ASDIN white paper: Management of cephalic arch stenosis endorsed by the American Society of Diagnostic and Interventional Nephrology

Abstract

Brachiocephalic arteriovenous fistulas (AVF) makeup approximately one third of prevalent dialysis vascular accesses. The most common cause of malfunction with this access is cephalic arch stenosis (CAS). The accepted requirement for treatment of a venous stenosis lesion is ⩾50% stenosis associated with hemodynamically abnormalities. However, the correlation between percentage stenosis and a clinically significant decrease in access blood flow (Qa) is low. The critical parameter is the absolute minimal luminal diameter (MLD) of the lesion. This is the parameter that exerts the key restrictive effect on Qa and results in hemodynamic and functional implications for the access. CAS is the result of low wall shear stress (WSS) resulting from the effects of increased blood flow and the unique anatomical configuration of the CAS. Decrease in WSS has a linear relationship to increased blood flow velocity and neointimal hyperplasia exhibits an inverse relationship with WSS. The result is a stenotic lesion. The presence of downstream venous stenosis causes an inflow-outflow mismatch resulting in increased pressure within the access. Qa in this situation may be decreased, increased, or within a normal range. Over time, the increased intraluminal pressure can result in marked aneurysmal changes within the AVF, difficulties with cannulation and the dialysis treatment, and ultimately, increasing risk of access thrombosis. Complete characterization of the lesion both hemodynamically and anatomically should be the first step in developing a strategy for management. This requires both access flow measurement and angiographic imaging. Patients with CAS present a relatively broad spectrum as relates to both of these parameters. These data should be used to determine whether primary treatment of CAS should be directed toward the anatomical lesion (small MLD and low Qa) or the pathophysiology (large MLD and high Qa).

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“…However, given the low restenosis rates reported in this study, flow reduction may be considered a reasonable alternative to repeat PTA in those with recurrent CAS and high access flow rates, necessitating flow measurement when performing PTA of recurrent CAS ( 43 ). Newer algorithms propose measuring flow as the first step of every case when a CAS is encountered so that a decision regarding primary treatment with PTA or flow-reduction can be made ( 43 ). Surgical revision is typically reserved for when other options, including PTA +/− stent placement, have failed to produce durable outcomes and when flow is not high enough to consider flow reduction.…”

“…The cephalic arch represents the terminal portion of the cephalic vein as it traverses the deltopectoral groove and claviculopectoral fascia prior to joining the axillary vein, which it does at a nearly perpendicular angle (42,111). CAS is the culprit lesion in approximately 40-75% of dysfunctional brachiocephalic fistulas, depending on the study, and less commonly seen in dysfunctional radiocephalic fistulas, where it has been found to represent 2-20% of lesions (12,34,43,44,112). Turbulent flow resulting from the perpendicular insertion of the cephalic arch make it prone to NIH and stenosis, and the lesion is more common in brachiocephalic fistulas due to the higher flow rates inherent of the brachial compared to the radial artery, with higher access flows demonstrating the greatest association with the development of CAS in a study by Jaberi et al (113).…”

“…No subsequent studies have been performed assessing flow reduction for the treatment of these lesions. However, given the low restenosis rates reported in this study, flow reduction may be considered a reasonable alternative to repeat PTA in those with recurrent CAS and high access flow rates, necessitating flow measurement when performing PTA of recurrent CAS (43). Newer algorithms propose measuring flow as the first step of every case when a CAS is encountered so that a decision regarding primary treatment with PTA or flowreduction can be made (43).…”

“…Access flow reduction via banding has been described in those with rapid cephalic arch restenosis after PTA and high flows within the fistula (>1,200 mL/min has been described) ( 43 , 122 ). Banding seeks to limit pathologic high flow, turbulence, and associated NIH within the cephalic arch by decreasing the luminal diameter in the juxta-anastomotic segment of the fistula, thereby decreasing inflow, and, subsequently, outflow.…”

“…Surgical revision is typically reserved for when other options, including PTA +/− stent placement, have failed to produce durable outcomes and when flow is not high enough to consider flow reduction. The most commonly employed surgical technique is outflow relocation via cephalic vein transposition, in which the healthy cephalic vein is incised proximal to the stenosis and re-anastomosed to the upper basilic or axillary vein ( 43 , 123 , 124 ).…”