Great Saphenous Vein Lumen: Intimal Openings.

Area of Science:

• Vascular Biology
• Surgical Anatomy
• Histology

Background:

• The human great saphenous vein (SV) is a critical conduit for coronary artery bypass grafting (CABG).
• Understanding the intricate morphology of the SV intima is essential for optimizing graft patency and function.
• Previous studies have not fully elucidated the nature of intimal openings and their relationship with vasa vasorum.

Purpose of the Study:

• To investigate the morphological characteristics of the human great saphenous vein (SV) luminal intima.
• To differentiate between vasa vasorum and tributary openings within the SV intima.
• To explore the potential role of intimal structures in SV graft function after CABG.

Main Methods:

• Laser confocal microscopy (LCM) for observing vessel-like profiles.
• Transmission electron microscopy (TEM) for detailed ultrastructural analysis.
• Scanning electron microscopy (SEM) for high-resolution imaging of intimal surfaces.

Main Results:

• LCM revealed apparent vessel-like profiles that may be misinterpreted as vasa vasorum.
• SV intima exhibits openings (5-20 μm), with larger ones (>10 μm) identified as tributary branches, not vasa vasorum.
• Smaller openings (<10 μm) lack clear vascular features, suggesting alternative functions; elongated openings (3x30 μm) may lead to inner media folds.

Conclusions:

• Intimal openings in the SV, particularly larger ones, represent tributary branches, not terminating vasa vasorum.
• The function of smaller intimal openings requires further investigation.
• Communication between SV lumen and vasa vasorum is potentially vital for graft anti-ischaemic protection, warranting further research.