Abstract 2323: Troponin after Cardiac Surgery: A Predictor or a Phenomenon?
Background: Increased cardiac troponin is observed after virtually every cardiac surgery, although the significance of this elevation is controversial. The objective of this study was to correlate postoperative troponin levels with Major Adverse Cardiac Events (MACE).
Methods: 1918 consecutive patients undergoing cardiac surgery were included (CABG =1515, valve surgery =229 and combined procedures =174). Troponin T (normal value < 0.1 ng/L) was measured 12–24 h post-op. Patients with recent MI (within 30 days) were excluded. The primary outcome was a composite of mortality, ECG-defined MI and low output syndrome (MACE).
Results: Patients were divided into quintiles based on their peak postoperative troponin level. Adverse outcomes were observed to be low in the quintiles 1, 2 and 3. A stepwise increase in adverse outcomes was observed in the higher quintiles (Table 1⇓). The numbers of patients undergoing combined procedures were increased in the highest risk quintile. Mean troponin T levels were 0.94±1.53, 1.2±2.9 and 1.3±1.2 (P=0.0004) in the CABG, valve and combined groups respectively. Mortality rates were 1.4%, 6.1% and 7% (P<0.001) and MACE were 17%, 35% and 44%, (P<0.0001) respectively. In the ROC analysis, a troponin cutoff of 0.8 ng/L was the most predictive for MACE, AUC= 0.67. Various multivariable analyses showed that troponin values more than 0.8 ng/ml (i.e. fourth and fifth quintiles) were independently associated with postoperative adverse outcomes controlling for other preoperative and procedural variables (Odds Ratio 2.71, 95% CI 2.08 – 3.54, p< 0.0001).
Conclusions: Moderate elevations of troponin T are very common after adult cardiac surgery, but are usually associated with a benign clinical course. Major adverse perioperative cardiac events are much more frequent for elevations greater than 0.8 ng/ml.