Evaluation of myocardial metabolism with microdialysis during bypass surgery with cold blood- or Calafiore cardioplegia.
BACKGROUND
For the first time, microdialysis was used to investigate in vivo and online the myocardial metabolism during and after cardiac surgery in patients treated with two different methods of myocardial protection.


METHODS
Thirty patients underwent standard CABG with one of two different methods of myocardial protection. The patients were randomised to receive either cold blood (COLD group) or warm modified Calafiore cardioplegia (WARM group). Microdialysis probes were implanted into the myocardium of left ventricular apical region of the heart. Cardioplegia was given antegrade only. Microdialysis measurements were performed at time intervals before, during and 24 h after cardiopulmonary bypass and analysed for glucose, lactate, pyruvate and glycerol.


RESULTS
Myocardial lactate concentrations were significantly higher in the WARM group compared with that of the COLD group, while serum lactate was comparable. Glycerol was significantly higher at the end of the clamping time in the WARM group. At the same time the glucose-lactate ratio as a marker of nutritional disorder had significantly lower levels in the WARM group. The cumulative CK-MB release over 24 h was significantly higher in those hearts protected with warm blood.


CONCLUSIONS
The oxidative stress measured was significantly higher in patients undergoing CABG using modified Calafiore cardioplegia, whereas the cold cardioplegia minimised the effects of aortic clamping. The results indicate that cold cardioplegia offers superior protection of the heart, in terms of more rapid normalisation of myocardial metabolism. In elective myocardial revascularisation, intermittent antegrade warm blood cardioplegia is a comparable safe method of myocardial protection. However, in patients referring to a long clamping time, advantages of cold cardioplegia for myocardial revascularisation may be magnified.
Pöling
Jochen
J
Department of Cardiac Surgery, Schüchtermann-Klinik Bad Rothenfelde, Ulmenallee 11, 49214 Bad Rothenfelde, Germany. jochen.poeling@freenet.de
Rees
Wolfgang
W
Mantovani
Vittorio
V
Klaus
Stephan
S
Bahlmann
Ludger
L
Ziaukas
Virgilius
V
Hübner
Norbert
N
Warnecke
Henning
H
D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D002314:Cardioplegic Solutions; D002315:Cardiopulmonary Bypass / Q000379:methods*; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000378:metabolism; D052279:Creatine Kinase, MB Form / Q000032:analysis; D005260:Female; D005990:Glycerol / Q000032:analysis; D006324:Heart Arrest, Induced / Q000379:methods*; D006801:Humans; D007432:Intraoperative Period; D007773:Lactates / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D018384:Oxidative Stress; D011773:Pyruvates / Q000032:analysis; D018709:Statistics, Nonparametric; D013696:Temperature; D013997:Time Factors
D001786:Blood Glucose; D002314:Cardioplegic Solutions; D007773:Lactates; D011773:Pyruvates; D052279:Creatine Kinase, MB Form; D005990:Glycerol