What is a peripheral angiogram and how is it performed?

Peripheral Angiogram: Explanation and Procedure

A peripheral angiogram is an invasive diagnostic imaging procedure that provides detailed visualization of the peripheral arterial system through the injection of contrast material, allowing for accurate assessment of vascular anatomy and identification of stenoses or occlusions that may require revascularization. 1

What is a Peripheral Angiogram?

• A peripheral angiogram (also called catheter angiography) is the reference standard for imaging peripheral arteries, providing a dynamic and accurate depiction of the peripheral vascular system 1
• It involves the insertion of a catheter into an artery, typically through the groin, followed by injection of contrast material to visualize blood vessels under X-ray guidance 1
• Digital subtraction angiography (DSA) enhances the ability to visualize vessels that are poorly opacified and permits multiple views while minimizing contrast dose 1
• It allows for visualization of the arterial lumen even in the presence of densely calcified arteries, especially in below-knee segments 1

How is a Peripheral Angiogram Performed?

Pre-procedure Preparation

• A complete vascular examination and medical history should be obtained to optimize decisions regarding access site and minimize contrast dose 1
• Patients with baseline renal insufficiency should receive hydration before undergoing contrast angiography 1
• For patients with renal insufficiency (creatinine >2.0 mg/dL), pre-treatment with n-acetylcysteine may be considered 1
• A history of contrast reactions should be documented and appropriate pretreatment administered if necessary 1

Procedure Steps

1. Access site selection: The femoral artery is the most common access site, though other sites may be used depending on the area being examined 1
2. Catheter insertion: After local anesthesia, a needle is used to access the artery, followed by insertion of a guidewire and catheter 1
3. Selective catheterization: Selective or superselective catheter placement is performed to enhance imaging, reduce contrast dose, and improve sensitivity and specificity 1
4. Contrast injection: Iodinated contrast material is injected through the catheter while X-ray images are taken 1
5. Image acquisition: Multiple views, including oblique projections, are obtained to visualize the arterial system without vessel overlap 1
6. Digital subtraction: Digital subtraction techniques are used to remove bone and soft tissue from the images, highlighting only the contrast-filled vessels 1
7. Pressure measurements: When the significance of an obstructive lesion is ambiguous, transstenotic pressure gradients and supplementary angulated views should be obtained 1

Post-procedure Care

• The catheter is removed and pressure is applied to the puncture site to prevent bleeding 1
• Patients are monitored for several hours after the procedure 1
• Follow-up clinical evaluation, including physical examination and measurement of renal function, is recommended within 2 weeks after contrast angiography to detect delayed adverse effects 1

Clinical Applications

• Peripheral angiography is indicated when revascularization is being considered for patients with functionally limiting claudication or critical limb-threatening ischemia 1
• It provides essential information about arterial anatomy for planning endovascular or surgical interventions 1
• It allows for simultaneous diagnosis and treatment during the same procedure 1
• It should not be performed solely for anatomic assessment in patients with confirmed PAD when revascularization is not being considered 1

Advantages and Limitations

Advantages

• Provides high-resolution, real-time imaging of the arterial system 1
• Allows for dynamic assessment of blood flow 1
• Enables immediate intervention if necessary 1
• Permits pressure gradient measurements across stenoses 1

Limitations

• Invasive procedure with risks of bleeding, infection, vascular access complications, atheroembolization, and contrast reactions 1
• Requires ionizing radiation 1
• Potential for contrast-induced nephropathy, especially in patients with baseline renal dysfunction 1
• Below-knee vessels may be difficult to identify by digital subtraction angiography 1
• Multiple projections may be necessary to visualize eccentric lesions 1

Alternative Imaging Modalities

• Duplex Ultrasound: Non-invasive, no radiation or contrast, but operator-dependent and may have limited visualization of certain vessels 1
• CT Angiography (CTA): Offers volumetric imaging with extensive post-processing capabilities but requires iodinated contrast and radiation exposure 2
• MR Angiography (MRA): Provides excellent soft tissue contrast without radiation but may be contraindicated in patients with certain implants or severe renal dysfunction 3, 4

When to Choose Peripheral Angiography vs. Non-invasive Imaging

• Non-invasive imaging modalities (MRA, CTA, duplex ultrasound) may be used before invasive imaging to develop an individualized diagnostic plan 1
• Peripheral angiography is preferred when immediate intervention is anticipated 1
• For patients with severe renal dysfunction where contrast dose for invasive angiography would be lower than that required for CTA, diagnostic catheter angiography may be preferred 1