Acute arterial mesenteric ischaemia: comparison of partial and complete occlusion of the superior mesenteric artery.

OBJECTIVES

To describe the characteristics and outcomes of patients with an incomplete occlusion of the superior mesenteric artery (SMA) (persistence of contrast-enhanced vessel lumen) and compare them to those with a complete occlusion of the SMA (complete interruption of the contrast-enhanced vessel lumen) in arterial acute mesenteric ischaemia (AMI).

MATERIAL AND METHODS

Retrospective study of arterial AMI patients (2006-2022). Demographics, laboratory tests, clinical characteristics, CT, treatments and outcomes were compared between patients with complete or incomplete SMA obstruction after adjusting for aetiology (embolic or atherosclerotic). The primary outcome was 30-day mortality, and the secondary outcome was 6-month gastrointestinal disability-free survival (no short bowel syndrome or parenteral nutritional support or permanent stoma).

RESULTS

151 patients (65 women, mean age 69) were included, 62 (41%) with incomplete and 89 (59%) with occlusive SMA occlusion. After adjusting for aetiology, chronic kidney failure (p = 0.03) and normal bowel enhancement on CT (p < 0.01) were associated with incomplete SMA occlusion. Patients with incomplete SMA occlusion were more frequently treated by endovascular revascularisation (p < 0.01) and stenting (p < 0.01), while patients with complete SMA occlusion were treated by open revascularisation. The 30-day mortality rate was 13% with no difference between incomplete (11%) and complete SMA occlusion (15%; p = 0.89). Nevertheless, complete SMA occlusion patients had a lower 6-month gastrointestinal disability-free survival rate (p = 0.01), more transmural necrosis (p < 0.01) and a higher risk of gastrointestinal disability (p = 0.02).

CONCLUSION

Incomplete SMA occlusion can cause AMI with a similar 30-day mortality rate to completely occlusive forms. However, it is associated with poorer gastrointestinal outcomes, regardless of aetiology.

CRITICAL RELEVANCE STATEMENT

Acute arterial mesenteric ischaemia caused by incomplete occlusion of the superior mesenteric artery demonstrates similar 30-day mortality to complete occlusion but distinctively better gastrointestinal outcomes, emphasising nuanced imaging evaluation for targeted management strategies in these patients.

KEY POINTS

Occlusive acute mesenteric ischaemia can be caused by incomplete superior mesenteric artery (SMA) occlusion. Acute mesenteric ischaemia caused by incomplete SMA occlusion has a similar 30-day mortality rate to complete SMA occlusion. A complete occlusion of the SMA is associated with poorer gastrointestinal outcomes.