Unspecific elevation of plasma troponin-T and CK-MB after coronary surgery

Area of Science:

• Cardiology
• Biochemistry
• Cardiac Surgery

Background:

• Elevated biochemical markers of myocardial injury are common post-cardiac surgery.
• A portion of these elevations is attributed to release unrelated to permanent myocardial damage.
• The characteristics of this 'diagnostic noise' are not well understood.

Purpose of the Study:

• To investigate the magnitude and temporal profile of biochemical marker release in cardiac surgery patients without permanent myocardial injury.
• To characterize the 'diagnostic noise' in troponin-T and creatine kinase-MB (CK-MB) levels post-coronary artery bypass grafting (CABG).

Main Methods:

• Utilized unique troponin-T release kinetics to identify patients with no or minimal permanent myocardial injury after CABG with cardiopulmonary bypass (CPB).
• Blood samples were collected pre-surgery and at multiple time points up to postoperative day 4.
• Identified a subgroup (n=77) with normalized troponin-T by day 4 and no ECG changes indicative of injury.

Main Results:

• In the selected subgroup, troponin-T peaked at 3 hours post-aortic unclamping (2.08 ± 1.42 µg/l).
• Creatine kinase-monobasic (CK-MB) peaked at 8 hours post-aortic unclamping (28.6 ± 11.3 µg/l).
• These substantial early elevations occurred despite no or minimal permanent myocardial injury.

Conclusions:

• Significant early elevations in plasma CK-MB and troponin-T are observed in CABG patients without permanent myocardial injury.
• This unspecific marker release is most pronounced during timeframes typically used to assess myocardial protection strategies or revascularization procedures.
• Findings highlight the need to consider non-specific marker release when interpreting results after cardiac surgery.