Once a deep vein thrombosis (DVT) has been diagnosed, treatment is based upon anticoagulation therapy. However this is modified by the size and position of the deep vein thrombosis. We do not try to remove the deep vein thrombosis (DVT) surgically from the vein as the surgery to the vein is more likely to damage it than to improve it.
Anticoagulation therapy, initially heparin which is injectable followed by an oral anticoagulant (either warfarin or coumarin), stops any more blood clotting and so stops the deep vein thrombosis (DVT) from extending. However anticoagulation does not actually break any clot down. What anticoagulants do is to allow the body's own immune system to start breaking the deep vein thrombosis (DVT) down by stopping the body from replacing it.
The human body is always in a dynamic state of forming clots and breaking them down. If this is not the case, we would always be bleeding from our bowel, gums and elsewhere in our body. Hence we are always forming little clots to stop bleeding and then breaking them down so blood vessels don't become completely blocked. When we use anticoagulation to stop clots from forming, we alter this balance allowing the body to break down any thrombus or clots without any more forming.
There are other drugs that can actually break down the thrombus or clots. These are called "fibrinolytic agents" - the original one was streptokinase which was superceeded by tissue plasminogen activator (TPA), and now different versions are becoming available. Fibrinolytic agents are very powerful drugs that are often used in the treatment of heart attacks. However, as they break down all clots, there is a risk if too much is given in the wrong area, the patient may start bleeding internally which will put the patient at risk. Therefore the risks of giving fibrinolytic agents are often more than the benefits that might be achieved. Hence these very powerful fibrinolytic agents are rarely used in treating deep vein thrombosis (DVT).
The position and size of the deep vein thrombosis (DVT) affects how aggressively the anticoagulation is given.
If there is only a small deep vein thrombosis in one of the tiny veins in the calf, then many doctors will treat it only with a graduated pressure stocking, exercise and sometimes aspirin or other antiplatelet drug, asking the patient to return within a few days to check that the deep vein thrombosis (DVT) hasn't got any bigger. Other doctors will treat these as any other deep vein thrombosis (DVT) with heparin injections followed by anticoagulation with warfarin or coumarin, usually for a period of three months.
When the deep vein thrombosis (DVT) is in the larger thigh veins or behind the knee, it is clearly bigger and therefore has more symptoms. The potential damage to the vein is also more and so heparin is given immediately on diagnosis and full anticoagulation with warfarin or coumarin for 3 to 6 months is usually recommended.
A deep vein thrombosis (DVT) in the groin or in the pelvic veins is clearly a much larger clot again and is often treated by admission to hospital and immediate intravenous heparin and full anticoagulation.
At this point it is worth noting one of the differences that are starting to appear in the treatment of deep vein thrombosis (DVTs).
Physicians and haematologists have traditionally decided to either treat deep vein thrombosis (DVT) with anticoagulation for three months if small, or six months if larger. Since phlebologists and interested vascular surgeons have been performing more duplex ultrasound
scans and have been seeing not only the deep vein thrombosis but the damage they cause if not completely cleared, there has been a push to start tailoring treatment to the patient.
Research from Prof CV Ruckley from Edinburgh (Scotland) has shown that if a deep vein thrombosis (DVT) forms and it is completely cleared very quickly with full anticoagulation, then the long-term damage to the deep vein and the deep venous valves is minimal or non-existent. However those patients who have damage to the deep veins and deep vein valves have usually had either recurrent deep vein thrombosis' (DVTs) or have had a long-term deep vein thrombosis (DVT) that has not been adequately cleared.
Thus it seems a far more sensible and logical way to treat patients by re-scanning them every three months and only advising the anticoagulation to stop when the veins are found to be completely clear. Being on anticoagulation is not risk-free and there are estimates that being fully anticoagulated causes a risk of a major bleed in 1% of people per year. Therefore the balance between clearing the veins completely but not having the risk of bleeding is best served by re-scanning every three months and stopping anticoagulation when the veins are clear.
Unfortunately this does not fit with most deep vein thrombosis (DVT) treatment guidelines that are currently around, but over the years it is likely that this logical treatment plan will become the norm.
Finally, as you can see from the discussion above, the treatment depends upon knowing how big the deep vein thrombosis (DVT) is and in which veins it is in. This is one of the reasons why although a blood test may be acceptable for screening, it is never acceptable for full planning of treatment. The optimal way of diagnosing people and planning treatment is to have a full duplex ultrasound
scan immediately as soon as possible and treatment recommended by an experienced phlebologist who can then take advice from a haematologist if there turns out to be thrombophilia present in the family.