Troponin I release after CABG surgery using two different strategies of myocardial protection and systemic perfusion.

BACKGROUND: Controversies still exist over the optimal temperature for blood cardioplegia and systemic perfusion. This study investigates the effect of temperature of blood cardioplegia and systemic perfusion on the release of troponin I and other biochemical markers. METHODS: One hundred and fifty-four consecutive patients were randomly assigned to one of two cardioplegic and systemic perfusion strategies of cold blood cardioplegia with moderate systemic hypothermia (27 degrees C) or tepid blood cardioplegia with mild systemic hypothermia (33 degrees C). Cardiac troponin I and other biochemical markers were measured at baseline, at the end of surgery, at 12 hours and daily thereafter. A two-way ANCOVA for repeated measure was performed to test the effect of cardioplegia on enzyme release independently of variables that were different between the two groups. RESULTS: The time course of dismission of troponin I, creatine kinase MB, and lactate dehydrogenase were significantly lower with tepid blood cardioplegia and mild systemic perfusion independently of the number of distal anastomoses, CPB time, cross clamp time or total volume of cardioplegia. There were no differences between the two groups in the release of total creatine kinase, aspartate transaminase and alanine transferase. CONCLUSIONS: Both strategies of myocardial protection and systemic perfusion guarantee subclinical minor myocardial damage. The strategy of tepid whole blood cardioplegia and mild systemic hypothermia seems to preserve myocardium better than whole blood cold cardioplegia.