The types of operative repairs may involve VSD clo- sure, right ventricle to-PA conduit placement, recon- struction of the pulmonary arteries, and replacement of the truncal (neoaortic) valve. Unifocalization of the pulmonary arteries may be necessary in very complex cases. The aorta may be dilated. Recommendations regarding assessment and management of truncus arteriosus can generally be inferred in the recommen- dations for the specific components, including right ventricle to-PA conduit, VSD, aortic valve disease, and aortopathies. 4.4.5. Double Outlet Right Ventricle Double outlet right ventricle is an anatomic descrip- tor that includes abnormalities similar to TOF in some patients (when the aorta is closely related to the VSD) and similar to d-TGA with a VSD in others (when the PA is more closely related to the VSD than the aorta). Repairs are predicated on the underlying anatomy and may involve VSD closure with relief of PS, right ventricle to-PA conduit, or Rastelli-type repair. In se- vere cases, single-ventricle physiology may be present. Consequently, recommendations for the management of a patient with double outlet right ventricle can gen- erally be inferred in the recommendations for the le- sion with the most similar anatomy and physiology (eg, TOF can reasonably be based on the recommen- dations in Section 4.4.1, recognizing that a patient with double outlet right ventricle is more likely to have residual LVOT obstruction). 4.4.6. Severe PAH and Eisenmenger Syndrome 4.4.6.1. Severe PAH Recommendations for Severe PAH Referenced studies that support recommendations are summarized in Online Data Supplement 49. 