Blood flow volume changes in the maturing arteriovenous access for hemodialysis

In our center, we start hemodialysis using arteriovenous accesses empirically 1 mo after surgery in nearly all patients, when the vein diameter reaches 5 mm and blood flow is assumed to be adequate. We measured blood flow and vessel diameter in the maturing autogenous and prosthetic access to determine if this approach can be justified by quantitative physiological parameters. Of 66 consecutive autogenous and prosthetic arteriovenous accesses created over 3 mo in 2004, 62 were prospectively examined by duplex ultrasonography preoperatively, immediately after surgery in the recovery room, at 10 d postoperatively and 1 mo after surgery before first cannulation. In the 20 forearm accesses, the immediate postoperative mean blood flow was 549 +/- 189 mL/min, 885 +/- 227 mL/min at 10 d and 934 +/- 260 mL/min at 1 mo. In the 22 upper-arm accesses, the immediate postoperative mean access blood flow was 858 +/- 292 mL/min, 1060 +/- 326 mL/min at 10 d and 1116 +/- 427 mL/min at 1 mo. In 20 prosthetic accesses, near maximal flow was attained immediately after surgery (990 +/- 256 mL/min). Most of the increased flow in autogenous accesses occurred early in the maturation process. This suggests that 1 mo is adequate for autogenous access maturation before use for hemodialysis. The process of access maturation appears to be less relevant in prosthetic accesses, where blood flow is high from the day of surgery and tissue incorporation is, therefore, more important.