The relationship between diastolic function characteristics and severe myocardial injury in coronary artery bypass graft surgery: a retrospective cohort study

Introduction: The clinical significance of parameters characterizing left ventricular diastolic function after cardiac surgery has not been sufficiently studied. Objective: The study was aimed to test the hypothesis about the relationship between echocardiographic parameters of left ventricular diastolic function and the severe perioperative myocardial injury. Methods: This retrospective cohort study included 220 patients who underwent isolated coronary artery bypass surgery under cardiopulmonary bypass. We analyzed the degree of diastolic dysfunction, and transmittal blood flow characteristics including left ventricular early diastolic filling velocity (E-wave), and the ratio of E-wave to left atrial systole filling velocity (E/A), left atrial volume index, tricuspid regurgitation velocity, mean mitral valve annulus velocity (e'), and E/e' ratio according to echocardiography before and after surgery. Severe perioperative myocardial injury (the primary outcome) was identified when the high-sensitivity troponin I concentration reached a level greater than 5,670 ng/L on the first day after surgery. Results: ROC analysis showed that E-wave greater than 71 cm/s and E/A greater than 1.3 were associated with severe perioperative myocardial injury. In addition, diastolic dysfunction of grade 2 and 3 was found in 13.1% of patients with postoperative troponin I levels less than 5,670 ng/L and in 42.9% of patients with levels greater than 5,670 ng/L (P = 0.009). Conclusion: Postoperative degree of diastolic dysfunction and transmitral blood flow parameters are associated with prognostically unfavorable troponin I levels.