PRE-BYPASS QUALITY ASSESSMENT OF THE LONG SAPHENOUS-VEIN WALL WITH ULTRASOUND AND HISTOLOGY

Objectives: Pre-existing unsuspected wall changes in saphenous vein gr afts have been implicated in the graft outcome. Pre-bypass assessment of the vein may identify grafts at high risk for failure. This study w as conducted to evaluate preoperatively the quality of the long saphen ous vein (LSV) wall with ultrasound and histology. Design: Prospective clinical study. Material and Methods: Three particular LSV segments, ankle, knee and mid-thigh, were evaluated preoperatively by ultrasound in 40 limbs of 38 patients, candidates for coronary artery bypass gra fting. The venous wall was characterised based on its thickness and ec hogenicity in three categories: normal, moderately and severely fibrot ic. LSV specimens taken from the above sites were also grouped into th e same three categories based on their fibrotic content found on histo logy. Results: In total, 89 vein specimens were evaluated. On ultrasou nd, 81 specimens were detected as normal (91%), seven as moderately (8 %) and one as severely fibrotic (1%). On histology, only eight specime ns were found normal (9%), 75 with moderate (84%) and six with severe fibrosis (7%). Similar wall characterisation with both examinations wa s found in only 19% (17/89) of the specimens. Eighty-one specimens (91 %) had some degree of fibrosis on histology. Different grades of fibro sis were found on histology in different sites of the same vein. Concl usions: Pre-existing wall changes are very common in vein grafts used for bypass surgery. However, the ultrasonic characterization of the ne rvous wall preoperatively cannot reliably identify these changes.