title: Preoperative arterial microcalcification and clinical outcomes of arteriovenous fistulas for hemodialysis.
abstract: BACKGROUND
  Arteriovenous fistulas (AVFs) often fail to mature, but the mechanism of AVF nonmaturation is poorly understood. Arterial microcalcification is common in patients with chronic kidney disease (CKD) and may limit vascular dilatation, thereby contributing to early postoperative juxta-anastomotic AVF stenosis and impaired AVF maturation. This study evaluated whether preexisting arterial microcalcification adversely affects AVF outcomes.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  127 patients with CKD undergoing AVF surgery at a large academic medical center.
  
  
  METHODS
  Preexisting arterial microcalcification (≥1% of media area) assessed independently by von Kossa stains of arterial specimens obtained during AVF surgery and by preoperative ultrasound.
  
  
  RESULTS
  Juxta-anastomotic AVF stenosis (ascertained by ultrasound obtained 4-6 weeks postoperatively), AVF nonmaturation (inability to cannulate with 2 needles with dialysis blood flow ≥ 300mL/min for ≥6 sessions in 1 month within 6 months of AVF creation), and duration of primary unassisted AVF survival after successful use (time to first intervention).
  
  
  RESULTS
  Arterial microcalcification was present by histologic evaluation in 40% of patients undergoing AVF surgery. The frequency of a postoperative juxta-anastomotic AVF stenosis was similar in patients with or without preexisting arterial microcalcification (32% vs 42%; OR, 0.65; 95% CI, 0.28-1.52; P=0.3). AVF nonmaturation was observed in 29%, 33%, 33%, and 33% of patients with <1%, 1% to 4.9%, 5% to 9.9%, and ≥10% arterial microcalcification, respectively (P=0.9). Sonographic arterial microcalcification was found in 39% of patients and was associated with histologic calcification (P=0.001), but did not predict AVF nonmaturation. Finally, among AVFs that matured, unassisted AVF maturation (time to first intervention) was similar for patients with and without preexisting arterial microcalcification (HR, 0.64; 95% CI, 0.35-1.21; P=0.2).
  
  
  CONCLUSIONS
  Single-center study.
  
  
  CONCLUSIONS
  Arterial microcalcification is common in patients with advanced CKD, but does not explain postoperative AVF stenosis, AVF nonmaturation, or AVF failure after successful cannulation.
authors.affiliation: Division of Nephrology, University of Alabama at Birmingham, Birmingham, AL. Electronic address: mdallon@uab.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Allon
authors.affiliation: Department of Radiology, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Robbin
authors.affiliation: Department of Radiology, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Heidi R
authors.initials: HR
authors.lastname: Umphrey
authors.affiliation: Division of Transplant Surgery, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Carlton J
authors.initials: CJ
authors.lastname: Young
authors.affiliation: Division of Transplant Surgery, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Deierhoi
authors.affiliation: Division of Transplant Surgery, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Goodman
authors.affiliation: Division of Transplant Surgery, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Michael
authors.initials: M
authors.lastname: Hanaway
authors.affiliation: Department of Radiology, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Lockhart
authors.affiliation: Department of Microbiology, Montana State University, Bozeman, MT.
authors.forename: Jill
authors.initials: J
authors.lastname: Barker-Finkel
authors.affiliation: Department of Pathology, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Silvio
authors.initials: S
authors.lastname: Litovsky
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001157:Arterial Occlusive Diseases / Q000150:complications* / Q000000981:diagnostic imaging; D001166:Arteriovenous Shunt, Surgical; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000473:pathology*; D002114:Calcinosis / Q000150:complications* / Q000000981:diagnostic imaging; D003925:Diabetic Angiopathies / Q000150:complications; D003928:Diabetic Nephropathies / Q000150:complications / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis; D051436:Renal Insufficiency, Chronic / Q000150:complications* / Q000628:therapy; D016896:Treatment Outcome; D014463:Ultrasonography
keywords: AVF non-maturation; AVF survival; Arteriovenous fistula (AVF); arterial micro-calcification; arteriovenous access; cannulation; chronic kidney disease (CKD); hemodialysis; juxta-anastomotic AVF stenosis; vascular access; vascular calcification; vascular ultrasound; von Kossa staining