Amputation Prevention in Black Populations: Tackling Venous Stasis Ulcers
Venous stasis ulcers, or simply stasis, are open wounds that occur around the lower leg or ankle. Venous ulcers are the most common cause of lower extremity ulcerations and affect about 1% of the U.S. population, most being women and older people. With venous ulcers accounting for about 80% of leg ulcers, it is imperative to shed more light on this cardiovascular condition. Below, we take a closer look at the causes, symptoms, risk factors, and treatment options for venous stasis ulcers.
Pathophysiology of Venous Stasis Ulcers
Various physiological processes are associated with the formation of venous stasis ulcers and can thus be considered the common causes of this condition.
Venous ulcers are generally caused by an increase in pressure in the veins due to the malfunction of venous valves. Other factors that contribute to venous hypertension are also considered to be contributors to the formation of venous ulcers. Such factors include superficial and deep vein insufficiencies, deep vein thrombosis, arteriovenous fistulas, perforator insufficiency, and calf muscle pump insufficiencies.
Venous ulcer formation usually arises when venous valves are unable to prevent the backflow of blood, resulting in blood pooling. Also, pressure increase causes the vein walls to stretch, allowing for the leaching of proteins into the subcutaneous tissues. This results in edema.
Fibrin Cuff Theory
According to this theory, intravascular pressure is elevated when there is an excessive deposit of fibrin around the capillary beds. This leads to the enlargement of endothelial pores, leading to further deposition of fibrinogen in the interstitium. The fibrin cuff surrounding the dermal capillaries decreases oxygen and nutrient permeability. Decreased diffusion of oxygen and nutrients leads to tissue hypoxia, resulting in impaired wound healing.
Inflammatory Trap Theory
Severe uncontrolled inflammation may arise when growth factors and inflammatory cells get trapped in the fibrin cuff, leading to the improper regeneration of wounds. When leukocytes get trapped in capillaries, they release proteolytic enzymes and reactive oxygen metabolites that damage endothelial cells.
The injured capillaries allow more macromolecules to permeate, which accentuates the deposition of fibrin. Blockage of capillaries by leukocytes also results in local ischemia, which increases tissue hypoxia.
Dysregulation of Cytokines
Abnormal regulation of growth factors and cytokines that promote inflammation could lead to the chronicity of venous ulcers.
Treatment Options for Venous Stasis Ulcers
Tackling venous stasis ulcers involves the diagnosis and assessment of the various treatment options based on the patient’s needs.
This is the standard of care for chronic venous insufficiency and venous stasis ulcers. One study showed that a treatment plan involving compression therapy resulted in faster healing of venous ulcers than one without. This form of treatment involves various methods, including elastic, inelastic, and intermittent pneumatic compression.
The compression stockings or devices create pressure that counteracts the venous pressure. This reduces pain and edema, improves venous reflux, and promotes faster healing of ulcers.
Inelastic compression therapy mainly involves the use of the Unna boot, which consists of a moist zinc-impregnated gauze that is allowed to harden after application. The Unna boot provides high working pressure during muscle contraction and ambulation. However, it doesn’t provide resting pressure. Due to its inelasticity, the Unna boot doesn’t conform to leg size changes, which may be uncomfortable.
Elastic compression therapy involves methods that conform to changes in the size of the leg. Such methods sustain compression during both activity and rest. Compression bandages and stockings can be used, but elastic wraps don’t provide sufficient pressure and are not recommended.
Intermittent pneumatic compression consists of a pump and inflatable and deflatable sleeves that are filled with air, providing intermittent compression. However, this form of compression therapy requires immobilization and is most applicable to bedridden patients.
It is often used in combination with compression therapy and is regarded as a standard of care. Raising the lower extremities above the heart’s level may help reduce edema, improve microcirculation and delivery of oxygen, and expedite ulcer healing.
Ideally, leg elevation is most effective when performed for thirty minutes, three or four times every day. Despite its efficacy, this treatment duration could be difficult to achieve in real-world settings.
These may be used under compression bandages to prevent the adherence of the bandage to the ulcer and to promote faster ulcer healing. The various types of dressings include hydrocolloids, transparent dressings, hydrogels, pastes, foams, and non-adherent dressings.
Another way of tackling venous stasis ulcers is by using medications. The most prominent is Pentoxifylline (Trental), a platelet aggregation inhibitor that reduces blood viscosity to improve microcirculation. It is an effective adjunctive treatment for venous stasis ulcers when used with compression therapy.
Pentoxifylline is also effective when used as monotherapy in venous ulcer patients who can’t tolerate compression bandaging. Despite its effectiveness, Pentoxifylline has adverse effects, including nausea, diarrhea, vomiting, loss of appetite, and heartburn.
Other medications used as an adjunctive treatment for venous ulcers include aspirin, oral zinc, iloprost, and antibiotics/antiseptics.
Chronic ulcers in lower extremities have poor healing rates, and surgical treatment and management may be an option for patients with venous stasis ulcers that are obstinate to other therapies.
The removal of bacterial burden and necrotic tissue through debridement is a common practice in wound care as it enhances healing. It may be sharp, biologic (using larvae), enzymatic, mechanical, or autolytic. However, purely venous ulcers may not need much debridement due to less necrotic tissue.
Surgery for Venous Insufficiency
Surgical treatment of venous ulcers is aimed at reducing venous reflux, expediting healing, and preventing ulcer recurrence. Surgical options include:
- Endovenous ablation of the saphenous vein
- Stenting for treating iliac vein obstruction
- Subfascial endoscopic surgery
- Phlebectomy for removal of varicose veins
- Laser therapy
Large or refractory venous stasis can be treated using autograft, allograft, or artificial skin. However, persistent edema makes skin grafting ineffective.
Malfunction of venous valves causes an increase in pressure in the veins, which contributes to the formation of venous stasis ulcers. Tackling venous ulcers involves treatment options such as compression therapy, medications and surgical treatment. The choice of treatment option is often guided by the severity of the condition and physician preference.