Subclinical Hypothyroidism and Its Association with Increased Cardiovascular Mortality

Radiation-Induced Hypothyroidism in Patients with Oropharyngeal Cancer Treated with IMRT: Independent and External Validation of Five Normal Tissue Complication Probability Models

Simple Summary

Hypothyroidism is a common complication of therapeutic irradiation in the neck area. Several dose-response models have been proposed to predict its’ occurrence based on clinical and radiomic features. We aimed to externally validate the results of five such models in a prospectively recruited cohort of 108 patients with oropharyngeal cancer. Two of the evaluated models, published by Rønjom et al. and by Boomsma et al., had satisfactory performance. Both models are based on mean thyroid dose and thyroid volume. Three remaining models, by Cella et al., Bakhshandeh et al. and Vogelius et al., performed significantly worse. Short-term change in the level of thyroid-stimulating hormone (TSH) after radiation therapy was not indicative of hypothyroidism development in long term. We conclude that the models by Rønjom et al. and by Boomsma et al. are feasible for long-term prediction of hypothyroidism in oropharyngeal cancer survivors treated with intensity-modulated radiation therapy.

Abstract

We aimed to externally validate five normal tissue complication probability (NTCP) models for radiation-induced hypothyroidism (RIHT) in a prospectively recruited cohort of 108 patients with oropharyngeal cancer (OPC). NTCP scores were calculated using original published formulas. Plasma thyrotropin (TSH) level was additionally assessed in the short-term after RT. After a median of 28 months of follow-up, thirty one (28.7%) patients developed RIHT. Thyroid mean dose and thyroid volume were significant predictors of RIHT: odds ratio equal to 1.11 (95% CI 1.03–1.19) for mean thyroid dose and 0.87 (95%CI 0.81–0.93) for thyroid volume in univariate analyses. Two of the evaluated NTCP models, published by Rønjom et al. and by Boomsma et al., had satisfactory performance with accuracies of 0.87 (95%CI 0.79–0.93) and 0.84 (95%CI: 0.76–0.91), respectively. Three remaining models, by Cella et al., Bakhshandeh et al. and Vogelius et al., performed significantly worse, overestimating the risk of RIHT in this patient cohort. A short-term TSH level change relative to baseline was not indicative of RIHT development in the follow-up (OR 0.96, 95%CI: 0.65–1.42, p = 0.825). In conclusion, the models by Rønjom et al. and by Boomsma et al. demonstrated external validity and feasibility for long-term prediction of RIHT in survivors of OPC treated with Intensity-Modulated Radiation Therapy (IMRT).

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

Background:

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

Objective:

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

Methods:

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

Results:

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

Conclusion:

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

Evaluation of cardiovascular risk by growth-differentiation factor-15 and tissue Doppler imaging in children with subclinical hypothyroidism

OBJECTIVE

Subclinical hypothyroidism, defined as increased TSH serum levels and normal serum free T4 concentrations, has been associated with an increased risk of heart disease in adults. But, data in children and adolescents are scanty and treatment of subclinical hypothyroidism is controversial. Growth differentiation factor-15 (GDF-15) is a promising biomarker of cardiac remodeling. This study aimed to evaluate the cardiovascular risk factors in children with subclinical hypothyroidism, measured with tissue Doppler echocardiography (TDE), and conventional echocardiography and GDF-15 level.

METHODS

The study comprised a total of 41 pediatric patients with subclinical hypothyroidism (SH) (mean age 9.6 ± 4.7 years) and 31 healthy children (mean age 11.2 ± 3.4 years) as the control group. Subclinical hypothyroidism was defined as a thyroid-stimulating hormone level higher than 4 mIU/l and a normal free-thyroxine level (0.6-1.8 ng/dl). Tissue Doppler echocardiography was performed to all individuals in the control group and patient group at the beginning of the study. Global systolic function as assessed by left ventricular ejection fraction was compared between groups. The serum GDF-15 level was measured.

RESULTS

There were no significant differences in demographic parameters between the SH and control groups. The left ventricular internal diameter end systole, interventricular septal end diastole, left ventricular posterior wall end diastole, and tricuspid annular plane systolic excursion values were significantly different between the SH and control groups (p = 0.038, 0.028, 0.005, and 0.000, respectively). The mean mitral isovolumic relaxation time value of the SH group was 57.2 ± 9.3 ms, compared to 44.5 ± 5.6 ms for the control group (p = 0.000). The mean tricuspid isovolumic contraction time value of the SH group was 58.7 ± 9.4 ms, and that of the control group was 45.1 ± 5.3 ms (p = 0.000). The mean tricuspid isovolumic relaxation time value of the SH group was 58.03 ± 9.5 ms, and that of the control group was 45.1 ± 5.3 ms (p = 0.000). There were no significant differences in the other m-mode or pulse Doppler echocardiography values between two groups. The GDF-15 value of the SH group was 382.6 ± 268.2 pg/mL, and that of the control group was 473.6 ± 337.9 pg/mL; this difference was not significant.

CONCLUSION

Patients with subclinical hypothyroidism versus healthy individuals had some changes in echocardiographic parameters that indicate involvement of diastolic function of the left ventricle. They were significantly different when compared SH group and the control group. This study demonstrated ventricle diastolic dysfunction in pediatric patients with hypothyroidism. The results of our study suggest that cardiac follow-up may be useful in patients with subclinical hypothyroidism and clinical trials are needed to explore therapeutic effects of T4 and T3 administration in this patients.

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

Objective

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

Methods

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

Results

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

Conclusions

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

Subclinical Hypothyroidism and Coronary Revascularization After Coronary Artery Bypass Grafting

We aimed to investigate long-term cardiovascular sequelae after coronary artery bypass grafting (CABG) in patients with subclinical hypothyroidism (SCH). All-cause and cardiovascular-related mortality, and cardiovascular events were retrospectively reviewed in 222 euthyroid and 36 SCH patients who underwent CABG. During a mean follow-up period of 8.2 ± 4.1 years, there were 90 incidents of all-cause deaths, 20 cardiovascular-related deaths, 70 major cardiovascular adverse events, 6 myocardial infarctions, 12 unstable anginas, 31 strokes, 23 hospitalizations due to heart failure, 15 atrial fibrillation (AF) events, and 27 coronary revascularizations. The incidence rate of coronary revascularization was significantly higher in patients with SCH (n = 6, 16.6%) than in euthyroid patients (n = 20, 9.0%), with a hazard ratio (HR) of 3.179 (95% confidence interval [CI] 1.174, 8.605; p = 0.023) after adjustment. In subgroup analysis, SCH patients who experienced postoperative AF within 3 months after CABG surgery had a significantly higher risk of coronary revascularization (n = 4, 25.0%) than euthyroid patients without AF (n = 14, 8.9%) after adjustment (HR 11.759, 95% CI 2.747, 50.343, p = 0.001). The frequency of fatal or nonfatal unstable angina was also higher in patients with SCH (n = 2, 12.5%) than in euthyroid patients (n = 4, 2.5%) (HR 16.999, 95% CI 2.242, 128.860, p = 0.006). In conclusion, preoperative SCH is associated with less favorable cardiovascular outcomes, especially coronary revascularization after CABG. Moreover, SCH patients who develop postoperative AF exhibit significantly increased risks of unstable angina and coronary revascularization. Preoperative evaluation of thyroid function may be helpful for predicting long-term outcomes after CABG.

Retracted: Subclinical Hypothyroidism and Its Association with Increased Cardiovascular Mortality

[This retracts the article DOI: 10.1155/2017/7539735.].