From the Guidelines
Angiography should be performed promptly for a patient with an ankle-brachial index (ABI) of 1.5 and a non-healing ulcer, as this combination suggests medial arterial calcification and potential peripheral arterial disease (PAD) that requires further evaluation. An ABI of 1.5 is abnormally high and typically indicates vessel non-compressibility due to calcification, which can mask underlying arterial obstruction, particularly in patients with diabetes or chronic kidney disease 1. The presence of a non-healing ulcer alongside this elevated ABI is concerning for critical limb ischemia that requires immediate vascular assessment.
Key Considerations
- The patient's elevated ABI and non-healing ulcer require prompt evaluation to determine the presence and severity of PAD, as the high ABI may indicate non-compressible arteries due to calcification 1.
- The preferred angiographic method would be computed tomography angiography (CTA) or magnetic resonance angiography (MRA), though conventional digital subtraction angiography may be necessary if revascularization is anticipated.
- While awaiting angiography, the patient should receive optimal wound care including debridement, infection control with appropriate antibiotics if infected, pressure offloading, and moisture balance.
- The angiography will help determine if revascularization procedures such as endovascular therapy or bypass surgery are needed to improve blood flow and promote ulcer healing, potentially preventing limb loss 1.
Rationale
The decision to perform angiography is based on the latest guidelines from the American College of Cardiology/American Heart Association, which recommend prompt evaluation and treatment of patients with suspected PAD and critical limb ischemia 1. The patient's elevated ABI and non-healing ulcer meet the criteria for further evaluation, and angiography is the most appropriate next step to determine the presence and severity of PAD.
Management
The patient should receive optimal wound care while awaiting angiography, and the results of the angiography will guide further management, including potential revascularization procedures. The goal of treatment is to improve blood flow and promote ulcer healing, potentially preventing limb loss.
From the Research
Angiography with Elevated Ankle-Brachial Index (ABI) and Non-Healing Ulcer
- An elevated ABI of 1.5 may indicate non-compressible vessels, which can lead to false negative results 2
- In patients with non-healing ulcers, it is essential to assess peripheral artery disease (PAD) accurately
- The toe-brachial index (TBI) can be a useful diagnostic tool in patients with non-compressible vessels, as it can provide valuable information when diagnosing PAD 3
Diagnostic Criteria for PAD
- An ABI < 0.9 is generally considered diagnostic of PAD, while an ABI > 1.3 may indicate non-compressible arteries 2
- A TBI < 0.8 has a negative predictive value for PAD of 0.99, and a TBI < 0.6 has a positive predictive value for PAD of 0.95 3
- Continuous wave Doppler (CWD) has been shown to have high sensitivity and specificity for detecting PAD in patients with and without diabetes 4
Clinical Utility of ABI and TBI in Diabetic Foot Ulcer Patients
- Both ABI and TBI can be used as screening tests for PAD in diabetic foot ulcer patients, with TBI being particularly useful in patients with non-compressible vessels 5
- The duration of diabetes and treatment of ABI were found to be significant factors related to the diagnosis of PAD in diabetic foot ulcer patients 5
- Angiography may be considered in patients with non-healing ulcers and elevated ABI, as it can provide detailed information about the vascular anatomy and help guide treatment decisions 6