(Ultrasound Review) To establish whether preoperative ultrasound labeling improved success rates for arteriovenous fistulas for dialysis, researchers from the University of Istanbul studied 124 patients with chronic renal failure. Results of the study recently were published in the Journal of Ultrasound in Medicine.
A color Doppler examination of both arms was performed on all patients preceding surgery. The patients performed intermittent clenching of their hands for 2–3 minutes prior to the ultrasound examination.
The cephalic vein was evaluated from the wrist to the subclavian vein for evidence of contour irregularities, relative wall thickening, and the presence of normal spontaneous and phasic venous flow. The radial artery volume was calculated by multiplying the average mean velocity by the vessel cross-sectional area. "In the literature, a minimum volume flow of 200mL/min is considered one of the prerequisites for angio access," the researchers said.
The patients were randomly split into two groups, and for the first group of 52 patients the surgeon only had the physical examination to assist in surgical planning. The post-surgical success rate for this group was 75%.
In the remaining 13 patients the fistulas did not function due to either chronic thrombotic changes in the cephalic vein or decreased volume flow in the radial artery. To facilitate surgical planning, the surgeon had full knowledge of the ultrasound examination for the second group of patients. This group of patients had functioning fistulas in 94.4% of cases. In the remaining four patients, the cause for dysfunction was low volume flow in the radial artery.
According to the authors, "The most common complications of fistulas are lack of patency, failure of maturation, and insufficient flow through dialysis. The factors affecting the success of fistula surgery and adequate fistula flow are adequate arterial volume flow (which must be >200mL/min) and patency, as well as adequate distention capacity of the vein."
Overall, the researchers found that color Doppler ultrasonography was very helpful and suggested that the use of this technique be emphasized with surgeons performing arteriovenous fistula construction.
"Cephalic vein and hemodialysis fistula -- surgeon’s observation versus color Doppler ultrasonographic findings"
Ismail Mihmanli et al
Dept of Radiology, Cerrahpasa Medical Faculty, University of Istanbul, Istanbul, Turkey
J Ultrasound Med 20 (March); 20:217–222
By Ultrasound Review
May 21, 2001
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