Summary
The standard diagnostic approach of suspected deep vein thrombosis (DVT) is serial
lower limb compression ultrasound (CUS) of proximal veins. Although it only assesses
the proximal veins, withholding anticoagulant treatment in patients with a negative
CUS on day one and after one week has been proven to be safe. However, in many centres,
distal DVT is systematically screened for and treated by anticoagulants. The objectives
of the review were 1) to evaluate the rate of extension of distal DVTs to proximal
veins 2) to compare the safety of proximal limited CUS versus single complete CUS.
We performed a MEDLINE search covering the period from January 1983 to January 2005
by using the key-words “calf vein thrombosis”, “distal thrombosis” and “compression
ultrasonography”. English, German and French language original studies were retrieved.
Moreover, references of retrieved articles were screened in order to detect missed
pertinent articles. We pooled data of management studies where proximal or complete
(i. e. proximal and distal) CUS were used, respectively. Studies evaluating CUS limited
to the proximal veins showed a good safety profile with a pooled estimate of the 3-month
thromboembolic rate of 0.6% (95% CI: 0.4–0.9%) in patients in whom anticoagulation
was withheld. Studies using proximal and distal CUS showed a similar pooled estimate
of the 3-month thromboembolic rate (0.4%, 95% CI: 0.1–0.6%) but distal DVT accounted
for as many as 50% of all diagnosed DVTs in those series. Therefore, searching for
distal DVT potentially doubles the number of patients given anticoagulant therapy
and entails a risk of over-treatment. Data suggesting that anticoagulation is indicated
for distal DVT are limited, and realizing distal CUS entails a risk of over-treatment.
There is an urgent need for randomised trials assessing the usefulness of anticoagulant
treatment in distal DVT.
Keywords
Calf thrombosis - distal deep vein thrombosis - compression ultrasonography - proximal
deep vein thrombosis