What causes intimal thickening of the celiac artery?

Causes of Intimal Thickening of the Celiac Artery

Atherosclerosis is the primary cause of intimal thickening in the celiac artery, characterized by massive fibrosis, calcification, and accumulation of extracellular fatty acids in the intimal layer. 1

Primary Pathophysiologic Mechanism

Atherosclerotic disease leads to gross thickening of the intima through several interconnected processes:

• The intima develops massive fibrosis and calcification with increased extracellular fatty acid deposition 1
• Histiocytic cells degrade the extracellular matrix, compromising the integrity of the intimal layer 1
• Degenerative changes within fibrous tissue occur, characterized by reduced cellularity and collagen fiber hyalinization 1
• These mechanisms lead to intimal rupture, most commonly at plaque edges 1

Secondary Consequences of Intimal Thickening

The thickened intima creates a cascade of vascular compromise:

• Increased distance between the endothelial layer and media compromises nutrient and oxygen supply to deeper vessel layers 1
• Adventitial fibrosis obstructs vessels feeding small intramural vasa vasorum 1
• Reduced nutritional supply causes medial thinning secondary to smooth muscle cell necrosis 1
• Fibrotic changes develop in the elastic structures of the medial layer 1
• These changes increase vessel stiffness and vulnerability to shear stress 1

Age-Related Progression

Intimal thickening in mesenteric arteries, including the celiac artery, increases progressively with age:

• In a postmortem study of 123 subjects (mean age 62 years), 51% showed at least minimal intimal thickening 2
• Significant luminal narrowing occurrence increases with advancing age 2
• A positive correlation exists between defects in the internal elastic lamina and intimal thickness 2
• Marked fragmentation of the internal elastic lamina accompanies atherogenesis 2

Risk Factors for Atherosclerotic Intimal Thickening

Hypertension is the dominant risk factor:

• Hypertension is present in 85% of patients with ruptured aneurysms and 52% with non-ruptured aneurysms 1
• Smoking and hypercholesterolemia are associated with increased incidence 1
• However, 60% of patients have cholesterol levels less than 240 mg/dL, indicating atherosclerosis can develop without severe hyperlipidemia 1

Alternative Causes of Celiac Artery Intimal Changes

While atherosclerosis predominates, other etiologies can affect the celiac artery intima:

• Spontaneous dissection creates an intimal flap separating true and false lumens, typically occurring 3 cm from the celiac artery origin 3
• Iatrogenic dissection during catheterization procedures can cause acute intimal injury 4
• Median arcuate ligament compression causes focal narrowing without calcification or atherosclerotic changes, present in approximately 20% of the population 5, 6
• Fibromuscular dysplasia and vasculitis are rare causes 1

Clinical Implications

The extent of atherosclerotic involvement in mesenteric vessels is substantial:

• Atherosclerotic disease of celiac and mesenteric vessels is common, though symptomatic chronic intestinal ischemia remains rare 1
• Significant atherosclerotic obstruction is present in 6-10% of unselected autopsies and 14-24% of patients undergoing abdominal arteriography 1
• Calcified atherosclerotic plaque with ostial narrowing of the celiac artery often occurs with concomitant superior and inferior mesenteric artery involvement 1

Diagnostic Considerations

Imaging characteristics help distinguish atherosclerotic from non-atherosclerotic causes:

• Atherosclerotic lesions typically occur at the vessel origin as protruding aortic plaques 1
• CT angiography reveals calcification and atherosclerotic changes in atherosclerotic disease 5
• Median arcuate ligament compression shows focal narrowing with characteristic hooked appearance without calcification 6
• The ratio of stenosis ranges from 35-50% in mild cases to 51-80% in severe cases of median arcuate ligament compression 6