Depending on the cause, a few things may be done to lower the risks of developing recurrent blood clots. Measures may include avoiding the use of oral contraceptives if you have other inherited or acquired risk factors and avoiding situations that cause prolonged immobilization.
Regardless of the cause, the treatment for the presence of a blood clot (acute thrombosis) is often fairly standard. It usually consists of short-term treatment with the anticoagulant heparin (or, more commonly, low-molecular weight heparin), followed by an overlap of treatment with heparin and warfarin (COUMADIN®), another anticoagulant, followed by several months or longer of warfarin therapy. During this treatment regimen, laboratory tests are used to monitor the effectiveness of therapy:
- Unfractionated (standard) heparin is monitored using the PTT test or occasionally heparin anti-Xa assay.
- Low molecular weight heparin (LMWH) is monitored with the heparin anti-Xa test.
- Warfarin therapy is monitored with the PT/international normalized ratio (INR) or occasionally factor X assay.
After several months of warfarin, a doctor will evaluate the risk of clot recurrence. The doctor must weigh the risk of recurrent clotting against the very real risk of bleeding episodes with continued anticoagulation. If someone is at a high risk of recurrent clotting, anticoagulant therapy may be continued indefinitely. If a person is at a lower risk, the anticoagulant will most likely be discontinued, but the person will need to be vigilant, going back to the doctor promptly if thrombotic symptoms return.
Those who are on continued anticoagulant therapy will have to plan ahead, with the help of their doctor, when they require medical procedures and surgeries. These usually involve taking the person off of their anticoagulant for a short period of time prior to their surgery. However, current recommendations suggest that warfarin does not need to be held for dental procedures.
Following surgery, most people, including those with no known clotting disorders, will receive a course of preventative anticoagulation therapy. This is especially true after procedures such as knee replacement surgery that may increase a person's risk of clotting, either because of the nature of the surgery itself or because of immobilization and an extended recovery after the surgery.
Women who are pregnant and have a blood clot will usually receive subcutaneous anticoagulation with low-molecular weight heparin. People who have antithrombin deficiencies may benefit from antithrombin factor replacement when they cannot take anticoagulant therapy (for example, around the time of surgery). Protein C concentrates can be used to temporarily replenish protein C deficiencies, and aspirin therapy (which affects platelet function) may be useful in some instances.