title: Prebypass histological and ultrastructural evaluation of the long saphenous vein as a predictor of early graft failure.
abstract: BACKGROUND
  Twenty percent of the long saphenous vein (LSV) grafts that are employed as coronary bypass conduits occlude during the first year after the operation. The aim of this study was to evaluate the morphological parameters of the LSV grafts before implantation as predictors for the early occlusion of the grafts.
  
  
  METHODS
  Forty-two samples of LSV grafts were examined via light, transmission electron, and scanning electron microscopy and evaluated clinically and by angiography at 6 months and 2 years after the operation. Morphological parameters were statistically analyzed and examined for their significance on the viability of the vein grafts.
  
  
  RESULTS
  Six (14.28%) of the examined grafts occluded within the first 6 months after the operation, and 11 grafts (26.19%) occluded within the first 2 years. The grafts that occluded at 6 months were characterized by thick intima (mean value, 206+/-32.29 vs. 67.44+/-10.17 in the group functioning normally and 98.42+/-34 in the group occluded within 2 years), low endothelial coverage (22.7+/-4.04 vs. 64.61+/-2.89 and 26.06+/-1.78 in the corresponding groups), and narrow lumen (46.73+/-9.69 vs. 527.18+/-45.78 and 204.26+/-16.5 in the corresponding groups). The presence of foam cells, edema, calcification, neovascularization, and thrombus in the lumen of the veins is frequently observed in the wall of the occluded vein grafts, whereas fibrosis does not seem to be related.
  
  
  CONCLUSIONS
  LSV grafts with low endothelial cell coverage, stenosis of the lumen, and thick walls are at an increased risk of developing intrawall lesions that lead to early graft failure.
authors.affiliation: Laboratory of Histology-Embryology, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece. kouzi@med.auth.gr <kouzi@med.auth.gr>
authors.forename: Kokkona
authors.initials: K
authors.lastname: Kouzi-Koliakos
authors.forename: M
authors.initials: M
authors.lastname: Kanellaki-Kyparissi
authors.forename: G
authors.initials: G
authors.lastname: Marinov
authors.forename: V
authors.initials: V
authors.lastname: Knyazhev
authors.forename: E
authors.initials: E
authors.lastname: Tsalie
authors.forename: Chr
authors.initials: C
authors.lastname: Batzios
authors.forename: D
authors.initials: D
authors.lastname: Kovachev
mesh_terms: D001026:Coronary Artery Bypass; D004730:Endothelium, Vascular / Q000648:ultrastructure; D005260:Female; D005500:Follow-Up Studies; D006083:Graft Occlusion, Vascular; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D011237:Predictive Value of Tests; D011379:Prognosis; D012501:Saphenous Vein / Q000473:pathology* / Q000637:transplantation / Q000648:ultrastructure