management and prevention of calf vein thrombosis
Thank you for your question about the treatment of calf vein
thrombosis. The issue of whether or not to treat calf vein thrombosis is
I think that the majority of calf DVT should be treated for the
(1) Calf vein DVT can propagate to the popliteal and femoral veins
causing damage to the veins and venous valves with the subsequent risk of
significant pulmonary embolus and venous incompetence
(2) There have been many case reports published where a patient who
has been diagnosed with a calf DVT has died of a pulmonary embolus. It is
possible in these cases that whatever risk factors caused the calf DVT
also caused a pelvic vein thrombosis which is the cause of the sudden
death, rather than the small below knee DVT
(3) Even small calf vein DVT can cause significant pain and swelling.
Treatment with anticoagulation can quickly relieve pain
My policy is that if patients have an obvious risk factor which has
caused the below knee DVT and the risk factor is still present then I
recommend anticoagulation. I would always treat calf vein DVT in patients
Patients with malignancy
Patients with leg in cast
Post-operative patients who are not fully mobile
I have explained the issues involved to many patients with a calf
vein DVT and almost everyone has elected to be treated with warfarin.
I have been involved in the outpatient treatment of DVT for the past
7 years and have seen many patients with a below knee DVT. In virtually
all cases there has been an obvious risk factor which is still present. I
can only recall a small number of patiets who were not treated and some of
these patients returned the following day because the pain was getting
worse and were subsequently treated with anticoagulation.
Patients with an untreated below knee DVT could have serial
ultrasound scans to check that the thrombus is not propagating but I have
never adopted this practice.
Using aspirin for calf vein DVT is also an interesting idea. Although
some centres may use aspirin in patients with below knee DVT I have not
had experience myself using aspirin.
Although there is evidence that aspirin can prevent pulmonary
embolism and DVT in high risk patients , I am not aware of any study
that has evaluated the use of aspirin in treating below knee DVT. I would
prefer to use warfarin initially, if only for 6 weeks.
Although there has been a lot of publicity about using aspirin prior
to air travel I am not aware of any study evaluating the use of aspirin in
preventing DVT in low risk patients. It is possible that if millions of
airline passengers took aspirin every year the small increased risk of
gastro-intestinal bleeding may outweigh any potential benefit of aspirin.
In high risk patients on long haul flights (eg patients with previous
DVT) I would recommend self injection of low molecular wight heparin
rather than aspirin (although there is no license for this indication in
 Pulmonary Embolism Prevention (PEP) Trial Collaborative Group.
Prevention of pulmonary embolism and deep vein thrombosis with low dose
aspirin: Pulmonary Embolism Prevention (PEP) trial. The Lancet
 Antiplatelet Trialists' Collaboration. Collaborative overview of
randomised trials of anti-platelet therapy-III: Reduction in venous
thrombosis and pulmonary embolism by antiplatelet prophylaxis among
surgical and medical patients. BMJ 1994;308:235-246.
I have been reimbursed by Pharmacia, the manufacturers of Fragmin, for attending a conference
Competing interests: No competing interests