Postoperative assessment of left ventricular function by two-dimensional strain (speckle tracking) after paediatric cardiac surgery.
Left ventricular (LV) dysfunction may complicate paediatric cardiac surgery with cardiopulmonary bypass, notably after long aortic cross-clamping (ACC). Assessment of occult myocardial injury by conventional echocardiographic variables may be difficult in the postoperative period. To evaluate the feasibility of two-dimensional (2D) strain in the postoperative period, and to assess the effect of ACC duration on this variable. Thirty-three paediatric patients (age<18years) with congenital heart disease undergoing cardiac surgery with cardiopulmonary bypass were included in this prospective single-centre study. Daily echocardiography was performed from the day before surgery to the fifth postoperative day. LV ejection fraction and LV 2D strain were measured. The cohort was divided into three groups according to ACC duration (group 1:<30minutes; group 2: 30-80minutes; group 3:>80minutes). Mean age and weight were 4.2±2.5years and 15.1±5.2kg, respectively. Feasibilities of longitudinal, circumferential and radial strains were good, and quite similar to conventional variables. Compared with conventional variables, intra- and interobserver agreements regarding 2D strain were better (r=0.916, P<0.001 and r=0.855, P<0.001 for longitudinal strain versus r=0.156, P=0.54 and r=0.064, P=0.80 for LV ejection fraction by Simpson's method). Postoperative evolution of longitudinal and circumferential strains was significantly different between the three groups (P<0.001), whereas there was no difference using conventional variables. Postoperative LV 2D strain is a feasible and reproducible method. Strain measurements seem to indicate correlation with ACC duration.