Longitudinal Strain by Speckle Tracking Echocardiography in Pediatric Heart Transplant Recipients

Heart transplant recipients are at risk for developing left ventricular (LV) dysfunction. While traditional echocardiographic parameters have limitations, speckle tracking echocardiography (STE) is a novel technique shown to be more sensitive and accurate in adult studies for evaluating ventricular systolic and diastolic function.

Pediatric heart transplant recipients undergoing routine cardiac catheterization were included. Ratio of mitral early diastolic velocity-to-strain rate during early LV filling (E/SR(E)) and global longitudinal peak systolic strain (GLPSS) was measured by STE imaging. These were compared with wedge pressures by catheterization and traditional echocardiographic parameters.

A total of 50 subjects (46% males) were included. Mean age of the subjects was 13.0 ± 6.3 years and time since transplant was 4.1 years (range 0.2-17.1 years). While peak mitral inflow to late diastolic velocity (E/A ratio) was the only traditional diastolic function parameter having significant correlation with pulmonary capillary wedge pressure (PCWP) (r = 0.3; P = .3), STE-derived E/SR(E) had modest correlation with PCWP (r = 0.55; P < .01). Also, while most traditional systolic function parameters were normal, 12 subjects (24%) had GLPSS > -18%. Interestingly, subjects with coronary artery disease (n = 6) had significantly higher E/SR(E) (71.9 ± 28.4) compared to subjects without (45.2 ± 10.8; P < .001).

Diastolic function parameters by STE imaging correlate better with gold standard PCWP measurement than traditional echocardiographic parameters. Also, utilizing STE, abnormalities of longitudinal LV systolic function may be more common than previously thought in pediatric heart transplant recipients without acute graft rejection, despite "normal" systolic function by traditional echocardiogram.