Optical coherence tomography for early detection of cardiac allograft vasculopathy in pediatric heart recipients

BACKGROUND: Cardiac allograft vasculopathy (CAV) is a leading cause of graft failure following pediatric heart transplantation (HT). Early detection could improve long-term outcomes, but conventional coronary angiography often misses early-stage disease. Optical coherence tomography (OCT), a high-resolution intravascular imaging modality, may enable earlier and more sensitive CAV detection. METHODS: This retrospective study analyzed pediatric HT recipients who underwent OCT between 2012 and 2024. OCT-derived maximal intima thickness (MIT) and cross-sectional area ratios were correlated with coronary angiography findings, hemodynamic data, CAV risk factors, and immunosuppressive regimens. Longitudinal analysis was performed in patients with serial OCT. RESULTS: In 214 examinations (386 vessels) from 67 patients (median age 3.1 years, IQR 1.8-8.2, 49 % female, median 5.1 years post-HT, IQR 2.6-9.4), OCT-detected CAV (MIT ≥ 0.3 mm) was present in 31.9 % of vessels versus 8.0 % detected by angiography. MIT correlated with recipient and donor age, donor-recipient age difference, episodes of antibody-mediated rejection and was higher in adult donor grafts. Everolimus therapy was associated with significant lower MIT (p < 0.001). Over time, 73 % of grafts showed OCT-CAV with earlier onset (p = 0.037) and higher incidence (p = 0.005) in vessels from adult donors. Presence of CAV by angiography or OCT was associated with increased graft loss or dysfunction (log rank p = 0.044, HR 4.21, 95 %CI 1.16-15.28). CONCLUSIONS: OCT detects early-stage CAV in pediatric heart transplant recipients with substantially greater sensitivity than angiography. Everolimus may mitigate early CAV progression. OCT offers significant potential for early detection and risk stratification.