Vasa vasorum of the no-touch saphenous vein graft observed using frequency-domain optical coherence tomography.

Objectives: One possible reason for the long-term patency of no-touch (NT) saphenous vein grafts (SVG) is the preservation of the vasa vasorum in the adventitia/perivascular adipose tissue (PAT). We investigated the vasa vasorum of the NT SVG in vivo using frequency-domain optical coherence tomography (FD-OCT), performed qualitative and quantitative analyses and compared them with the conventional SVG.

Methods: An FD-OCT study was performed on 14 SVG at the postoperative coronary angiography 1-2 weeks postoperatively (NT group, n = 9; conventional group, n = 5).

Results: Many signal-poor tubular lumen structures that can be recognized in the cross-sectional and longitudinal profiles, which indicates the vasa vasorum, were observed in the adventitial/PAT layer in the NT SVG. In contrast, the vasa vasorum were less abundant in the conventional SVG. The volume of vasa vasorum per millimetre of graft in the no-touch group was significantly higher than in the conventional group [0.0020 (0.0017, 0.0043) mm3 and 0.0003 (0.0000, 0.0006) mm3, P = 0.023].

Conclusions: FD-OCT showed abundant vasa vasorum in the thick adventitia/PAT layer of NT saphenous veins in vivo. In contrast, few vasa vasorum were observed in the conventional SVG.