Troponin I after Cardiac Surgery and 30-Day Mortality

Devereaux et al. corroborate the independent negative prognostic effect of increased levels of cardiac troponin I after cardiac surgery,1 reinforcing the notion derived from a meta-analysis of earlier studies2 that the predictive thresholds of 5670 ng per liter after coronary-artery bypass grafting (CABG) and aortic-valve replacement or repair and of 12,981 ng per liter after other cardiac surgery are much higher than the cut-off points endorsed in guidelines3 and provide sufficient prognostic information for identifying those patients with levels below these thresholds for whom there is a low likelihood of a complicated course. Although the authors were unable to differentiate ischemic myocardial damage from procedural injury, it is well recognized that levels of cardiac troponin I increase almost universally after cardiac surgery, and the magnitude of this increase varies depending on the surgical procedure performed and the anesthesia and cardioplegia used.1,4 We believe that their data beg the question of what is now the truly abnormal value of cardiac troponin I after cardiac surgery, because they have moved the threshold bar to particularly high values, thereby suggesting that caution has to be paid as to the clinical judgment used when integrating the variable elevated cardiac troponin I levels into the complex puzzle of other known powerful independent predictors of worse postoperative outcome.1