Heart Care Info - Heart Disease Prevention & Treatment

Protection by remote ischemic preconditioning during coronary artery bypass graft surgery with isoflurane but not propofol–a clinical trial

E Kottenberg, M Thielmann... - Acta ..., 2012 - Wiley Online Library... Aussage P, Vicaut E, Pons A, Lehot JJ. Sevoflurane preconditioning at 1 MAC only provides limited protection in patients undergoing coronary artery bypass surgery: a randomized bi-centre trial. Br J Anaesth 2007; 99: 62431.

Finally, many diabetic patients undergoing CABG surgery take KATP channel blockers such as the sulfonylurea glibenclamide that interfere with signal transduction of ischemic and anesthetic preconditioning.[31] Furthermore, diabetes[32] and also hyperglycemia[33] in the nondiabetic myocardium abolish anesthetic preconditioning, but their effect on RIPC is unknown. In our study, these potential confounders were excluded since patients with any type of diabetes mellitus were not enrolled. Our study had strict exclusion criteria and our patients represent a rather homogenous cohort. Thus, while restriction to a narrow group of patients may be considered a disadvantage for consideration of assessment of the effects of RIPC in broad, inhomogeneous patients populations, we feel that this approach at the present state of knowledge is advantageous. It was not the goal of the present study to assess the overall effect of RIPC but, rather, to assess the interaction of RIPC with two anesthetic regimens. Extra caution is also needed when interpreting the results based on a small sample size. In fact, we feel that we exercised this extra caution and did not overstretch the interpretation of the data obtained. As a matter of fact, most previous studies addressing the effects of RIPC have done so in unselected patients, have mixed in their cohorts patients undergoing ischemic (fibrillation) aortic cross clamping and cardioplegia,[17] have included patients with and without diabetes,[34] and have mixed various anesthetic regimens and dosages.[16, 17, 34] In our study, we did not address the question of whether or not RIPC in a large surgical population attenuates troponin release and, when generally employed, might clinically help patients along their way. Rather, we were interested in the question of whether RIPC and the specific anesthetics used, isoflurane or propofol, possibly interact in altering troponin release in CABG patients. To our knowledge, the present study addresses for the first time the influence of the anesthetic regime on the effects of RIPC in patients undergoing elective CABG surgery. Nevertheless, the data of our study derive from a small cohort, need confirmation in larger studies, and should not be extrapolated to other anesthetic techniques, other dosages used, or to patient cohorts with other characteristics.