Evaluation of pituitary-thyroid axis response to acute myocardial infarction

Abstract

We have studied with seriated controls for a period of 9 days 18 patients admitted to our hospital for acute myocardial infarction (AMI). Slight, but non significant variations in thyroidal hormone pattern were observed: slight decrease of T3 and T4 levels, increase of reverse T3 on day 3, low free T4 levels, slight increase of TSH levels until the 3rd day. However, hormonal pattern was clearly different in patients who presented a clinical improvement (group 1a) and in patients who died for AMI (group 1b). In fact, a significant TSH increase was recorded in patients of group 1a; on the contrary, a significant decrease of TSH, T4 and free T4 concentrations was observed for subjects of group 1b, suggesting an inadequate response of pituitary-thyroid axis. In conclusion, the evaluation of thyroid hormones and thyrotropin levels can be of clinical usefulness in the management of patients with AMI. The decrease of plasma T4 and free T4 concentrations, accompanied with low TSH levels, can be associated with unfavorable course of the disease and therefore can be considered a bad prognostic sign.

Short term triiodo-l-thyronine treatment inhibits cardiac myocyte apoptosis in border area after myocardial infarction in rats

“…This study shows a significant decrease in serum T3 and T4 levels and a tendency for increased serum TSH levels after MI, which is consistent with previous reports [6,7,9,10]. T3 treatment significantly increased serum T3 level, decreased serum T4 levels, and tended to decrease serum TSH level, suggesting inhibition of the pituitary-thyroid axis by exogenous thyroid hormone.…”

“…Correspondingly, severe heart diseases including MI are often accompanied by altered metabolism of TH, characterized by low serum T3, T4, FT3 and FT4 levels, high serum rT3 levels, and normal or low serum TSH levels. These changes have been demonstrated in both animal and clinical studies [6,7,8,9,10,11]. It is not known if reduced TH activity after MI is beneficial or detrimental.…”

Relationship between circulating cytokine levels and thyroid function following bone marrow transplantation

“…The patients with low T 4 level at post-BMT 3 weeks had lower 1-year survival rate than those with normal T 4 level, which is in agreement with previous data. [7][8][9][10] No significant differences in thyroid hormone parameters were found according to the presence or severity of GVHD, which is similar to the finding of Vexiau et al 11 Cytokines were not significantly different between those patients who have subsequently died before 1 year post-BMT and those surviving.…”

“…When serum T 4 levels falls below 4 mg/dl, the probability of death is about 50%, and at below 2 mg/dl the probability of death reaches 80%. [7][8][9][10] In patients undergoing bone marrow transplantation (BMT), the development of ESS indicates a poor prognosis. 11,12 Recently, attention has been focused on the role of cytokines in the pathogenesis of ESS.…”

Changes in Thyroid Hormone Parameters after Acute Myocardial Infarction

“…By definition, such changes can be attributed to the illness only in the absence of a primary disorder of the hypothalamus, pitu itary or thyroid glands, and may reflect disturbances in thyroid hormone physiology affecting the hypothalamicpituitary-thyroid hormone negative feedback axis as well as the peripheral tissue metabolism [2], Mechanisms responsible for this fact may include alterations in the concentration and/or affinity of the serum carrier proteins and disturbances in hormone production, clearance, dis tribution and degradation, as well as in target organ response [2,5], A number of trials have been performed determining changes in thyroid parameters during aMI [6][7][8][9][10][11][12], How ever, patient characteristics, therapy as well as time for blood sampling differed greatly in these studies. We could show that a significant decrease in T4, 1T4, T3 and fT3 occurs already 2 h following admission.…”