Feasibility and interpretation of global longitudinal strain imaging in pediatric heart transplant recipients

Evaluation of myocardial mechanics after heart transplant is important in monitoring allograft function and identifying rejection. Speckle tracking global longitudinal strain (GLS) may be more sensitive to early regional changes from rejection. This study aimed to determine feasibility of GLS in pediatric hearts during surveillance echocardiograms, compare their GLS to published norms (-18% to -22%), and assess association of GLS with other indices of graft function. Retrospective review of transplant echocardiograms from 2013 to 2014. Philips QLAB was used for post-acquisition GLS analysis. Multiple linear regression was used to assess the association of GLS with echocardiographic/catheterization indices, and B-type natriuretic peptide (BNP). Forty-seven patients (84 studies) were included. Calculation of GLS was feasible in 82 studies (97%) with inter- and intra-observer variability of 0.71 and 0.69. Patients (n=9) with rejection had GLS of -16.4% (SD=3.5%) compared to those without [-16.8% (SD=3.7%)]. GLS worsened linearly with increasing Ln(BNP) (P=<.001), left ventricular volume in diastole (P=<.001), septal a' wave (P=<.001), and pulmonary capillary wedge pressure (P=<.001). Speckle tracking-based GLS is feasible and reproducible in pediatric heart recipients and is reduced at baseline. The role of GLS and BNP in detecting early systolic dysfunction warrants further investigation.