Creatine kinase MM isoforms in serum after cardiac surgery

Area of Science:

• Biochemistry
• Cardiology
• Clinical Diagnostics

Background:

• Perioperative myocardial injury diagnosis is crucial after cardiac surgery.
• Creatine kinase (CK) and lactate dehydrogenase (LD) are established biomarkers.
• CK isoform analysis is explored for enhanced diagnostic accuracy.

Purpose of the Study:

• To evaluate the utility of serum creatine kinase (CK) MM3:MM1 isoform ratios for diagnosing perioperative myocardial injury.
• To assess the diagnostic performance of CK-MB and LD concentrations in this context.

Main Methods:

• Serum samples were analyzed from cardiac surgery patients.
• CK MM3:MM1 isoform ratios were measured.
• CK-MB and total LD concentrations were determined.
• LD isoenzyme ratios (LD1:LD2, LD5:LD2) were assessed.

Main Results:

• CK MM3:MM1 isoform ratios did not differ significantly between patients with and without myocardial complications.
• Ratios decreased substantially by the first postoperative day in all patients.
• CK-MB and LD concentrations showed the most significant differences between groups.
• Parallel testing of CK-MB and LD yielded 77% sensitivity and 87% specificity.

Conclusions:

• CK-MM isoform analysis offers no additional diagnostic information for perioperative myocardial injury immediately after cardiac surgery.
• CK-MB and LD concentrations correlate with myocardial injury but may not meet clinical utility standards due to limitations in sensitivity and specificity.