Serum cardiac troponin I after conventional and minimal invasive coronary artery bypass surgery

We evaluated myocardial release of cardiac troponin I (cTnl) in patients treated with conventional coronary artery bypass grafting (CABG), which employs extracorporeal circulation, and different kinds of minimal invasive coronary artery bypass grafting (MICABG), a surgical technique where the operation is performed without extra-corporeal circulation. Furthermore, we evaluated the usefulness of serum cTnl measurement to detect perioperative myocardial infarction (PMI) after coronary artery bypass surgery. Thirty-one patients were included: sixteen underwent CABG, fifteen underwent different MICABG and five patients had PMI. Blood specimens for cTnl measurements were collected up to 72 hours after opening the graft. Aortic cross-clamping time was a minor determinant of myocardial damage; on the other side, the trauma during surgery correlated with the number of involved arteries and with the manoeuvre employed to obtain heart dislocation, and appeared a more important determinant of myocardial damage. In patients with PMI, the cumulative release of cTnl was higher than in patients free from PMI; however, only after 24-72 hours we observed significant differences in serum cTnl values, because the increased perioperative values of cTnl complicated the interpretation of the myocardial status and a single cut-off could not be used to exclude PMI.