Warm myocardial protection has had a strong impact on modern cardiac surgery. The O2 consumption of a heart, arrested by potassium-enriched normothermic blood is 90% less than baseline values. Hypothermia gives only a slight reduction in oxygene consumption.
The aim of this study: was to test the quality of myocardial protection provided by intermittent antegrade warm blood cardioplegia (IAWBC) by comparing it with cold blood cardioplegia.
Material and methods: We designed a prospective randomized study by using 2 different temperatures of blood cardioplegia: warm, from 35 degrees C to 37 degrees C (group I--36 men and 14 women, mean age 56 +/- 7); and cold, from 6 degrees C to 8 degrees C (group II--40 men and 10 women, mean age 58 +/- 9). Cardiac troponin I release was the criterion used to evaluate the adequacy of myocardial protection,
Results: The heartbeat in 92% of patients treated with warm cardioplegia converted to normal sinus rhythm spontaneously after removal of the aortic crossclamp compared with only 18% of the cold cardioplegia group. Cardiac troponin I concentration was significantly higher in the cold group. Our study demonstrates a significant reduction of myocardial cell damage with the use of IAWBC.
Conclusion: Our clinical results have shown that IAWBC is a superior method compared to intermittent cold cardioplegia.