PDE5A and pulmonary arterial hypertension: This question might be relevant because a therapy proven to be effective in the treatment of PH, e.g., phosphodiesterase-5 (PDE5) inhibition by sildenafil [4, 5], generally used as a vasodilator agent to antagonize the vasoconstriction present in pulmonary hypertension, could be extended to treat also the negative effects of pulmonary hypertension such as subsequent hypoxia.