Abstract Background The definition of periprocedural myocardial infarction (PMI) after coronary artery bypass grafting (CABG) remains debated, particularly regarding the use of cardiac troponins vs creatine kinase MB isoform (CK-MB), and biomarker thresholds seem outdated 10×, 35×, or 70× multiples of upper reference limits (URL). We studied high-sensitivity cardiac troponin T (hs-cTnT) and I (hs-cTnI), and CK-MB, following CABG patients with an emphasis on those with an uncomplicated course. Methods Patients undergoing isolated on-pump CABG and minimally invasive direct CABG (MIDCAB) were prospectively included. Blood was collected preoperatively and then postoperatively at intensive care unit (ICU) arrival, 5 h and 8 h subsequently, and postoperative days 1 and 3. hs-cTnT (Roche), hs-cTnI (Abbott), and CK-MB (Roche) were measured and normalized using URLs according to package inserts or the Universal Sample Bank. Results Sixty-one on-pump CABG and 22 MIDCAB patients were included. On-pump CABG patients showed a median (interquartile range) hs-cTnT peak of 610 (466–879) ng/L, hs-cTnI 3918 (2154–6713) ng/L, and CK-MB 22.0 (14.9–34.8) µg/L 5 h after ICU arrival. When normalized according to package inserts, this corresponds to 44× (33×–63×) URL, 150× (82×–256×) URL, 4.5 × (3.0×–7.1×) URL, respectively. These values slightly differ when sex-specific or other URL definitions are used (P 0.05). In subgroup analyses, MIDCAB patients had reduced biomarker concentrations, and significant differences were observed between cardioplegia regimens (P 0.001). Conclusion The postoperative kinetics of hs-cTnT, hs-cTnI, and CK-MB in CABG patients with an uncomplicated course demonstrate that hs-cTnT, in particular, surpasses current diagnostic cutoffs for PMI. This varies in time, across hs-cTn assays, surgical approaches, and cardioplegia regimens.
Denessen et al. (Thu,) studied this question.