What I can conclude from your statement is she is suffering from Primary Pulmonary Hypertension
. It is not related to hypothyroidism
. There will be an increase in the pulmonary artery
(the blood vessels in the lungs) pressure because of no reason. Because of that, patient will have valve leak as a back pressure. Subsequently the right side of the heart gets enlarged.
By doing cath study she can be assessed weather she will improve with medication or not. there is no permanent cure but symptoms can be controlled with medication.