Background: Cardiac allograft vasculopathy (CAV) is an important predictor of outcome in patients
following pediatric heart transplantation (pHTX). It is standard of care at most pediatric
heart transplant centers to perform regular coronary angiograms to detect early coronary
artery changes and adjust medical management accordingly. Recently, optical coherence
tomography (OCT) imaging has been suggested as a more sensitive marker of CAV. It
was the aim of this study to characterize systemic arterial characteristics in patients
following pHTX with or without angiographic or OCT evidence of CAV.
Method: Prospective cohort study comparing pHTX patients with evidence of CAV (CAV-HTX) based
on angiography (ISHLT grade ≥1) and/or OCT (grade ≥2) to pHTX patients without CAV
(Control-HTX). Descriptive variables including comorbidities such as chronic kidney
disease (CKD) were documented. Common carotid intima media thickness (cIMT) was analyzed
with ultrasound. Central blood pressure, central augmentation index corrected to a
heart rate of 75/minute (cAIx75) and carotid-femoral pulse wave velocity (PWV) were
measured (SpygmoCor XCEL). Reactive hyperemia index (RHI) as a measure of endothelial
function and peripheral AIx75 (pAIx75) were determined (EndoPAT). Retinal vessels
were assessed by arteriolar-to-venular ratio (AVR; iMedos). Data are expressed as
mean ± standard deviation; groups compared using the Student t-test, linear and logistic regression analyses.
Results: Twenty patients were included in group CAV-HTX, 19 in group Control-HTX. CAV-HTX
patients were significantly older (21 ± 7 vs. 15 ± 7 years, p = 0.006) and had undergone pHTX earlier than controls (16 ± 8 vs 10±6, p=0.014),
but were transplanted at similar age (7 ± 7 vs. 6 ± 6, p = 0.714). CKD was significantly associated with CAV (OR: 10, p = 0.004), and there was a trend towards an association with diabetes (p = 0.119). Following correction for age and sex, there was no significant difference
in weight, heart rate, brachial and central blood pressure as well as PWV (p = 0.490), pAIx75 (p = 0.366), RHI (B = 0.4, p = 0.082), and AVR (p = 0.970). However, IMT (B = 0.03, p = 0.041) was significantly thicker in the CAV-HTX group, while cAIx75 was lower (B = −9, p = 0.026).
Conclusion: CAV following pHTX in our cohort is associated with IMT thickening and CKD. We suggest
that these markers be followed closely in pHTX patients. Surprisingly, cAIx75—describing
relative pulse wave reflection—was decreased in group CAV-HTX in spite of similar
blood pressure. This could be related to confounders not analyzed herein.