Effect of treatment with epoprostenol and endothelin receptor antagonists on the development of thyrotoxicosis in patients with pulmonary arterial hypertension.

Thyroid disease is known to be associated with pulmonary arterial hypertension (PAH). We investigated the prevalence of thyroid disease in patients with idiopathic PAH (IPAH) or heritable PAH (HPAH), and the factors affecting the pathogenesis of thyroid disease. We retrospectively evaluated 59 patients with IPAH or HPAH who had been diagnosed with PAH before the age of 20 years. Thyrotoxicosis was detected in 12 of the 59 patients (6 patients with Graves' disease, 3 with hashitoxicosis, and 3 with silent thyroiditis) after the start of PAH treatment. The proportion of patients who received epoprostenol in the thyrotoxicosis group was significantly higher than that in the euthyroid group (12/12 vs. 27/47, p=0.015). In the 39 patients treated with epoprostenol, the proportion of patients who received combination therapy with epoprostenol and an endothelin receptor antagonist (ERA) in the thyrotoxicosis group was significantly lower than that in the euthyroid group (5/12 vs. 23/27, p=0.016). Logistic regression analysis revealed that thyrotoxicosis development was significantly associated with administration of epoprostenol (odds ratio [OR] 8.22, 95% confidence interval [CI] 1.26-53.74, p=0.028) and non-administration of ERA (OR 5.33, 95% CI 1.29-22.06, p=0.021). The prevalence of thyrotoxicosis was high in patients with IPAH or HPAH. The onset of thyrotoxicosis might be promoted by epoprostenol and inhibited by ERA.