Guidelines for Anticoagulation Therapy for Secondary Prevention After Deep Vein Thrombosis
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The following questions were submitted by viewers and answered by the presenters, Robert McBane, MD from the Division of Hematopathology at Mayo Clinic in Rochester, Minnesota. Questions are presented as submitted (unedited).
What are the follow up parameters, and when, in both DVT and PE after the 3 months of warfarin therapy?
Beyond what was discussed in the session, I always obtain an ultrasound of the leg veins involved in the thrombotic process. This helps to redefine the baseline venous anatomy against which to compare in the future if the patient develops signs or symptoms of DVT in the same limb. It can be very difficult to diagnose acute or chronic DVT by ultrasound especially if you don’t have an interval study to document the degree of resolution (or lack thereof). In contrast, I do not repeat CT imaging of the chest if the patient had suffered a PE as this is often low yield and requires radiation exposure. Most patients will resolve their PE rather promptly over time. This is not true for DVT of the leg which can be very slow to resolve.
It is also very important to talk with the patient and review their experience while on warfarin therapy to determine whether the treatment was complicated (fluctuating INRs, difficult to attain time in the therapeutic range, bleeding complications) as this will help the health care provider determine the risk of continued therapy versus the benefits.
At 3 months is a good time to perform thrombophilia testing if not previously performed. The impact of the thrombus on plasmatic variables should have resolved by this time.