309. Eighty eight (53.7%) had sick euthyroid (84 had low fT3 only), 14 had overt hypothyroidism and 9 had thyroiditis. Median (IQR) levels of serum fT3 showed significant decline from mild category [4.54 (3.81, 5.27)], to moderate [3.95 (3.67, 4.24)] and severe category [3.56 (3.22, 3.89)]; P = 0.011. Low fT3 had significant risk [odds ratio (95% CI)] of death [2.634 (1.01, 6.87); P = 0.031] and elevated IL-6 [2.575 (1.084, 6.118); P = 0.021].

CONCLUSION

Sick euthyroid was seen in the majority of patients hospitalized with COVID. Low fT3 was associated with death and increased inflammation, suggesting poor prognosis.

The Year in Cardiothoracic Critical Care: Selected Highlights from 2019

In 2019, cardiothoracic and vascular critical care remained an important focus and subspecialty. This article continues the annual series to review relevant contributions in postoperative critical care that may affect the cardiac anesthesiologist. Herein, the pertinent literature published in 2019 is explored and organized by organ system.