Thyroid Hormones and Cardiovascular Function and Diseases

Changes of cardiac function: cardiac adaptation in patients with hypothyroidism assessed by cardiac magnetic resonance-a meta-analysis

Objective

The meta-analysis aimed to explore the cardiac adaptation in hypothyroidism patients by cardiac magnetic resonance.

Research methods and procedures

Databases including PubMed, Cochrane Library, Embase, CNKI, and Sinomed for clinical studies of hypothyroidism on cardiac function changes. Databases were searched from the earliest data to 15 June 2023. Two authors retrieved studies and evaluated their quality. Review Manager 5.4.1 and Stata18 were used to analyze the data. This study is registered with the International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY), 202440114.

Results

Six studies were selected for further analysis. Five of them reported differences in cardiac function measures between patients with hypothyroidism and healthy controls, and three studies reported cardiac function parameters after treatment in patients with hypothyroidism. The fixed-effect model combined WMD values for left ventricular ejection fraction (LVEF) had a pooled effect size of -1.98 (95% CI -3.50 to -0.44], P=0.01), implying that LVEF was lower in patients with hypothyroidism than in healthy people. Analysis of heterogeneity found moderate heterogeneity (P = 0.08, I² = 50%). WMD values for stroke volume (SV), cardiac index (CI), left ventricular end-diastolic volume index(LVEDVI), left ventricular end-systolic volume (LESVI), and left ventricular mass index(LVMI) were also analyzed, and pooled effect sizes showed the CI and LVEDVI of patients with hypothyroidism ware significantly decrease (WMD=-0.47, 95% CI [-0.93 to -0.00], P=0.05, WMD=-7.99, 95%CI [-14.01 to -1.96], P=0.009, respectively). Patients with hypothyroidism tended to recover cardiac function after treatment [LVEF (WMD = 6.37, 95%CI [2.05, 10.69], P=0.004), SV (WMD = 7.67, 95%CI [1.61, 13.74], P=0.01), CI (WMD = 0.40, 95%CI [0.01, 0.79], P=0.05)], and there was no difference from the healthy controls.

Conclusion

Hypothyroidism could affect cardiac function, although this does not cause significant heart failure. It may be an adaptation of the heart to the hypothyroid state. There was a risk that this adaptation may turn into myocardial damage. Cardiac function could be restored after treatment in patients with hypothyroidism. Aggressive levothyroxine replacement therapy should be used to reverse cardiac function.

Systematic review registration

https://inplasy.com, identifier (INPLASY202440114).

Hypothyroidism and metabolic cardiovascular disease

Cardiovascular disease (CVD) remains the leading cause of death worldwide, representing a major health issue of social and economic relevance. Both hyperthyroidism and hypothyroidism are very common in the adult population, and both disorders may contribute to the onset and progression of CVD. After a brief description of the role of thyroid hormones (THs) on the physiology of the cardiovascular system and the potential mechanism that links THs alterations with changes in cardiac function, blood pressure, endothelial function, and lipid levels, we review updated data about the clinical impact of overt hypothyroidism (OH) and subclinical hypothyroidism (SCH) on CV risk, CVD, and mortality. Furthermore, we summarize the current evidence for treating SCH with levothyroxine (L-T4). Several guidelines of distinguished endocrine societies recommend treatment for SCH with TSH higher than 10 mIU/L, where the benefit of L-T4 therapy is more evident for younger people, but still controversial in those aged over 65 years. Based on current knowledge, more research efforts are needed to better address the clinical management of CV risk and CVD in the elderly affected by SCH.

Long-term Effect of Thyrotropin-binding Inhibitor Immunoglobulin on Atrial Fibrillation in Euthyroid Patients

OBJECTIVE

Individuals with hyperthyroidism are at an increased risk of atrial fibrillation (AF), but the association between autoantibodies and AF or cardiovascular mortality in individuals who have returned to normal thyroid function remains unclear.

METHODS

The study utilized electronic medical records from National Taiwan University Hospital between 2000 and 2022. Each hyperthyroidism patient had at least 1 thyrotropin-binding inhibiting immunoglobulin (TBII) measurement. The relationship between TBII levels and the risk of AF and cardiovascular mortality was assessed using multivariable Cox regression models and Kaplan-Meier survival analysis.

RESULTS

Among the 14 618 enrolled patients over a 20-year timeframe, 173 individuals developed AF, while 46 experienced cardiovascular mortality. TBII values exceeding 35% were significantly associated with an elevated risk of AF for both the first TBII (hazard ratio {HR} 1.48 [1.05-2.08], P = .027) and mean TBII (HR 1.91 [1.37-2.65], P < .001). Furthermore, after free T4 levels had normalized, a borderline association between first TBII and AF (HR 1.59 [0.99-2.56], P = .056) was observed, while higher mean TBII increased AF (HR 1.78 [1.11-2.85], P = .017). Higher first and mean TBII burden continued to significantly impact the incidence of cardiovascular mortality (HR 6.73 [1.42-31.82], P = .016; 7.87 [1.66-37.20], P = .009). Kaplan-Meier analysis demonstrated that elevated TBII levels increased the risk of AF and cardiac mortality (log-rank P = .035 and .027, respectively).

CONCLUSION

In euthyroid individuals following antithyroid treatment, elevated circulating TBII levels and burden are associated with an elevated risk of long-term incident AF and cardiovascular mortality. Further reduction of TBII level below 35% will benefit to clinical outcomes.

Partial Resistance to Thyroid Hormone-Induced Tachycardia and Cardiac Hypertrophy in Mice Lacking Thyroid Hormone Receptor β

Background: Thyroid hormones regulate cardiac functions mainly through direct actions in the heart and by binding to the thyroid hormone receptor (TR) isoforms α1 and β. While the role of the most abundantly expressed isoform, TRα1, is widely studied and well characterized, the role of TRβ in regulating heart functions is still poorly understood, primarily due to the accompanying elevation of circulating thyroid hormone in TRβ knockout mice (TRβ-KO). However, their hyperthyroidism is ameliorated at thermoneutrality, which allows studying the role of TRβ without this confounding factor. Methods: Here, we noninvasively monitored heart rate in TRβ-KO mice over several days using radiotelemetry at different housing temperatures (22°C and 30°C) and upon 3,3',5-triiodothyronine (T3) administration in comparison to wild-type animals. Results: TRβ-KO mice displayed normal average heart rate at both 22°C and 30°C with only minor changes in heart rate frequency distribution, which was confirmed by independent electrocardiogram recordings in freely-moving conscious mice. Parasympathetic nerve activity was, however, impaired in TRβ-KO mice at 22°C, and only partly rescued at 30°C. As expected, oral treatment with pharmacological doses of T3 at 30°C led to tachycardia in wild-types, accompanied by broader heart rate frequency distribution and increased heart weight. The TRβ-KO mice, in contrast, showed blunted tachycardia, as well as resistance to changes in heart rate frequency distribution and heart weight. At the molecular level, these observations were paralleled by a blunted cardiac mRNA induction of several important genes, including the pacemaker channels Hcn2 and Hcn4, as well as Kcna7. Conclusions: The phenotyping of TRβ-KO mice conducted at thermoneutrality allows novel insights on the role of TRβ in cardiac functions in the absence of the usual confounding hyperthyroidism. Even though TRβ is expressed at lower levels than TRα1 in the heart, our findings demonstrate an important role for this isoform in the cardiac response to thyroid hormones.

Canonical and Noncanonical Contribution of Thyroid Hormone Receptor Isoforms Alpha and Beta to Cardiac Hypertrophy and Heart Rate in Male Mice

Background: Stimulation of ventricular hypertrophy and heart rate are two major cardiac effects of thyroid hormone (TH). The aim of this study was to determine in vivo which TH receptor (TR)-α or β-and which mode of TR action-canonical gene expression or DNA-binding independent noncanonical action-mediate these effects. Methods: We compared global TRα and TRβ knockout mice (TRαKO; TRβKO) with wild-type (WT) mice to determine the TR isoform responsible for T3 effects. The relevance of TR DNA binding was studied in mice with a mutation in the DNA-binding domain that selectively abrogates DNA binding and canonical TR action (TRαGS; TRβGS). Hearts were studied with echocardiography at baseline and after 7 weeks of T3 treatment. Gene expression was measured with real-time polymerase chain reaction. Heart rate was recorded with radiotelemetry transmitters for 7 weeks in untreated, hypothyroid, and T3-treated mice. Results: T3 induced ventricular hypertrophy in WT and TRβKO mice, but not in TRαKO mice. Hypertrophy was also induced in TRαGS mice. Thus, hypertrophy is mostly mediated by noncanonical TRα action. Similarly, repression of Mhy7 occurred in WT and TRαGS mice. Basal heart rate was largely dependent on canonical TRα action. But responsiveness to hypothyroidism and T3 treatment as well as expression of pacemaker gene Hcn2 were still preserved in TRαKO mice, demonstrating that TRβ could compensate for absence of TRα. Conclusions: T3-induced cardiac hypertrophy could be attributed to noncanonical TRα action, whereas heart rate regulation was mediated by canonical TRα action. TRβ could substitute for canonical but not noncanonical TRα action.

Subclinical central hypothyroidism in patients with hypothalamic-pituitary disease: does it exist?

Central hypothyroidism (CH) is characterized by decreased thyroid hormone production due to insufficient stimulation of an otherwise normal thyroid gland by TSH. In patients with established hypothalamic-pituitary disease, a low FT4 concentration is considered highly specific, although poorly sensitive, for the diagnosis of CH. That would be comparable to diagnosing primary hypothyroidism in patients at risk only when serum FT4 concentrations are below the reference range, missing all patients with subclinical primary hypothyroidism and preventing proper therapy in patients in which thyroxine replacement is clearly beneficial. Cardiac time intervals, especially the isovolumic contraction time (ICT), have been considered the gold standard of peripheral thyroid hormone action. Using Doppler echocardiography, we have previously shown a very high proportion of prolonged ICT in patients with hypothalamic-pituitary disease and serum FT4 levels indistinguishable from controls. As ICT decreased/normalized after thyroxine-induced increases in FT4 concentrations within the normal reference range, prolonged ICT was considered a bona fide diagnostic biomarker of subclinical CH. Those findings challenge the usual interpretation that FT4 concentrations in the mid-reference range exclude hypothyroidism in patients with hypothalamic-pituitary disease. Rather, subclinical central hypothyroidism, a state analogous to subclinical primary hypothyroidism, seems to be frequent in patients with hypothalamic-pituitary disease and normal FT4 levels. They also challenge the notion that thyroid function is usually the least or the last affected in acquired hypopituitarism. The relevance of Doppler echocardiography to correctly diagnose and monitor replacement therapy in both clinical and subclinical forms of CH should improve quality of life and decrease cardiovascular risk, as already demonstrated in patients with clinical and subclinical primary hypothyroidism.

Polymorphisms of DNA Repair Genes in Thyroid Cancer

The incidence of thyroid cancer, one of the most common forms of endocrine cancer, is increasing rapidly worldwide in developed and developing countries. Various risk factors can increase susceptibility to thyroid cancer, but particular emphasis is put on the role of DNA repair genes, which have a significant impact on genome stability. Polymorphisms of these genes can increase the risk of developing thyroid cancer by affecting their function. In this article, we present a concise review on the most common polymorphisms of selected DNA repair genes that may influence the risk of thyroid cancer. We point out significant differences in the frequency of these polymorphisms between various populations and their potential relationship with susceptibility to the disease. A more complete understanding of these differences may lead to the development of effective prevention strategies and targeted therapies for thyroid cancer. Simultaneously, there is a need for further research on the role of polymorphisms of previously uninvestigated DNA repair genes in the context of thyroid cancer, which may contribute to filling the knowledge gaps on this subject.

Cardiovascular mechanisms of thyroid hormones and heart failure: Current knowledge and perspectives

A multiple hormonal imbalance that accompanies heart failure (HF) may have a significant impact on the clinical course in such patients. The non-thyroidal illness syndrome (NTIS), also referred to as euthyroid sick syndrome or low triiodothyronine syndrome, can be found in about 30% of patients with HF. NTIS represents a systemic adaptation to chronic illness that is associated with increased cardiac and overall mortality in patients with HF. While conclusions on thyroid-stimulating hormone, free triiodothyronine, total and free thyroxine are currently unresolved, serum total triiodothyronine levels and the ratio of free triiodothyronine to free thyroxine seem to provide the best correlates to the echocardiographic, laboratory and clinical parameters of disease severity. HF patients with either hyper- or hypothyroidism should be treated according to the appropriate guidelines, but the therapeutic approach to NTIS, with or without HF, is still a matter of debate. Possible treatment options include better individual titration of levothyroxine therapy, combined triiodothyronine plus thyroxine therapy and natural measures to increase triiodothyronine. Future research should further examine the cellular and tissue mechanisms of NTIS as well as new therapeutic avenues in patients with HF.

Impaired Thyroid Hormone Sensitivity Increases Risk of Cardiovascular Events in Patients Undergoing Coronary Angiography

CONTEXT

Previous studies found inconsistent results on the relationship between thyroid function and cardiovascular risks.

OBJECTIVE

This study aimed to investigate the association of thyroid hormone sensitivity with the risk of major adverse cardiovascular events (MACE) and cardiovascular death in a euthyroid population undergoing coronary angiography.

METHODS

This prospective cohort study enrolled 1470 euthyroid participants who underwent coronary angiography between March and November of 2013. The participants were followed up from July to November in 2022. Thyrotroph thyroxine resistance index (TT4RI), TSH index (TSHI), and feedback quantile-based index (TFQI) were calculated to evaluate the sensitivity to thyroid hormone. Kaplan-Meier curve and multivariable Cox proportional hazard model were performed to analyze the association between thyroid hormone sensitivity and risk of MACE and cardiovascular death.

RESULTS

Among 1089 participants who completed the follow-up, 342 cases of MACE and 77 cardiovascular deaths were identified during a medium follow-up duration of 111 months. In the multivariable Cox proportional hazard model, the higher levels of TFQI (hazard ratio [HR] = 1.41; 95% CI, 1.08-1.84; P for trend = .01), TT4RI (HR = 1.40; 95% CI, 1.06-1.84; P for trend = .02) and TSHI (HR = 1.61; 95% CI, 1.22-2.13; P for trend = .001) were associated with increased risk of MACE. The higher levels of TFQI (HR = 2.21; 95% CI, 1.17-4.17; P for trend = .02) and TSHI (HR = 2.05; 95% CI; 1.08-3.91; P for trend = .03) were also associated with increased risk of cardiovascular death.

CONCLUSION

Impaired sensitivity to thyroid hormone is associated with higher risks of MACE and cardiovascular death in a euthyroid population undergoing coronary angiography.

Triglyceride Glucose Index: A Potential Indicator in the Evaluation of Graves Ophthalmopathy

PURPOSE

To determine the relationship between Graves ophthalmopathy (GO) and triglyceride glucose index (TGI) and to evaluate the predictive importance of this index in terms of GO activity.

METHODS

This retrospective study included 20 inactive GO patients, 20 active GO patients, and 20 healthy controls. TGI was calculated using fasting plasma triglyceride and fasting plasma glucose levels and values were compared between the groups. The receiver operating characteristics curve was used to calculate the optimal TGI cutoff value and the sensitivity and specificity of this value between active and inactive GO groups.

RESULTS

No significant difference was detected between the groups in terms of age and gender (p = 0.561 and p = 0.762, respectively). TGI value was 8.49 (8.41, 8.67) in the control group, 8.76 (8.74, 8.87) in the inactive GO group, and 9.06 (8.87, 9.08) in the active GO group (p < 0.001 for control group vs. inactive GO group; p < 0.001 for control group vs. active GO group; p = 0.001 for inactive GO group vs. active GO group). The optimal receiver operating characteristics cutoff value of TGI between active and inactive GO groups was 8.86 with 85% sensitivity and 75% specificity (area under curve: 0.837, p < 0.001, 95% confidence interval: 0.711-0.964).

CONCLUSION

TGI was higher in both inactive and active GO patients compared with controls. It also appears that TGI may be used as a predictive marker indicating GO activity. This cheap and easily accessible parameter may be beneficial in detecting the disease and monitoring its activity in clinical practice.

Thyroid function effect on cardiac structure, cardiac function, and disease risk: Evidence of causal associations in European ancestry

BACKGROUND

Thyroid hormones play a crucial role in cardiovascular physiology. Subclinical thyroid dysfunction has been associated with adverse cardiovascular outcomes, but evidence is mixed regarding causality.

OBJECTIVE

The purpose of this study was to investigate the potential causal relationships of thyroid-stimulating hormone (TSH), free thyroxine, hypothyroidism, and hyperthyroidism with cardiovascular outcomes, including atrial fibrillation (AF), coronary artery disease, myocardial infarction, heart failure, and ischemic stroke, as well as their effect on cardiac structure and function assessed by cardiac magnetic resonance imaging.

METHODS

A comprehensive 2-sample Mendelian randomization analysis was performed using summary data from large-scale meta-analyses of European ancestry individuals.

RESULTS

Genetically determined lower TSH levels (odds ratio 0.928; 95% confidence interval 0.884-0.974; P = .003) and genetic risk of hyperthyroidism (odds ratio 1.049; 95% confidence interval 1.016-1.083; P = .003) were associated with increased AF risk. These associations remained significant even after adjusting for cardiovascular risk factors. Colocalization and multivariable Mendelian randomization revealed height as a key mediator between TSH/hyperthyroidism and AF. These findings were further corroborated in the independent FinnGen cohort. However, no clear evidence was found for relationships between thyroid function and other cardiovascular outcomes and cardiac structure and function.

CONCLUSION

Our study shows that reduced TSH levels and hyperthyroidism heighten AF risk, with height serving as an important mediator in these associations. The primary focus of thyroid management in cardiovascular health should be on preventing and treating arrhythmias, particularly AF. Our research highlights the importance of routine screening and timely treatment of thyroid dysfunction to optimize the prevention and management of arrhythmias.

Serum klotho associated with thyroid hormone in adults: A population-based cross-sectional research

BACKGROUND AND STUDY AIM

The klotho protein, a multifunctional protein, has been shown to be associated with a wide range of endocrine diseases and has been linked to thyroid tumourigenesis. However, the relationship between serum klotho levels and thyroid hormones remains poorly understood. This study aimed to explore the correlation between serum klotho levels and thyroid hormones.

METHODS

Data was obtained from the NHANES cycles 2007-2008, 2009-2010, and 2011-2012. A total of 4674 participants were recruited for this study. Statistical analysis was using multiple linear regression analyses, and restricted cubic spline plots (RCS) to investigate the association between serum klotho levels and serum levels of thyroid hormones.

RESULTS

In the unadjusted covariate model, ln(klotho) significantly positively correlated with tT3, tT4, fT3, tT4/fT4, and tT3/fT3 (all P<0.01) and negatively correlated with TSH, tT4/tT3, and fT4/fT3 (all P<0.05). Furthermore, tT3, tT4, fT3and tT3/fT3 (P < 0.05) were still significant in the adjusted model. And it is worth noting that there is an approximately L-shaped nonlinear relationship between ln(klotho) and fT3,tT3 with a cut-off point of 6.697 (P-non-linear < 0.05). The stratification analysis showed gender and iodine level differences in the relationship between serum Klotho levels and thyroid hormones.

CONCLUSION

There is an L-shaped nonlinear relationship between ln(klotho) and fT3, tT3, suggesting that klotho could be involved in the physiological regulation of thyroid function.

Blood pressure in hyperthyroid cats before and after radioiodine treatment

BACKGROUND

Hyperthyroid cats commonly have systemic hypertension, with a reported prevalence of 7% to 48%. Although hypertension might be expected to resolve once treatment restores euthyroidism, it can persist or only first develop after treatment.

OBJECTIVES

To determine the proportion of hyperthyroid cats with hypertension (systolic blood pressure [SBP] ≥160 mm Hg), persistence or first development of hypertension after successful radioiodine treatment, and correlation of post-treatment hypertension with azotemia or hypothyroidism.

ANIMALS

Four hundred one hyperthyroid nonazotemic cats were included in the study.

METHODS

Prospective, cross-sectional and before-and-after studies. All hyperthyroid cats had SBP measured by Doppler; 255 had SBP rechecked 6 months after successful radioiodine (131I) treatment.

RESULTS

Of untreated hyperthyroid cats, 108/401 (27%) were hypertensive. A higher proportion of hypertensive cats were nervous/excited compared with normotensive cats (47% vs 12%; P < .001). Of the initially hypertensive cats, 87/108 cats were reexamined after 131I treatment; 43/87 (49%) cats normalized SBP, whereas 44/87 (51%) remained hypertensive. Of the initially normotensive cats, 16/168 (9.5%) first developed hypertension after successful 131I treatment. 7/60 (12%) of the 131I-treated hypertensive cats were azotemic and 9/60 (15%) were hypothyroid. A higher proportion of cats remaining hypertensive had nervous/excited demeanor than did normotensive cats (50% vs 17%; P < .001).

CONCLUSIONS/CLINICAL IMPORTANCE

Hypertension, when present, resolves in many hyperthyroid cats after successful treatment. Hyperthyroid cats uncommonly develop new hypertension after treatment. Persistent or newly detected hypertension was unrelated to azotemia or iatrogenic hypothyroidism. More frequently perceived nervousness/anxiety in radioiodine-treated hypertensive cats suggests that many of these cats might have "situational" hypertension, as hyperthyroid-induced hypertension should resolve after treatment.

Relationship between Thyroid Feedback Quantile-based Index and cardiovascular diseases in a population with normal thyroid function: Evidence from the National Health and Nutrition Examination Survey 2007-2012

BACKGROUND

Previous study has demonstrated a link between TFQI, indicating the central sensitivity of thyroid hormones, and conditions like obesity, diabetes, and metabolic syndrome.

HYPOTHESIS

Nevertheless, the potential relationship between TFQI and cardiovascular disease (CVD) in individuals with normal thyroid function has yet to be established.

METHODS

The present research is a retrospective cohort investigation that included a total of 6297 individuals who had normal function of the thyroid and no history of thyroid disorders. These participants were selected from National Health and Nutrition Examination Survey data set, covering the years 2007-2012. The calculation of TFQI was performed depending on FT4 and TSH. Given the complex survey design and sample weights, we used multivariate linear regression models and stratified analysis to evaluate TFQI's correlation with CVD.

RESULTS

Subjects with CVD had greater levels of TFQI than those with no CVD. After adjusting for other covariates, TFQI exhibited a positive association with CVD risk, and the OR was 1.706 (p = .005). In subgroup analyses that were stratified by sex and BMI, it was shown that female individuals who had CVD had greater levels of TFQI in comparison to female participants without CVD (p = .002). Furthermore, elevated levels of TFQI were consistently connected to a raised incidence of CVD in the BMI (>28 kg/m2) group after regulating for different covariates. Furthermore, correlation analysis showed an association between TFQI and metabolic biomarkers.

CONCLUSIONS

The levels of TFQI are strongly connected to the prevalence of CVD, indicating that energy metabolism may be related to the occurrence of CVD.

Subclinical Hypothyroidism Predicted Adverse Cardiovascular Events in Patients with Ejection Fraction Preserved Heart Failure

Background

Subclinical hypothyroidism (SH) increases the risk of cardiovascular events, however the influence of SH on prognosis of ejection fraction preserved heart failure (HFpEF) is not fully understood.

Methods

In this prospective observational study, patients with HFpEF were divided into euthyroidism group (n = 413) and SH group (n = 79). Patients were followed up for at least 30 months to examine the association between SH and cardiovascular events in patients with HFpEF. The primary end point was composite cardiovascular events (cardiovascular death and re-hospitalization). The patients underwent flow-mediated dilation (FMD) measurement by ultrasound in order to value endothelial function.

Results

The rate of composite cardiovascular events was higher in SH group than in euthyroidism group (54.49% and 26.36%, respectively; p < 0.001). The higher risk of cardiovascular events in SH group was primarily due to a higher risk of re-hospitalization compared to euthyroidism group (45.56% and 20.58%, respectively; p < 0.001). The rate of cardiovascular death was higher in SH group than in euthyroidism group (13.92% and 5.81%, respectively; p = 0.017). Cox proportional hazards regression showed that SH (hazard ratios [HR] 1.921, 95% confidence interval [CI] 1.139-3.240), level of TSH (HR 1.025, 95% CI 1.010-1.054), age (HR 1.017, 95% CI 1.002-1.034), LVEF (HR 0.975, 95% CI 0.953-0.996), atrial fibrillation (HR 1.581, 95% CI 1.083-2.307), eGFR (HR 0.987, 95% CI 0.978-0.997), and NYHA cardiac function (HR 2.342, 95% CI 1.649-3.326) were independent predictors of cardiovascular events in patients with HFpEF (all P < 0.05).

Conclusion

Subclinical hypothyroidism was associated with increased cardiovascular events and death in patients with HFpEF.

Thyroid cancer and cardiovascular diseases: a Mendelian randomization study

Background

Multiple observational studies have shown associations between thyroid cancer (TC) and cardiovascular diseases (CVDs). However, the results were inconsistent, and the potential causal genetic relationship remains unclear.

Methods

The genetic instruments of TC and CVDs were derived from data obtained through genome-wide association studies (GWAS). We performed the two-sample Mendelian randomization(MR) methods to investigate the causality of TC on CVDs. Summary-level statistics for CVDs, including heart failure (HF), atrial fibrillation (AF), coronary artery disease (CAD), myocardial infarction (MI), ischemic stroke (IS) and venous thromboembolism (VTE). The primary method employed in this MR analysis was the Inverse Variance Weighted (IVW) approach, and four additional algorithms were used: MR-Egger, weighted median, simple mode, and weighted mode. Additionally, we assessed the reliability of the causal relationship through pleiotropy, heterogeneity and leave-one-out sensitivity analysis.

Results

In this MR analysis, we only detected causality of genetically predicted TC on HF (IVW method, odds ratio (OR) = 1.00134, 95% confidence interval (CI): 1.00023-1.00244, p = 0.017). However, There were no causal associations of TC with CAD, MI, AF, IS, and VTE.

Conclusion

Our results confirmed the causal association between TC and HF. It is crucial to closely monitor the incidence of HF in TC patients and give comprehensive clinical intervention based on conventional treatment.

Thyroid dysfunction in nonvalvular atrial fibrillation and clinical outcomes

BACKGROUND

Thyroid dysfunction's effects on those who have been diagnosed with atrial fibrillation have not been well investigated. We looked at how thyroid function among patients with pre-existing atrial fibrillation related to thromboembolic risk and clinical outcomes.

METHODS

We gathered the medical information of patients diagnosed with nonvalvular atrial fibrillation (NVAF) between 2016 and 2020 at Dongguan People's Hospital. We then assessed the correlation between thyroid dysfunction and thrombotic risk (CHA2DS2-VASc) as well as the occurrence of clinical composite endpoint (all-cause death, heart failure, systemic embolism and hemorrhage events).

RESULTS

Of 1329 patients were admitted, 82.6% were euthyroid, 7.4% had subclinical hyperthyroidism, 4.2% had subclinical hypothyroidism, and 6.7% had low triiodothyronine (T3) syndrome. Lower levels of total triiodothyronine (TT3) were linked to an increased risk of thromboembolism (P < 0.005). During a median follow-up period of 1.84 years, there were 608 clinical composite endpoint occurrences. In the adjusted model, Low T3 syndrome was linked to a higher risk of the clinical composite endpoint (HR, 1.68; 95% CI, 1.20-2.37; P < 0.05) in comparison to euthyroidism. Specifically, low T3 syndrome was linked to a higher risk of heart failure (HR, 1.52; 95%CI, 1.01-2.30; P < 0.05) and all-cause death (HR, 3.34; 95% CI, 1.76-6.36; P < 0.001).

CONCLUSION

Low T3 syndrome are linked to an increased risk of heart failure and all-cause death in individuals with NVAF. And Patients with NVAF and low TT3 levels have a higher risk of thromboembolism.

Associations between per- and polyfluoroalkyl substances exposure and thyroid hormone levels in the elderly

This study aimed to measure the exposure of the elderly to per- and polyfluoroalkyl substances (PFAS) and explore their effects on thyroid hormone levels. A cross-sectional study of plasma samples from 746 elderly people (aged >60 years) from Taiyuan, China was conducted. Fourteen PFASs were determined using liquid chromatography-tandem mass spectrometry and five thyroid function indicators, thyroid-stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3), free T4 (FT4), and free T3 (FT3), using an enzyme-linked immunoassay. Descriptive analysis was used to investigate PFC exposure and the toxic equivalent quantity (TEQ) was used to calculate the transthyretin (TTR)-disrupting toxicity of combined exposure to PFAS. Linear additive and multiple linear regression models were used to explore the relationship between PFAS and hormones, using PFC concentration as quartiles and continuous variables. Among the PFAS identified, 12 PFASs had detection rates >80 %, with perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) having the highest concentrations. Perfluorodecanoic acid (PFDA), PFOS, and perfluorononanoic acid (PFNA) were negatively correlated with TSH levels and each interquartile range (IQR) concentration increase caused a reduction in TSH levels by 2.14 %, 1.78 %, and 3.04 %, respectively. Perfluorotridecanoic acid (PFTrA) and perfluoropentanoic acid (PFPA) were positively correlated with T4 and T3 levels, respectively, and levels increased by 4.52 % (T4) and 1.14 % (T3) with IQR concentration increase. Perfluorobutanoic acid (PFBA) was negatively correlated with FT4 levels, which decreased by 1.89 % with IQR concentration increase. A negative correlation was found between the combined exposure indices of TEQ and TSH levels; IQR increase in TEQ decreased the TSH concentration by 1.91 %. In conclusion, exposure to PFAS was common in the elderly population and was associated with decreased TSH and FT4 levels and increased T4 and T3 levels. These results indicated that PFASs may cause thyroid-disrupting effects in the elderly population.

Predictive value of free triiodothyronine to free thyroxine ratio on contrast-associated acute kidney injury and poor prognosis in euthyroid patients after percutaneous coronary intervention

PURPOSE

The purpose of the study was to explore the predictive value of free triiodothyronine to free thyroxine ratio (FT3/FT4) on contrast-associated acute kidney injury (CA-AKI) and poor prognosis in euthyroid patients after percutaneous coronary intervention (PCI).

METHODS

The present study included 3,116 euthyroid patients who underwent elective PCI. The main outcome was CA-AKI, and the secondary outcome was long-term mortality. All patients were divided into three groups according to the tertiles of FT3/FT4 levels.

RESULTS

During hospitalization, a total of 160 cases (5.1%) of CA-AKI occurred. Restricted cubic spline (RCS) analysis indicated a linear and negative relationship between FT3/FT4 and CA-AKI risk (P for nonlinearity = 0.2621). Besides, the fully-adjusted logistic regression model revealed that patients in tertile 3 (low FT3/FT4 group) had 1.82 times [odds ratio (OR): 1.82, 95% confidence interval (CI): 1.13-3.02, P = 0.016] as high as the risk of CA-AKI than those in tertile 1 (high FT3/FT4 group). Similarly, patients in tertile 3 were observed to have a higher incidence of long-term mortality [fully-adjusted hazard ratio (HR): 1.58, 95% CI: 1.07-2.32, P = 0.021]. Similarly, the Kaplan-Meier curves displayed significant differences in long-term mortality among the three groups (log-rank test, P < 0.001).

CONCLUSION

In euthyroid patients undergoing elective PCI, low levels of FT3/FT4 were independently associated with an increased risk of CA-AKI and long-term mortality. Routine evaluation of FT3/FT4 may aid in risk stratification and guide treatment decisions within this particular patient group.

Metabolic Messengers: Thyroid Hormones

Thyroid hormones (THs) are key hormones that regulate development and metabolism in mammals. In man, the major target tissues for TH action are the brain, liver, muscle, heart, and adipose tissue. Defects in TH synthesis, transport, metabolism, and nuclear action have been associated with genetic and endocrine diseases in man. Over the past few years, there has been renewed interest in TH action and the therapeutic potential of THs and thyromimetics to treat several metabolic disorders such as hypercholesterolemia, dyslipidaemia, non-alcoholic fatty liver disease (NAFLD), and TH transporter defects. Recent advances in the development of tissue and TH receptor isoform-targeted thyromimetics have kindled new hope for translating our fundamental understanding of TH action into an effective therapy. This review provides a concise overview of the historical development of our understanding of TH action, its physiological and pathophysiological effects on metabolism, and future therapeutic applications to treat metabolic dysfunction.

Pulmonary and Systemic Hemodynamics in Patients with Hyperthyroidism

BACKGROUND

There is an association between hyperthyroidism and pulmonary hypertension. However, the prevalence of pulmonary hypertension in hyperthyroidism and the underlying mechanisms are incompletely defined.

METHODS

Consecutive patients with severe hyperthyroidism, mostly due to Graves disease, were included in this single-center study. Echocardiographic assessment of pulmonary hemodynamics was performed at the time of hyperthyroidism diagnosis (baseline) and after normalization of thyroid hormones (follow-up; median 11 months). In a subset of patients, right heart catheterization and noninvasive assessment of central hemodynamics was performed.

RESULTS

Among all 99 patients, 31% had pulmonary hypertension at baseline. The estimated systolic pulmonary artery pressure correlated significantly with the estimated left ventricular filling pressure (E/e'). The invasively measured systolic pulmonary artery pressure correlated well with the estimated systolic pulmonary artery pressure. Cardiac output, E/e', left and right ventricular dimensions were significantly reduced from baseline to follow-up, whereas the estimated pulmonary vascular resistance did not differ. Diastolic blood pressure was significantly higher at follow-up, with no change in systolic blood pressure. The central systolic blood pressure, however, exhibited a trend for a reduction at follow-up, while the pulse wave velocity was significantly lower at follow-up.

CONCLUSIONS

Approximately one-third of patients with hyperthyroidism have evidence of pulmonary hypertension. Our data suggest that an increased cardiac output and left ventricular filling pressure are the main mechanisms underlying the elevated systolic pulmonary artery pressure in hyperthyroidism, whereas there is no evidence of significant pulmonary vascular disease.

Subclinical hypothyroidism and clinical outcomes after cardiac surgery: A systematic review and meta-analysis

Background

Subclinical hypothyroidism (SCH) is associated with major adverse cardiovascular events. Despite the recognized negative impact of SCH on cardiovascular health, research on cardiac postoperative outcomes with SCH has yielded conflicting results, and patients are not currently treated for SCH before cardiac surgery procedures.

Methods

We performed a study-level meta-analysis on the impact of SCH on patients undergoing nonurgent cardiac surgery, including coronary artery bypass grafting and valve and aortic surgery. The primary outcome was operative mortality. Secondary outcomes were hospital length of stay (LOS), intensive care unit (ICU) stay, postoperative atrial fibrillation (POAF), intra-aortic balloon pump (IABP) use, renal complications, and long-term all-cause mortality.

Results

Seven observational studies, with a total of 3445 patients, including 851 [24.7%] diagnosed with SCH and 2594 [75.3%] euthyroid patients) were identified. Compared to euthyroid patients, the patients with SCH had higher rates of operative mortality (odds ratio [OR], 2.57; 95% confidence interval [CI], 1.09-6.04; P = .03), prolonged hospital LOS (standardized mean difference, 0.32; 95% CI, 0.02-0.62; P = .04), a higher rate of renal complications (OR, 2.53; 95% CI, 1.74-3.69; P < .0001), but no significant differences in ICU stay, POAF, or IABP use. At mean follow-up of 49.3 months, the presence of SCH was associated with a higher rate of all-cause mortality (incidence rate ratio, 1.82; 95% CI, 1.18-2.83; P = .02).

Conclusions

Patients with SCH have higher operative mortality, prolonged hospital LOS, and increased renal complications after cardiac surgery. Achieving and maintaining a euthyroid state prior to and after cardiac surgery procedures might improve outcomes in these patients.

Association of stress and primary hypothyroidism

Background

Hypothyroidism is the result of impaired production and secretion of thyroid hormones. The cardiovascular system is affected by fluctuations in thyroid hormone levels. Stressful events or stressors can affect the hypothalamic-pituitary-thyroid (HPT) axis and psychological and physiological responses. Stress increases thyroid hormone levels while decreasing TSH levels, which exacerbates autoimmune thyroid disease.

Aim

To evaluate the relationship between stress and primary hypothyroidism.

Methods

A total of 77 newly diagnosed hypothyroid patients (TSH >5.0 mIU/L) and 77 healthy adults (TSH 0.5-5.0 mIU/L) were enrolled. During a brief general physical examination, the following values were measured: height, weight, blood pressure, pulse, and pulse rate. A brief systemic examination of the cardiovascular system and lungs was also performed to rule out systemic diseases. Heart rate variability (HRV) processing and analysis were performed using Pro LabChart (PowerLab 8Pro) data analysis software from AD Instrument.

Results

Mean Avg. RR was significantly higher, RM SSD and pRR50 were significantly lower in cases than in controls. Mean HF was significantly lower and LF/HF (frequency range) was significantly higher in cases than in controls. Mean PSS was significantly higher in cases (25.82 ± 2.83) than in controls (22.47 ± 2.10). The majority of cases (54.5%) had a high stress level. The TSH level showed a highly significant correlation with the LF/HF ratio and with the PSS score.

Conclusion

The mean Avg. RR and HF were significantly higher, RM SSD and pRR50 and LF/HF (frequency range) were significantly lower in hypothyroid patients.

Thyroid dysfunction and mortality in cardiovascular hospitalized patients

Background

Thyroid dysfunction (TD) is associated with increased cardiovascular morbidity and mortality. Early detection may influence the clinical management.

Objective

To determine the prevalence, predictors, and prognostic value of TD among hospitalized cardiac patients.

Methods

A retrospective analysis of a 12-year database consisting of nonselectively adult patients admitted to a Cardiology Department and who were all screened for serum thyroid-stimulation-hormone (TSH) levels . Statistical analysis of demographic and clinical characteristics, mortality and length of hospital stay (LOS) was performed.

Results

A total of 14369 patients were included in the study; mean age was 67 years, 38.3% females. 1465 patients (10.2%) had TD. The most frequent type of TD was mildly elevated TSH (5.4%) followed by mildly reduced TSH (2.1%), markedly elevated TSH (1.5%), and markedly reduced TSH (1.2%). Female gender, history of hypothyroidism, heart failure, atrial fibrillation, renal failure and amiodarone use were significantly associated with TD. During follow-up 2975 (20.7%) patients died. There was increased mortality in the mildly reduced TSH subgroup (hazard ratio [HR] =1.44), markedly elevated TSH subgroup (HR=1.40) and mildly elevated TSH subgroup (HR=1.27). LOS was longer for patients with TD; the longest stay was observed in the markedly elevated TSH subgroup (odds ratio=1.69).

Conclusion

The prevalence of TD in hospitalized cardiac patients is 10.2%. TD is associated with an increased mortality rate and LOS. Consequently, routine screening for thyroid function in this population is advisable, particularly for selected high-risk subgroups. Future studies are needed to determine whether optimizing thyroid function can improve survival in these patients.

Cardiac recovery from pressure overload is not altered by thyroid hormone status in old mice

Introduction

Thyroid hormones (THs) are known to have various effects on the cardiovascular system. However, the impact of TH levels on preexisting cardiac diseases is still unclear. Pressure overload due to arterial hypertension or aortic stenosis and aging are major risk factors for the development of structural and functional abnormalities and subsequent heart failure. Here, we assessed the sensitivity to altered TH levels in aged mice with maladaptive cardiac hypertrophy and cardiac dysfunction induced by transverse aortic constriction (TAC).

Methods

Mice at the age of 12 months underwent TAC and received T4 or anti-thyroid medication in drinking water over the course of 4 weeks after induction of left ventricular pressure overload.

Results

T4 excess or deprivation in older mice had no or only very little impact on cardiac function (fractional shortening), cardiac remodeling (cardiac wall thickness, heart weight, cardiomyocyte size, apoptosis, and interstitial fibrosis), and mortality. This is surprising because T4 excess or deprivation had significantly changed the outcome after TAC in young 8-week-old mice. Comparing the gene expression of deiodinases (Dio) 2 and 3 and TH receptor alpha (TRα) 1 and the dominant-negative acting isoform TRα2 between young and aged mice revealed that aged mice exhibited a higher expression of TRα2 and Dio3, while expression of Dio2 was reduced compared with young mice. These changes in Dio2 and 3 expressions might lead to reduced TH availability in the hearts of 12-month-old mice accompanied by reduced TRα action due to higher TRα2.

Discussion

In summary, our study shows that low and high TH availability have little impact on cardiac function and remodeling in older mice with preexisting pressure-induced cardiac damage. This observation seems to be the result of an altered expression of deiodinases and TRα isoforms, thus suggesting that even though cardiovascular risk is increasing with age, the response to TH stress may be dampened in certain conditions.

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.

Association of thyroid autoimmunity with extra-thyroid diseases and the risk of mortality among adults: evidence from the NHANES

Background

Thyroid autoimmunity is one of the most prevalent autoimmune diseases. However, its association with extra-thyroid diseases and mortality risk in the general population remains uncertain. Our study aims to evaluate the association of thyroid autoimmunity with extra-thyroid disease and the risk of mortality.

Methods

A prospective cohort study was conducted using data from the National Health and Nutrition Examination Survey (NHANES) with participants from 2007-2008, 2009-2010, and 2011-2012, tracking their mortality until 2019. Associations between thyroid autoimmunity, which was defined as having positive thyroid peroxidase antibody (TPOAb) and/or thyroglobulin antibody (TgAb), and extra-thyroid disease including diabetes, hypertension, cardiovascular disease, chronic lung disease, arthritis, cancer and chronic renal disease and the risk of mortality were investigated.

Results

A total of 7431 participants were included in this study. Positive The prevalence of positive TgAb was 7.54%, and positive TPOAb prevalence was 11.48%. TgAb was significantly associated with diabetes (Model 1: OR=1.64, 95% CI:1.08-2.50; Model 2: OR=1.93, 95% CI: 1.21-3.08) and hypertension (Model 1: OR=0.67, 95% CI: 0.49-0.91; Model 2: OR=0.62, 95% CI: 0.44-0.88). TPOAb was associated with a lower prevalence of chronic lung disease (model 1: OR=0.71, 95% CI: 0.54-0.95; model 2: OR=0.71, 95% CI: 0.53-0.95). No associations were observed between TgAb, TPOAb and other extra-thyroid diseases. Neither TgAb nor TPOAb were associated with all-cause mortality or heart disease mortality.

Conclusion

TgAb was linked to a higher prevalence of diabetes and a lower prevalence of hypertension, while TPOAb was associated with a decreased prevalence of chronic lung disease. However, neither TgAb nor TPOAb posed a risk for all-cause mortality or heart disease mortality.

Protein-protein interaction network-based integration of GWAS and functional data for blood pressure regulation analysis

BACKGROUND

It is valuable to analyze the genome-wide association studies (GWAS) data for a complex disease phenotype in the context of the protein-protein interaction (PPI) network, as the related pathophysiology results from the function of interacting polyprotein pathways. The analysis may include the design and curation of a phenotype-specific GWAS meta-database incorporating genotypic and eQTL data linking to PPI and other biological datasets, and the development of systematic workflows for PPI network-based data integration toward protein and pathway prioritization. Here, we pursued this analysis for blood pressure (BP) regulation.

METHODS

The relational scheme of the implemented in Microsoft SQL Server BP-GWAS meta-database enabled the combined storage of: GWAS data and attributes mined from GWAS Catalog and the literature, Ensembl-defined SNP-transcript associations, and GTEx eQTL data. The BP-protein interactome was reconstructed from the PICKLE PPI meta-database, extending the GWAS-deduced network with the shortest paths connecting all GWAS-proteins into one component. The shortest-path intermediates were considered as BP-related. For protein prioritization, we combined a new integrated GWAS-based scoring scheme with two network-based criteria: one considering the protein role in the reconstructed by shortest-path (RbSP) interactome and one novel promoting the common neighbors of GWAS-prioritized proteins. Prioritized proteins were ranked by the number of satisfied criteria.

RESULTS

The meta-database includes 6687 variants linked with 1167 BP-associated protein-coding genes. The GWAS-deduced PPI network includes 1065 proteins, with 672 forming a connected component. The RbSP interactome contains 1443 additional, network-deduced proteins and indicated that essentially all BP-GWAS proteins are at most second neighbors. The prioritized BP-protein set was derived from the union of the most BP-significant by any of the GWAS-based or the network-based criteria. It included 335 proteins, with ~ 2/3 deduced from the BP PPI network extension and 126 prioritized by at least two criteria. ESR1 was the only protein satisfying all three criteria, followed in the top-10 by INSR, PTN11, CDK6, CSK, NOS3, SH2B3, ATP2B1, FES and FINC, satisfying two. Pathway analysis of the RbSP interactome revealed numerous bioprocesses, which are indeed functionally supported as BP-associated, extending our understanding about BP regulation.

CONCLUSIONS

The implemented workflow could be used for other multifactorial diseases.

Prevalence and risk factors for subclinical hypothyroidism in older patients with major depressive disorder

BACKGROUND

Subclinical hypothyroidism (SCH) is highly correlated with major depressive disorder (MDD). However, the prevalence and risk factors for SCH in older patients with MDD have rarely been reported in China.

METHODS

This cross-sectional study included 266 older MDD patients with SCH was performed. Clinical and anthropometric, biochemical, and thyroid function data were collected. Depression, anxiety, and psychotic symptoms were assessed using the Hamilton Depression Scale, the Hamilton Anxiety Scale, and the Positive and Negative Syndrome Scale positive subscale, respectively.

RESULTS

Among older patients with MDD, the prevalence of SCH was 64.7% (172/266). Compared to patients without SCH, older MDD patients with SCH had a longer disease course and higher TSH, A-TG, A-TPO, HDL-C, LDL-C, TC, FPG, and systolic pressure levels (all P ≤ 0.002). Furthermore, disease progression (OR 1.082, 95% CI 1.020-1.147, P = 0.009), A-TG (OR 1.005, 95% CI 1.001-1.009, P = 0.017), TC (OR 2.024, 95% CI 1.213-3.377, P = 0.007), FPG (OR 2.916, 95% CI 1.637-5.194, P < 0.001), systolic pressure (OR 1.053, 95% CI 1.008-1.100, P = 0.022) were independently associated with SCH, in older patients with MDD.

CONCLUSIONS

Our findings suggest a high prevalence of SCH in older patients with MDD. Several demographic and clinical variables were independently associated with SCH in older patients with MDD.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Patients With Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

Thyroid Disorders and Peripheral Arterial Disease

Hypothyroidism and hyperthyroidism, both overt and subclinical, are associated with increased risk of cardiovascular morbidity and mortality. The association between thyroid-stimulating hormone levels and cardiovascular risk has been demonstrated in large epidemiological studies and meta-analyses and is now considered a U-shaped curve. Several pathophysiological mechanisms linking thyroid and cardiovascular disease are known; however, specific clinical complications of peripheral arterial disease as endpoints of clinical trials have not been adequately investigated. The potential mechanisms linking hypothyroidism and peripheral arterial disease are endothelial dysfunction, blood pressure changes, dyslipidemia, and low-grade systemic inflammation. The potential mechanisms linking hyperthyroidism and peripheral arterial disease are hyperdynamic circulation, elevated systolic blood pressure, hypercoagulability, and possibly increased arterial inflammation.

Hypothyroidism and Cardiovascular Disease: A Review

Hypothyroidism is an endocrine disorder more commonly in older adults. Simultaneously, this population has an increased incidence of cardiovascular risk factors and disease, which remains the leading cause of death worldwide. Thyroid hormones (THs) promote adequate function of the cardiovascular system as they exert their effects through receptors located in the myocardium and the vasculature. In hypothyroidism, this homeostasis is disrupted, which leads to the emergence of pathogenic pathways that accelerate the progression of cardiovascular disease and aggravate its outcomes in these individuals. This article has reviewed existing literature on the relationship between hypothyroidism and cardiovascular disease (CVD). We have explored the pathogenic mechanisms linking both conditions and highlighted the prevalence of cardiovascular risk factors as well as the increased incidence of cardiovascular events in overt and subclinical diseases. Furthermore, indications of hormone replacement therapy in subclinical disease and its efficacy in reducing CVD morbidities in a particular subset of patients have been discussed.

Thyrotoxic Cardiomyopathy Unveiled: Insights From a Compelling Case Report

Thyrotoxicosis is a clinical condition characterized by inappropriately elevated thyroid hormone levels in the bloodstream, leading to systemic effects on the body. In fact, the thyrotoxic state has tight regulatory control over the cardiovascular system through genomic and non-genomic mechanisms. This study highlights a rare presentation of thyrotoxic cardiomyopathy (TCM), which, to the best of our knowledge, is one of the very few case reports involving heart failure with preserved ejection fraction (HFpEF) and only atrial involvement, compared to the previous literature. A 37-year-old female presented to the outpatient clinic with abdominal distention and neglected signs and symptoms consistent with thyrotoxicosis for a year. Investigations revealed high N-terminal pro-b-type natriuretic peptide (NT-proBNP) levels of 1788 pg/mL. Cardiac MRI and trans-thoracic echocardiogram (TTE) revealed bilateral atrial dilatation, a left ventricular ejection fraction (LVEF) of 60%, and diastolic dysfunction. Additionally, severe free-flowing tricuspid and mitral valve regurgitation were observed, with no evidence of pericardial effusion or ventricular abnormalities. Therefore, a diagnosis of TCM was suspected and eventually confirmed by excluding other differential diagnoses. Besides a diffuse goiter on ultrasonography, the thyroid panel test revealed low thyroid-stimulating hormone (TSH) levels of <0.01 mIU/L, a free thyroxine T4 of >100 pmol/L, and positive anti-thyroid peroxidase (TPO) and TSH receptor antibodies. Accordingly, a team of endocrinologists, cardiologists, and internists managed the patient with anti-thyroid medications alongside symptomatic treatment. A few days later, she was discharged in good condition, and a follow-up visit was arranged with the endocrinology and cardiology clinics. It is crucial to maintain a high level of suspicion to detect and treat TCM promptly, and a multidisciplinary approach should ideally be employed. This is not only important for the prevention of but also reversing potentially life-threatening cardiovascular complications.

Fetal cardiac left ventricle functional changes in pregnancies with maternal hypothyroidism

OBJECTIVES

To evaluate fetal cardiac function in cases with overt and subclinical hypothyroidism and to determine the effect of levothyroxine (LT4) treatment and Anti-thyroid peroxidase (Anti-TPO) antibody status on fetal cardiac functions in cases with subclinical hypothyroidism.

METHODS

Within the scope of the study, fetuses of 23 overt hypothyroid, 52 subclinical hypothyroid and 250 control group pregnant women were evaluated. Fetal cardiac function was assessed via cardiac Doppler.

RESULTS

Isovolumetric relaxation time (IRT) and myocardial performance index (MPI) values in the overt hypothyroid group were significantly higher than both the subclinical hypothyroid group (p: .006, p: .000, respectively) and the control group (p: .000, p: .000, respectively). In addition, both IRT and MPI were significantly higher in the subclinical hypothyroid group than in the control group (p: .000, p: .000, respectively). In the subclinical hypothyroid group, there was no significant difference in terms of cardiac function parameters in the fetuses of pregnant women who received LT4 therapy and those who did not. When pregnant women with subclinical hypothyroidism were evaluated according to their Anti-TPO antibody status, IRT and MPI values were found to be significantly higher in fetuses of Anti-TPO (+) pregnant women (respectively, p: .005, p: .019).

CONCLUSION

In the presence of maternal overt or subclinical hypothyroidism, fetal cardiac functions may be affected as early as the second trimester. Anti-TPO antibody positivity in cases with subclinical hypothyroidism seems to negatively affect fetal cardiac functions.

Association of serum thyroid hormone and coronary artery calcification in patients who underwent invasive coronary angiography: an observational study

BACKGROUND

Thyroid hormones (TH) are known to have a range of effects on the cardiovascular system. However, there is still controversy regarding the relationship between thyroid function and coronary artery calcification (CAC). The purpose of this paper is to investigate the relationship between TH and CAC, especially severe CAC, in patients who underwent invasive coronary angiography (ICA). This may provide further insights into the potential role of TH in the development and progression of cardiovascular disease.

METHOD

This observational study included 4221 patients who underwent ICA after completing CTA in a single center. We collected demographic, clinical, and laboratory data from electronic medical records and measured CAC scores via non-contrast cardiac CT.

RESULT

The study found that there is a negative correlation between the CAC score and FT3 level, even after adjusting for potential confounding factors, but there was no correlation between the CAC score and FT4 or TSH. When categorized into quartiles, the highest quartile of FT3 was associated with a decrease (β = -104.37, 95%CI: -172.54, -36.21) in calcification score compared to the lowest quartile. This correlation was more significant in the subgroup of individuals with diabetes or hypertension.

CONCLUSION

The study found a negative correlation between FT3 and CAC in patients who underwent ICA. The correlation was consistent with other studies and may suggest that low levels of FT3 are associated with severe CAC. The study may provide new evidence for future research on CAC and potential therapeutic approaches.

Low T3 syndrome predicts more adverse events in patients with hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a common cardiac genetic disorder that clinically manifests with sudden death and progressive heart failure. Moreover, thyroid dysfunction is associated with increased cardiovascular morbidity and mortality risks. Therefore, this study aimed to clarify whether thyroid hormones could serve as an independent predictor of adverse events in patients with HCM.

METHODS

The cohort consisted of 782 patients with HCM who had thyroid hormones baseline data and were admitted to the Affiliated Hospital of Jiaxing University. Patients were divided into two groups according to serum levels of free triiodothyronine (fT3): the normal fT3 and low triiodothyronine (T3) syndrome groups. Low T3 syndrome was defined as fT3 < 2.43 pmol/L with a normal thyroid-stimulating hormone (TSH) level. Patients whose TSH levels were abnormally high or abnormally low were excluded from this study. The primary endpoint was the occurrence of sudden cardiac death (SCD) events, and the secondary endpoint was a composite of worsening heart failure (WHF) events, including heart failure death, cardiac decompensation, hospitalization for heart failure, and HCM-related stroke. The Kaplan-Meier and Cox regression were performed for the survival analysis.

RESULTS

After a median follow-up of 52 months, 75 SCD events and 134 WHF events were recorded. The Kaplan-Meier survival curves showed that the cumulative incidence of SCD events and WHF events were significantly higher in patients with low T3 syndrome (log-rank p = .02 and log-rank p = .001, respectively). Furthermore, multivariate Cox regression analysis demonstrated that low T3 syndrome is a strong predictor of SCD events and WHF events (adjusted hazard ratio [HR: 1.53, 95% confidence interval [CI]: 1.13-2.24, p < .01; HR: 3.87, 95% CI: 2.91-4.98, p < .001, respectively).

CONCLUSIONS

Low T3 syndrome is highly prevalent among patients with HCM and was independently associated with an increased risk of SCD events and WHF events. The routine assessment of serum fT3 levels may provide risk stratification in this population.

Circulating thyroid hormones and clinical parameters of heart failure in men

Heart failure (HF) is a multiple hormonal deficiency syndrome which includes alterations in the serum concentration of thyroid hormones (TH). This cross-sectional study enrolled 215 male patients hospitalised for acute HF. Data on cardiovascular risk factors, chronic medications, cardiac function assessed by echocardiography, and clinical parameters of HF were prospectively collected. The independent predictive association of TH with all investigated parameters of the HF severity were assessed. The patient's mean age was 74.4 years, 57.2% had arterial hypertension, 54.0% were consuming alcohol, and 42.3% were diabetics. Multivariate analysis revealed that total triiodothyronine (TT3) was an independent predictor of greater left ventricular ejection fraction (LVEF; β = 0.223, p = 0.008), less progressed left ventricular diastolic dysfunction (LVDD; β = - 0.271, p = 0.001) and lower N-terminal pro-brain natriuretic peptide (NT-proBNP; β = - 0.365, p < 0.001). None of the TH other than TT3 was associated with LVDD or NT-proBNP, whereas free triiodothyronine (β = - 0.197, p = 0.004), free thyroxine (β = - 0.223, p = 0.001) and total thyroxine (β = - 0.140, p = 0.041) were inversely associated with LVEF. The present study suggests that, among TH, serum TT3 level is most closely associated with echocardiographic, laboratory and clinical parameters of the severity of HF in men.

Prevalence and clinical correlates of thyroid dysfunction in first-episode and drug-naïve major depressive disorder patients with metabolic syndrome

BACKGROUND

Few studies have investigated the relative factors of thyroid dysfunction in major depressive disorder (MDD) patients with Metabolic syndrome (MetS). This study aimed to explore the prevalence and related factors associated with thyroid dysfunction in drug-naïve (FEDN) MDD patients with MetS.

METHODS

1718 FEDN MDD patients were recruited and their demographic data, clinical data were collected. Various biochemical indicators including fasting blood glucose (FBG), blood lipids and thyroid hormones were measured. The 17-item Hamilton Rating Scale for Depression (HAMD-17), 14-item Hamilton Anxiety Rating Scale (HAMA-14) and positive subscale of the Positive and Negative Syndrome Scale (PANSS) were used to assess clinical symptoms.

RESULTS

Among FEDN MDD patients, MetS was an independent risk factor for TSH abnormality (P < 0.001, Adjusted OR = 3.77, 95%CI: 2.82-5.05). In patients with MetS, those with TSH abnormality had significantly longer duration of illness, higher HAMD, HAMA, and PANSS positive subscale scores, higher levels of TC, LDL-C, blood glucose, pressure, lower levels of HDL-C, and a higher probability of suicide attempt (all P < 0.01).

CONCLUSIONS

MetS is significantly associated with thyroid dysfunction in patients with FEDN MDD. Related factors for thyroid dysfunction include a number of clinical indicators and psychiatric symptoms.

Impact of subclinical hypothyroidism on in-hospital outcomes and long-term mortality among acute myocardial infarction patients with diabetic mellitus

BACKGROUND

Thyroid-stimulating hormone (TSH) has been regarded as a predictor of poor outcomes in patients with acute myocardial infarction (AMI). AMI complicated by diabetes mellitus (DM) tends to have a high prevalence and a worse prognosis. We aim to evaluate the association between thyroid dysfunction and in-hospital outcomes and short- and medium-term mortality in diabetic patients with AMI.

METHODS

From January 2017 to November 2020, a total of 432 patients with AMI were included in this study, including 209 DM patients and 223 non-DM patients. Baseline characteristics, medical history, and laboratory parameters of patients were recorded after admission. In-hospital outcomes and 30-day mortality were recorded, and long-term mortality was recorded with a median follow-up of 34.2 ± 5.6 months.

RESULTS

Subclinical hypothyroidism (SCH) was defined as an elevated TSH level of more than with a normal range of circulating thyroid hormones. In AMI with DM group, 26/209 (12.4%) patients were complicated with SCH, these patients tend to be older and experienced worse in-hospital outcomes compared to patients without SCH, including higher rates of acute heart failure, acute kidney injury, and atrial fibrillation. Moreover, patients with SCH had a higher prevalence of 30-day mortality and long-term mortality, compared with patients without SCH.

CONCLUSIONS

Diabetic AMI patients with SCH had worse in-hospital outcomes and higher 30-day and long-term mortality. Patients with diabetic AMI should pay attention to thyroid function, and SCH is an independent risk factor for short-term and long-term mortality in diabetic AMI patients.

Thyroid dysfunction associated with iodine-contrast media: A real-world pharmacovigilance study based on the FDA adverse event reporting system

Objective

To comprehensively analyze characteristics of thyroid dysfunction associated with iodine contrast media (ICM) based on data from the FDA adverse event reporting system (FAERS).

Methods

Disproportionate analysis was employed to identify signals of thyroid dysfunction caused by ICM, and descriptive analysis was performed to examine the clinical characteristics of reported cases involving ICM-related thyroid dysfunctions.

Results

A total of 83 adverse event reports were identified, documenting thyroid dysfunctions associated with ICM agents. Treatment with ICM was significantly associated with higher reporting of hypothyroidism ([ROR] = 2.21, 95 % CI: 1.59-3.08; IC025 = 0.58) and hyperthyroidism (ROR = 3.49, 95 % CI: 2.37-5.13; IC025 = 1.14). Among the six ICM agents investigated, iodixanol demonstrated the highest signal strength in both hypothyroidism (ROR = 9.47) and hyperthyroidism (ROR = 5.44). Hypothyroidism and hyperthyroidism almost occurred in the first 30 days after ICM administration (76.9 % and 70 % of patients, respectively). Furthermore, the proportion of severe outcomes in hyperthyroidism was significantly higher than that in hypothyroidism (12/26 vs. 2/35, P = 0.009).

Conclusion

The present study highlights the varying risks of thyroid dysfunction associated with different ICM agents, with iodixanol exhibiting the highest signal intensity. Hypothyroidism and hyperthyroidism associated with ICM generally manifest within the first month following administration. Consequently, monitoring of thyroid function during this period is strongly recommended for ICM agents presenting higher risk profiles.

Higher Peripheral Thyroid Sensitivity Is Linked to a Lower Risk of Heart Failure After Acute Myocardial Infarction

CONTEXT

It is still not clear how the free triiodothyronine (FT3) to free thyroxine (FT4) ratio affects the prognosis of acute myocardial infarction (AMI), especially the risk of heart failure (HF) subsequent to AMI.

OBJECTIVE

The purpose of this study was to see how peripheral sensitivity to thyroid hormones, as measured by the FT3/FT4 ratio, affected HF and mortality after AMI.

METHODS

Our study was a retrospective cohort study. The primary endpoint was HF after AMI during and after hospitalization. The secondary endpoints were all-cause death and cardiovascular death after hospitalization.

RESULTS

The main sample included 3648 inpatients with AMI with a median age of 61.0 years; 68.9% were male. In the fully adjusted model, compared with patients in the lowest Q1 of the FT3/FT4 ratio, the risk of in-hospital HF in the highest Q4 patients was reduced by 44% (OR 0.56, 95% CI 0.44-0.72, P trend < .001), the risk of out-of-hospital HF was reduced by 37% (HR 0.63, 95% CI 0.48-0.84, P trend < .001), and the risks of all-cause and cardiovascular death were also significantly reduced. The analysis of different subgroups is consistent with the overall results. Furthermore, the sensitivity analysis of the euthyroid sample of 2484 patients was consistent with the main sample. Mediation analysis showed that altered levels of amino-terminal pro-B-type natriuretic peptide were mediators between the FT3/FT4 ratio and all endpoints in our study.

CONCLUSION

The thyroid hormone peripheral sensitivity of the FT3/FT4 ratio is an independent predictor of HF and mortality after AMI.

Association Between Thyroid Parameters and Subclinical Atherosclerosis in Hospitalised Euthyroid Patients with Type 2 Diabetes Mellitus

Purpose

To explore the association between thyroid parameters and subclinical atherosclerosis (AS) in hospitalised euthyroid patients with type 2 diabetes mellitus (T2DM).

Patients and Methods

A retrospective analysis was conducted involving 1245 inpatients with T2DM. Free triiodothyronine (FT3), free thyroxine (FT4), and thyroid stimulating hormone (TSH) levels were measured, and carotid artery ultrasonography was performed. Thyroid hormone (TH) sensitivity was evaluated using thyroid feedback quantile-based index (TFQI), TSH index (TSHI), thyrotropin thyroxine resistance index (TT4RI), and free triiodothyronine/free thyroxine ratio (FT3/FT4).

Results

In inpatients with T2DM having normal thyroid function, the incidence of subclinical AS declined with increasing levels of FT3, FT4, and FT3/FT4 (P trend < 0.05). Logistic regression analysis revealed that FT4 (OR, 0.914; 95% CI, 0.845-0.989), FT3 (OR, 0.374; 95% CI, 0.277-0.504), and FT3/FT4 (OR, 0.036; 95% CI, 0.013-0.061) were independently associated with subclinical AS (P < 0.05). However, TSH, TFQI, TSHI, and TT4RI levels were not associated with subclinical AS (P > 0.05). FT3/FT4 demonstrated superior predictive accuracy for subclinical AS than that of FT3 or FT4 alone (P < 0.001), with a cutoff point of 0.25.

Conclusion

In euthyroid inpatients with T2DM, subclinical AS exhibited negative correlation with FT3, FT4, and FT3/FT4 levels, independent of other risk factors for AS. Additionally, FT3/FT4 ratio had a good predictive value for subclinical AS.

GlycA as a Novel Biomarker of Systemic Inflammation in Hypothyroidism

Background: GlycA is a novel glycoprotein biomarker of systemic inflammation and cardiovascular risk. Our objective was to assess the levels of GlycA in individuals with hypothyroidism. We also explored whether levothyroxine (LT4)-treated patients had different levels of GlycA, with attention to thyrotropin (TSH) levels. Methods: We performed a cross-sectional analysis, using baseline data from the ELSA-Brasil cohort study. We included only participants with serum TSH and GlycA levels measurements, using magnetic resonance spectroscopy (n = 4745). We excluded individuals with endogenous hyperthyroidism and those using drugs impacting thyroid function. Participants not taking LT4 and whose serum TSH was 0.4-4.0 mIU/L were classified as euthyroid (EU) and those with elevated TSH as undiagnosed hypothyroidism (UH). For those on LT4 (n = 345), adequacy of treatment was defined as TSH within the reference range. Those with TSH <0.4 mIU/L were considered over-treated (OT), and those >4.0 mIU/L, under-treated (UT). Both (UT+OT) were considered inadequately treated (IT). Group comparisons were performed by Kruskal-Wallis, adjusted Chi-square, and the post hoc Dunn test. Additional subgroup analysis were performed in patients with circulating thyroperoxidase antibodies (TPO-Ab+). Respective multivariable analyses were performed to evaluate the relationship between thyroid-related variables and GlycA levels (Generalized Linear Model), as well as an abnormal GlycA (>400 μmol/L; Logistic Binary Regression). Results: The prevalence rate of UH was 9.8% (467/4745) and, among those on LT4, only 61.7% (213/345) were adequately treated (AT). GlycA levels were higher in IT in comparison to EU (429 vs. 410 μmol/L, p < 0.01) but did not differ between UH (413 μmol/L) and euthyroidism. However, the subgroup analysis of those TPO-Ab+ showed that not only those with IT, but also those with UH, had higher levels of GlycA in comparison to euthyroidism (423 and 424 vs. 402 μmol/L, p = 0.04). This association between higher levels of GlycA and IT was maintained even in multivariable analysis (odds ratio 1.53, confidence interval 1.03 to 2.31) Lower levels of GlycA were detected in AT (405 μmol/L,) compared with OT (432 μmol/L, 0.04) and UT (423 μmol/L, p = 0.02). Conclusions: Patients with IT, both OT and UT, had higher GlycA levels, which may be associated with low-grade systemic inflammation and, possibly, increased cardiovascular risk.

Renal function changes in patients with subclinical hyperthyroidism: a novel postulated mechanism

BACKGROUND

Subclinical hyperthyroidism (SCH) is found to be associated with renal dysfunction. Hyperthyroidism is a well-known cause of secondary systolic hypertension. However, the effect of SCH on the kidney and its vasculature is still unknown.

AIM

To assess the presence of renal function changes and renal vasodysfunction in SCH patients and their relation to hypertension.

METHODS

The study included 321 patients with SCH and 80 healthy matched controls. Laboratory investigations included thyroid function tests, anti-TSH receptor antibody (TRAb), creatinine, estimated glomerular filtration rate (eGFR), serum osmolarity (S. Osmol), urine osmolarity (U. Osmol), Fractional Excretion of Sodium (FeNa), Fractional Excretion of Potassium (FeK), copeptin (CPP), and aldosterone/renin ratio (ARR). Ultrasound for the thyroid gland, echocardiography, total peripheral resistance (TPR), flow-mediated dilatation (FMD), and Renal Arterial distensibility (RAD) was also done.

RESULTS

Serum creatinine was significantly lower while eGFR was significantly higher in SCH patients compared to euthyroid subjects (mean 0.59 ± 0.11 mg/dl Vs mean 0.8 ± 0.1 mg/dl, p = 0.001 and mean 128.28 ± 14.69 ml/min/1.73m2 Vs mean 100.49 ± 14.9 ml/min/1.73m2, p = 0.013, respectively). The TPR and FMD showed a significant decrease in SCH group compared to controls (mean 975.85 ± 159.33 mmHg.min/L Vs mean 1120.24 ± 135.15 mmHg.min/L, p = 0.045 and mean 7.03 ± 4.02% Vs mean 13.48 ± 4.57%, p = 0.003, respectively). RAD was significantly higher in hypertensive SCH patients compared to normotensive SCH patients (mean 17.82 ± 2.46 mmHg Vs mean 11.98 ± 3.21 mmHg, p = 0.001).

CONCLUSION

SCH patients showed vascular resistance reduction. Alterations in thyroid hormones and blood pressure could be the driving mechanisms for the change in renal functions in patients with SCH.

Subclinical Hypothyroidism, Kidney, and Heart from Normal to Uremic Milieu

Thyroid hormone (TH) imbalances, particularly subclinical hypothyroidism (SCHT), are associated with chronic kidney disease (CKD) and end-stage kidney disease (ESKD). SCHT is more prevalent in CKD and ESKD patients than in the general population, and this condition increases the risk of cardiovascular disease (CVD) morbidity and mortality. The risk of CVD is higher in CKD and ESKD patients compared with the general population. Traditional and nontraditional risk factors, including TH abnormalities, contribute to the high CVD burden in CKD and ESKD patients. The review discusses the link between CKD and hypothyroidism, with a focus on SCHT, and the mechanisms that lead to CVD burden.

Data Analysis and Systematic Scoping Review on the Pathogenesis and Modalities of Treatment of Thyroid Storm Complicated with Myocardial Involvement and Shock

Thyroid storm (TS) is a rare and fatal endocrine emergency that occurs due to undiagnosed and inadequately treated hyperthyroidism after stressful conditions in patients with thyroid disorders. The objective of this systematic scoping review was to better understand the pathophysiology of TS and its complications, in terms of myocardial affection, tachyarrhythmia, and cardiogenic shock. In addition, we explored the pharmacological, mechanical, and surgical treatments for TS. We also evaluated the outcomes of TS according to sex and cardiac involvement. Additionally, analytical analysis was performed on the selected data. A literature review of peer-reviewed journals was carried out thoroughly using medical terms, MeSH on PubMed, Google Scholar, and combinations such as thyrotoxicosis-induced cardiomyopathy, thyroid storm, cardiogenic shock, myocardial infarction, endocrine emergency, Burch-Wartofsky score, extracorporeal circulatory support, and thyroidectomy. A total of 231 papers were eligible (2 retrospective studies, 5 case series, and 224 case reports) with a total of 256 TS patients with cardiac involvement between April 2003 and August 2023. All age groups, sexes, patients with TS-induced cardiomyopathy, non-atherosclerotic myocardial infarction, tachyarrhythmia, heart failure, shock, and different forms of treatment were discussed. Non-English language articles, cases without cardiac involvement, and cases in which treatment modalities were not specified were excluded. Female sex was predominant, with 154 female and 102 male patients. Approximately 82% of patients received beta-blockers (BBs), 16.3% were placed on extracorporeal membrane oxygenation (ECMO) support, 16.3% received therapeutic plasma exchange (TPE), and 13.8% underwent continuous renal replacement therapy (CRRT), continuous venovenous hemofiltration (CVVHD), or dialysis. Overall, 18 females and 16 males died. BB-induced circulatory collapse, acute renal failure, CRRT, and ventricular fibrillation were significantly associated with mortality. Awareness of TS and not only thyrotoxicosis is vital for timely and appropriate treatment. The early diagnosis and management of TS in cardiac settings, including pharmacological, mechanical, and surgical modalities, can save high-risk patients. Sex matters in the presentation, treatment, and mortality of this population. However, further large-scale, and well-designed studies are required.

Iodine-Induced Hyperthyroidism and Long-term Risks of Incident Atrial Fibrillation and Flutter

CONTEXT

Although iodine-induced hyperthyroidism is a potential consequence of iodinated radiologic contrast administration, its association with long-term cardiovascular outcomes has not been previously studied.

OBJECTIVE

To investigate the relationships between hyperthyroidism observed after iodine contrast administration and incident atrial fibrillation/flutter.

METHODS

Retrospective cohort study of the U.S. Veterans Health Administration (1998-2021) of patients age ≥18 years with a normal baseline serum thyrotropin (TSH) concentration, subsequent TSH <1 year, and receipt of iodine contrast <60 days before the subsequent TSH. Cox proportional hazards regression was employed to ascertain the adjusted hazard ratio (HR) with 95% CI of incident atrial fibrillation/flutter following iodine-induced hyperthyroidism, compared with iodine-induced euthyroidism.

RESULTS

Iodine-induced hyperthyroidism was observed in 2500 (5.6%) of 44 607 Veterans (mean ± SD age, 60.9 ± 14.1 years; 88% men) and atrial fibrillation/flutter in 10.4% over a median follow-up of 3.7 years (interquartile range 1.9-7.4). Adjusted for sociodemographic and cardiovascular risk factors, iodine-induced hyperthyroidism was associated with an increased risk of atrial fibrillation/flutter compared with those who remained euthyroid after iodine exposure (adjusted HR 1.19, 95% CI 1.06-1.33). Females were at greater risk for incident atrial fibrillation/flutter than males (females, HR 1.81, 95% CI 1.12-2.92; males, HR 1.15, 95% CI 1.03-1.30; P for interaction = .04).

CONCLUSION

Hyperthyroidism following a high iodine load was associated with an increased risk of incident atrial fibrillation/flutter, particularly among females. The observed sex-based differences should be confirmed in a more sex-diverse study sample, and the cost-benefit analysis of long-term monitoring for cardiac arrhythmias following iodine-induced hyperthyroidism should be evaluated.

The Impact of Metformin on the Development of Hypothyroidism and Cardiotoxicity Induced by Cyclophosphamide, Methotrexate, and Fluorouracil in Rats

Cyclophosphamide (CYP), methotrexate (MTX), and 5-fluorouracil (5-FU) are extensively utilized in the therapeutic management of various malignancies. It is noteworthy, however, that potential chemotherapy-related complications include the occurrence of hypothyroidism and cardiotoxicity. Metformin (MET) is a pharmacological agent for managing type 2 diabetes. It has been reported to mitigate certain toxic manifestations associated with chemotherapy. This study's primary objective is to investigate MET's protective effects against hypothyroidism and cardiotoxicity induced by CMF treatment. A total of forty male rats were allocated into four distinct groups, each consisting of ten rats per group. These groups were categorized as follows: saline, MET, CMF, and CMF + MET. The experimental group of rats were administered CMF via intraperitoneal injection, receiving two doses of CMF, and fed MET in their daily drinking water, with a 2.5 mg/mL concentration. Blood samples were collected into EDTA tubes for assessment of TSH, free and total (T4 and T3), troponin I, CK, and CK-MB levels utilizing Electrochemiluminescence Immunoassays (ECI). The saline and MET groups did not exhibit significant alterations in thyroid hormones or cardiotoxic biomarkers. In contrast, in the CMF group, there was a notable reduction in T4, FT4, T3, and FT3 levels but no significant changes in TSH levels; however, troponin I, CK, and CK-MB levels were notably elevated. MET co-treatment with CMF did not ameliorate these effects caused by CMF. In conclusion, CMF treatment induced hypothyroidism and cardiotoxicity in rats, but MET co-treatment did not rescue the reduction of thyroid hormones or the elevation of cardiotoxic biomarkers.

Association of Acculturation and Hispanic/Latino Background with Endogenous Sex and Thyroid-Related Hormones Among Middle-Aged and Older Hispanic/Latino Adults: the HCHS/SOL Study

BACKGROUND

Hormones are linked to cardiometabolic diseases and may be impacted by acculturation though multiple mechanisms. We evaluated associations of Hispanic/Latino background and acculturation with levels of sex- and thyroid-related hormones and the potential mediating effect of adiposity, lifestyle factors, and sleep apnea syndrome on these associations.

METHODS

We studied 1789 adults, aged 45-74, from a sub-cohort of the Hispanic Community Health Survey/Study of Latinos. Peri/pre-menopausal women and individuals on medications related to hormones were excluded. Our study assessed eleven sex- and thyroid-related hormones, Hispanic/Latino background, and five acculturation measures. Associations were assessed using multivariable linear and logistic regression adjusted for survey design and confounding variables. We explored potential mediation using a path analysis.

RESULTS

In postmenopausal women, acculturation score-MESA was associated with decreased thyroid-stimulating hormone (β = - 0.13;95%CI = - 0.22, - 0.03) while age at immigration greater than the median (vs US-born) was associated with decreased (β = - 14.6; 95%CI = - 28.2, - 0.99) triiodothyronine (T3). In men, language acculturation and acculturation score-MESA were associated with increased estradiol and sex hormone-binding globulin (SHBG) while age at immigration greater and lesser than the median (vs US-born) was associated with decreased SHBG. Hispanic/Latino background (Mexicans as reference) were selectively associated with sex- and thyroid-related hormone levels in both sexes. Current smoking and sleep apnea syndrome partially mediated the association of Cuban and Puerto Rican heritage (vs Mexican) with T3 levels in men and postmenopausal women, respectively.

CONCLUSION

Selected acculturation measures were associated with thyroid-related hormones in postmenopausal women and sex-related hormones in men. Understanding the mechanisms involved in the relationship of acculturation and Hispanic/Latino background with hormones warrants additional investigation.