European Journal of Cardio-Thoracic Surgery, Vol 12, 753-758, Copyright © 1997 by European Association for Cardio-thoracic Surgery
Ischemic preconditioning prior to myocardial protection with cold blood cardioplegia in coronary surgery
J Cremer, G Steinhoff, M Karck, T Ahnsell, M Brandt, OE Teebken, D Hollander and A Haverich
Department of Cardiovascular Surgery, Christian-Albrechts-University, Kiel, Germany.
OBJECTIVE: Encouraging results on myocardial preconditioning in
experimental models of infarction, stunning or prolonged ischemia raise the
question whether preconditioning techniques may enhance conventional
cardioplegic protection used for routine coronary surgery. METHODS: A
prospective clinical trial was conducted to investigate the effect of
additional ischemic normothermic preconditioning prior to cardioplegic
arrest applying cold blood cardioplegia in patients scheduled for routine
coronary surgery (3 vessel disease, left ventricular ejection fraction >
50%). Two cross clamp periods of 5 min with the hearts beating in sinus
rhythm were applied followed by 10 min of reperfusion, each (n = 7, group
I). Inducing moderate hypothermia cold blood cardioplegia was delivered
antegradely. In control groups, cold intermittent blood cardioplegia (n =
7, group II) was used alone. Coronary sinus effluents were analyzed for
release of creatine kinase (CK), CK-MB, lactate, and troponin T at 1, 3, 6,
9, and 12 h. In addition, postoperative catecholamine requirements were
monitored. RESULTS: The procedure was tolerated well, and no perioperative
myocardial infarction in any of the groups studied occurred. Concentrations
of lactate tended to be higher in group I, but this difference was not
significant. In addition, no significant differences for concentrations of
CK, CK-MB, and troponin T were found. Following ischemic preconditioning an
increased dosage of dopamine was required within the first 12 h
postoperatively (group I: 2.63 +/- 1.44 microg/kg/min, group II: 0.89 +/-
1.06 microg/kg/min). CONCLUSIONS: Combining ischemic preconditioning and
cardioplegic protection with cold blood cardioplegia does not appear to
ameliorate myocardial protection when compared to cardioplegic protection
applying cold blood cardioplegia alone. Inversely, contractile function
seemed to be impaired when applying this protocol of ischemic
preconditioning.