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Deep Venous Thrombosis

Deep Venous Thrombosis (DVT) is common, and internal medicine and family practice physicians commonly diagnose and appropriately treat this condition without specialist consultation.  However, there are many complex and unresolved issues associated with the evaluation and therapy, including the following:

Should a hypercoagulable workup be performed?  This is probably the most common question we hematologists receive; the answer has been in flux and varies from hematologist to hematologist.  Often the main reason I perform a workup is to convince a patient with an unprovoked DVT (especially proximal) to remain on anticoagulation (AC) for life, as the recurrence rate off coumadin broaches 10% per year.  Distal (calf) DVT does not generally require a workup. Unprovoked, recurrent DVT does not usually require workup, because that patient should receive AC for life.  I usually do not recommend workup if there are obvious causes of DVT such as surgery or malignancy. I do not believe one should perform a hypercoaguable workup to determine familial risk, as it is extremely unlikely that an asymptomatic patient with an inherited or acquired thrombophilia would be treated prophylactically (without a personal history of clotting).

How long should patients be treated?  Obviously, this is related to etiology and indication.  I treat distal clots for three month, whether provoked or not. I follow these patients carefully, often with serial scans to document resolution.  In younger patients I treat unprovoked proximal clots indefinitely because the risk of a recurrent clot ranges from 5–10% per year.  For patients with a clot and malignancy, I institute lifelong AC, or at least until the patient is definitively disease free.  There is preliminary data that cancer patients live longer with AC.  Antiphospholipid antibody syndrome patients are treated lifelong, and are at the highest risk of clotting through Coumadin.

What is the role for pharmacologic or surgical thrombectomy?  This is a complicated question of risk versus benefit.  Most physicians agree that an attempt is worthwhile in the setting of phlegmasia cerulea dolens  (massive swelling, pain, cyanosis with impending gangrene). In less severe settings, the benefits are clearly documented and include improved time to resolution of clot, more complete resolution, as well as decreased incidence of disability due to post phlebitis syndrome (significant and disabling long-term swelling).  The disadvantages include risk of bleeding, rare deaths, and the cost of the procedure.  In patients with pain and swelling, a clear and detailed discussion of the risks and benefits is certainly reasonable. 

When will an easy oral anticoagulant therapy be available?Your guess is as good as mine!  Ximelagatran was scheduled for release in the U.S. years ago, but was blocked by the FDA because of an unacceptable rate of liver dysfunction.  We hematologists have been expecting oral direct thrombin inhibitors to be released for years.  Hopefully dabigatran (which is already available in 40 countries) will be released in the U.S. within a year. Expect the cost to be high!  However also expect the ease of administration (no more need for protimes) to result in a blockbuster drug. 

Matthew Sirott, M.D., is a medical oncologist/hematologist with the Diablo Valley Oncology/Hematology Medical Group at the California Cancer and Research Institute in Pleasant Hill. He may be reached at (925) 677-5041 begin_of_the_skype_highlighting              (925) 677-5041      end_of_the_skype_highlighting or visit www.diablovalleyoncology.md.