Colonic epithelial apoptosis during conventional and endoluminal aortic surgery.

BACKGROUND

This study characterized the initial modes of colonic mucosal injury during aneurysm surgery and correlated these with proinflammatory cytokine release into the colonic and systemic circulations.

METHODS

Twenty-four patients undergoing conventional open aortic aneurysm repair and ten who had endovascular aneurysm repair (EVAR) were recruited. Mucosal biopsies were taken from the sigmoid colon immediately before and after surgery, for histological examination. Inferior mesenteric vein (IMV) and peripheral blood from patients who had conventional surgery was assayed for interleukin (IL) 1 beta, IL-6 and tumour necrosis factor (TNF) alpha. Only peripheral blood from patients who had EVAR was assayed.

RESULTS

Conventional aneurysm repair resulted in a threefold increase in columnar epithelial apoptosis. There was a 26-fold increase in IL-6 in IMV blood within 5 min of reperfusion, with an equivalent rise in peripheral blood after 30 min. A 20-fold rise in peripheral blood TNF-alpha was observed after surgery. Splanchnic IL-6 correlated positively with cross-clamp time and increased apoptosis. No histological changes were seen after EVAR. There were no intraoperative cytokine changes during EVAR, although a postoperative increase in IL-6 and TNF-alpha was observed.

CONCLUSION

The lack of columnar epithelial apoptosis following EVAR reflects the relatively minor ischaemic injury incurred during this procedure.