title: Hyperhomocysteinemia, anticardiolipin antibody status, and risk for vascular access thrombosis in hemodialysis patients.
abstract: BACKGROUND
  Vascular access failure is an important cause of morbidity in end-stage renal failure patients on hemodialysis. Currently, little is known about risk factors that predispose certain hemodialysis patients to recurrent access thrombosis. Hyperhomocysteinemia (common in patients with renal failure) predisposes people with normal renal function to recurrent and early-onset venous thrombosis, although the effect on vascular access thrombosis is currently unknown. Previous studies have suggested that high titers of IgG anticardiolipin antibody (IgG-ACA) predispose hemodialysis patients to access thrombosis. This cross sectional study was designed to assess for an association between two predictive variables, hyperhomocysteinemia and elevated titers of IgG-ACA, and vascular access thrombosis in patients undergoing chronic hemodialysis.
  
  
  METHODS
  Risk factors for vascular access thrombosis were documented, and the number of episodes of access thrombosis was recorded for the previous three years in patients undergoing hemodialysis. Midweek predialysis total homocysteine and IgG-ACA levels were measured in all subjects.
  
  
  RESULTS
  Of the 118 patients who were enrolled, 75.4% had a native arteriovenous fistula. Episodes of vascular access thrombosis were recorded for the previous three years; 34 (28.8%, 95% CI 20.9 to 37.9%) patients had 72 episodes of access thrombosis over the period of risk. Mean homocysteine levels were not significantly different between these 34 patients (28.6 micromol/liter, 95% CI 24.5 to 32.7) and the patients who had no episodes of graft thrombosis (29.8 micromol/liter, 95% CI 26.7 to 32.9). Sixty-seven unselected patients had IgG-ACA levels drawn for analysis, and all assays were negative. The only variable that was associated with a higher risk for graft thrombosis was the type of vascular access placed (odds ratio 4.0, 95% CI 1.6 to 9.6 for patients with a synthetic graft compared with those with an arteriovenous fistula).
  
  
  CONCLUSIONS
  No association was found between homocysteine levels or anticardiolipin antibody and vascular access thrombosis in our patient population.
authors.affiliation: Department of Medicine, and Department of Pediatrics and Medical Genetics, University of Calgary, Calgary, Alberta, Canada.
authors.forename: B J
authors.initials: BJ
authors.lastname: Manns
authors.forename: E D
authors.initials: ED
authors.lastname: Burgess
authors.forename: H G
authors.initials: HG
authors.lastname: Parsons
authors.forename: J P
authors.initials: JP
authors.lastname: Schaefer
authors.forename: M E
authors.initials: ME
authors.lastname: Hyndman
authors.forename: N W
authors.initials: NW
authors.lastname: Scott-Douglas
mesh_terms: D017153:Antibodies, Anticardiolipin / Q000097:blood*; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects; D001807:Blood Vessel Prosthesis / Q000009:adverse effects; D002408:Catheters, Indwelling / Q000009:adverse effects*; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007676:Kidney Failure, Chronic / Q000097:blood / Q000276:immunology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis / Q000009:adverse effects*; D012307:Risk Factors; D013927:Thrombosis / Q000209:etiology*
chemical_list: D017153:Antibodies, Anticardiolipin; D007074:Immunoglobulin G; D006710:Homocysteine