Background: Cardiac troponin I (cTnI) is a highly sensitive and specific biomarker which has been shown to predict patient outcome pre- and postoperatively following elective coronary artery bypass surgery (CABG). Whether preoperatively elevated cTnI levels similarly predict the outcome in patients undergoing emergency CABG with acute myocardial infarction (AMI) is currently unknown.
Methods and results: A possible correlation between preoperative cTnI and in-hospital mortality and major adverse cardiac events (MACE) was investigated in 57 patients with ST-elevation AMI (STEMI) in group 1 and 197 with Non-ST-elevation AMI (NSTEMI) in group 2, who were operated within 24 hours after onset of symptoms. Primary study end point was all-cause in-hospital mortality. Secondary end points were low cardiac output syndrome (LCOS) and hospital course. CTnI levels on admission were higher in group 1 compared with group 2 (7.1+/-1.8 versus 1.4+/-1.8 ng/mL; P<0.001). Overall in-hospital mortality was higher in group 1 compared with group 2 (14.3 versus 4.1%; odds ratio [OR], 3.9, 95% confidence interval [CI], 1.3 to 12.3; P<0.01). LCOS occurred in 16/57 (28.1%), and 18/197 (9.1%) patients, respectively (OR, 3.9, 95% CI, 1.7 to 8.8; P<0.001). Postoperative ventilation time, intensive care, and hospital stay were significantly longer in group 1 versus group 2. Multivariate logistic regression analyses revealed preoperative cTnI as the strongest independent predictor for in-hospital mortality (P<0.001) and MACE (P<0.001) in all AMI patients, regardless whether ST-elevation was included as an additional risk factor or not.
Conclusions: Preoperative cTnI measurement before emergency CABG appears as a powerful and independent determinant of in-hospital mortality and MACE in acute STEMI and NSTEMI.