Abstract 3416: Does Myocardial Strain and Strain Rate in Pediatric Cardiac Patients on Extracorporeal Membrane Oxygenation Predict Outcome? A Velocity Vector Imaging Study
Background: Survival after Extracorporeal Membrane Oxygenation (ECMO) for post-operative management in pediatric patients after cardiac surgery has been reported to be 37%. Conventional evaluation of the ventricular function in these patients prior to decannulation from ECMO has not been a sensitive predictor of the outcome. Myocardial strain and strain rate have been shown to be a sensitive imaging modality for quantitative assessment of ventricular function. We hypothesized that quantitative assessment of ventricular strain and strain rate using Velocity Vector Imaging (VVI) may predict survival of pediatric cardiac patients on ECMO.
Methods: Echocardiographic images of all consecutive pediatric cardiac patients on ECMO in 2005 were retrospectively analyzed. Patients with single ventricle were excluded. Patients were divided into two groups. Group A - survivors. Group B - nonsurvivors with endpoints: death, assist device, or transplantation. Two-dimensional echocardiographic images in the four chamber view were analyzed using VVI to determine strain and strain rate at the level of mitral and tricuspid valve annuli while patients were on ECMO. Ejection fraction (EF) was also obtained from VVI technique. Echocardiographic measurements were compared between the two groups by two tail t-test.
Results: Eight patients who survived ECMO were compared to twelve patients who reached an endpoint. The mean age between the two groups were not statistically different (7.6±8.6 months vs.8.4±9.6 months, p=NS). Survivors had higher mitral valve strain than nonsurvivors (−16±9% vs. −7±3%, p≤0.03). EF between the two groups was not statistically significant (25±15% vs. 13±9%, p=0.08). Mitral strain rate and tricuspid strain and strain rate were not statistically significant.
Conclusions: Myocardial strain can be used as a noninvasive tool in evaluating ventricular function. Mitral valve strain obtained by Velocity Vector Imaging may predict survival in pediatric cardiac patients on ECMO. Global ventricular systolic function measured by EF was not a predictor for survival.