Three-dimensional imaging of pulmonary arterial vasa vasorum using optical coherence tomography in patients after bidirectional Glenn and Fontan procedures

Aims: We evaluated pulmonary arterial (PA) vasa vasorum (VV) in Fontan candidate patients with a novel three-dimensional (3D) imaging technique using optical coherence tomography (OCT).

Methods and results: This prospective study assessed the development of adventitial VV in the distal PA of 10 patients with bidirectional Glenn circulation (BDG group, 1.6 ± 0.3 years) and Fontan circulation (Fontan group, 3.3 ± 0.3 years), and in 20 children with normal PA haemodynamics and morphology (Control group, 1.5 ± 0.3 years). We assessed the PA VV with two-dimensional (2D) cross-sectional, multi-planar reconstruction (MPR), and volume rendering (VR) imaging. VV development was evaluated by the VV area/volume ratio, defined as the VV area/volume divided by the adventitial area/volume. Compared to the control group, the observed VV number and diameter on 3D images of MPR and VR were significantly higher, and curved and torturous-shaped VV were more frequently observed in the BDG and Fontan groups (P < 0.001, all). The median VV volume ratio was significantly greater in the BDG than in the control group (3.38% vs. 0.61%; P < 0.001). Although the VV volume ratio decreased significantly after the Fontan procedure (2.64%, P = 0.005 vs. BDG), the ratio remained higher than in the control group (P < 0.001 vs. control).

Conclusion: 3D OCT imaging is a novel method that can be used to evaluate adventitial PA VV and may provide pathophysiological insight into the role of the PA VV in these patients.