The release of myocardial necrosis biomarkers after off-pump coronary artery bypass grafting (OPCAB) frequently occurs. However, the correlation between biomarker release and the diagnosis of procedure-related myocardial infarction (MI) (type 5) has been controversial. This study aimed to evaluate the amount and pattern of cardiac biomarker release after elective OPCAB in patients without evidence of a new MI on cardiac magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE).
Patients with normal baseline cardiac biomarkers referred for elective OPCAB were prospectively included. CMR with LGE was performed in all patients before and after interventions. Measurements of troponin I (cTnI) and creatine kinase MB fraction (CK-MB) were systematically performed before and after the procedure. Patients with new LGE on the postprocedure CMR were excluded.
All of the 53 patients without CMR evidence of a procedure-related MI after OPCAB exhibited a cTnI elevation peak above the 99th percentile. In 48 (91%), the peak value was >10 times this threshold. However, 41 (77%) had a CK-MB peak above the limit of the 99th percentile, and this peak was >10 times the 99th percentile in only 7 patients (13%). The median peak release of cTnI was 0.290 (0.8–3.7) ng/mL, which is 50-fold higher than the 99th percentile.
In contrast with CK-MB, considerable cTnI release often occurs after an elective OPCAB procedure, despite the absence of new LGE on CMR.