Does the combination of sevoflurane preconditioning and postconditioning improve myocardial preservation compared to either intervention alone in Langendorff perfused rat hearts?
Sevoflurane postconditioning is as effective as preconditioning in protecting myocardial function after global ischemia, but their combination offers no additional benefit.
In Brief BACKGROUND: Recent investigations demonstrate that anesthetic preconditioning and postconditioning reduce myocardial infarct size to a degree comparable to that achieved with ischemic preconditioning. We hypothesized that the combination of sevoflurane preconditioning and postconditioning would result in greater preservation of myocardium. METHODS: Langendorff perfused rat hearts were divided into four groups: control, preconditioning, postconditioning, and preconditioning plus postconditioning. During reperfusion, left ventricular function (left ventricular developed pressure, left ventricular end diastolic pressure, and dp/dt) were measured. At the end of reperfusion, the infarct sizes were measured with 2,3,5 triphenyltetrazolium chloride staining. Nuclear magnetic resonance was used to measure intracellular pH, Na+, and Ca2+. RESULTS: Left ventricular developed pressure, left ventricular end diastolic pressure, left ventricular dp/dtmax and dp/dtmin were significantly improved in the treatment groups when compared with those in the controls. Myocardial infarct size (24% ± 7%, 16% ± 8%, and 22% ± 7% in preconditioning, postconditioning, and pre-plus postconditioning groups versus 44% ± 8% in the control group, P < 0.05) and intracellular Na+ and Ca2+ were significantly decreased in all experimental groups at the end of reperfusion when compared with those in control. However, there were no differences between these variables in each treatment group. CONCLUSION: Sevoflurane postconditioning is as effective as preconditioning in protecting myocardial function after global ischemia. The combination of sevoflurane preconditioning and postconditioning offered no additional benefit over either intervention alone. IMPLICATIONS: The results of this study support the hypothesis that exposure to sevoflurane during the early minutes of reperfusion (anesthetic postconditioning) attenuates reperfusion injury resulting in preservation of myocardial function and decreased infarct size comparable to anesthetic preconditioning. The combination of anesthetic preconditioning and postconditioning offered no additional benefit over either intervention alone.
Deyhimy et al. (Tue,) studied this question.