The role of thyroid hormones in acute coronary syndromes: Prognostic value of alterations in thyroid hormones

The prognosis of acute coronary syndromes (ACS) is affected by many factors. Normal thyroid homeostasis is known to alter during various critical illnesses, a condition that has been shown to correlate with the severity of the disease and increased mortality. The purpose of this article is to review literature to emphasize the considerable association of thyroid function with the cardiovascular system and summarize all existing evidence with regard to the role of thyroid hormones alterations during ACS. The electronic databases of PubMed, Medline, Scopus, and Cochrane were searched for relevant literature and studies. Alterations in thyroid hormone plasma concentrations, especially low triiodothyronine (T3) levels, represent a hormonal imbalance that is not uncommon among patients suffering an acute coronary event. Many studies have identified this abnormal thyroid hormonal status to be related to worse prognosis. Although further large-scale clinical trials are needed, the low T3 syndrome manifesting in patients during ACS might be useful in prognostic stratification.