Evaluation of Changes in Myocardial Deformation Parameters Assessed by Speckle -Tracking Echocardiography following Coronary Artery Bypass Grafting: A Prospective Observational Study

Background: Coronary artery bypass grafting (CABG) uses native conduits to bypass blocked coronaries. It relieves anginal symptoms, reduces incidences of further myocardial infarction, improves myocardial function, and prevents sudden death. Left ventricular ejection fraction (LVEF) that is most commonly to use to quantify myocardial contractility is not a good marker post CABG. Long term follow-up studies have found conflicting results. Speckle tracking echocardiography (STE) is a promising way to objectively quantify left ventricular function. Global longitudinal strain (GLS) has been found to be a better predictor after CABG. We attempted to see improvement in myocardial function by assessing changes in GLS, post systolic index (PSI) and peak strain dispersion (PSD) 4 weeks and 3 months after CABG. Methods: In our prospective observational study, we examined 70 patients undergoing CABG. Baseline LVEF, GLS, PSI, and PSD were compared with postoperative values at 4 weeks and 3 months. Results: We found that GLS, PSI, and PSD improved significantly at 3 months post-surgery after showing deterioration at 4 weeks in patients with LVEF 45%. However, in patients with LVEF <45%, Only GLS showed statistically significant improvement at 3 weeks even though all 3 had deterioration at 4 weeks. LV EF did not change much in our study in either of the groups Conclusion: STE provides useful, efficient tools to monitor improvement in left ventricular function post CABG. This improvement follows an initial deterioration in function at 4 weeks.