Abstract 16060: Cardiac Magnetic Resonance Imaging Diastolic Indices Correlate With Cardiac Catheterization Filling Pressures in Pediatric Heart Transplant Recipients

Abstract

Background: Atrial and ventricular filling pressures are routinely used in pediatric heart transplant (HTx) recipients to assess graft function. Cardiac magnetic resonance (CMR) can provide a non-invasive assessment of diastolic function, but data are lacking in pediatric HTx. We hypothesized that CMR indices of diastolic function correlate with filling pressures, providing a non-invasive approach to assessment of ventricular dysfunction. Method: Pediatric HTx recipients were prospectively enrolled at the time of cardiac catheterization. Pulmonary capillary wedge pressure (PCWP) and right atrial pressure (RAP) were measured. CMR included standard volumetric analysis and T1 and extracellular volume (ECV) mapping in the short axis at the mid-left ventricle (LV) to evaluate extracellular matrix expansion. Filling curves were calculated by contouring every phase in the short axis stack and global longitudinal and circumferential strain (GLS, GCS) were calculated using feature tracking. Correlations were analyzed using Spearman’s correlation. Results: A total of 31 patients with a mean age of 16.2 y/o were included, 9 with biopsy-proven acute rejection. The median time from transplant was 6.9 years and the mean LVEF was 58%. Peak LV ejection rate/end-diastolic volume (PER/EDV) correlated with PCWP (rho=-0.43, p=0.02, Fig 1) and RAP (rho=-0.40, p=0.03). GLS and GCS correlated with RAP (rho=0.51 p=0.007, and rho=0.38 p=0.05, respectively); GLS also correlated with PCWP (rho=0.46, p=0.02). Native T1 time-correlated with PCWP (rho=0.54, p=0.003), while the correlation between ECV and PCWP did not reach statistical significance (rho=0.37, p=0.06). Conclusion: CMR can be a useful non-invasive modality to assess for early signs of diastolic dysfunction in patients after pediatric HTx. Further research is needed to describe the clinical significance of these associations.