Cardiac allograft vasculopathy: Differences of absolute and relative intimal hyperplasia in children versus adults in optical coherence tomography

Background: Intracoronary imaging enables an early detection of intimal changes. To what extend the development of absolute and relative intimal hyperplasia in intracoronary imaging differs depending on age and post transplant time is not known. Methods: Aim of our retrospective study was to compare findings between 24 pediatric (cohort P) and 21 adult HTx patients (cohort A) using optical coherence tomography (OCT) at corresponding post-transplant intervals ( _5 years: P1 (n = 11) and A1 (n = 10); _ 10 years: P2 (n = 13) and A2 (n = 11),. Coronary intima thickness (IT), media thickness (MT) and intima to media ratio (I/M) were assessed per quadrant. Maximal IT 0.3 mm was considered absolute, I/M > 1 relative intimal hyperplasia. Results: Compared to A1, I/M was significantly higher in P1 (maximal I/M: P1: 5.41 [2.81-13.39] vs. A1: 2.30 [1.55-3.62], p = 0.005), whereas absolute IT values were comparable. In contrast, I/M was comparable between P2 and A2, but absolute IT were significantly higher in A2 (maximal IT: P2: 0.16 mm [0.11-0.25] vs. A2: 0.40 mm [0.30-0.71], p < 0.001). A2 presented with higher absolute IT (maximal: A1 : 0.16 mm [0.12-0.44] vs. A2: 0.40 mm [0.30-0.71], p = 0.02) and I/M (maximal I/M A1: 2.30 [1.55-3.62] vs. A2: 3.79 [3.01-5.62], p = 0.04). Conclusion: Our results suggest an ageand time-dependent difference in the prevalence of absolute and relative intimal hyperplasia in OCT, with an early peak in children and a progressive increase in adults. <(c)> 2020 Elsevier B.V. All rights reserved.