EHIT Class (Endothermal Heat-Induced Thrombosis)
The classification of endothermal heat-induced thrombosis (EHIT), from the American Venous Forum and Society for Vascular Surgery 2021 consensus revising Kabnick 2006.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- How far the thrombus extends
- Propagation into the adjacent deep vein, occupying more than 50…
Result: EHIT Class III: more than 50 percent of the lumen, not occlusive.
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Class Ia
- No propagation into the deep vein, peripheral to the superficial epigastric vein. No treatment or surveillance suggested.
- Class Ib
- No propagation into the deep vein, central to the superficial epigastric vein. This is exactly the original 2006 class I.
- Class II
- Propagation occupying less than 50 percent of the deep vein lumen. No treatment suggested, with weekly surveillance.
- Class III
- More than 50 percent of the lumen, not occlusive. Therapeutic anticoagulation with weekly surveillance is recommended.
- Class IV
- Occlusive deep vein thrombus contiguous with the treated vein. Treatment is recommended to be individualized.
- Not Lawrence
- The separate six-level Lawrence system collapses its levels 1 to 3 into class I here, so a Lawrence level 3 is not a class III.
What you enter
- How far the thrombus extends.
Full field descriptions
- How far the thrombus extends. A bare "I" is not accepted - choose Ia or Ib, where Ib is the original 2006 class I [Ia = Thrombus without propagation into the deep vein, peripheral to the superficial epigastric vein. Ib = Thrombus without propagation into the deep vein, central to the superficial epigastric vein, up to and including the deep vein junction. II = Propagation into the adjacent deep vein, occupying less than 50 percent of the deep vein lumen. III = Propagation into the adjacent deep vein, occupying more than 50 percent of the lumen, but not occlusive. IV = Occlusive deep vein thrombus contiguous with the treated superficial vein.]
How this is calculated
Kabnick LS, Sadek M, Bjarnason H, et al. Classification and treatment of endothermal heat-induced thrombosis: recommendations from the American Venous Forum and the Society for Vascular Surgery. J Vasc Surg Venous Lymphat Disord. 2021;9(1):6-22. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.