title: Access survival amongst hemodialysis patients referred for preventive angiography and percutaneous transluminal angioplasty.
abstract: OBJECTIVE
  Referring hemodialysis patients for elective access angiography and percutaneous transluminal angioplasty (PTA) is commonly done to prevent access failure, yet the effectiveness of this procedure remains unclear. DESIGN, SETTING, PARTICIPANTS, & MEASURES: An observational matched cohort analysis among 40,132 Medicare beneficiaries receiving hemodialysis with a fistula or graft was performed. Cox regression was used to determine whether access intervention was associated with improved 1-year access survival.
  
  
  RESULTS
  Nonsurgical access intervention was found to be frequent at a rate of 20.9 procedures per 100 access years. In the 1-year period after intervention using angiography and PTA, the overall access failure rate was 53.7 per 100 access years in the intervention group and 49.6 in the nonintervention group (HR = 1.02; 95% CI, 0.96 to 1.08). Similar findings were also seen when the analysis was repeated in only fistulas (HR = 1.06; 95% CI, 0.98 to 1.15) and grafts (HR = 0.95; 95% CI, 0.86 to 1.05). In patients with a low intra-access flow rate (HR = 0.86; 95% CI, 0.75 to 0.99) or a new access (HR = 0.79; 95% CI, 0.71 to 0.89), angiography and PTA significantly increased access survival when compared with nonintervention (P for interaction was <0.0001). Angiography-PTA-related upper-extremity hematoma, vessel injury, or embolism-thrombosis occurred in 1.1% of all patients.
  
  
  CONCLUSIONS
  Access characteristics significantly modify the survival benefits of angiography and PTA intervention where the benefits of these interventions are most seen in newer accesses or accesses with insufficient flow.
authors.affiliation: Clinical Research Division, Fresenius Medical Care North America, Waltham, MA 02451, USA. kevin.chan@fmc-na.com
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Chan
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Pflederer
authors.forename: David J R
authors.initials: DJ
authors.lastname: Steele
authors.forename: Michael P
authors.initials: MP
authors.lastname: Lilly
authors.forename: T Alp
authors.initials: TA
authors.lastname: Ikizler
authors.forename: Frank W
authors.initials: FW
authors.lastname: Maddux
authors.forename: Raymond M
authors.initials: RM
authors.lastname: Hakim
mesh_terms: D000368:Aged; D000800:Angioplasty, Balloon / Q000009:adverse effects; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003251:Constriction, Pathologic; D005260:Female; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy*; D016014:Linear Models; D008297:Male; D006278:Medicare; D008875:Middle Aged; D016016:Proportional Hazards Models; D011859:Radiography; D012039:Regional Blood Flow; D006435:Renal Dialysis; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States; D014654:Vascular Patency