Investigation of aortic stiffness and augmentation index in patients with subclinical hyperthyroidism

Objective: Subclinical hyperthyroidism is defined as a condition in which serum thyroid stimulating hormone levels are below the reference range and serum free thyroid hormone levels are within the normal reference range. It is known that subclinical hyperthyroidism is associated with cardiovascular disorders such as increased atrial fibrillation and deterioration in diastolic functions. The leading cardiovascular disease is large artery diseases. In this study, we aimed to investigate the relationship between subclinical hyperthyroidism and large artery diseases, which are the precursors of cardiovascular mortality and morbidity, with aortic stiffness and augmentation index values. Methods: Our study was conducted prospectively on 46 patients with subclinical hyperthyroidism and 51 euthyroid control group individuals who applied to the Endocrinology and Metabolic Diseases outpatient clinic of Necmettin Erbakan University Faculty of Medicine Hospital between December 2022 and May 2023 and voluntarily agreed to participate in the study. Demographic data, laboratory values, and pulse wave velocity and augmentation index values determined by the 24-hour TA Holter device of those included in the study were examined. Results: In our study, pulse wave velocity values of patients in the subclinical hyperthyroidism group were found to be higher than those in the euthyroid control group, creating a statistically significant difference(p=0,031). On the other hand, the difference between the groups in terms of augmentation index of the subclinical hyperthyroidism and euthyroid control groups were not statistically significant (p = 0.501). Conclusion: This study shows that awareness of aortic stiffness, which is a predictor of cardiovascular mortality and morbidity, should be raised in the patient group with subclinical hyperthyroidism, patients should be evaluated together with other cardiovascular risk factors, and subclinical hyperthyroidism treatment should be arranged taking these risks into consideration. Keywords: Subclinical hyperthyroidism, pulse wave velocity, cardiovascular disease