Pathophysiological aspects of development myocardial infarction type 2 in subclinical hypothyroidism

Abstract

The main purpose of the following article is to highlight one of the most pressing and poorly studied issues both for cardiology and endocrinology – treatment and prognosis for patients with severe coronary pathology and subclinical hypothyroidism (SH). Pathophysiological mechanisms of type 2 myocardial infarction (MI) development with SH as a background and hormone replacement therapy issues are considered. SH is a modifiable risk factor (RF) for cardiovascular diseases (CVD) and mortality that does not depend on traditional cardiovascular RF. SH is associated with high risk of developing coronary artery disease, MI, heart failure, and CVD mortality. SH incidence of morbidity increases with age, usually the course is oligo- or asymptomatic. SH leads to a number of pathological conditions that cause an imbalance between the myocardial oxygen demand and delivery with a possible development of type 2 MI. Clinical case of type 2 MI development in a patient with severe coronary atherosclerosis and SH is presented. The key point of type 2 MI development mechanism is insufficient oxygen (O2) supply to cardiomyocytes due to multivessel coronary artery atherosclerotic stenosis and sharp increase in O2 demand as a result of cardiomyocyte hypertrophy. Older patients with severe cardiac pathology and SH should refrain from treatment with levothyroxine or start treatment after myocardial revascularization, selecting the dose of the drug individually.