What is the distance from the Inferior Mesenteric Artery (IMA) to the common iliac arteries for stent placement?

Distance from Inferior Mesenteric Artery to Common Iliac Arteries for Stent Placement

The inferior mesenteric artery (IMA) typically originates from the abdominal aorta approximately 3-5 cm above the aortic bifurcation where the common iliac arteries begin. 1

Anatomical Considerations

The distance between the IMA and common iliac arteries is a critical measurement when planning endovascular interventions, particularly for stent placement. This anatomical relationship has important implications for:

• Preserving mesenteric blood flow
• Preventing bowel ischemia
• Planning appropriate stent landing zones

Key Measurements

Based on the TransAtlantic Inter-Society Consensus (TASC) guidelines:

• The IMA typically originates from the anterior aspect of the abdominal aorta approximately 3-5 cm above the aortic bifurcation 1
• The common iliac arteries begin at the aortic bifurcation and extend distally
• Type A iliac lesions (suitable for endovascular treatment) are defined as single stenoses less than 3 cm of the common iliac artery 1

Clinical Implications

Risk of Bowel Ischemia

When planning stent placement in the common iliac arteries, preserving blood flow to the bowel is critical:

• The IMA provides important collateral circulation to the distal colon
• This becomes especially important when the hypogastric (internal iliac) arteries are compromised
• Studies show that hypogastric arteries make at least as great or slightly greater contribution to IMA back pressure than the middle colic artery 2

Recommendations for Stent Placement

1. Maintain a safe distance from the IMA origin when placing common iliac stents to prevent inadvertent coverage

2. Preserve at least one hypogastric artery when treating common iliac artery aneurysms or ectasia to decrease the risk of pelvic ischemia 1

3. Consider IMA preservation techniques in patients with:

   • Bilateral internal iliac artery occlusion
   • Significant IMA (≥4-5 mm diameter)
   • High risk for bowel ischemia

Special Considerations

In cases where both internal iliac arteries are compromised and the IMA must be preserved:

• Chimney graft techniques for the IMA may be considered in high-risk patients 3, 4
• This approach allows preservation of IMA flow while still treating aortoiliac aneurysmal disease
• Such techniques should be reserved for patients with high risk of bowel ischemia

Pitfalls and Caveats

• Anatomical variations exist: Rare cases of IMA arising from the common iliac artery have been reported 5
• Pre-procedural imaging is essential: CT angiography should be used to determine the exact distance in each individual patient
• Stent coverage of IMA: If unavoidable, assess collateral circulation and consider monitoring for signs of bowel ischemia post-procedure

When planning common iliac artery stent placement, maintaining the 3-5 cm distance from the IMA origin is crucial to preserve mesenteric circulation and prevent potentially serious complications related to bowel ischemia.