Early and late troponin T determination after elective cardiac surgery. Two different meanings.

Aim: Although Troponins are demonstrated to be better predictors than CK-MB in quantification of myocardial damage, the relation between cut-off values for the diagnosis of perioperative myocardial infarction (PMI) and sample time is still not clear. In the present study we sought to analyse the clinical consequence of an early and late cTnt determinations after elective cardiac surgery.

Material Of Study: Data of 117 patients undergone elective open heart surgery between January 2006 and June 2007 were prospectively collected. PMI was detected on the basis of postoperative electrocardiography/echocardiography and hemodynamic state.

Results: The in-hospital mortality was 1.7%. Eight patients (6.8%) presented PMI. Receiver-operating characteristic (ROC) analyses showed a cTnt cut-off of 1.22 mg/L (CI 0.94 to 0.99, P = 0.0001, 100% sensitivity and 96% specificity) on arrival to ICU for the diagnosis of PMI. On the second post-operative day the cut-off value was 2.8 mg/L (CI 95% 0.84 to 0.98, P = 0.0001) (sensitivity 66% and specificity 100%). At this time the Pearson's test revealed the best correlation to ICU (P = 0.008) and in-hospital (P = 0.01) length of stay (LOS).

Discussion: A better sensibility of cTnt in diagnosis of PMI in the early postoperative period has been demonstrated to be associated to an increasing specificity in the late post-operative period.

Conclusions: PMI must be suspected in patients with a cTnt > 1.22 mg/L. A second later assessment on the 2nd post-operative can exclude false positives and significantly predict the ICU and the in-hospital length of stay.