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The predictive value of serum enzymes for perioperative myocardial infarction after cardiac operations. An autopsy
F Van Lente1, A Martin, N B Ratliff
1Department of Biochemistry, Cleveland Clinic Foundation, Ohio 44195.
Insights
Serum enzyme and isoenzyme activities can help detect perioperative myocardial infarction after cardiac surgery. Creatine kinase MB showed the strongest association, offering 96% accuracy in diagnosing heart attacks in these patients.
Area of Science:
- Cardiology
- Biochemistry
- Pathology
Background:
- Perioperative myocardial infarction (PMI) is a significant complication after cardiac surgery.
- Accurate detection of PMI is crucial for patient management and outcomes.
Purpose of the Study:
- To evaluate the diagnostic utility of serum enzyme and isoenzyme activities for detecting autopsy-proven PMI.
- To identify specific enzyme markers with the highest diagnostic accuracy for PMI.
Main Methods:
- Studied 79 patients undergoing coronary artery bypass grafting or valve replacement with autopsy confirmation.
- Compared serum enzyme activities (creatine kinase, creatine kinase MB, aspartate aminotransferase, lactate dehydrogenase-1/lactate dehydrogenase-2 ratio) between patients with and without PMI.
- Utilized logistic regression to analyze postoperative enzyme changes in relation to PMI.
Main Results:
- Statistically significant differences in mean activities of creatine kinase, creatine kinase MB, aspartate aminotransferase, and LDH-1/LDH-2 ratio were observed between groups.
- Creatine kinase MB demonstrated the strongest diagnostic association with PMI.
- Adjusting creatine kinase-MB cutoff to 133 U/L at 15 hours post-operation yielded 0.60 sensitivity and 1.0 specificity.
- No enzyme combination could completely discriminate all PMI cases.
Conclusions:
- Serum creatine kinase MB activity is a valuable marker for diagnosing perioperative myocardial infarction.
- While not perfectly discriminatory, creatine kinase MB measurement offers high accuracy (96%) for PMI detection at 10% prevalence.
- Lactate dehydrogenase-1/lactate dehydrogenase-2 ratio showed a lesser correlation with infarction.
Abstract:
We evaluated the utility of serum enzyme and isoenzyme activities for detecting autopsy-proved perioperative myocardial infarction in patients who died after cardiac operations. We studied 79 patients who had autopsies performed after coronary artery bypass grafting or valve replacement, or both. Thirty-seven had histologic evidence of a perioperative myocardial infarction. We found statistically significant differences between the group of patients with infarction and the group without infarction when we compared the mean activities of creatine kinase, creatine kinase MB, aspartate aminotransferase, and the lactate dehydrogenase-1/lactate dehydrogenase-2 ratio. The postoperative changes in serum enzymes were analyzed by logistic regression for their relation to perioperative myocardial infarction. Creatine kinase MB exhibited the best diagnostic association with the presence of perioperative myocardial infarction. The lactate dehydrogenase-1/lactate dehydrogenase-2 ratio correlated to a lesser extent with infarction. Adjustment of the diagnostic cutoff to 133 U/L for creatine kinase-MB measured 15 hours after operation yielded a sensitivity of 0.60 and a specificity of 1.0. This study demonstrates that no combination of enzyme activity changes after operation can completely discriminate all patients with perioperative myocardial infarction from those without. Nonetheless, measurement of creatine kinase MB activity provide 96% accuracy for diagnosing infarction at a prevalence of 10%.