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 gra ft and an arteriovenous fistula might be a valuable option. However, i n these patients little information is available regarding preoperativ e and postoperative microcirculatory hemodynamics after this type of i ntervention. Methods: With the use of intravital capillary microscopy, we studied the effect of distal revascularization on the microcircula tion 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 pro spectively investigated and divided into two groups: 12 patients recei ved a femorocrural bypass with polytetrafluoroethylene grafts, and 14 patients underwent the same procedure with the creation of an arteriov enous fistula at the site of the distal anastomosis and ligation of th e proximal vein. Red blood cell velocity was measured before and after arterial occlusion to determine microcirculatory hemodynamic alterati ons. Results: Immediate postoperative graft patency was achieved in al l 26 patients. The 1-year cumulative graft patency rate was 64% in the group that had creation of an arteriovenous fistula, which was signif icantly higher (p < 0.01) compared with that in the group in which a f istula was not created (21%). The 1-year cumulative foot salvage rate was 72% in the patients with an arteriovenous fistula and 43% in the p atients without a fistula (p < 0.05). Red blood cell velocity increase d similarly in both groups after the bypass procedure. Peak and time t o peak red blood cell velocity also improved significantly in both gro ups; however, comparing both groups, peak and time to peak red blood c ell 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 adjuncti ve arteriovenous fistula at the distal anastomosis of a prosthetic gra ft 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 isch emia who have no usable veins.