Clinical relevance of distal deep vein thrombosis.

PURPOSE OF REVIEW: To discuss pros and cons of anticoagulant treatment in the presence of symptomatic distal deep vein thrombosis. RECENT
FINDINGS: Available data are responsible for a lack of consensus regarding treatment of distal deep vein thrombosis.
SUMMARY: One standard diagnostic approach of suspected deep vein thrombosis consists of serial lower limb compression ultrasound of proximal veins. Studies evaluating compression ultrasound limited to the proximal veins performed on two occasions separated by 1 week showed good safety with a pooled estimate of the 3-month thromboembolic events rate of 0.6% (95% confidence interval: 0.4-0.9%) in untreated patients. However, performing two lower limbs compression ultrasound is cumbersome and expensive. Recently, studies using a single complete (proximal and distal) compression ultrasound showed a similar pooled estimate of the 3-month thromboembolic risk (0.3%, 95% confidence interval: 0.1-0.6%) but distal deep vein thrombosis accounted for as many as 50% of all diagnosed deep vein thrombosis in those series. Comparing these studies may suggest that systematically searching for calf deep vein thrombosis potentially doubles the number of patients given anticoagulant treatment without reducing the 3-month thromboembolic risk. Despite these data, many physicians still search for and treat distal deep vein thrombosis in the fear of proximal extension and of pulmonary embolism. However, robust data in favour of anticoagulation for distal deep vein thrombosis are limited. Randomized trials assessing the usefulness of anticoagulation in distal deep vein thrombosis are therefore urgently needed.