EDN1 and pulmonary arterial hypertension: Several additional biochemical markers, including BNP, TNT, ET-1, and CRP, have been proposed, (Nagaya et al., 1999; Leuchte et al., 2007; Castillo-Martínez et al., 2016; Kylhammar et al., 2018), but serum UA may be superior in that it performs as a predictor of the disease severity and mortality of patients with PAH-CHD over long-term follow-up.