The cause of chronic pulmonary heart disease is mainly due to increased pulmonary vascular resistance, which increases the contraction force required for the right heart to eject blood to the outside. The peripheral blood in the human circulation eventually flows back to the right heart. In patients with pulmonary heart disease, the right heart is not fully functional and the ejection capacity is reduced, causing more residual blood in the ventricle and obstruction of peripheral blood return, resulting in bilateral lower limb edema. Patients with right heart insufficiency not only have hypertrophy and enlargement of the right heart, but also may have edema of both lower extremities, and even generalized edema and peritoneal effusion, which may also be accompanied by water and sodium retention.