Creation of a distal arteriovenous fistula improves microcirculatory hemodynamics of prosthetic graft bypass in secondary limb salvage procedures.

PURPOSE

In patients with critical limb ischemia, poor distal arterial runoff, and absence of autogenous veins, the use of an artificial graft and an arteriovenous fistula might be a valuable option. However, in these patients little information is available regarding preoperative and postoperative microcirculatory hemodynamics after this type of intervention.

METHODS

With the use of intravital capillary microscopy, we studied the effect of distal revascularization on the microcirculation in 26 patients with critical limb ischemia. All patients had had failed vascular reconstructive operations, and artificial grafts were required because of the absence of autogenous veins. Patients were prospectively investigated and divided into two groups: 12 patients received a femorocrural bypass with polytetrafluoroethylene grafts, and 14 patients underwent the same procedure with the creation of an arteriovenous fistula at the site of the distal anastomosis and ligation of the proximal vein. Red blood cell velocity was measured before and after arterial occlusion to determine microcirculatory hemodynamic alterations.

RESULTS

Immediate postoperative graft patency was achieved in all 26 patients. The 1-year cumulative graft patency rate was 64% in the group that had creation of an arteriovenous fistula, which was significantly higher (p < 0.01) compared with that in the group in which a fistula was not created (21%). The 1-year cumulative foot salvage rate was 72% in the patients with an arteriovenous fistula and 43% in the patients without a fistula (p < 0.05). Red blood cell velocity increased similarly in both groups after the bypass procedure. Peak and time to peak red blood cell velocity also improved significantly in both groups; however, comparing both groups, peak and time to peak red blood cell velocity were significantly better (p < 0.05) in the patients with an arteriovenous fistula and remained significantly higher during the follow-up period.

CONCLUSIONS

In conclusion, creation of an adjunctive arteriovenous fistula at the distal anastomosis of a prosthetic graft appears to improve microcirculatory hemodynamics in the nutritional capillary vascular bed. Improved graft patency and foot salvage rates suggest that this procedure benefits patients with critical limb ischemia who have no usable veins.