Creatine kinase (CK): its use in the evaluation of perioperative myocardial infarction.

Establishing the diagnosis of acute perioperative myocardial infarction by the mere presence of a serum CK-MB band alone is not valid. Laboratory investigations have shown that tissues other than ventricular myocardium hold appreciable quantities of CK-MB. Moreover, each of the laboratory methods commonly used for measuring serum total CK and its isoenzymes have inherent strengths and weaknesses. Hence, accurate evaluation of perioperative CK-MB bands requires determination of the amplitude and the temporal course of the elevation. Confirmation of the CK-MB findings by analysis of another enzyme system is advisable. Serum lactate dehydrogenase isoenzymes can fulfill this role. Institution of a dual enzyme evaluation is achieved easily in most hospitals and can yield a very high degree of sensitivity and specificity. The final step in diagnostic accuracy is completed by continuing evaluation of the enzyme diagnostic system in each individual institution.