title: Preoperative Vascular Medial Fibrosis and Arteriovenous Fistula Development.
abstract: Arteriovenous fistula maturation requires an increase in the diameter and blood flow of the feeding artery and the draining vein after its creation. The structural properties of the native vessels may affect the magnitude of these changes. We hypothesized that an increase in the collagen content of the vascular media (medial fibrosis) preoperatively would impair vascular dilation and thereby, limit the postoperative increase in arteriovenous fistula diameter and blood flow and clinical arteriovenous fistula maturation.
  
  
  
  We enrolled 125 patients undergoing arteriovenous fistula creation between October of 2008 and April of 2012 and followed them prospectively. Any consenting subject was eligible. Arterial and venous specimens were sampled during arteriovenous fistula surgery. Masson's trichrome-stained samples were used to quantify medial fibrosis. Arteriovenous fistula diameter and blood flow were quantified using 6-week postoperative ultrasound. Clinical arteriovenous fistula maturation was assessed using a predefined protocol. The association of preexisting vascular medial fibrosis with arteriovenous fistula outcomes was evaluated after controlling for baseline demographics, comorbidities, and the preoperative venous diameter.
  
  
  
  The mean medial fibrosis was 69%±14% in the arteries and 63%±12% in the veins. Arterial medial fibrosis was associated with greater increases in arteriovenous fistula diameter (Δdiameter =0.58 mm; 95% confidence interval [95% CI], 0.27 to 0.89 mm; P<0.001) and arteriovenous fistula blood flow (Δblood flow =85 ml/min; 95% CI, 19 to 150 ml/min; P=0.01) and a lower risk of clinical arteriovenous fistula nonmaturation (odds ratio, 0.71; 95% CI, 0.51 to 0.99; P=0.04), all per 10% absolute difference in medial fibrosis. In contrast, venous medial fibrosis was not associated with the postoperative arteriovenous fistula diameter, blood flow, or clinical maturation.
  
  
  
  Preoperative arterial medial fibrosis was associated with greater arteriovenous fistula diameter and blood flow and a lower risk of clinical arteriovenous fistula nonmaturation. This unexpected observation suggests that medial fibrosis promotes arteriovenous fistula development by yet undefined mechanisms or alternatively, that a third factor promotes both medial fibrosis and arteriovenous fistula maturation.
authors: Divisions of Nephrology and Hypertension, and.
authors: Yan-Ting
authors: YT
authors: Shiu
authors: Departments of Pathology.
authors: Silvio H
authors: SH
authors: Litovsky
authors: Divisions of Nephrology and Hypertension, and.|Renal Section, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah.|Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China; and.
authors: Alfred K
authors: AK
authors: Cheung
authors: Divisions of Nephrology and Hypertension, and.
authors: Daniel B
authors: DB
authors: Pike
authors: Divisions of Nephrology and Hypertension, and.
authors: Jason Chieh Sheng
authors: JCS
authors: Tey
authors: Epidemiology, University of Utah, Salt Lake City, Utah.
authors: Yingying
authors: Y
authors: Zhang
authors: Surgery, and.
authors: Carlton J
authors: CJ
authors: Young
authors: Radiology, and.
authors: Michelle
authors: M
authors: Robbin
authors: Department of Bioengineering, University of Texas at Dallas, Dallas, Texas.
authors: Kenneth
authors: K
authors: Hoyt
authors: Division of Nephrology University of Alabama at Birmingham, Birmingham, Alabama.
authors: Michael
authors: M
authors: Allon
mesh_terms: D000328:Adult; D000368:Aged; D001158:Arteries / Q000000981:diagnostic imaging / Q000473:pathology* / Q000502:physiology; D001166:Arteriovenous Shunt, Surgical; D003094:Collagen / Q000378:metabolism*; D054459:Elasticity Imaging Techniques; D005260:Female; D005355:Fibrosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D057234:Preoperative Period; D011446:Prospective Studies; D012039:Regional Blood Flow; D017540:Tunica Media / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology*; D014680:Veins / Q000000981:diagnostic imaging / Q000473:pathology* / Q000502:physiology
chemical_list: D003094:Collagen
keywords: Arteriovenous Shunt, Surgical; Collagen; Demography; Humans; Odds Ratio; Tunica Media; Veins; arteries; arteriovenous fistula; fibrosis; hemodialysis