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, 1.60.3years) and Fontan circulation (Fontan group, 3.3 +/- 0.3years), and in 20 children with normal PA haemodynamics and morphology (Control group, 1.5 +/- 0.3years). 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.