Coronary flow reserve after L-thyroxine therapy in Hashimoto's thyroiditis patients with subclinical and overt hypothyroidism

Systematic review and meta-analysis of levothyroxine effect on blood pressure in patients with subclinical hypothyroidism

This study aims to evaluate the effect of levothyroxine therapy on blood pressure (BP) in patients with subclinical hypothyroidism (SCH). Were searched Six databases, and randomized controlled trials (RCT) and prospective cohort studies evaluating the effect of levothyroxine therapy on BP in patients with SCH were included. 37 articles (9 RCTs and 28 prospective cohorts) were included in this meta-analysis. Pooled analysis of RCT studies was insignificant; however, pooled analysis of 28 prospective cohort studies showed a significant difference before and after the therapy, reducing both systolic blood pressure (SBP) and diastolic blood pressure (DBP) (MD=-4.02 [-6.45, -4.58] and MD=-2.13 [-3.69, -0.56], both P-values<0.05). Levothyroxine therapy can play a role in lowering BP in patients with SCH. However, this effect is more observed in Caucasians, SCH patients with higher initial TSH followed by more remarkable TSH change to normal levels, and SCH patients with hypertension.

Specific impact of cardiovascular risk factors on coronary microcirculation in patients with subclinical hypothyroidism

Background

Although thyroid hormones have significant effect on cardiovascular system, the impact of subtle thyroid dysfunction such as subclinical hypothyroidism (SCH) remains to be determined. We investigated coronary flow reserve (CFR) in patients with subclinical hypothyroidism.

Methods

Thirty two subjects with SCH and eighteen control subjects with normal serum thyroid hormones and thyroid-stimulating hormone (TSH) levels were included in the study. TSH, free thyroxine, free triiodothyronine, glucose, insulin, HbA1c, cholesterol, triglyceride and plasma levels of C-reactive protein were measured. Coronary diastolic peak flow velocities in left anterior descending coronary artery were measured at baseline and after adenosine infusion. CFR was calculated as the ratio of hyperemic to baseline diastolic peak velocity.

Results

CFR values were not significantly different between the two groups (SCH 2.76±0.35 vs controls 2.76±0.42). There was a significant correlation of CFR with waist to hip ratio, hypertension, smoking habits, markers of glucose status (glucose level, HbA1c, insulin level, HOMA IR), cholesterol, LDL-cholesterol and triglyceride levels in SCH group, whereas only cholesterol level showed significant correlation with CFR in controls. There was no correlation between CFR and thyroid hormones.

Conclusions

We concluded that there is a different impact of cardiovascular risk factors on CFR in SCH patients compared to healthy control and that these two groups behave differently in the same circumstances under the same risk factors. The basis for this difference could be that the altered thyroid axis "set point" changes the sensitivity of the microvasculature in patients with SCH to known risk factors.

Clinical Characteristics and Outcomes of Patients With Takotsubo Syndrome

BACKGROUND

Characteristics and outcomes of patients with takotsubo syndrome remain to be defined. The goal of this study was to report the characteristics and long-term outcomes of patients presenting with takotsubo syndrome compared with other patients presenting with acute myocardial infarction (AMI) in a community-based population.

METHODS

This retrospective population-based study included patients hospitalised for AMI from 2006 to 2016. Those patients with takotsubo syndrome were compared with the patients with AMI. The primary outcome was all-cause mortality. Matching was performed to assemble a cohort of patients with similar baseline characteristics.

RESULTS

Among 26,015 patients hospitalised with an initial diagnosis of AMI, 530 (2.0%) were diagnosed with takotsubo syndrome. Patients with takotsubo syndrome were older (68.3 ± 11.3 vs 65.6 ± 12.2 years) and more likely to be women (93.4% vs 30.7%). Concomitant hypothyroidism, rheumatologic disorders, and lung disease were more prevalent in the takotsubo syndrome group, whereas diabetes and hyperlipidemia were less prevalent. Mortality was lower in the takotsubo syndrome group (1-year mortality 4.0% vs 8.9%; P < 0.001). The 530 patients with takotsubo syndrome were matched with 1,315 AMI patients with similar baseline characteristics. At a follow-up of 5.4 ± 3.3 years, patients with takotsubo syndrome had a lower risk for all-cause death than other patients who presented with AMI (hazard ratio 0.59, 95% CI 0.47-0.76).

CONCLUSIONS

Among patients presenting with AMI, patients with takotsubo syndrome were older and more likely to be women. Patients with takotsubo syndrome had better long-term outcomes compared with matched AMI patients.

Effect of Levothyroxine on Blood Pressure in Patients With Subclinical Hypothyroidism: A Systematic Review and Meta-Analysis

Background: Patients with subclinical hypothyroidism (SCH) have elevated blood pressure, but the effect of levothyroxine (LT4) therapy on blood pressure among those patients is still unclear. This study aimed to assess whether LT4 therapy could reduce blood pressure in SCH patients through a systematic review and meta-analysis. Methods: PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science were searched. Randomized controlled trials (RCTs) assessing the effect of LT4 therapy on blood pressure or prospective follow-up studies comparing the blood pressure level before and after LT4 treatment were included, and the mean difference of systolic blood pressure (SBP) or diastolic blood pressure (DBP) was pooled using random-effect meta-analysis. Results: Twenty-nine studies including 10 RCTs and 19 prospective follow-up studies were eligible for the analysis. Meta-analysis of 10 RCTs suggested that LT4 therapy could significantly reduce SBP in SCH patients by 2.48 mmHg (95% CI -4.63 to -0.33, P = 0.024). No heterogeneity was observed among these 10 RCTs (I² = 0%). Meta-analysis of the 19 prospective follow-up studies found that LT4 therapy significantly decreased SBP and DBP by 4.80 mmHg (95%CI -6.50 to -3.09, P < 0.001) and 2.74 mmHg (95%CI -4.06 to -1.43, P < 0.001), respectively. Conclusion: The findings suggest that LT4 replacement therapy can reduce blood pressure in SCH patients, which needs to be validated in more clinical trials with larger samples.

One-year GH replacement therapy reduces early cardiac target organ damage (TOD) in adult GHD patients

Hypopituitarism reduces life expectancy and increases the risk of cardiovascular and cerebrovascular diseases, as well as death. Abnormalities in the cardiovascular system may be independently related to GH deficiency (GHD). The aim of this study was to prospectively investigate coronary flow reserve and diastolic function in GHD adult patients at diagnosis and after 1 year of GH replacement therapy. As control group, an age- and sex-matched population was chosen. All patients and controls were non-smokers, non-diabetic, and normotensive, with no history of vascular disease. 14 patients with adult-onset GHD and 17 controls represent the two study groups. Anthropometric data, blood pressure, lipid profile, glycosylated hemoglobin (HbA1c) and IGF-I plasma levels, coronary flow reserve (CFR), and LV diastolic function (evaluated by E/A) were collected in all subjects before and after 12 months of GH replacement therapy. Compared with controls, systolic and diastolic blood pressure and LDL cholesterol levels were significantly higher at baseline and return, comparable to controls after 1 year of GH replacement (GHRT). GHD patients showed a blunted CFR at baseline (P < 0.001) and a significant improvement after GHRT, returning to values comparable with those recorded in the control group. In addition, after therapy a significant (P < 0.001) improvement in E/A was recorded. One year of GH therapy improves CFR and E/A in the patient population analyzed, thereby encouraging the early start of GHRT.

Thyroid Dysfunction in Primary Biliary Cholangitis: A Comparative Study at Two European Centers

OBJECTIVES

Primary biliary cholangitis (PBC) is often associated with other autoimmune diseases, but little is known about the influence of thyroid disease (TD) on the natural history of PBC. Our aim is to analyze the association between PBC and TD, and the latter's impact on the natural history of PBC at two European centers.

METHODS

The study involved 921 PBC patients enrolled between 1975 and 2015 in Padova (376 patients) and Barcelona (545 patients), with a mean follow-up of 126.9±91.7 months. Data were recorded on patients' histological stage at diagnosis, biochemical data, associated extrahepatic autoimmune conditions, and clinical events, including hepatic decompensation.

RESULTS

A total of 150 patients (16.3%) had TD, including 94 patients (10.2%) with Hashimoto's thyroiditis; 15 (1.6%) with Graves' disease; 22 (2.4%) with multinodular goiter; 7 (0.8%) with thyroid cancer; and 12 (1.3%) with other thyroid conditions. The prevalence of different types of TD was similar in Padova and Barcelona, except for Graves' disease and thyroid cancer, which were more frequent in the Padova cohort (15.7 vs. 5.0%, and 8.6 vs. 1.3%, respectively, P<0.05). Overall, there were no differences between PBC patients with and without TD in terms of their histological stage at diagnosis, hepatic decompensation events, occurrence of HCC, or liver transplantation rate. The presence of associated TD was not associated with lower survival for PBC patients in either cohort.

CONCLUSIONS

TDs, and autoimmune TD like Hashimoto's thyroiditis in particular, are often associated with PBC, but the presence of TD does not influence the rate of hepatic complications or the natural history of PBC.

NO-mediated anticontractile effect of the endothelium is abolished in coronary arteries of adult rats with antenatal/early postnatal hypothyroidism

INTRODUCTION

Thyroid hormones are essential for proper development of many systems and organs, including circulatory system. Thyroid deficiency during pregnancy may affect the cardiovascular function in children early on and later in adulthood. However, long-term effects of early thyroid deficiency are poorly understood. We hypothesized that antenatal/early postnatal hypothyroidism will influence anticontractile effect of NO in coronary arteries of adult rats.

DESIGN AND METHODS

To model antenatal/early postnatal hypothyroidism dams were treated with 6-propyl-2-thiouracil (PTU) in drinking water (0.0007%, w/v) from the first day of pregnancy till 2 weeks after delivery. Control females were supplied with pure water. Their male offspring was grown up till the age of 10-12 weeks. Systolic blood pressure was measured using tail cuff method. Septal coronary arteries were isolated and studied in wire myograph. Blood serum thyroid hormones concentrations (ELISA) and NO metabolites level (Griess method) were evaluated.

RESULTS

At the age of 10-12 weeks thyroid hormones, TSH concentrations, NO metabolites and systolic blood pressure level didn't differ between groups. Arterial responses to acetylcholine and exogenous NO-donor DEA/NO were similar in control and PTU groups. Along with that, in control rats endothelium denudation strongly potentiated basal tone of arteries and their contractile responses to thromboxane A2 receptor agonist U46619. The effects of endothelium denudation were absent in PTU rats indicating that anticontractile effect of endothelium is abolished in their arteries. Further, NO-synthase inhibitor L-NNA (100 μM) caused significant elevation of basal tone and increased U46619-induced contraction of endothelium-intact arteries only in control rats, while had no effect in PTU group.

CONCLUSIONS

Our data demonstrate that NO-mediated anticontractile effect of endothelium is eliminated in coronary arteries of adult rats, which suffered from antenatal/early postnatal hypothyroidism. Therefore, maternal thyroid hormones deficiency may have detrimental consequences in adult offspring including coronary circulation pathologies, despite normal blood levels of thyroid hormones.

Takotsubo Cardiomyopathy Associated with Severe Hypothyroidism in an Elderly Female

Takotsubo cardiomyopathy, also known as stress cardiomyopathy, is a syndrome that affects predominantly postmenopausal women. Despite multiple described mechanisms, intense, neuroadrenergic myocardial stimulation appears to be the main trigger. Hyperthyroidism, but rarely hypothyroidism, has been described in association with Takotsubo cardiomyopathy. Herein, we present a case of stress cardiomyopathy in the setting of symptomatic hypothyroidism.

Risk of Depression, Chronic Morbidities, and l-Thyroxine Treatment in Hashimoto Thyroiditis in Taiwan: A Nationwide Cohort Study

The aim of this study was to evaluate the risk of depression in and effect of L-thyroxine therapy on patients with Hashimoto thyroiditis (HT) in Taiwan.In this retrospective, nationwide cohort study, we retrieved data from the Longitudinal Health Insurance Database 2000. We collected data of 1220 patients with HT and 4880 patients without HT for the period 2000 to 2011. The mean follow-up period for the HT cohort was 5.77 years. Univariate and multivariate Cox proportional hazards regression models were used to estimate the risk of depression in the HT cohort.In the HT cohort, 89.6% of the patients were women. Compared with the non-HT cohort, the HT cohort exhibited a higher prevalence of diabetes mellitus, hyperlipidemia, and coronary artery disease. Furthermore, the HT cohort showed a higher overall incidence of depression compared with the non-HT cohort (8.67 and 5.49 per 1000 person-year; crude hazard ratio [HR] = 1.58, 95% confidence interval [CI] = 1.18-2.13). The risk of depression decreased after administration of L-thyroxine treatment for more than 1 year (adjusted HR = 1.02; 95% CI = 0.66-1.59).In Taiwan, the overall incidence of depression was greater in the young HT cohort. L-thyroxine treatment reduced the risk of depression.

Pulmonary hypertension and Hashimoto's thyroiditis: does a relationship exist?

Several studies examined the possibility that idiopathic pulmonary hypertension is related to thyroid autoimmune diseases. The aim of our study was to highlight the possible correlations between the pulmonary hypertension and Hashimoto's thyroiditis (HT). A total of 93 patients were enrolled, 70 suffering from HT in euthyroidism state and 23 controls. All underwent anthropometric [weight (Kg); height (m); Body Mass Index (Kg/m(2)): waist circumference (cm)] and biochemical [fasting blood glucose (mg/dl), TSH (µUI/mL), FT3 (pg/ml), FT4 (pg/ml), total, HDL and LDL-cholesterol (mg/dl), triglycerides (mg/dl)] evaluations. All patients underwent two-dimensional trans-thoracic echocardiographic evaluations in order to measure systolic (sPAP) and the end-diastolic pressure of the pulmonary artery (dPAP). There were no differences between the two populations regarding anthropometric and biochemical parameters. Patients with HT had higher sPAP values than controls (Hashimoto: 20.06 ± 6.56 mmHg vs controls: 19.96 ± 8.58 mmHg, p = 0.044). Patients with HT had lower dPAP values than controls (2.51 ± 0.90 mmHg vs. controls 3.17 ± 1.58 mmHg, p < 0.0001), and there was a statistically significant difference in the left ventricle ejection fraction between the two groups (60.57 ± 1.60 % in patients with HT vs. 61.04 ± 2.03 % in controls, p = 0.037). The multivariate regression analysis did not confirm such results. We demonstrated that patients with HT did not show relevant pulmonary hypertension when compared to healthy controls.

Is autoimmune thyroiditis a risk factor for early atherosclerosis in premenopausal women even if in euthyroid status?

Autoimmune thyroiditis (AIT) is a systemic disease. It is well-known that overt thyroid dysfunction is a cardiovascular risk factor. However, the influence of euthyroid status is unclear. The aim of this study was to evaluate the metabolic parameters and carotid intima-media thickness (CIMT) in euthyroid premenopausal women with AIT. Fourty-eight premenopausal women and 18 age-matched healthy controls attending the Endocrinology and Metabolism Clinic from 2008 to 2009 were enrolled to this cross-sectional study. Patients were divided into 2 groups according to TSH levels; patients in group 1 (n = 23) had TSH levels ≤ 2.5 μIU/mL and patients in group 2 had TSH levels > 2.5 μIU/mL (n = 25). All participants were evaluated by ultrasound for CIMT (mean of three segments in both carotid arteries) by the same experienced investigator. Fasting venous blood samples were collected to evaluate insulin resistance (HOMA-IR), TSH, FT4, plasma lipids, high-sensitive CRP (Hs-CRP), homocysteine, and fibrinogen. Carotid intima-media thickness was found to be significantly higher in patients than the controls (p < 0.001). However, there was no significant difference in average CIMT between group 1 and 2 (0.66 ± 0.08 vs 0.63 ± 0.09 mm). Anti-Tg levels were independently associated with CIMT in the patient group (p = 0.014). There were no significant correlations between serum TSH levels and BMI; waist circumference, serum lipids, and glucose levels. However, there was a positive significant correlation between TSH levels and blood pressure in the patients (for systolic blood pressure r = 0.466, p = 0.001, for diastolic blood pressure r = 0.372, p = 0.009). In the present study, it was shown that CIMT is increased in euthyroid premenopausal women with autoimmune thyroiditis compared to age-matched healthy controls.

Postprandial lipaemia suppresses endothelium-dependent arterial dilation in patients with hypothyroidism

Endothelial dysfunction represents an early step in the development of atherosclerosis. The purpose of this study was to investigate the relationship between postprandial lipaemia and endothelial dysfunction in patients with overt hypothyroidism (oHT) and subclinical hypothyroidism (sHT). Female subjects with oHT and sHT, as well as female healthy subjects with euthyroid state were enrolled (10 cases in each group). The examination of flow-mediated dilation (FMD) was performed before and after an oral fat-loading by high resolution ultrasound. Endothelial dysfunction after an oral fat challenge was related to the extent of hypertriglyceridemia and free radicals. FMD decreased significantly at 4-h point in 3 groups, (p < 0.05) and then FMD in control and sHT restored to baseline at 8-h point, it was lower than baseline in sHT group at 6-h point (p = 0.042). However, FMD continued to decrease at 6-h point (p < 0.001), and then increased toward to baseline at 8-h point, which was still lower than baseline (p = 0.039) in oHT. Spearman's analysis showed a negative correlation between FMD and triglyceride, a negative correlation between FMD and thiobarbituric acid reactive substances (TBARS), and a positive correlation between triglyceride and TBARS levels during oral lipid-loading test in hypothyroid patients (p < 0.001) and controls (p < 0.05). In hypothyroid subjects including oHT and sHT, even in healthy individuals, FMD was impaired after an oral fat challenge. The endothelial dysfunction observed after an oral fat challenge was related to the extent of hypertriglyceridemia and oxygen-derived free radicals.