Assessment of Thyroid Function in Idiopathic Pulmonary Hypertension

BACKGROUND: Idiopathic pulmonary hypertension (IPAH) is a rare, debilitating, and fatal disease. Late-onset treatment can lead to right heart failure, multiple organ damage, and death. Since the thyroid plays a major role in the metabolism and hemodynamics in humans, the screening of thyroid function is crucial. Thyroid dysfunction has been reported to cause pulmonary hypertension, but the thyroid is also involved in IPAH. OBJECTIVES: The aim of this study was to evaluate thyroid function in IPAH patients. PATIENTS AND METHODS: Fifty-three IPAH patients aged 16 - 75 years-old were enrolled in this cross sectional study, and their right ventricular functions, hemodynamics, and six minute walk tests (SMWTs) were evaluated. Thyroid function tests were conducted, and their associations with the patients’ pulmonary arterial pressures (PAPs) and functional capacities were assessed. The data were analyzed using the SPSS 15 statistical software. RESULTS: In this research, 84.8% of the participants were women. The mean PAP was 51.6 mmHg (31-87) and mean thyroid stimulating hormone (TSH) level was 4.2 mIU/ml (0.7 - 10). Subclinical hypothyroidism was detected in 26 patients (49.1%). There were significant correlations of the TSH level with the right ventricular (RV) end diastolic dimension (P value = 0.05) and triiodothyronine (T3) with the tricuspid annular plane systolic excursion (TAPSE) (P value = 0.04), an inverse relationship between the SMWT and the TSH level (P value = 0.004), but no significant relationship between these parameters and the thyroxine (T4) level. CONCLUSIONS: IPAH is associated with subclinical hypothyroidism and low patient functional capacity, and is more common in RV failure.