Dysthyroidism and Chronic Heart Failure: Pathophysiological Mechanisms and Therapeutic Approaches

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.

Rapid progression of heart failure secondary to radioactive iodine treatment of hyperthyroidism: A case report

BACKGROUND

The deterioration of thyroid health is involved in the progression of heart failure (HF). This is usually a lengthy process, so there are almost no reports on its rapid development. Here we report a case of a young male who rapidly developed hypothyroid cardiomyopathy secondary to radioactive iodine treatment, suggesting that severe HF might occur even after a short period of hypothyroidism.

CASE SUMMARY

A 26-year-old man was referred to our hospital for HF presenting with dyspnea on exertion and chest discomfort lasting for 1 mo. He received radioactive iodine treatment for hyperthyroidism 1 year ago and had an almost normal echocardiogram 6 mo ago. Admission echocardiogram and cardiac magnetic resonance (CMR) revealed left ventricle (LV) global hypokinesia and severely depressed systolic function. In addition, late gadolinium enhancement indicated no obvious changes in the myocardium. Thyroid function tests showed decreased serum levels of thyroid hormone (TH) and elevated thyroid-stimulating hormone. Based on an exclusionary examination, the patient was diagnosed with hypothyroid cardiomyopathy and was started on replacement therapy. His HF symptoms were completely relieved during the six-month follow-up, and echocardiogram and CMR revealed recovered LV size and ejection fraction.

CONCLUSION

This report demonstrates that severe fluctuations in TH levels may lead to acute HF, which can completely recover with timely thyroid hormone replacement. In addition, our findings highlight the importance of routinely detecting cardiac function in patients treated with radioactive iodine.

Rapid progression of heart failure secondary to radioactive iodine treatment of hyperthyroidism: A case report

BACKGROUND

The deterioration of thyroid health is involved in the progression of heart failure (HF). This is usually a lengthy process, so there are almost no reports on its rapid development. Here we report a case of a young male who rapidly developed hypothyroid cardiomyopathy secondary to radioactive iodine treatment, suggesting that severe HF might occur even after a short period of hypothyroidism.

CASE SUMMARY

A 26-year-old man was referred to our hospital for HF presenting with dyspnea on exertion and chest discomfort lasting for 1 mo. He received radioactive iodine treatment for hyperthyroidism 1 year ago and had an almost normal echocardiogram 6 mo ago. Admission echocardiogram and cardiac magnetic resonance (CMR) revealed left ventricle (LV) global hypokinesia and severely depressed systolic function. In addition, late gadolinium enhancement indicated no obvious changes in the myocardium. Thyroid function tests showed decreased serum levels of thyroid hormone (TH) and elevated thyroid-stimulating hormone. Based on an exclusionary examination, the patient was diagnosed with hypothyroid cardiomyopathy and was started on replacement therapy. His HF symptoms were completely relieved during the six-month follow-up, and echocardiogram and CMR revealed recovered LV size and ejection fraction.

CONCLUSION

This report demonstrates that severe fluctuations in TH levels may lead to acute HF, which can completely recover with timely thyroid hormone replacement. In addition, our findings highlight the importance of routinely detecting cardiac function in patients treated with radioactive iodine.

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.

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 Disorders and Prognosis in Chronic Heart Failure: A Long-Term Follow-Up Study

BACKGROUND

Thyroid disorders may have a negative impact on the prognosis of patients affected by chronic heart failure (CHF).

OBJECTIVE

The aim of the current study was to evaluate the prognostic role of all thyroid disorders over a long term follow-up in a single centre large sample of CHF outpatients.

METHODS

In all patients, the function of the thyroid was evaluated at the enrolment and during the follow- up. On the basis of free triiodothyronine (T3), free thyroxine (fT4) and thyroid-stimulating hormone (TSH) serum levels, patients were classified into one of the following four categories: euthyroid subjects, patients affected by hypothyroidism, low T3 (LT3) syndrome and hyperthyroidism. During the follow-up, death for all causes was assessed as primary end-point, whereas time to the first hospitalization for heart failure worsening was the secondary end-point analyzed.

RESULTS

Among 762 patients, 190 patients were affected by hypothyroidism (Hypo). LT3 syndrome was diagnosed in 15 patients and 59 patients were affected by hyperthyroidism (Hyper). During a long term follow-up (5.1±3.7 years), 303 patients died. Patients with Hypo showed an increased risk of death as well as of hospitalization due to heart failure worsening at univariate regression analysis. At multivariate regression analysis, Hypo remained associated with hospitalization after correction for age >75 years, ischemic aetiology, diabetes, therapy with ACE-inhibitors or ARBs, therapy with betablockers and with aldosterone antagonists, NYHA class 3, systolic arterial pressure <95 mmHg, left ventricular ejection fraction <30%, estimated glomerular filtration rate <60 ml/min, hyponatremia and NTproBNP> 1000 pg/ml. At multivariate analysis, the independent association with death was significant only for the subgroup of patients with TSH >10 mIU/L. LT3 was independently associated with both heart failure hospitalization and death, whereas Hyper was not associated with any of the two considered end-points.

CONCLUSION

Hypo is associated with a worse prognosis over a long-term follow-up. The association with heart failure hospitalization is not dependent on the baseline TSH levels, whereas the association with death is significant only when TSH >10 mIU/L. Finally, Hyper does not have any association with a worse prognosis.