Inflammatory responses in abdominal aortic aneurism repair
Introduction: Abdominal aortic aneurysm (AAA) repair is associated with a systemic inflammatory response. Ischaemia-reperfusion injury (IRI) to the gastrointestinal tract and lower limbs plays an important role in the initiation and mediation of this inflammatory response. I investigate which of these regions plays the most significant role in the initiation of the inflammatory response. The null hypothesis for this thesis is that there is no difference in the contributions made by the gastrointestinal tract and lower limbs to the systemic inflammatory response.;Method: Patients undergoing elective AAA repair were recruited and had blood sampled from the radical artery, femoral vein, portal vein, inferior mesenteric vein and inferior vena cava at induction of anaesthesia (systemic samples only), immediately prior to aortic clamping, immediately prior to aortic clamp removal (ischaemia) and after 30 minutes of reperfusion. Control patients undergoing major abdominal surgery were included to investigate the inflammatory response in patients undergoing major operations but without IRI.;Results: 46 patients with AAA, and 10 controls were studied. The majority of patients (61%, n=28) demonstrated a positive inflammatory response, as represented by the development of the Systemic Inflammatory Responses Syndrome (SIRS), and increases in the inflammatory markers described. Patients exhibited high levels of Interleukin-6 in the venous effluent of the gastrointestinal tact (P=0.001), and high numbers of activated neutrophils in the venous effluent from the lower-limbs (P=0.013) during reperfusion.;Conclusions: The work of this thesis confirms that patients undergoing AAA repair exhibit an inflammatory response. Significant differences in regional inflammatory responses were also demonstrated, and therefore the null hypothesis was rejected. This suggests that during AAA repair, the gastrointestinal tract is responsible for Interleukin-6 production, and that neutrophil activation occurs in the lower-limbs.