Chart 1. Classification system for endothermal heat-induced thrombosis described by Kabnick et al.⁸.

Class	Extension of thrombosis	Treatment
I	Up to the junction of superficial and deep venous systems.	Watchful waiting, with serial ultrasound follow-up.
II	Extends beyond the junction, with a cross-sectional diameter < 50%.	Low molecular weight heparin until resolution of the thrombus, with ultrasound follow-up.
III	Extends beyond the junction, with a cross-sectional diameter > 50%.	Low molecular weight heparin and vitamin k antagonist.
IV	Totally occlusive deep venous thrombosis.	Low molecular weight heparin and vitamin k antagonist.