Diagnosing PAD on Diabetic Patients

Peripheral Arterial Disease (PAD) is more common in patients with diabetes, and around half of patients with a diabetic foot ulcer have coexisting PAD1-3. PAD is defined as any atherosclerotic arterial occlusive disease below the level of the inguinal ligament, resulting in a reduction in blood flow to the lower extremity.

PAD in diabetes is a condition predominantly of the infra‐inguinal vasculature and is distinct from that in patients without diabetes in its characteristics, treatment and outcomes. Identifying PAD among patients with foot ulceration is important because its presence is associated with worse outcomes, such as a slower (or lack of) healing of foot ulcers, lower extremity amputations, subsequent cardiovascular events and premature mortality4,5. Diagnosing PAD is challenging in patients with diabetes, as they frequently lack typical symptoms, such as claudication or rest pain, even in the presence of severe tissue loss1,6,7. Arterial calcification8-10, foot infection, oedema and peripheral neuropathy, each of which is often present with diabetic foot ulceration, may adversely affect the performance of diagnostic tests for PAD.

When clinicians diagnose PAD, they should consider its potential adverse effects on ulcer healing and risk of amputation. For each patient, the clinician should estimate the potential for infection resolution, wound healing and avoidance of amputation by balancing the severity of the perfusion deficit and the perfusion required for good outcomes11. The amount of blood flow required is affected by factors such as the presence of infection, extent of tissue loss and abnormal mechanical loading of the foot during walking.

Diagnosis

Which symptoms and signs (clinical examination) should clinicians examine for in a patient with diabetes in order to identify or exclude Peripheral Artery Disease?

  1. Examine a patient with diabetes annually for the presence of PAD with MESI ABPI MD; this should include, at a minimum, taking a history and palpating foot pulses.
  2. Evaluate a patient with diabetes and a foot ulcer for the presence of PAD with MESI ABPI MD. Determine, as part of this examination, ankle or pedal Doppler arterial wave forms; measure both ankle systolic pressure and systolic ankle brachial index (ABI).

These recommendations are in line with other international guidelines on the management of diabetes, recommending yearly screening for PAD in subjects with diabetes.12  

Symptoms and signs of PAD, such as claudication, absent pulses and a low ABI, were identified as predictors of future ulceration in a recent systematic review.13 

Patients with diabetes and these signs of PAD should be reviewed on a regular basis by a member of a specialist foot care team. Moreover, individuals found to have PAD have an elevated risk of other cardiovascular diseases, necessitating strategies to address these problems as well.14

Up to 50% of the patients with diabetes and a foot ulcer have PAD, and these patients have been consistently shown to be at increased risk for failure to heal the ulcer and lower‐limb loss.4,15 Identification of the patient with PAD is essential to optimise management of the foot ulcer and in undertaking other measures to mitigate cardiovascular risk.16 Patients should be informed that they have PAD and that it confers an increased risk to their foot.

Which diagnostic procedure, alone or in combination, has the best performance in diagnosing or excluding Peripheral Artery Disease in an asymptomatic person with diabetes?

Why Mesi.png

3. We recommend the use of non‐invasive tests to exclude PAD such as MESI ABPI MD.

4. Measuring ABI (with <0.9 considered abnormal) is useful for the detection of PAD. Tests that largely exclude PAD are the presence of ABI 0.9–1.3, toe brachial index ≥0.75 and the presence of triphasic pedal Doppler arterial waveforms.