Arteries clog. why do they never treat clogged veins?

Many veins present: Arterial blockage causes lack of flow, resulting in pain, claudication (tightening of muscle like a cramp) even death of tissue. Opening of the blockage allows resolution of symptoms. Venous blockage results in local pain, redness, swelling over the superficial vein involved. Deep venous thrombosis requires anticoagulation. Many other veins take over the function.