title: Lumen loss in the first year in saphenous vein grafts is predominantly a result of negative remodeling of the whole vessel rather than a result of changes in wall thickness.
abstract: BACKGROUND
  The use of saphenous vein grafts (SVG) in coronary artery bypass surgery is established but little is known of SVG remodeling during the first year in vivo.
  
  
  RESULTS
  The feasibility of measuring total vessel diameter (lumen plus wall), lumen diameter, and wall thickness by a novel computed tomography (CT) method was established in phantom model tubes (r=0.98 for lumen diameter and r=0.98 for wall thickness) and in an initial clinical study of 14 patients correlating CT and intravascular ultrasound measurements of SVG (r=0.88 for total vessel diameter, r=0.85 for lumen diameter and r=0.89 for wall thickness). In a separate group of 42 patients (aged 66+/-10 years; 36 male, 6 female) undergoing coronary artery bypass grafting, SVG total vessel diameter, lumen diameter, and wall thickness were determined prospectively with multi-slice CT angiography at 1 and 12 months postoperatively. Mean total vessel diameter decreased from 5.95+/-0.83 mm to 5.39+/-0.87 mm, P<0.001 (range, -39% to +8% change). Twenty-six patients (62%) had a decrease of SVG vessel diameter (negative remodeling) >5%. Mean lumen diameter decreased from 3.69+/-0.66 mm to 3.36+/-0.68 mm, P<0.001, (range, -40 to +11% change). Surprisingly, mean wall thickness decreased from 1.14+/-0.27 mm to 1.01+/-0.21 mm (P<0.001; range, -48 to +33% change).
  
  
  CONCLUSIONS
  Lumen loss in SVG between postoperative months 1 and 12 is predominantly caused by negative remodeling of the whole vessel rather than to changes in wall thickness. Therapies targeting negative remodeling may be required for optimal maintenance of SVG lumen in the first postoperative year.
authors.affiliation: Department of Cardiology 3W, Concord Hospital, University of Sydney, Hospital Rd, Concord, NSW 2139, Australia.
authors.forename: George T
authors.initials: GT
authors.lastname: Lau
authors.forename: Lloyd J
authors.initials: LJ
authors.lastname: Ridley
authors.forename: Paul G
authors.initials: PG
authors.lastname: Bannon
authors.forename: Louise A
authors.initials: LA
authors.lastname: Wong
authors.forename: Joseph
authors.initials: J
authors.lastname: Trieu
authors.forename: David B
authors.initials: DB
authors.lastname: Brieger
authors.forename: Harry C
authors.initials: HC
authors.lastname: Lowe
authors.forename: Ben S
authors.initials: BS
authors.lastname: Freedman
authors.forename: Leonard
authors.initials: L
authors.lastname: Kritharides
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000368:Aged; D015331:Cohort Studies; D001026:Coronary Artery Bypass / Q000379:methods* / Q000706:statistics & numerical data; D023903:Coronary Restenosis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000494:pharmacology; D008875:Middle Aged; D019047:Phantoms, Imaging; D011184:Postoperative Period; D012501:Saphenous Vein / Q000000981:diagnostic imaging / Q000473:pathology / Q000637:transplantation*; D016037:Single-Blind Method; D014057:Tomography, X-Ray Computed; D014183:Transplantation, Heterologous; D018084:Ultrasonography, Interventional
chemical_list: D000319:Adrenergic beta-Antagonists; D008790:Metoprolol