The effect of L-thyroxine treatment on ventricular dysfunction and pulmonary arterial stiffness in patients with subclinical hypothyroidism

OBJECTIVE: In our study, we aimed at evaluating the change in biventricular functions and pulmonary arterial stiffness (PAS) in patients with subclinical hypothyroidism (SH) in whom euthyroidism was achieved with L -thy-roxine therapy.PATIENTS AND METHODS: 70 SH patients and 75 healthy volunteers were included in our study consecutively. Baseline demographic and echocardiographic data of the participants were recorded. The data obtained in the control eval-uation 6 months after the euthyroidism were achieved in the SH group patients started on L-thyroxine treatment and then compared with the baseline measurements.RESULTS: The mean age of patients in the SH group was 44.1 +/- 9.4 years and 47.1% were wom-en. Euthyroidism in SH patients was achieved with a mean daily L-thyroxine treatment of 59 mu g/day for a mean of 16.1 +/- 4.5 weeks. Positive changes in metabolic and hormonal profiles were achieved after L-thyroxine treatment in SH patients. It was determined that left ventricular and right ven-tricular isovolumetric relaxation and myocardial performance index were higher in SH patients compared to the control group, and these mea-surements were observed to decrease significant-ly with L-thyroxine treatment (p < 0.05 for each). While PAS was 16.9 +/- 3.1 kHz/ms in the control group, it was 25.2 +/- 5.3 kHz/ms in the SH group (p < 0.05). After L-thyroxine treatment, PAS measure-ments decreased to 17.2 +/- 3.2 kHz/ms (p < 0.05) in the SH group and showed a positive change. Thyroid-stimulating hormone (TSH) change (Delta TSH) with Delta EJA ratio (r:-0.407, p < 0.001), right ventricular myocardial performance index (Delta RV MPI) change (r: 0.404, p < 0.001) and PAS change (Delta PAS) (r: 0.458, p < 0.001) found to be correlated.CONCLUSIONS: SH is associated with dys-function in the biventricular and pulmonary vas-cular bed. Biventricular functions and PAS change positively in SH patients with L-thyroxine treatment.