APLNR and pulmonary arterial hypertension: The G protein‐coupled apelin receptor (Alexander et al., 2017) is emerging as a novel therapeutic target for pulmonary arterial hypertension (PAH; Yang, Maguire, & Davenport, 2015) with evidence of the beneficial effect of enhancing apelin receptor signalling in PAH, supported by a small number of studies from PAH patients and animal models.