Is It an Arterial or Venous Ulcer?

Although there are several types of ulcers that can develop on the lower extremities, venous and arterial ulcers are the most common. It can be a challenge to tell the difference between the two since they have many similarities. However, it is necessary to identify which one you are dealing with since the treatments are significantly different. At any time from 0.3% to 2% of people will have an active leg ulcer, depending on their age and underlying medical condition. 

The treatment can be complex and expensive. Many factors contribute to the development and chronicity of these wounds, including the origin of the wound, and underlying neuropathy or metabolic disorders. The first step is to determine the type of leg ulcer so your treatment plan has a higher potential for success.

What to Look For

While many wounds will heal without difficulty, arterial and venous ulcers are subject to factors that slow healing and may prevent wound closure, potentially leading to necrosis and amputation. Chronic non-healing wounds are affected by several factors, not the least of which is the blood supply.

Arterial and venous wounds have unique characteristics that offer a clue as to which type of ulcer you are treating. During your assessment, evaluate the wound location on the lower extremity, wound bed, and pain triggers. An accurate assessment of the type of wound leads to more effective wound management but requires an understanding of the underlying physiology and expected reactions from different types of wound dressings. 

If an arterial wound undergoes treatment for a venous ulcer, it is likely to progress and get worse quickly. It is essential assessment is an ongoing process during treatment, and that documentation is detailed and accurate.

Venous Ulcers Originate From an Outflow Problem

The venous system moves blood from the periphery back to the heart and lungs where it can pick up oxygen and get rid of carbon dioxide. In the lower extremity, there are large veins that run parallel with large arteries, but the smaller veins form an irregular network. Inside the veins are small valves that are pushed closed if the blood tries to back up into a vein and flow backward. The valves open as the blood is flowing towards the heart.

Venous hypertension is also called venous insufficiency and may lead to visible varicose veins, swelling in the lower extremities, venous thrombosis, and brown-colored skin near the ankles. Common causes of venous hypertension include: 

• Obesity
• Pregnancy
• Family history
• Lack of exercise
• Smoking
• Phlebitis
• Deep vein thrombosis
• Long periods of standing or sitting increasing the blood pressure in the leg veins
• Calf muscle pump failure

It is helpful to remember that with exercise, the tension in the normal venous system will decrease as a result of the calf muscle pump. As the muscles relax at rest, the valves help prevent reflux, keeping the pressure low. However, incompetent valves can contribute to higher venous pressure, forcing fluid out of the vascular system and into the surrounding tissue. 

A typical location for a venous ulcer is the front of the shin, the pretibial area. The fluid forced out of the veins and into the surrounding tissue contributes to a moist wound bed with minimal to copious exudate. You will likely find granulation tissue in the wound, but impaired venous return slows or stops healing. The patient will have pain with the leg in the dependent position since gravity triggers more fluid loss into the interstitial space and increases swelling. 

Obstructed Blood Delivery Develops Arterial Ulcers

The arterial system delivers oxygen and nutrients to the cells. Arterial insufficiency is caused by an impairment to the blood flow that leads to tissue ischemia and possible necrosis. These ulcers are also called ischemic ulcers because they’re caused by poor perfusion to the lower extremities. As the skin and tissue are deprived of oxygen, the cells die and form an open wound. 

The lack of blood supply can also result in cuts and scrapes that fail to heal and ultimately develop into an ulcer. The most common cause of arterial ulcerations is atherosclerotic disease in the medium and large arteries. Arterial ulcers can also be caused by diabetes, thalassemia, sickle cell disease, and vasculitis. Damage to the arterial system can happen with hypertension, which also reduces blood supply and results in tissue damage. 

Patients with arterial insufficiency in the lower extremities may also suffer with intermittent claudication. This is pain experienced while walking that is relieved by rest. With rest, the arterial system can deliver enough oxygen to relieve the hypoxic tissues. 

While people with venous ulcers experience greater pain when their lower extremity is dependent, people with arterial insufficiency have pain when the leg is elevated above the level of the heart as it becomes more difficult for the blood to be pumped to the lower extremity and the tissues become hypoxic. The extremity is often cool to the touch and you’ll see a decrease in capillary refill. Normal refill is in 3 seconds or less, while refill greater than 4 seconds implies arterial disease.

Arterial ulcers typically show up on the feet, over the toes, heels or bony prominences. The wound bed is usually dry and pale with very minimal exudate as compared to a venous ulcer, where the wound bed is moist, with granulating tissue and can have copious exudate. Although not diagnostic, arterial ulcers may be characterized by a “punched out” wound with well-defined and even margins.

Define and Treat the Ulcer

As you can see, the origin of venous and arterial ulcers is vastly different. The ulcers need different treatments since compression for a venous ulcer to help hemostasis in the lower extremities would contribute to growing tissue hypoxia in an arterial ulcer and may result in necrosis and amputation.

Assessment is a critical part of leg ulcer treatment. In patients who have significant vascular compromise with a mix of venous and arterial insufficiency, treatment options must be thoroughly evaluated for the impact it may have on both systems and customized to the patient. Only through experience can a practitioner become adept at prescribing interventions that correspond with the etiology of the ulcer.

Gayle Morris BSN, MSN, VWCN, is a freelance writer, who has been creating engaging content on health and wellness for more than ten years. She spent over 20 years as a certified nurse and nurse practitioner before hanging up her stethoscope and picking up the pen.  

As a nurse, Gayle cared for patients at Cincinnati Children’s Hospital, Riley Children’s Hospital, Chicago Children’s Hospital (now Lurie Children’s Hospital), and at Methodist Hospital in Indianapolis where she assisted with wound care education and treatment. As a PNP, she worked at Mary Free Bed Rehabilitation Hospital in Grand Rapids, MI. She currently works for Vohra Wound Physicians.