The effects of hemodialysis on the coagulation system are not completely understood. The purpose of these studies was to determine the effects of hemodialysis on platelet deposition in prosthetic graft fistulas. Nine patients with polytetrafluoroethylene graft fistulas and two with native vein fistulas were studied. Dialysis was performed thrice weekly with blood flow rates of 400 to 450 mL/min and regenerated cellulose hollow-fiber dialyzers. Platelets were labeled with oxine-111indium. Images of the fistula were obtained immediately after injection (baseline study), postdialysis the same day, the following morning, and before and after the next two routine treatments. Images were analyzed by drawing regions of interest, and activities were expressed as counts per pixel and percent baseline after correction for background and biologic clearance and physical decay. There was a marked dialysis-associated enhancement of platelet deposition in sites along the graft. More than a twofold increase in uptake was noted most frequently in the arterial anastomosis, arterial loop, midloop, venous loop, and venous anastomosis regions. The arterial loop and midloop regions were most consistently affected. The arterial side of the loop during the first dialysis treatment showed an increase from 15 ± 3 counts/pixel (± SE) predialysis to 46 ± 14 counts/pixel postdialysis (P = 0.03, Mann-Whitney). The uptake increased with dialysis in the midloop region from 12 ± 2 counts/pixel to 40 ± 11 counts/pixel (P = 0.04, paired t-test). The uptake was nearly reversed by the next dialysis treatment. Subsequent treatments had a similar pattern. No significant change in activity was found in the two patients with native vein fistulas. These studies show that hemodialysis treatments are associated with enhanced deposition of platelets in polytetrafluoroethylene graft fistulas. This method of imaging platelet deposition may be useful for examining preventive treatments, such as antiplatelet therapies.
- Vascular access
- native vein fistulas