Role of troponin I in choice of surgical approach after coronary artery bypass grafting (according to AMIRI-CABG Trial)

Introduction . Coronary artery bypass grafting is worldwide accepted method of treatment of ischemic heart disease. Nevertheless, intraoperative ischemic-reperfusion injury, especially when associated with graft dysfunction, could influence on surgical outcomes. There is no data about precise cut-off level of troponin I associated with graft failure after coronary artery bypass grafting. Aim – to evaluate relationship between troponin I elevation and probability of graft thrombosis. Materials and methods . During single-center non-randomized clinical trial involving 336 patients, admitted for elective coronary artery bypass grafting, role of troponin I level for surgical approach after coronary artery bypass grafting was evaluated in three groups: off-pump, n=181, on-pump, n=128 and pump-assisted (with cardiopulmonary bypass without aortic cross-clamping), n=27. Results . In patients with cardiac index >2.2, troponin I level exceeded the upper reference limit by almost 100 times: 0.5 ng/ml in off-pump group, 4.5 ng/ml in on-pump group. In patients with cardiac index <2.2, troponin I level was more than 2 times higher than in patients with cardiac index >2.2 and amounted to 1.6 ng/ml in off-pump group and 13 ng/ml in on-pump group. In patients with graft thrombosis, troponin I level was 1.6 ng/ml in off-pump group and 25.8 ng/ml in on-pump group. Conclusion . Troponin I level has an important role in choice of surgical approach after coronary artery bypass grafting. Intraoperative ultrasound examination of grafts with assessment of blood flow according to Doppler sonography and visualization of the stenotic area, if any, could be recommended for early diagnosis of graft failure and choice of surgical approach after coronary artery bypass grafting.