Nakova Valentina Velkoska, Krstevska Brankica, Kostovska Elizabeta Srbinovska, Vaskova Olivija, Ismail Ljubica Georgievska
University "Goce Delchev", Faculty of Medical Science, Clinical Hospital, Shtip, R. Macedonia.
University Clinic of Endocrinology, Diabetes and Metabolic Disorders, Medical Faculty, Skopje, R. Macedonia.
Arch Endocrinol Metab. 2018 Aug;62(4):392-398. doi: 10.20945/2359-3997000000052.
Treatment of subclinical hypothyroidism (ScH), especially the mild form of ScH, is controversial because thyroid hormones influence cardiac function. We investigate left ventricular systolic and diastolic function in ScH and evaluate the effect of 5-month levothyroxine treatment.
Fifty-four patients with newly diagnosed mild ScH (4.2 <TSH < 10.0 mU/L) and 30 euthyroid subjects matched by age were analysed. Laboratory analyses and an echocardiography study were done at the first visit and after 5 months in euthyroid stage in patients with ScH.
Compared to healthy controls, patients with ScH had a lower E/A ratio (1.03 ± 0.29 vs. 1.26 ± 0.36, p < 0.01), higher E/e' sep. ratio (762 ± 2.29 vs. 6.04 ± 1.64, p < 0.01), higher myocardial performance index (MPI) (0.47 ± 0.08 vs. 0.43 ± 0.07, p < 0.05), lower global longitudinal strain (GLS) (-19.5 ± 2.3 vs. -20.9 ± 1.7%, p < 0.05), and lower S wave derived by tissue Doppler imaging (0.077 ± 0.013 vs. 0.092 ± 0.011 m/s, p < 0.01). Levothyroxine treatment in patients with ScH contributed to higher EF (62.9 ± 3.9 vs. 61.6 ± 4.4%, p < 0.05), lower E/e' sep. ratio (6.60 ± 2.06 vs. 762 ± 2.29, p < 0.01), lower MPI (0.43 ± 0.07 vs. 0.47 ± 0.08%, p < 0.01), and improved GLS (-20.07 ± 2.7 vs. -19.55 ± 2.3%, p < 0.05) compared to values in ScH patients at baseline. Furthermore, in all study populations (ScH patients before and after levothyroxine therapy and controls), TSH levels significantly negatively correlated with EF (r = -0.15, p < 0.05), E/A (r = -0.14, p < 0.05), GLS (r = -0.26, p < 0.001), and S/TDI (r = -0.22, p < 0.01) and positively correlated with E/e' sep. (r = 0.14, p < 0.05).
Patients with subclinical hypothyroidism versus healthy individuals had subtle changes in certain parameters that indicate involvement of systolic and diastolic function of the left ventricle. Although the values of the parameters were in normal range, they were significantly different compared to ScH and the control group at baseline, as well as to the ScH groups before and after treatment.The results of our study suggest that patients with ScH must be followed up during treatment to assess improvement of the disease. Some of the echocardiography obtained parameters were reversible after levothyroxine therapy.
亚临床甲状腺功能减退症（ScH）的治疗，尤其是轻度ScH的治疗存在争议，因为甲状腺激素会影响心脏功能。我们研究了ScH患者的左心室收缩和舒张功能，并评估了5个月左甲状腺素治疗的效果。
分析了54例新诊断的轻度ScH患者（4.2＜促甲状腺激素（TSH）＜10.0 mU/L）和30例年龄匹配的甲状腺功能正常的受试者。对ScH患者在首次就诊时以及处于甲状腺功能正常阶段5个月后进行了实验室分析和超声心动图研究。
与健康对照组相比，ScH患者的E/A比值较低（1.03±0.29对1.26±0.36，p＜0.01），E/e' sep.比值较高（7.62±2.29对6.04±1.64，p＜0.01），心肌性能指数（MPI）较高（0.47±0.08对0.43±0.07，p＜0.05），整体纵向应变（GLS）较低（-19.5±2.3对-20.9±1.7%，p＜0.05），组织多普勒成像得出的S波较低（0.077±0.013对0.092±0.011 m/s，p＜0.01）。ScH患者接受左甲状腺素治疗后，与基线时的ScH患者相比，射血分数（EF）更高（62.9±3.9对61.6±4.4%，p＜0.05），E/e' sep.比值更低（6.60±2.06对7.62±2.29，p＜0.01），MPI更低（0.43±0.07对0.47±0.08%，p＜0.01），GLS有所改善（-20.07±2.7对-19.55±2.3%，p＜0.05）。此外，在所有研究人群（左甲状腺素治疗前后的ScH患者及对照组）中，TSH水平与EF（r = -0.15，p＜0.05）、E/A（r = -0.14，p＜0.05）、GLS（r = -0.26，p＜0.001）和S/组织多普勒成像（TDI）（r = -0.22，p＜0.01）呈显著负相关，与E/e' sep.呈正相关（r = 0.14，p＜0.05）。
与健康个体相比，亚临床甲状腺功能减退症患者在某些参数上有细微变化，表明左心室收缩和舒张功能受累。尽管这些参数值在正常范围内，但与基线时的ScH组和对照组以及治疗前后的ScH组相比仍有显著差异。我们的研究结果表明，ScH患者在治疗期间必须进行随访以评估疾病的改善情况。左甲状腺素治疗后，一些超声心动图获得的参数是可逆的。
