High-sensitivity cardiac troponin T (hs-cTnT) after cardiac surgery: Correlation to postoperative complications and comparison with creatine kinase-MB

Objectives: It is well known that concentrations of cardiac troponin T, a marker of cardiomyocyte injury, may increase in patients undergoing cardiac surgery. It was our aim to assess the prognostic value of different postoperative cTNT-levels, measured with a new highly sensitive assay, especially in correlation to further biomarkers like creatine kinase-MB.

Methods: In 618 patients undergoing cardiac surgery between 01/2011 and 06/2011, postoperative blood samples for hs-cTnT-measurement were taken. At the same time CK, CK-MB, Lactat and LDH were determined in these patients.

Results: In 72 patients (12%) all postoperative TnT-values were less than 300 pg/ml (group A). Postoperative peak-levels between 300 and 1200 could be found in 420 patients (68%) (group B). In 126 patients (20%) (group C) TnT-values of more than 1200 pg/ml could be detected.

There were significant differences with regard to postoperative catecholamine support (A:8%, B:37%, C:47%), for duration of mechanical ventilation (A:11±12 hours, B:20±35h, C:31±63h) and for stay on ICU (A:1.1±0.9 days, B:2.6±3.6d, C:4.1±5.5d) (p<0.05) and total in-hospital stay (A:11.9±5.1d; B:15.4±9.4d; C:14.5±5.0d).

The incidence of minor and major postoperative complications could be correlated to peak levels of TnT.

Peak-values of CK-MB were significantly different between all three groups. However, the peaks of hs-cTnT preceded those of CK and CK-MB significantly.

Conclusions: Our results clearly showed that a postoperative cTnT-elevation is not always a prognostic tool to predict an adverse outcome after cardiac surgery. However, the incidence of a complicated course rises with increasing cTnT-levels. A cTnT-value of more than 1200 pg/ml is a reliable marker for ongoing complications.