Fact File - Assessing mixed venous and arterial leg ulcers

VOL: 102, ISSUE: 44, PAGE NO: 58

Caroline Dowsett, MSc, Bsc, DipN

nurse consultant, tissue viability, Newham PCT, London

Mixed venous and arterial disease accounts for approximately 13-15% of all leg ulceration (Kippel and Dieppe, 1998; Baker et al, 1991). These ulcers cause considerable pain and distress for patients and pose a difficult wound-management problem for health professionals. Many patients have significant oedema that needs to be controlled but also have some degree of arterial disease where compression bandaging is contraindicated.

Mixed venous and arterial disease accounts for approximately 13-15% of all leg ulceration (Kippel and Dieppe, 1998; Baker et al, 1991). These ulcers cause considerable pain and distress for patients and pose a difficult wound-management problem for health professionals. Many patients have significant oedema that needs to be controlled but also have some degree of arterial disease where compression bandaging is contraindicated.

Aetiology

Venous hypertension occurs in limbs where the venous valves are damaged or where the calf-muscle pump is inactivated. When a person is mobile dorsiflexion of the foot activates the calf-muscle pump which forces venous blood back to the heart but when patients become immobile the calf-muscle pump is inactivated. This leads to increased venous hypertension causing expansion of the capillaries in the lower limbs and blood cells to leak into the tissue resulting in oedema and then ulceration.

Atherosclerosis is the most common cause of insufficient arterial blood supply to the lower limb. It is caused by the deposition of fatty material on the walls of blood vessels which form plagues leading to a narrowing of the lumen of the artery. It may also lead to thrombi, emboli and ischemia (Rose, 1991). Older people usually have some degree of atherosclerosis and the extent of resultant ischemia depends on the site of the occlusion and whether there is an effective collateral circulation.

Assessment

Assessment is the key to effective management of mixed venous and arterial ulcers and should include the past medical history as well as presenting signs and symptoms can help to differentiate between the degree of venous and arterial disease. Diagnosis can be complex, given that these patients present with characteristics of both diseases (Table 1).

It is important to remember that patients who originally present with venous ulceration may develop arterial disease, particularly as they get older (Simon et al, 1994).

All patients presenting with a new leg ulcer should have a full and detailed assessment, as should patients who have a change in their condition during treatment for ulceration (RCN, 1998). Box 1 lists the key components of the assessment.

Table 1. Characteristics of arterial and venous ulcers

Arterial ulcer

Venous ulcer

Cause	Arterial disease	Chronic venous hypertension
Site	Lower foot or toes Often an area of pressure	Gaiter area or medial malleolus
Oedema	Dependent oedema	Greater at end of day
Foot pulses	Absent or diminished	Present
Skin changes	Shiny, pale hairless, cold to touch Blanching on elevation	Warm to touch, brown pigmentation, eczema, ankle flare (visible capillaries around the ankle), varicose veins

Pain	Severe pain, on elevation of the limb and exercise. Intermittent claudication, rest pain	Heavy, aching feeling. Pain with infection and oedema
Appearance of the ulcer	Deep with necrotic base. Tendon or bone visible	Shallow and flat. May have granulation tissue present
Associated past medical history	Peripheral vascular disease, rheumatoid arthritis, diabetes, hypertension	Varicose veins, deep vein thrombosis, multiple pregnancies, family history, trauma to lower limbs

Box 1. Components of assessment

• Past medical history
• Current history
• Mobility
• Nutritional status
• Pain
• Quality-of-life related issues
• Ankle circumference
• Episodes of ulceration
• Ulcer duration
• Ulcer location
• Wound bed type
• Condition of surrounding skin
• Measure ABPI

Vascular assessment

A Doppler assessment should be undertaken to determine the patient's ABPI. It is important to remember that the diagnosis should not be based solely on the results of the Doppler but on the combination of the patient's history, presenting signs and symptoms and the Doppler result.

The Doppler test determines the percentage of arterial blood supply into the limb and can indicate the level of compression that is appropriate for that patient. However, the ABPI reading may not always be reliable, particularly in patients with diabetes or those with calcification of the arteries, who may have a falsely elevated reading.

The European Wound Management (2003) position document, Understanding Compression Therapy, proposes a diagnosis and treatment pathway to guide the practitioner in making a differential diagnosis. This pathway breaks mixed arterial and venous ulcers into two categories:

• Mixed arterial and venous ulcer where there is a moderate degree of arterial insufficiency with an ABPI of 0.5-0.8;
• Mixed arterial and venous ulcer where there is severe arterial insufficiency with an ABPI of <0.5.

Further vascular investigation including a Duplex scan will be carried out to see the extent of arterial occlusion and the appropriateness and type of vascular surgery required. Angioplasty may be given to those who are unfit for bypass surgery.

Treatment

Reduced compression has been shown to be effective in the management of patients with mixed venous arterial ulcers with an ABPI of between 0.5-0.8 (Simon et al, 1996; Moffatt et al, 1992; Stevens et al, 1992). This should be carried out in consultation with a specialist nurse and the vascular team.

Reduced compression effectively applies 15-25mmHg compression (European Wound Management Association, 2003). This can be achieved by omitting a bandage layer in a multi-layer system or by using specific kits that are now available to give reduced compression. The degree of patient tolerance should be closely monitored.

There is also evidence to support the use of short stretch bandages in mixed venous and arterial disease, particularly where patients experience pain at rest or at night, as these bandages apply low pressure to the limb when the patient is resting but higher pressure is exerted on movement (Butcher, 2002; Poore, 1998). For some patients intermittent pneumatic compression therapy will be successful (Vowden, 2001).

Patients need to be monitored regularly for increased levels of pain or a reduction in ABPI. If the patient's pain increases, the ulcer fails to respond or deteriorates, or the ABPI reduces, further investigations should be considered (Anderson and King, 2006).

Management of the wound bed

The wound bed in mixed arterial and venous ulcers is often sloughy, exudative and can become infected. The choice of primary dressing used to cover the wound will be determined by identifying the treatment objective, which may be debridement, moisture balance or infection control.

The skin surrounding the ulcer should be protected with a barrier film, cream or zinc paste bandage strips (Stevens, 2004).

Conclusion

The management of patients with mixed venous/arterial leg ulcers is challenging. Many patients can be successfully managed with reduced compression, however, the decision to undertake this treatment should be based on a detailed assessment, and in consultation with the multidisciplinary team that must include a vascular consultant.

References
Anderson, I., King, B. (2006) Mixed aetiology leg ulcers. Nursing Times; 102: 16, 45-50.

Baker, S.R. et al (1991) Epidemiology of chronic venous ulcers. British Journal of Surgery; 78: 7, 864-867.

Butcher, M. (2002) Managing mixed aetiology leg ulcers. Practice Nurse; 13: 4, 161-166.

European Wound Management (2003)Understanding Compression Therapy.London: MEP.

Kippel, J.H., Dieppe, R.A. (1998) Rheumatology (2nd edn). London: Mosby.

Moffatt C.J, et al (1992) Community clinics for leg ulcers and impact on healing. British Medical Journal; 305:1389-1392.

Poore, S. (1998) How a short stretch can work wonders. Nursing Times; 94: 45, 87-90.

RCN (1998) Clinical Practice Guidelines. The Management of Patients with Venous Leg Ulcers. London: RCN Institute.

Rose, G. (1991) Epidemiology of atherosclerosis. British Medical Journal; 303: 1537-1539.

Simon, D.A, et al (1994) Progression of arterial disease in patients with healed venous ulcers. Journal of Wound Care; 3: 4, 179-180.

Simon, D.A., et al (1996) Community leg ulcer clinics: a comparative study in two health authorities. British Medical Journal; 312: 1648-1651.

Stevens, J.M. et al (1992) A community/hospital leg ulcer service. Journal of Wound Care; 6: 2, 62-68.

Stevens, J.M. (2004) Diagnosis, assessment and management of mixed aetiology ulcers using reduced compression. Journal of Wound Care; 13: 8, 339-343.

Vowden, K. (2001) The use of intermittent pneumatic compression in venous ulceration. British Journal of Nursing; 10: 8, 491-509.