From the Guidelines
A Computed Tomography Angiography (CTA) runoff should be ordered when evaluating patients with suspected peripheral arterial disease (PAD), particularly those with symptoms like claudication, rest pain, or tissue loss who may require intervention, as it provides detailed anatomical information about arterial blockages from the abdominal aorta down to the feet, helping to determine the location and severity of stenosis or occlusions 1. When considering the use of CTA runoff, it's essential to weigh the benefits of this imaging modality against potential risks, such as contrast-induced nephropathy in patients with renal insufficiency (eGFR <30 ml/min) 1.
Key Indications for CTA Runoff
- Patients with critical limb ischemia, non-healing wounds, or when planning revascularization procedures
- Patients with abnormal ankle-brachial index (ABI) measurements below 0.9, suggesting significant arterial obstruction
- Those with symptoms like claudication, rest pain, or tissue loss who may require intervention
Considerations for CTA Runoff
- CTA runoff is preferred over conventional angiography for initial assessment because it's less invasive while still offering excellent visualization of vessels 1
- However, CTA should be used cautiously in patients with renal insufficiency (eGFR <30 ml/min) due to the risk of contrast-induced nephropathy, and alternative imaging like MRA might be considered for these patients 1
- Proper hydration before and after the procedure helps minimize kidney injury risk when CTA is necessary
Imaging Modalities for PAD
- CTA abdomen and pelvis with bilateral lower extremity runoff with IV contrast is usually appropriate for the initial imaging assessment for revascularization in the setting of lower extremity arterial claudication, and is considered an equivalent alternative to other imaging modalities such as US duplex Doppler, MRA, or arteriography 1
From the Research
Indications for Computed Tomography Angiography (CTA) Run-off
- CTA run-off is indicated in patients with suspected peripheral arterial disease (PAD) and intermittent claudication (IC) to discriminate the underlying causes of IC symptoms 2.
- It is also useful in evaluating acute limb ischemia, a medical emergency that requires rapid diagnosis and treatment 3, 4.
- CTA run-off can help identify vascular, musculoskeletal, and combined causes of IC in patients with suspected PAD, guiding specific therapy 2.
- In patients with critical limb ischemia (CLI), CTA run-off can help determine the feasibility and approach to arterial revascularization 5.
Clinical Scenarios for CTA Run-off
- Patients with acute or chronic intermittent claudication (Fontaine stages I to IIB) 2.
- Patients with suspected peripheral arterial disease (PAD) and signs of lower extremity peripheral vascular disease 4.
- Patients with critical limb ischemia (CLI) and ischemic pain at rest or tissue loss 5.
- Patients with acute limb ischemia, a medical emergency that requires rapid diagnosis and treatment 3, 4.
Benefits of CTA Run-off
- Allows identification of vascular, musculoskeletal, and combined causes of IC in patients with suspected PAD 2.
- Provides a rapid and accurate means to diagnose and grade the extent of vascular disease in the acute care setting 4.
- Helps determine the feasibility and approach to arterial revascularization in patients with CLI 5.
- Can guide specific therapy and improve patient outcomes 2, 3, 4, 5.