In the present study, the LVEF remained preserved in patients undergoing both operative techniques and did not show any difference in the long-term follow-up. Although the on-pump group showed a more significant release of necrosis biomarkers, even so, it did not result in impaired ventricular function. In this scenario, a significant decrease in the ejection fraction was observed in both groups when the release of necrosis biomarkers was accompanied by acute myocardial infarction.
This result was observed in individuals with multivessel coronary disease, in 95% of patients with documented ischemia, and in patients with similar demographics, clinical, laboratory, and ventricular function characteristics who underwent either surgery. Despite the groups’ similarities, the technical differences between the surgeries, especially regarding CPB, such as cannulation, aortic clamping, cardioplegic solution, and its systemic effects caused by the inflammatory response to the circuit, resulted in higher releases of myocardial necrosis biomarkers.
The release of myocardial necrosis biomarkers is a frequent occurrence after myocardial revascularization, and the pathophysiology underlying this phenomenon is complex and poorly understood . Usually, cardiac injury is associated with direct myocardial trauma that results from manipulation of the heart, inadequate intraoperative cardiac protection, or microvascular events related to reperfusion and induced by oxygen free radical generation, which are potentially reversible conditions . However, functional impairment presents when a cardiac injury meets the clinical criteria for myocardial infarction.
Data showed a slight decrease in the ejection fraction, which was observed in patients in both groups at the long-term follow-up. This decrease, within the normal range, can be explained by aging of the heart and the atherosclerosis of intramyocardial vessels. The heart undergoes complex changes during aging that affect the cellular composition, marked by a decrease in the absolute number of cardiomyocytes and exemplified by pathological alterations, including hypertrophy, altered left ventricular (LV) diastolic function, diminished LV systolic reverse capacity, increased arterial stiffness, and impaired endothelial function 
Achieving complete revascularization is challenging, and these challenges were present in this study. Although the surgical plan was created to balance the samples of the two groups before randomization, it was not implemented. The results showed greater completeness of revascularization in the patients in the on-pump group. On the other hand, considering the invasiveness of the procedure, patients in the on-pump group had longer intubation times, more significant bleeding and longer stays in the intensive care unit, without the added risk of impaired ventricular function. Even so, there was no significant change in LVEF over time.
Different operative techniques for surgical revascularization are complementary. The completeness of revascularization could compensate for the nonphysiological nature of CPB, and early hospital discharge compensates for the shortened surgical time. All of this without compromising LVEF.
To the best of our knowledge, our study was the only study that reassessed and compared systolic function between surgical techniques after 5 years. We performed an ECHO, an accessible, reproducible, and harmless diagnostic test for the patient, to estimate LVEF, a method of measuring systolic function validated from a diagnostic, therapeutic, and prognostic point of view in clinical practice .
There were some limitations. First, this analysis of measurements performed at 5.9 years did not include any patient who died before that time. Therefore, these results only applied to patients who were alive at the end, so it is possible that patients with a lower LVEF died before our evaluation. We performed an ECHO, which is an exam in which image acquisition is limited; however, intra- and interobserver variability, in terms of the method of measuring ventricular function, may present oscillations of magnitude that is equivalent to the median of the delta obtained at the end of the follow-up .