Left Atrial Function Correlates With Fibrosis in Pediatric Heart Transplant Recipients

Area of Science:

• Cardiology
• Transplant Medicine
• Echocardiography

Background:

• Pediatric heart transplant (PHT) surveillance for chronic graft failure (CGF) is challenging.
• Left atrial strain (LAS) shows promise in assessing diastolic dysfunction (DD).
• The utility of LAS in PHT for CGF surveillance, especially with left atrial anastomosis and without significant DD, is understudied.

Purpose of the Study:

• To investigate the role of novel echocardiographic parameters, specifically left atrial strain (LAS), in the surveillance of chronic graft failure (CGF) in pediatric heart transplant patients (PHT).
• To assess the correlation between various LAS parameters (global and segmental) and diastolic dysfunction indicators with histopathological findings of fibrosis and hemodynamic measurements from cardiac catheterization in PHT.
• To evaluate LAS in PHT patients, considering the presence of left atrial anastomosis and in the absence of significant diastolic dysfunction or acute rejection.

Main Methods:

• Echocardiograms were performed on 84 PHT patients within 3 months of surveillance cardiac catheterization, excluding those with acute rejection on endomyocardial biopsy (EMB).
• Measurements included left atrial reservoir, conduit, and contractile strain (LAS-r, LAS-cd, LAS-ct), segmental LAS-r, mitral valve E/A, average E/e', and indexed LA volume.
• EMB fibrosis (0-5 scale) and pulmonary capillary wedge pressure (PCWP) from catheterization were used for correlation analysis with echocardiographic variables.

Main Results:

• Mean LAS-r was significantly decreased in PHT patients compared to age-matched normative data (23.4% vs. normal).
• Decreased septal and lateral wall LAS-r correlated with elevated PCWP.
• Fibrosis score correlated with mitral valve E/A (r=0.32, p=0.009) and LAS-ct (r=-0.22, p=0.043).

Conclusions:

• Left atrial strain (LAS) is diminished in pediatric heart transplant patients, even with preserved left ventricular systolic function.
• Global and segmental LAS measurements correlate with endomyocardial biopsy fibrosis and pulmonary capillary wedge pressure, suggesting utility in CGF surveillance.
• Further longitudinal studies are necessary to establish the direct relationship between these diastolic function measures and chronic graft failure outcomes in PHT.