Eastern Cardiothoracic Surgical Society

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Elevated Troponin I Before Coronary Artery Bypass Grafting: Do the Level and Timing Matter?
Carlos Martinez Licha, Emma J. Morone, Lava R. Timsina, Niharika Namburi, James B. Milward, Aaron J. Clark, Lawrence S. Lee.
Indiana University, Indianapolis, IN, USA.

Objective: The optimal timing of coronary artery bypass grafting (CABG) in patients with elevated cardiac troponin (cTnI) levels following acute coronary syndrome is unknown. We sought to investigate the relationship between cTnI level and outcomes after CABG; we evaluated the effects of both the absolute maximum (“peak") cTnI level as well as timing of surgery in relation to this peak value.
Methods: Retrospective single center study with data obtained from an institutional Society of Thoracic Surgeons registry and patient records. Inclusion criteria were patients who underwent isolated CABG between the years 2009 and 2016 and had a pre-operative cTnI result available. Preoperative, intraoperative, and postoperative variables were analyzed. Bivariate, multivariate, and receiver operating characteristic (ROC) analyses were performed.
Results: 608 patients were included. ROC analysis identified 5.74 ng/mL as the level associated with adverse postoperative outcomes. Patients with peak cTnI > 5.74 ng/mL were twice as likely to experience an adverse postoperative outcome (OR, 1.98; p=0.004) and had 2.8 day longer postoperative length of stay (p=0.000) than those without. cTnI level was not associated with mortality or 30-day readmission. Time of peak cTnI relative to surgery was not associated with adverse outcomes.
Conclusion: Elevated cTnI up to a certain level (5.74 ng/mL at our institution) is associated with worse postoperative outcomes, but the absolute degree of elevation beyond that value does not incrementally increase risk. Delaying CABG until after the cTnI level “peaks" does not affect postoperative outcomes.
Multivariable Regression – Peak Troponin > 5.74 ng/mL
OutcomeOR (95% CI)P-value
Mortality0.71 (0.26-1.93)0.502
LOS (days, surgery to discharge)1.90(0.41-3.38)*0.012
Surgery Status = emergent or urgent2.61(0.86-7.88)0.089
Intra-operative events0.67 (0.18-2.51)0.551
Any in-hospital postoperative event1.98 (1.24-3.15)0.004
Postoperative SSI †0.89 (0.08-10.51)0.927
Postoperative sepsis †1.08 (0.27-4.31)0.912
Postoperative neurological event1.16 (0.41-3.30)0.781
Postoperative pulmonary event1.99 (1.14-3.46)0.015
Postoperative vascular event †4.57 (1.03-20.27)0.045
Postoperative renal failure0.93 (0.34-2.53)0.885
Other postoperative event1.25 (0.74-2.12)0.400
Readmission < 30 days0.76 (0.39-1.49)0.427
Note: Models adjusted for age, sex, smoking status, BMI, and comorbidities.
†estimates from penalized logistic regression
*regression coefficient provided rather than OR
Abbreviations: LOS, length of stay; SSI, surgical site infection


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