Uticaj subkliničke tiroidne disfunkcije na kardiovaskularni sistem

Abstract

Subklinička tiroidna disfunkcija karakteriše se normalnim vrednostima tiroidnih hormona (tiroksina i trijoditironina) uz povišene ili snižene vrednosti TSH. Poznato je da tiroidni hormoni imaju veliki uticaj na metabolizam lipida, glukoze, funkciju srca i krvnih sudova. U klinički izraženoj hipotireozi i hipertireozi opisane su značajne promene dijastolne i globalne srčane funkcije što vodi povećanom kardiovaskularnom riziku. Kada je u pitanju subklinički poremećaj funkcije tireoideje do sada dobijeni rezultati su prilično nesaglasni. Cilj studije bio je da se utvrdi da li je subklinička hipotireoza udružena sa aterogenim lipidnim profilom, insulinskom rezistencijom i poremećajem dijastolne i globalne funkcije leve komore i da li su ove promene reverzibilne nakon uvođenja supstitucione terapije levotiroksinom. Takođe, da li postoji poremećaj insulinske senzitivnosti i funkcije leve komore u subkliničkoj hipertireozi. Metod: u studiju je bilo uključeno 47 žena sa subkliničkom hipotireozom, 31 žena sa subkliničkom hipertireozom i kontrolnu grupu je činilo 45 žena slične starosti. Svim ispitanicama su urađene analize hormona, lipidni status, HOMA indeksom je procenjena insulinska rezistencija i urađen je ehokardiografski pregled, uz korišćenje tehnike pulsnog tkivnog Dopplera. Pacijentkinjama sa subkliničkom hipotireozom uvedena je supstituciona terapija levotiroksinom i nakon godinu dana od normalizovanja vrednosti TSH ponovljene su laboratorijske analize i ehokardiografski pregled. Rezultati: pacijentkinje sa subkliničkom hipotireozom imale su povišene vrednosti ukupnog holesterola (6±1mmol/l vs 5±0.95mmol/) kao i LDL-C (3.8±0.93mmol/l vs 3±0.9mmol/l) u odnosu na kontrolnu grupu. Insulinska rezistencija procenjena HOMA-IR bila je prisutna i kod pacijenkinja sa subkliničkom hipotireozom (2±1,03) i kod pacijentkinja sa subkliničkom hipertireozom (1.71±0.97). Kod pacijentkinja sa subkliničkom hipotireozom utvrđen je poremećaj dijastolne funkcije leve komore procenjen odnosom E/A (1.15±0.17) koji se nakon jednogodišnje terapije levotiroksinom popravlja (1.3±0.18)...

Subclinical thyroid dysfunction is characterized by thyroid hormone (thyroxin and triiodothyronine) levels within their reference ranges, with either elevated or decreased levels of TSH. Thyroid hormones regulate the metabolism of lipids and glucose, and the function of blood vessels and the heart. In clinically pronounced hypothyroidism and hyperthyroidism, significant changes in diastolic and global heart function increase the risk of cardiovascular disease. However, research of subclinical thyroid dysfunction has produced conflicting results and medical opinions. One of the goals of this study was to determine whether subclinical thyroid dysfunction is associated with an aterogenic lipid profile, insulin resistance, and abnormal diastolic and global function of the left ventricle, as well as whether such pathological changes were reversed following levothyroxin replacement therapy. Another goal of this study was to evaluate insulin sensitivity and left ventricle function in subclinical hypothyroidism. Method: The study recruited 47 women with subclinical hypothyroidism, 31 women with subclinical hyperthyoidism, and 45 women of comparable age for the control group. All participants were tested for their hormone levels, lipid status, insulin resistance (evaluated by HOMA index), and heart function (evaluated via echocardiogram, using pulsed tissue Doppler imaging). Patients with subclinical hypothyroidism received levothyroxin replacement therapy, and underwent testing one year after their TSH levels reached reference range. Results: Relative to the control group, patients with subclinical hypothyroidism had elevated levels of cholesterol (6±1 mmol/l vs. 5±0.96 mmol/l) and LDL-C (3.8±0.93 mmol/l vs 3±0.9 mmol/l). Insulin resistance determined by HOMA-IR was found in patients with subclinical hypothyroidism (2±1.03) and subclinical hyperthyroidism (1.71±0.97). Patients with subclinical hypothyroidism had decreased diastolic function of the left ventricle, as determined by the E/A ratio (1.15±0.17), which improved after 1-year levothyroxin replacement therapy (1.3±0.18). The Tei index, which indicates global function of the left ventricle, improved in these patients after the 1-year therapy (0.52±0.08 vs. 0.46 ±0.07)...