The impact of sex-differences on the release of cardiac biomarkers after coronary artery bypass grafting (CABG) remains unknown. The aim of our study was to (a) investigate the impact of sex-differences in cardiac biomarker release after CABG and (b) determine sex-specific thresholds for high-sensitivity troponin (hs-cTn) and creatine kinase-MB (CK-MB) associated with 30-day major adverse cardiovascular event (MACE) and mortality.

A consecutive cohort of 3687 patients (female: n= 643 (17.4%); male: 3044 (82.6%) undergoing CABG from 2008-2021 in two tertiary university centers with serial postoperative cTn and CK-MB measurement was analyzed. The composite primary outcome was MACE at 30 days. Secondary endpoints were 30-day mortality and five-year mortality and MACE. Sex-specific thresholds for cTn and CK-MB were determined.

Lower levels of cTn were found in women after CABG (69.18 vs. 77.57 xURL; p<0.001). Optimal threshold value for cTn was calculated at 94.36 times the URL for female and 206.07 times the URL for male patients to predict 30-day MACE. Female patients missed by a general threshold had increased risk for MACE or death within 30 days (cTn: MACE: OR 3.78 CI: 1.03-13.08; p=0.035; death: OR 4.98; CI: 1.20.-20.61; p=0.027; CK-MB: MACE: OR 10.04; CI: 2.07-48.75; p<0.001; death: OR 13.59; CI: 2.66-69.47; p=0.002).

We provide evidence for sex-specific differences in the outcome and biomarker release after CABG. Sex-specific cut-offs are necessary for the diagnosis of perioperative myocardial injury to improve outcomes of women after CABG.