In vivo three-dimensional FD-OCT visualization of microvascular structures consistent with vasa vasorum in a conventionally harvested saphenous vein graft.

BACKGROUND: The no-touch (NT) saphenous vein graft (SVG) technique improves long-term graft patency. Proposed mechanisms include maintenance of adventitial and perivascular structures and avoidance of high-pressure distension. Whether adventitial structures consistent with VV remain detectable in carefully harvested conventional SVGs without a thick tissue pedicle remains uncertain. CASE PRESENTATION: A 75-year-old woman underwent aortic valve replacement and coronary artery bypass grafting. The SVG was harvested using a carefully performed conventional technique that retained an approximately 1-2 mm rim of surrounding adipose tissue and protected the adventitia. Graft dilation was performed using cardiopulmonary bypass arterial-line pressure (approximately 100 mmHg), avoiding manual high-pressure distension. Two weeks postoperatively, frequency-domain optical coherence tomography (FD-OCT) demonstrated low-signal tubular structures within the adventitial layer. Three-dimensional reconstruction showed longitudinal continuity of structures morphologically consistent with vasa vasorum externae. CONCLUSIONS: This case demonstrates localized adventitial structures consistent with VV in a carefully harvested conventional SVG. Although functional patency could not be confirmed, the findings are hypothesis-generating and warrant further comparative investigation.