Can Intraoperative Cardiac Cycle Efficiency Values Predict Postoperative Myocardial Injury?

Background and Objectives: Myocardial injury after noncardiac surgery (MINS) is a major determinant of perioperative morbidity and mortality. Its largely silent clinical course often makes early diagnosis difficult and challenging. Cardiac Cycle Efficiency (CCE), is a new parameter that reflects the energy efficiency of the cardiovascular system. This study aimed to evaluate the relationship between intraoperative CCE values and postoperative myocardial injury. Materials and Methods: This prospective observational study included 50 adult patients. The CCE parameters, including baseline CCE, minimum CCE, mean CCE, ΔCCE, and the duration and percentage of CCE<0, were continuously recorded. In all patients, high-sensitivity troponin I (hs-TnI) levels were measured on the postoperative days 1, 2, and 3. The primary endpoint was defined as exceeding the 99th percentile upper limit of the hs-TnI values. Results: Postoperative troponin elevation above the 99th percentile upper reference limit was identified in 11 patients (22%); none of these patients had accompanying ischemic symptoms or new ECG changes. Comparison of CCE-derived parameters between the elevated and normal troponin groups yielded no statistically significant differences for any variable (MinCCE p=0.87, MeanCCE p=0.74, DeltaCCE p=0.69, CCE index p=0.50, time with CCE<0 p=0.19, CCE<0 percentage p=0.51). Spearman rank correlation analysis similarly demonstrated no significant association between any CCE parameter and peak troponin levels; the closest trend was observed for MinCCE (r=–0.244, p=0.08), which nonetheless did not reach statistical significance. On ROC curve analysis, none of the CCE parameters exhibited meaningful discriminative ability, with the highest AUC recorded for cumulative time with CCE below zero (AUC=0.63, 95% CI: 0.43–0.83, p=0.19). Conclusions: Intraoperative CCE parameters failed to predict postoperative troponin elevation in patients at low-to-moderate risk undergoing elective noncardiac surgery. These findings indicate that CCE is not a reliable, standalone predictive marker in this patient population. Studies involving higher-risk patient groups and larger sample sizes are required.