title: Isometric exercise increases the size of forearm veins in patients with chronic renal failure.
abstract: OBJECTIVE
  Delay in maturation or failure of maturation of Cimino-Brescia fistulae contributes to the significant vascular access-related morbidity of chronic hemodialysis patients. Increased size and capacitance of native veins before the formation of vascular access has been considered an important variable in the success rate of native fistulae. We evaluated whether a formal exercise program might alter the size of native veins.
  
  
  METHODS
  The effect of exercise on venous size was evaluated in 5 patients with severe chronic renal failure [glomerular filtration rate, 30.6 +/- 5.3 mL/min (mean +/- SD)]. Five male patients with a mean age of 57 +/- 9 years underwent a 6-week forearm exercise training program, involving nondominant arms, that included isometric hand-grip contractions to 25 to 35% of MVC lasting 40 to 120 seconds and repetitive squeezing of squash and racquet balls. Both the volume and intensity of exercise training was increased weekly based on strength measured by hand-grip dynamometer and on the patients' indicated level of comfort. Cephalic vessel size in both the nondominant (trained) and dominant (control) arms, with and without a tourniquet, were obtained using Doppler ultrasound before and after the 6-week exercise training program.
  
  
  RESULTS
  The size of the cephalic vein of the exercised arm increased significantly ( < 0.05) compared with the control arm when measured in both the absence (048 +/- 0.016 versus 0.024 +/- 0.023 cm ) and the presence of a tourniquet (0.056 +/- 0.022 versus 028 +/- 0.027 cm ).
  
  
  CONCLUSIONS
  These findings indicate that a simple, incremental resistance, exercise-training program can cause a significant increase in the size of the cephalic vein commonly used in the creation of an arteriovenous fistula. The increase in size and resultant probable increase in blood flow might accelerate the maturation of native arteriovenous fistulae, thereby lessening the morbidity associated with vascular access.
authors.affiliation: Division of General Medicine, Greater Los Angeles VA Healthcare System, Los Angeles, CA 90073, USA. david.leaf@med.va.gov
authors.forename: David A
authors.initials: DA
authors.lastname: Leaf
authors.forename: Holden S-H
authors.initials: HS
authors.lastname: MacRae
authors.forename: Edward
authors.initials: E
authors.lastname: Grant
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Kraut
mesh_terms: D000368:Aged; D001166:Arteriovenous Shunt, Surgical; D015444:Exercise / Q000502:physiology*; D005542:Forearm / Q000098:blood supply*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis / Q000401:mortality; D014680:Veins