Clinical grading of limb venous insufficiency: Grade 0: no visible or palpable signs of venous disease; Grade 1: capillary dilatation, reticular veins, ankle flushing; Grade 2: varicose veins; Grade 3: edema; Grade 4: skin changes due to venous disease, such as hyperpigmentation, eczema, and skin sclerosis; Grade 5: skin changes due to venous disease and healed ulcers; Grade 6: skin changes due to venous disease and ongoing ulcers.