Abstract
Abdominal aortic aneurysm (AAA) repair through a transperitoneal approach induces
a systemic interleukin-6 (IL-6) response which may be related to manipulation of the
bowel and mesenteric traction. This study investigates the effect of avoiding intestinal
manipulation on IL-6 production by comparing the use of extraperitoneal and transperitoneal
approaches in elective infrarenal AAA repair. Patients undergoing elective AAA repair
were randomized into either transperitoneal (n=10) or extraperitoneal (n=8) groups.
Samples of systemic and portal blood were collected intraoperatively before, during
and after aortic cross clamping. In addition, systemic blood samples were obtained
pre-induction, post-induction, and 6, 12, 24, and 48 hours after abdominal incision.
Plasma IL-6 concentration was measured using a bioassay based on the proliferation
of IL-6 dependent B9 Hybridoma cells (sensitivity of assay is 30–40 pg/ml). In the
extraperitoneal group, IL-6 was not detected in either the portal or systemic circulations
intraoperatively. With the transperitoneal group, IL-6 was detected in 15 of 40 (38%)
portal, and 8 of 40 (20%) systemic intraoperative samples (p<0.001,x
2
test). Postoperatively, IL-6 was detected in only 14 of 32 (44%) samples taken during
the 48 hours after extraperitoneal repair but in 35 of 40 (88%) samples after transperitoneal
repair (p<0.001,x
2
test). At 6 hours, the systemic IL-6 concentration was significantly higher in the
transperitoneal group (p<0.01, Mann-Whitney U test). No correlation was seen between the plasma IL-6 concentration and aortic clamp
time, duration of operation, or amount of blood lost or transfused. These results
supports the suggestion that intestinal manipulation plays an important role in driving
the systemic inflammatory response that may be seen after transperitoneal AAA repair.
