Venous insufficiency- Signs and symptoms vein veins blood flow interruption venous system valve incompetence reflux venous obstruction venous return backflow blood hypertension hydrostatic transmural pressure in postcapillary vessels capillary dilatation vessel permeability extravasation RBCs interstitial hemoglobin released degraded hemosiderin deposits hemosiderosis brown discolouration high pressure superficial venous circulation varicose veins tortuous dilated superficial veins distended veins compress somatic nerves achy pain protein-rich exudate edema peripheral ankle edema tissue perfusion metabolic exchange stasis dermatitis dermal fibrosis lipodermatosclerosis fibrotic thickened skin pruritus chronic inflammation risk of thrombus local ischemia embolus skin integrity venous ulcer risk of infection Adderley gagnon Waechter