High-Sensitivity Troponin and Mortality After Cardiac Surgery
- This single-center study including 8,292 patients showed that elevated high-sensitivity troponin values following cardiac surgery are associated with 30-day mortality.
- Greater increases in high-sensitivity troponin are seen following CABG than aortic valve replacement (AVR).
- High-sensitivity troponin elevations above procedure-specific thresholds have greater prognostic significance following CABG than AVR (hazard ratios for 30-day mortality: 12.56 following CABG, 4.44 following AVR).
What is the association between perioperative myocardial injury, as evidenced by postoperative troponin release, and mortality following cardiac surgery?
This retrospective study included consecutive patients undergoing cardiac surgery from 2010–2020 at a single center in Austria. Patients who underwent cardiac surgery without cardiopulmonary bypass and those without pre- and postoperative high-sensitivity cardiac troponin T (hs-cTnT) values were excluded. Operative risk was assessed with the current European System for Cardiac Operative Risk Evaluation score (EuroSCORE II). The primary outcome was 30-day mortality, and the secondary outcome 5-year mortality.
The study included 8,292 patients (median age 68 years, 31.1% female, median body mass index 26.0 kg/m2, mean EuroSCORE II 4.2%). The median preoperative hs-cTnT value was 13.8 ng/L. Isolated coronary artery bypass grafting (CABG) was performed in 2,676 patients (32.3%), isolated aortic valve replacement (AVR) in 1,159 patients (14.0%), and other cardiac surgery in 4,457 patients (53.8%). Median follow-up time was 4.5 years.
Overall 30-day mortality was 2.5%. The median peak concentration of postoperative hs-cTnT was higher in the CABG group than in the AVR group (1044 vs. 502 ng/L). Risk of 30-day mortality increased with every unit of log peak hs-cTnT after all types of surgery. In receiver operating characteristic analyses, the highest predictive value of hs-cTnT was for CABG patients (area under the curve [AUC] 0.796) and lower in AVR patients (AUC 0.694). The threshold hs-cTnT levels for predicting 30-day mortality were 2385 ng/L (170 x upper limit of normal) for CABG (hazard ratio, 12.56; p < 0.001) and 568 ng/L (41 x upper limit of normal) for AVR (hazard ratio, 4.44; p = 0.004). In Kaplan-Meier analyses, patients with above-threshold postoperative hs-cTnT had significantly increased 5-year mortality following CABG but not AVR.
Following cardiac surgery, high hs-cTnT levels are associated with increased 30-day mortality. Greater increases in hs-cTnT are seen following CABG than AVR, and hs-cTnT elevations have greater prognostic significance following CABG than AVR. Five-year mortality is increased in patients with high hs-cTnT following CABG but not AVR.
These findings would need to be validated in multicenter studies before routine pre- and postoperative troponin assessments could be justified in routine clinical practice. Thresholds for hs-cTnT would likely vary in obese and nonobese populations.
Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention
Keywords: Biomarkers, Cardiac Surgical Procedures, Coronary Artery Bypass, Transcatheter Aortic Valve Replacement, Troponin T
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