Early Effect of Surgical Revascularisation on Left Ventricular Twist Function

The direct effect of coronary artery bypass graft (CABG) surgery on early recovery of myocardial function, particularly twist and rotation is not well studied. Aim: To assess the early response of the 3 myocardial components, circumferential, longitudinal and oblique to CABG in patients with isolated coronary disease. Methods: We studied 14 patients, age 64±10 years, before CABG and before hospital discharge using various Doppler echocardiographic techniques including speckle tracking, and compared them with 28 age matched controls. Results: Before surgery: Compared to controls, patients had significantly reduced LVEF (p=0.01) but maintained stroke volume (SV) (p=0.5). Diastolic LV function indices were statistically abnormal (p=0.01). LV lateral wall long axis amplitude and myocardial systolic velocities were both reduced (p=0.01) as was septal amplitude of motion (p=0.05). LV peak global longitudinal strain (GLS) was reduced as were systolic and early diastolic global longitudinal strain rates (p=0.01 for all). LV peak basal and apical rotations, twist and torsion were not different. Q-peak basal rotation was shorter than controls (p=0.01). After surgery: None of these measurements changed except peak GLS which further reduced (p=0.01). Pre-operatively, SV correlated with global LV function: twist (r= -0.65, p=0.01), and LV torsion (r=-0.66, p=0.01) but LVEF did not correlate with either. Post-operatively, SV correlated with E/A ratio (r=0.66, p=0.01), and the time interval Q- peak basal rotation rate (r=0.8, p=0.002). Conclusion: CABG does not result in significant early segmental LV functional improvement along its three myocardial components, but SV becomes dependent on early basal rotation and filling pressures.