2.3. Pathohistological Protocol
CVH, EVH
The 1 cm long vein sample was taken from all patients immediately after finishing the harvesting and before vein distension by syringe (in CVH and EVH groups). The saphenous vein samples were fixed in a 4% buffered formalin solution (immersion fixation) and molded into paraffin. The paraffin blocks were sectioned at a thickness of 4 µm, then deparaffinized, rehydrated, and stained with hematoxylin and eosin (H&E), followed by standard protocols. Two independent pathologists observed all vein samples for the structure changes with a detailed examination of the entire H&E section for each patient. The extent of the vein wall changes was based on the estimation of all three layers: tunica intima, media, and adventitia (