Angiography (Fistulography)

Abstract

Angiography is not only a prerequisite to performing percutaneous angioplasty but also allows immediate assessment of its efficacy. High and good quality imaging is indispensable in arriving at a good and accurate diagnosis; maneuvering guidewires, catheters, and stents; evaluating the results of dilation, declotting, or stenting; and looking for complications. Iodinated contrast agents diluted to 90 % are used in pre-dialysis patients. The principle is to assess the whole stretch of the vascular access which starts from the feeding arteries, spans the arteriovenous anastomosis, and ends at the central veins. Angiography can be performed through a retrograde cannulation of the brachial artery at the elbow or by direct puncture of the vein. The arterialized vein caliber should be larger than its feeding artery unless it is stenosed. Determining whether a venous stenosis is significant enough to justify dilation is not always a straightforward affair. Stenoses can form at any arterial or venous segment of a forearm AVF but are more commonly found at the juxta-anastomotic area. Upper arm AVFs on the other hand develop stenosis more commonly downstream to the cannulation area. Brachial–cephalic AVFs are prone to developing cephalic arch stenosis. Grafts commonly develop stenoses at their venous anastomosis.