Effect of preoperative sonographic mapping on vascular access outcomes in hemodialysis patients

Background. Current DOQI guidelines encourage placing arteriovenous (AV) fi stulas in more hemodialysis patients. However, many new fistulas fail to ma ture sufficiently to be useable for hemodialysis. Preoperative vascular map ping to identify suitable vessels may improve vascular access outcomes. The present study prospectively evaluated the effect of routine preoperative v ascular mapping on the type of vascular accesses placed and their outcomes. Methods. During a 17-month period, preoperative sonographic evaluation of t he upper extremity arteries and veins was obtained routinely. The surgeons used the information obtained to plan the vascular access procedure. The ty pes of access placed, their initial adequacy for dialysis, and their longte rm outcomes were compared to institutional historical controls placed on th e basis of physical examination alone. Results. The proportion of fistulas placed increased from 34% during the hi storical control period to 64% with preoperative vascular mapping (P < 0.00 1). When all fistulas were assessed, the initial adequacy rate for dialysis increased mildly from 46 to 54% (P = 0.34). For the subset of forearm fist ulas, the initial adequacy increased substantially from 34 to 54% (P = 0.06 ); the greatest improvement occurred among women (from 7 to 36%, P = 0.06) and diabetic patients (from 21 to 50%, P = 0.055). In contrast, the initial adequacy rate of upper arm fistulas was not improved by preoperative vascu lar mapping (59 vs. 56%, P = 0.75). Primary access failure was higher for f istulas than grafts (46.4 vs. 20.6%, P = 0.001), but the subsequent long-te rm failure rate was higher for grafts than fistulas (P < 0.05). Moreover, g rafts required a threefold higher intervention rate (1.67 vs. 0.57 per year , P < 0.001) to maintain their patency. The overall effect of this strategy was to double the proportion of patients dialyzing with a fistula in our p opulation from 16 to 34% (P < 0.001). Conclusions. Routine preoperative vascular mapping results in a marked incr ease in placement of AV fistulas, as well as an improvement in the adequacy of forearm fistulas for dialysis. This approach resulted in a substantial increase in the proportion of patients dialyzing with a fistula in our pati ent population. Fistulas have a higher primary failure rate than grafts, bu t have a lower subsequent failure rate and require fewer procedures to main tain their long-term patency.