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DOI: 10.1055/s-2007-967340
Detection of perioperative myocardial hypoperfusion by interstitial fluids
Aims: Postoperative ischemia after CABG is well described but sufficient intervention mandates immediate diagnosis. One possible way of increasing efficacy of the perioperative myocardial monitoring is by using the microdialysis technique.
Methods: In 30 patients undergoing routine coronary artery bypass grafting a microdialysis catheter was inserted in the left heart in an area of abnormal ventricular contraction. A second catheter was placed in the normal tissue of the right ventricle. Microdialysis measurements were performed at time intervals before, during and 24 hours after cardiopulmonary bypass (CPB) and retrospectively compared to standard clinical monitoring and clinical course.
Results: During CPB both ventricles showed signs of a poor tissue oxygenation. Glycerol was significantly higher in the left myocardium (146±67 vs. 72±36µmol/l) and the glucose-lactate-ratio (GLR) as a marker of nutritional disorder of the right ventricle (41±15% vs. 67±17%, p<0.05) had significant better values at this point. Myocardial lactate concentrations were significantly higher in the dyskinetic segments (2.82±0.81 vs. 1.5±0.81µM). No abnormal clinical standard monitoring results were seen in this period. Postoperative significantly increased lactate-pyruvate-ratio of three patients were clinically associated with perioperative myocardial infarction (108±67 vs. 38±9, p<0.05). Lactate-pyruvate-ratio started rising before any other standard monitoring tools showed abnormal values.
Conclusions: Perioperative microdialytic measurements of ischemia related parameters can be safely performed in a clinical setting, resulting in faster and more reliable detection of ongoing or new ischemia.