Sex-specific troponin and creatine kinase thresholds after coronary bypass surgery.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Complexity of coronary artery disease and the release of cardiac biomarkers after CABG.

Objective: In patients with complex coronary artery disease (CAD) undergoing cardiac surgery, myocardial protection might be impaired due to microvascular obstruction, resulting in myocardial injury and subsequent biomarker release. Therefore, this study investigated the correlation between the complexity of CAD, reflected by the SYNTAX Score, and the release of cardiac biomarkers after CABG. Methods: In a consecutive series of 919 patients undergoing isolated CABG SYNTAX scores I and II were calculated to assess the complexity of CAD. Levels of high sensitivity cardiac troponin T (hs-cTnT) and creatine kinase-myocardial band (CK-MB) were routinely measured once before and serially after surgery. Patients were divided into tertiles according to their SYNTAX Scores I and II. Spearman correlations and regression models were performed to measure the degree of association between the release of hs-cTnT and CK-MB and the SYNTAX Scores. Results: Patients with a higher SYNTAX Score I had more comorbidities reflected in a higher EuroSCORE II. Preoperatively, higher levels of cardiac biomarkers were found in patients with higher SYNTAX Score II. No correlation was observed between hs-cTnT, CK-MB and SYNTAX Score I or II. Regression models did not show any association between cardiac biomarkers and the complexity of CAD. Conclusion: The complexity of CAD is not associated with the release of cardiac biomarkers after CABG. Factors influencing postoperative biomarker release need to be elucidated in future trials to include postoperative biomarker release into risk stratification models predicting outcome after cardiac surgery.

Postoperative cardiac biomarker release is not associated with myocardial mass in computer tomography scans.

OBJECTIVES: Myocardial hypertrophy results in increased levels of cardiac biomarkers in healthy individuals and in patients suffering from acute myocardial infarction. The influence of cardiac mass on postoperative cardiac biomarkers release remains unclear. This study investigated the correlation between myocardial mass and the release of high-sensitivity cardiac Troponin T (hs-cTnT) and creatine kinase-myocardial band (CK-MB) after isolated aortic valve replacement (AVR) or bypass surgery. METHODS: Myocardial mass of a consecutive retrospective series of patients was measured automatically using preoperative computer tomography scans (636 patients, AVR = 251; bypass surgery = 385). Levels of cardiac biomarkers were measured before and serially after surgery. Spearman and Pearson correlation and a multivariate regression model was performed to measure the degree of association between myocardial mass and the release of hs-cTnT and CK-MB. RESULTS: Patients were divided into 3 tertiles according to their myocardial mass index. Higher biomarker levels were measured preoperatively in the upper tertile of patients undergoing AVR (P = 0.004) or bypass surgery (P < 0.001). Patients with different heart sizes showed no differences in postoperative biomarker release neither after AVR nor bypass surgery. No statistical significant correlation was observed between myocardial mass index and postoperative release of hs-cTnT or CK-MB in any subgroup (ρ maximum 0.106). CONCLUSIONS: Postoperative biomarker release is not correlated with myocardial mass. Patient factors leading to increased postoperative biomarker levels need to be elucidated in future studies.

Association of High-Sensitivity Cardiac Troponin T With 30-Day and 5-Year Mortality After Cardiac Surgery.

BACKGROUND: The relevance of perioperative myocardial injury (PMI) after cardiac surgery for 30-day mortality and long-term survival remains to be determined. OBJECTIVES: This study assessed the association of PMI after cardiac surgery, reflected by postoperative troponin release, with 30-day mortality and long-term survival after: 1) coronary artery bypass grafting (CABG); 2) isolated aortic valve replacement (AVR) surgery; and 3) all other cardiac surgeries. METHODS: A consecutive cohort of 8,292 patients undergoing cardiac surgery with serial perioperative high-sensitivity cardiac troponin T (hs-cTnT) measurements was retrospectively analyzed. The relationship between postoperative hs-cTnT release and 30-day mortality or 5-year mortality was analyzed after adjustment with EuroSCORE II using a Cox proportional hazards model. hs-cTnT thresholds for 30-day and 5-year mortality were determined for isolated CABG (32.3%), AVR (14%), and other cardiac surgery (53.8%). RESULTS: High postoperative hs-cTnT levels were associated with higher 30-day mortality but not 5-year mortality. In CABG, median peak concentration of postoperative hs-cTnT was 1,044 ng/L, in AVR it was 502 ng/L, and in other cardiac surgery it was 1,110 ng/L. hs-cTnT thresholds defining mortality-associated PMI were as follows: for CABG, 2,385 ng/L (170× the upper reference limit of normal in a seemingly healthy population [URL]); for AVR, 568 ng/L (41× URL); and for other cardiac procedures, 1,873 ng/L (134× URL). hs-cTnT levels above the cutoffs resulted in an HR for 30-day mortality for CABG of 12.56 (P < 0.001), for AVR of 4.44 (P = 0.004), and for other cardiac surgery of 3.97 (P < 0.001). CONCLUSIONS: PMI reflected by perioperative hs-cTnT release is associated with the expected 30-day mortality but not 5-year mortality. Postoperative hs-cTnT cutoffs to identify survival-relevant PMI are higher than suggested in current definitions.