Abstract 15732: Myocardial Strain by Velocity Vector Imaging as a Marker For Function and Rejection in Pediatric Heart Transplant Recipients
OBJECTIVE: To identify and characterize any correlation of left ventricular (LV) peak longitudinal strain, as measured by Velocity Vector Imaging (VVI), to cardiac hemodynamics measured by catheterization and graft rejection by endomyocardial biopsy in pediatric recipients of orthotopic heart transplant (OHT).
METHODS: Twenty-seven sets of simultaneous echocardiographic and catheterization data were collected on 15 pediatric OHT recipients in a prospective, observational, single-center study from February 2007 through March 2008. Echo images were acquired from standard views. LV peak longitudinal strain was calculated post-procedure using VVI software (Siemens Medical Solutions). Catheterization hemodynamic data included cardiac index and pulmonary capillary wedge pressure. Rejection was graded according to ISHLT criteria from right ventricular endomyocardial biopsies. Statistical analysis included linear regression modeling and Spearman rank correlation.
RESULTS: LV peak longitudinal strain was positively and significantly correlated to cardiac index (Beta=4.34, 95% CI [2.17, 6.52], p<0.001, R2=0.41). Peak strain was negatively and significantly correlated to wedge pressure (Beta=-0.50, 95% CI [-0.82, -0.18], p=0.003, R2=0.30). A comparison of subjects demonstrating Grades 0 (n=8), 1R (n=12), and 2R rejection (n=7) suggested a trend toward negative correlation, albeit one lacking strict statistical significance (correlation coefficient=-0.31, 95% CI [-0.61, 0.09] p=0.12).
CONCLUSIONS: In pediatric OHT recipients, non-invasive echocardiographic measurement of LV peak longitudinal strain by VVI correlates with invasive measurements of cardiac hemodynamics. There is a trend toward lower LV peak longitudinal strain in subjects with relatively more severe graft rejection. Further evaluation incorporating a larger subject population is necessary to confirm and more precisely quantify the reliability of calculated LV peak longitudinal strain as an adjunct or alternative to current invasive standards of graft surveillance.
- © 2011 by American Heart Association, Inc.