Venous hypertension is caused by venous blood regurgitation or poor venous return, for example, venous hypertension in the lower extremities is caused by incompetence of the saphenous vein valve, and venous blood regurgitates from the top to the saphenous vein through the incompetent valve, which causes venous hypertension in the saphenous vein, which is the cause of primary saphenous vein. Then there is venous return obstruction, for example, deep vein thrombosis in the lower extremity or iliac vein compression, Buga syndrome, right heart insufficiency, pulmonary hypertension, all of which will cause venous return obstruction and a large amount of blood will gather in the lower extremity, which will cause venous hypertension in the lower extremity.