title: Ongoing vascular laboratory surveillance is essential to maximize long-term in situ saphenous vein bypass patency.
abstract: OBJECTIVE
  The purpose of this study was to assess the contribution of ongoing graft surveillance to maximize long-term patency of lower limb in situ saphenous vein bypasses.
  
  
  METHODS
  From January 1981 to October 1994, 556 autogenous grafts were constructed in 499 patients. The distal anastomosis was at the popliteal level in 207 (37%) and the tibial level in 349 (63%). All patients were enrolled in a prospective surveillance protocol to identify lesions that compromise graft patency and were evaluated at 1 day, 1 week, 6 weeks, and 3 months. Surveillance studies were then obtained every 3 months for the first 2 postoperative years and every 6 months thereafter.
  
  
  RESULTS
  Four-hundred-fifty abnormalities were detected in 236 grafts. The median interval from the initial procedure to detection of an abnormality was 12 months (range 0 to 113 months) and varied with the location of the defect. Later in the life of the graft, progression of atherosclerotic disease manifested as inflow obstruction at a median of 15 months, and outflow disease threatened the graft at a median of 29 months (r = 0.0003). Of the 450 surveillance abnormalities, 294 (65%) occurred within the first 2 years after operation, and 156 (35%) developed more than 2 years after operation. Of the 236 grafts that developed surveillance abnormalities, 50 (21%) developed the initial defect more than 2 years after the initial bypass procedure. Eleven percent of grafts remaining free of abnormality after 2 years went on to fail. Sixty-seven interventions were performed on 62 extremities after 24 months, with 30 involving previously unrevised grafts.
  
  
  CONCLUSIONS
  Because lesions amenable to revision continue to develop years after vein bypass construction, perpetual surveillance is required to ensure optimal rates of graft patency.
authors.affiliation: Department of Vascular Surgery, Medical College of Wisconsin, Milwaukee 53226, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Erickson
authors.forename: J B
authors.initials: JB
authors.lastname: Towne
authors.forename: G R
authors.initials: GR
authors.lastname: Seabrook
authors.forename: J A
authors.initials: JA
authors.lastname: Freischlag
authors.forename: R A
authors.initials: RA
authors.lastname: Cambria
mesh_terms: D000704:Analysis of Variance; D005260:Female; D005500:Follow-Up Studies; D006083:Graft Occlusion, Vascular / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D006439:Hemodynamics; D006801:Humans; D015993:Life Tables; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods / Q000706:statistics & numerical data; D011446:Prospective Studies; D012501:Saphenous Vein / Q000502:physiology / Q000637:transplantation*; D018709:Statistics, Nonparametric; D015996:Survival Rate; D013997:Time Factors; D014182:Transplantation, Autologous