[Contribution of ultrasonography in late maturation of native fistulae for chronic hemodialysis].

Early failure of arteriovenous fistulae for chronic hemodialysis can be avoided with early preoperative physical examination and complementary explorations. Nevertheless, insufficient development of the arteriovenous fistula after 3 months remains a frequent problem which is sometimes difficult to manage clinically. Duplex-Doppler is the fundamental exploration allowing distinction between pseudo-retard in maturation and true retard with low flow rate. In the first case, blood flow and venous and arterial caliber are normal but unfavorable anatomic conditions may result in superficialization. In the second case, blood flow is too with a true insufficiency in the venous caliber. An exhaustive exploration of the venous and arterial vessels allows accurate diagnosis of arterial strictures limiting inflow or venous strictures limiting dilatation to a diameter sufficient for puncture (6-7 mm). Different situations may occur: --anastomotic or justa-anastomotic strictures with a normal arterial and venous, suggesting the fistulae should be reoperated (excepting the rare situation resulting from intrinsic compression due to a postoperative hematoma); --focal stricture which generally requires interventional radiology on both the arterial and venous sides; --arterial strictures with diffuse calcification, requiring a new arterial site; --insufficient drainage via the elbow or a small or absent cephalic and/or basilary vein.