Creatine kinase BB isozyme in the blood during open heart surgery--comparison with creatine kinase MB and MM isozymes.

By using a recently developed highly sensitive enzyme immunoassay method, concentrations of the 3 forms of cytoplasmic creatine kinases (CK-BB, CK-MB and CK-MM) were determined in blood samples serially taken from 18 patients who received mitral valve replacement. Blood CK-BB levels, 0.64 +/- 0.32 ng/ml at the beginning of anesthesia, rose sharply after reperfusion reaching the peak level (23.3 +/- 7.56 ng/ml) 2 hours after reperfusion, and then fell rapidly. The response of CK-BB in blood was rapider and more sensitive than that of CK-MB or CK-MM. The CK-BB concentrations were significantly higher in coronary sinus samples than in arterial samples. These results suggest that the major portion of elevated blood CK-BB level in the early phase after reperfusion are derived from the heart muscle.