Remote ischaemic preconditioning does not alter perioperative cytokine production in high-risk cardiac surgery.
BACKGROUND
Remote ischaemic preconditioning (RIPC) is a novel cardioprotective strategy that uses brief intermittent limb ischaemia to protect the myocardium and other organs from perioperative ischaemic damage. The precise mechanism through which this protective effect occurs is unknown, but potentially could be related to changes in blood-borne mediators such as cytokines.


OBJECTIVE
To determine whether RIPC alters inflammatory cytokine expression in a double-blind, randomised, controlled trial of patients undergoing high-risk cardiac surgery.


RESULTS
Serum interleukin (IL)-6, IL-8, and IL-10 levels from 95 patients randomised to RIPC (n=47) or control treatment (n=48) were measured preoperatively, and 1, 2, 3, 6 and 12 h after cross-clamp removal. Systemic concentrations of all cytokines were increased from baseline following surgery, and, compared with simple procedures, complex surgeries were associated with significantly higher release of IL-6 (ratio of mean area under the curves 1.54 (95% CI 1.02 to 2.34), p=0.04) and IL-10 (1.97 (1.16 to 3.35), p=0.012). No significant difference in mean cytokine levels between the RIPC and control groups was detected at any time point, irrespective of the type of surgery undergone.


CONCLUSIONS
High levels of IL-6, IL-8 and IL-10 are produced during high-risk cardiac surgery, and RIPC does not alter these elevated perioperative cytokine concentrations. Identification of factors that influence the ability to induce RIPC-mediated cardioprotection should be the priority of future research.


BACKGROUND
is in the Australian New Zealand Clinical Trials Registry (http://www.anzctr.org.au; ACTRN12609000965202).
School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand.
Jenni M
JM
Williams
Capital and Coast District Health Board, Wellington, New Zealand; Medical Research Institute of New Zealand, Wellington, New Zealand.
Paul
P
Young
Medical Research Institute of New Zealand, Wellington, New Zealand.
Janine
J
Pilcher
Mark
M
Weatherall
School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand.
John Holmes
JH
Miller
Capital and Coast District Health Board, Wellington, New Zealand; Medical Research Institute of New Zealand, Wellington, New Zealand.
Richard
R
Beasley
School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand.
Anne Camille
AC
La Flamme