Clinical value of perioperative myocardial strain assessment by transesophageal speckle-tracking echocardiography in patients undergoing off-pump coronary artery bypass grafting

Objective To evaluate the clinical value of perioperative global longitudinal strain (GLS) derived from transesophageal two-dimensional speckle-tracking echocardiography (2D-STI) in predicting biomarker-defined postoperative myocardial injury and early cardiac functional alterations in patients undergoing off-pump coronary artery bypass grafting (OPCABG). Methods A total of 113 patients scheduled for OPCABG between February 2025 and February 2026 were enrolled. GLS was measured after anesthesia induction (T0), after graft reperfusion and protamine neutralization (T1), and 1.5 h after reperfusion (T2). Δ1 and Δ2 were calculated as T1−T0 and T2−T0. Transit-time flow measurement (TTFM) parameters were recorded after reperfusion. CK-MB, hs-cTnI, BNP, and left ventricular ejection fraction (LVEF) were assessed perioperatively. Patients were classified into high-risk and low-risk groups according to postoperative hs-cTnI thresholds for biomarker-defined myocardial injury. Spearman correlation, repeated-measures ANOVA, multivariable logistic regression, and receiver operating characteristic (ROC) analyses were performed. Results Of the 113 patients, 47 were classified as high risk and 66 as low risk. Compared with the low-risk group, the high-risk group had significantly lower GLS values at T0, T1, and T2, as well as lower Δ1 and Δ2 values. Among TTFM parameters, only total PI differed significantly between groups. Repeated-measures ANOVA showed significant time, group, and interaction effects for GLS. GLS at all time points was negatively correlated with 48-hour peak CK-MB, hs-cTnI, and BNP, and was also associated with ICU length of stay. In multivariable logistic regression, GLS at T0, T1, and T2 remained independently associated with biomarker-defined postoperative myocardial injury, with odds ratios of 0.319, 0.437, and 0.408, respectively. Both Δ1 and Δ2 also showed independent predictive value, with Δ2 showing a stronger effect. ROC analysis showed that T0 GLS, T2 GLS, and Δ2 had predictive value for biomarker-defined postoperative myocardial injury, with AUCs of 0.885, 0.884, and 0.840, respectively. Conclusion Perioperative GLS derived from transesophageal 2D-STI, particularly GLS after anesthesia induction, GLS at 1.5 h after graft reperfusion, and their dynamic changes, was associated with hs-cTnI elevation-defined postoperative myocardial injury and early cardiac functional alterations in patients undergoing OPCABG. Compared with TTFM, GLS provides complementary information on myocardial function and may help support intraoperative risk assessment.