Lower-extremity ulceration is a debilitating phenomenon, not only by itself, but as a symptom of even more serious underlying medical conditions. Peripheral artery disease (PAD) is a good example as it can manifest, if not treated in a timely manner, as arterial insufficiency ulcers, which are particularly difficult and expensive to treat.
Arterial insufficiency ulcers are not the most common type of lower-extremity ulcers as they come in distant second place to venous leg ulcers: the latter represent 72% and the former 10–30% of all cases of leg ulcers. However, what they lack in prevalence, they substitute in treatment difficulty, which is mirrored in the high cost of procedures. A study conducted in the USA on the costs of chronic wound treatments in 2014 revealed that on average the treatment costs 9105 dollars per patient. Treatment of venous ulcers, in contrast, costs only 1252 dollars.
The reason for such a high difference in costs lies in the underlying pathophysiological mechanism: chronic venous disease (CVD) and PAD. CVD is a fairly common vascular disorder that affects up to 83.6% of world population in the 35–65 years age bracket and may manifest as relatively benign conditions like telangiectasias, or more serious ones like chronic venous insufficiency (CVI) and associated venous ulcers. Conversely, in nearly all forms, PAD is a serious and complex cardiovascular disease whose severity and the incidence of adverse outcomes can also be greatly enhanced by comorbid conditions such as diabetes mellitus. Additionally, it is often asymptomatic as only about 10% of patients have typical symptoms (i.e. intermittent claudication). Fortunately, there is an easy and fast way of diagnosing PAD, which is also valuable for differentiating between venous and arterial wounds.
Why is ABI a (necessary) first step in compression therapy?
Both arterial wounds and venous ulcers require treatment, but the exact methods differ greatly for each condition and may even be mutually exclusive. Venous ulcers are usually managed with a combination of bed rest, leg elevation and compression therapy, while more severe cases require surgical intervention. The most used management method is compression therapy, which is usually well tolerated by the patient and prevents occurrence of new venous ulcers. However, it is not without drawbacks: patients with congestive heart failure have difficulty tolerating compression therapy as do those with peripheral neuropathy.
Differentiating between the two types of ulcers solely based on visual appearance and previous diagnosis of CVD or PAD is a reckless and dangerous approach, which can invariably lead to inappropriate treatment and malpractice claims. The ABI measurement is a far better option and has the added benefit of assessing the severity of PAD and the viability of compression therapy.
There are two established methods of measuring ABI, one involving the use of a Doppler probe and a sphygmomanometer, and the other an oscillometric-plethysmographic diagnostic device. The first method is reliable and accurate, but only when performed by a skilled examiner and, even then, may take up to 30 minutes. A diagnostic device working on the oscillometric-plethysmographic principle like MESI ABPI MD or MESI mTABLET ABI is a far better option as it eliminates user error and can perform the measurement in 1 minute.
Regardless of the method used, an ABI assessment is a must when evaluating lower-extremity ulcers and deciding on the use of compression therapy and level of compression. But is this the standard protocol in practice? The answer is unfortunately no. A comprehensive study conducted in the UK found that about 40% of patients with lower-extremity ulcers had not received an ABI assessment or it was unclear whether a recording had been taken. The same study also revealed that at least 31% of patients with venous ulcers included in the analysis were not receiving compression therapy.
Complications arising from misdiagnosis or a lack of diagnosis and subsequent improper treatment are numerous and do not need to be additionally emphasised. What is worth highlighting is the diagnostic value of ABI that goes beyond its usability in diagnosing PAD and wound care. First, it might indicate that the patient has incompressible arteries and requires additional examination like a Toe-Brachial Index (TBI) assessment. Secondly, the ABI is an important indicator of cardiovascular health and can improve the accuracy of cardiovascular risk prediction.
Many patients might have their ABI measured for the first time as a part of compression therapy viability assessment. This is also an excellent opportunity to assess the patient’s overall cardiovascular health, take note of the ABI score and enter the data in the patient’s medical record or immediately send the information to the patient’s personal physician. This is probably not the case in practice as wound care specialists or compression therapy providers might not even have access to the patient’s record or forget to forward the results by other means. An electronic health record (EHR) system with the option of easy sharing of data or even directly integrated in a diagnostic device would eliminate this and many other issues in communication between healthcare professionals.
Formulation of proper lower-extremity ulcer treatment involving compression therapy should invariably include an ABI assessment for diagnosing PAD and evaluating its severity, differentiating between venous and arterial ulcers, and detecting the presence of ulcers of mixed aetiology.