In pulmonary hypertension (PH), upregulated signaling by ActRIIA ligands, such as myostatin, activin A and GDF11, activates SMAD2/3 mediated pathways that drive pulmonary vascular remodeling and right ventricular dysfunction. Therapeutic blockade of these ligands using ligand traps such as sotatercept improves vascular remodeling and ameliorates PH pathology.