Abstract 18106: 2d Strain is a More Accurate Measure of Systolic Function Than Shortening Fraction and Ejection Fraction in Pediatric Patients Following Orthotopic Heart Transplant

Abstract

Introduction: 2D strain by echocardiography is a sensitive technique for assessing LV systolic function in pediatric heart transplant patients, although it is under-utilized clinically. Methods: We prospectively compared 2D LV 4-chamber Lagrangian longitudinal strain (LS) in 34 echo studies against cardiac output indexed to body surface area (cardiac index, Ci) via cardiac catheterization to assess accuracy of LS. Of those echos, 31/34 were simultaneous with cath, and 3/34 were within 10 days of catheterization. Ci was also compared to LV shortening fraction (SF) and single plane ejection fraction (EF). FS via M-mode in parasternal short-axis and EF via 4 chamber were measured. Strain was obtained in the 4 chamber apical view as an average of 6 segments. Right heart catheterization was performed and evaluated by a cardiac interventionalist blinded to echo data. Pearson’s correlation coefficient was used to assess relationships. Results: Mean age was 10.2 years (0.3 - 19 years), 11 males. Mean HR was 99 bpm (64-155) for catheterization, and 97 bpm (66-148) for echocardiography, mean frame rate 72 f/sec (47-109). Mean Ci was 3.8 L/min/m2 (95% CI 1.9 to 5.73). LS was diminished for this cohort, mean -13.7 (95% CI - 4 to -23.3), however, EF and SF were normal (mean EF 59.1% (95% CI 32.58%- 85.6%), mean FS 35.6% (95% CI 24%- 47%)). There was moderate positive correlation between LS and Ci, (r = 0.48, p = 0.002). FS and EF did not correlate with Ci (r = 0.34, p = 0.03, and r = 0.15, p = 0.39 respectively). There was fair positive correlation between LS and EF and LS and SF (r = 0.36, p = 0.03 and r = 0.38, p = 0.02 respectively). Conclusion: 4 chamber LV LS may be a more sensitive and reliable non-invasive method to assess systolic function in pediatric heart transplant patients. Further investigation in a larger sample using global (18 segment) strain is warranted.