Endovascular approach to abdominal aortic aneurysms limits the postoperative systemic immune response

Objectives: endovascular repair of abdominal aortic aneurysms (E-AAA) has in recent years developed as an alternative to the conventional open repair (C-AAA). Adverse outcomes following the open approach may relate to immune cell activation and the systemic inflammatory response syndrome (SIRS) and organ failure but the benefits in this respect of the endovascular approach are unclear. This study evaluated this question and focused on T-cell activation and function.

Design: prospective clinical study.

Materials: twenty patients undergoing abdominal aortic aneurysm repair (12 C-AAA and 8 E-AAA).

Methods: peripheral T-cell expression of surface markers CD69, CD62L and CD25 in vivo and Interleukin 2 (IL-2) and Interleukin-10 (IL-10) responses to the superantigen staphylococcal enterotoxin B (SEB) in vitro were measured preoperatively, 24 h and 1 week postoperatively.

Results: there was no significant increase (p=0.23) in the incidence of SIRS in the open compared with the endovascular group. Enhanced T cell activation occurred following C-AAA and this was associated with significantly greater IL-2 production in response to SEB, with no change in IL-10 production.

Conclusions: E-AAA attenuates proinflammatory T-cell changes compared with C-AAA repair. A reduction in T-cell activation and impaired responsiveness to superantigen suggests that the immunological sequelae of the endovascular approach to aneurysm repair is more favourable than after the open approach with potentially less risk of adverse outcomes. Proof of this thesis will require a larger prospective study.