Drs Katz and Rapoport-Glick raise an important issue that has not been addressed in
most clinical trials investigating the treatment of DVT: management of patients who
present with lower limb swelling or pain and are diagnosed with DVT of the distal
(or calf) veins. This issue is seen increasingly in clinical practice with improved
venous ultrasound techniques that can, in many patients, show the distal as well as
the proximal (above-knee) deep venous system.1
Several questions relating to the management of distal DVT deserve comment. First,
should all patients with distal DVT receive anticoagulant therapy, as in patients
with proximal DVT? Second, if anticoagulants are given, what is the optimal duration
of treatment? Third, do such patients warrant additional investigations, such as
looking for thrombophilia or occult cancer, as might be the case in some patients
with proximal and, in particular, unprovoked (or idiopathic) DVT?
In general, patients who have symptomatic DVT, whether proximal or distal, warrant
conventional anticoagulant therapy with low-molecular-weight heparin and
warfarin.2 Without anticoagulant therapy,
patients with symptomatic distal DVT have about a 20% chance that the DVT will
extend into the proximal veins, which could cause life-threatening pulmonary
embolism.3 Furthermore, anticoagulant
therapy helps to alleviate leg pain and swelling that can be severe, even in
patients with less extensive distal DVT. However, in patients with
superficial vein thrombophlebitis that does not involve the
deep veins, initial treatment with a nonsteroidal anti-inflammatory drug or a 2- to
4-week course of a low-dose heparin preparation could be considered.2 There is no consensus on the optimal duration
of anticoagulation for distal DVT, although a 3-month course is reasonable, assuming
that symptoms have resolved and there are no ongoing risk factors for disease
recurrence, such as active cancer or immobility.4
Finally, as to whether further investigation to assess etiology is warranted in such
patients, the key point perhaps is that DVT is a single disease and the same
management principles should apply, whether DVT is proximal or distal. Thus,
thrombophilia testing would be reasonable in patients with unprovoked DVT,
particularly if they are young (<50 years) and have a personal or family
history of venous thromboembolism. A workup for occult cancer would depend on
associated clinical features, such as a change in bowel habits in elderly patients,
which might suggest a tumour site, or the presence of risk factors, such as heavy
smoking.
References
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1.Zierler BK. Ultrasonography and diagnosis of venous thromboembolism. Circulation. 2004;109(12 Suppl 1):19–14. doi: 10.1161/01.CIR.0000122870.22669.4a. [DOI] [PubMed] [Google Scholar]
-
2.Bates SM. Clinical Practice. Treatment of deep-vein thrombosis. N Engl J Med. 2004;351(3):268–277. doi: 10.1056/NEJMcp031676. [DOI] [PubMed] [Google Scholar]
-
3.Lagerstedt CI. Need for long-term anticoagulant treatment in symptomatic
calf-vein thrombosis. Lancet. 1985;2:515–518. doi: 10.1016/s0140-6736(85)90459-3. [DOI] [PubMed] [Google Scholar]
-
4.Büller HR. Antithrombotic therapy for venous thromboembolic disease: the
Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest. 2004;126(3 Suppl):401–428. doi: 10.1378/chest.126.3_suppl.401S. [DOI] [PubMed] [Google Scholar]
