Interleukin 6 production during abdominal aortic aneurysm repair arises from the gastrointestinal tract and not the legs.

BACKGROUND

Abdominal aortic aneurysm (AAA) repair is associated with a systemic inflammatory response. This inflammatory response probably arises as a result of an ischaemia-reperfusion injury to the legs and gastrointestinal tract. In this study the relative contributions of these areas to the inflammatory response were assessed during elective AAA repair.

METHODS

Blood was sampled from the femoral vein, portal vein and radial artery of 14 patients undergoing elective AAA repair at five time points during the procedure. Plasma was snap-frozen for subsequent batch analysis of interleukin (IL) 6.

RESULTS

The plasma IL-6 concentration rose steadily throughout the procedure at all three locations. The increase in plasma IL-6 was significantly greater in the portal vein than in the radial artery during ischaemia (P = 0.020). The plasma IL-6 concentration was also significantly higher in the portal vein than in the femoral vein (P < 0.001) and radial artery (P < 0.001) during reperfusion. There were no significant differences between radial artery and femoral vein IL-6 levels at any time point.

CONCLUSION

Ischaemia and reperfusion during AAA repair were associated with a marked increase in IL-6 concentration in the portal vein, suggesting that IL-6 was produced by the gastrointestinal tract.