It seems that you have a long standing chronic venous insufficiency as a result of DVT. From the description it is not clear if you have had any new attack of thrombosis or if you are giving the details of the residual occlusion of the veins. There are many issues associated with this condition, which need to be addressed. These are mentioned hereunder.
1. That the DVT with residual narrowing is the result of the partial resolution of the Thrombosis. There is never complete recovery of the lumen unless the thrombolytic therapy is instituted within few hours of the occurrence of DVT, which is not the case in most patients as the diagnosis is missed in the early stages which makes the thrombus organised and hence the loss of lumen. The net result is that you have to live with the disability of the CVI (chronic venous insufficiency).
2. Second factor to consider is the root cause of the DVT, considering that you are a 32 years old male and has had DVT for eight years, one has to fully investigated the cause like Thrombotic profile and connective tissue disorder and conditions like anti-phospholytic antibodies. Many times a painstaking search for these conditions can reveal a treatable condition, which may prevent further episodes of DVT and further progression in the disabling effects of CVI. If there is no definite diagnosis then one has to seriously consider long term anticoagulant therapy, particularly as in this case where the vena cava is involved.
3. The third and equally important factor to consider is the management of the side effects and sequelae of the CVI, these should be treated early and that is the only way to keep more serious problems at bay. Lastly that there is no simple answer as to how to treat the DVT. This is a serious condition and should be always suspected or at least kept in mind, diagnosed early investigated thoroughly and treated effectively and even then the residual effects of the DVT and CVI are difficult to avoid.