Pulsatility Index in Carotid Arteries is Increased in Levothyroxine-Treated Hashimoto Disease

Abstract

The aim of this case-control study was to evaluate carotid hemodynamic variables and traditional cardiovascular risk factors in women with Hashimoto thyroiditis (HT). The study group consisted of 31 females with HT on levothyroxine (L-T4) and 26 euthyroid women with HT without L-T4 matched for age and body mass index (BMI) as controls. Carotid intima-media thickness (CIMT), carotid extra-media thickness (CEMT), and pulsatility indexes in common carotid artery (PI CCA) and in internal carotid artery (PI ICA) were measured. BMI, waist circumference, lipid profile, fasting glucose and insulin levels, and parameters of thyroid function [TSH, free thyroxine (FT4) and antithyroperoxidase antibodies (TPOAbs)] were assessed. The study and the control groups did not differ in age, BMI, waist circumference, lipid profile, fasting glucose, and insulin levels. Results are expressed as median (IQR). Treated HT group had higher FT4 levels than nontreated [17.13 (5.11) pmol/l vs. 14.7 (2.27) pmol/l; p=0.0011] and similar TSH [1.64 (2.08) IU/ml vs. 2.07 (3.14) IU/ml; p=0.5915]. PI CCA and PI ICA were higher in the study group than in controls (p=0.0224 and p=0.0477, respectively). The difference remained statistically significant for PI ICA and PI CCA after adjustment for other variables (coefficient=0.09487; standard error=0.04438; p=0.037 and coefficient=0.1786; standard error=0.0870; p=0.0449, respectively). CIMT and CEMT were similar in both groups (p=0.8746 and p=0.0712, respectively). Women with HT on L-T4 replacement therapy have increased PI in common and internal carotid arteries than nontreated euthyroid HT patients. Therefore, it seems that hypothyroidism, but not autoimmune thyroiditis per se, influences arterial stiffness.

Arterial Stiffness in Thyroid and Parathyroid Disease: A Review of Clinical Studies

“…Timing and magnitude of reflected waves was determined by hypothyroidism and improved after replacement therapy, indicating a positive effect on arterial stiffness [ 40 ]. Other studies focused on biomarkers of structural arterial stiffening, as β index [ 25 , 42 , 43 ], pulsatility index in carotid arteries [ 44 ] or brachial-ankle PWV [ 21 ]. One large study conducted in a large population, with brachial-ankle PWV, did not find a significant difference between hypothyroid and euthyroid subjects, which adds heterogeneity in the results [ 45 ].…”

“…One large study conducted in a large population, with brachial-ankle PWV, did not find a significant difference between hypothyroid and euthyroid subjects, which adds heterogeneity in the results [ 45 ]. More recently, studies that evaluated the gold-standard measure of aortic stiffness, the carotid-femoral PWV [ 33 , 44 ] or the heart-femoral PWV [ 35 ], found an increase in arterial stiffness markers in patients with overt hypothyroidism.…”

Clinical application of pulsatility index

“…PI CCA and PI ICA were both increased in the study group when compared to the controls (p = 0.02 and p = 0.047), while CIMT and CEMT were similar in both groups. The authors concluded, that it was the hormonal imbalance of hypothyroidism that influences arterial stiffness, and not the autoimmune disease process itself, that causes arterial stiffness [48]. In a more recent study by Kalantari [49], he investigated the use of color doppler and gray scale ultrasound on predicting thyroid nodule malignancy.…”

Effect of restoration of euthyroidism on visfatin concentrations and body composition in women

“…Thus, both hypo- and hyperthyroidism significantly alter these processes, resulting in significant changes in body composition ( 7 , 8 ). Moreover, many thyroid disorders are associated with chronic inflammation, with the latter altering systemic response independently of thyroid hormones ( 9 , 10 ).…”