PDE5A and pulmonary arterial hypertension: Sildenafil is a highly selective and potent inhibitor of PDE5A, which has been potentially used in clinical drug therapies for PAH.[49] Increasing number of clinical trials have demonstrated the beneficial effect of sildenafil to improve exercise capacity and hemodynamic parameters in PAH patients.[50, 51, 52] In the present study, we noticed that miR‐30d could directly target PDE5A in PAH, which prompted us to further explore whether miR‐30d could be involved in the protective effect of sildenafil against PAH.