Guest: Dr. Christian de Virgilio is the Chair of the Department of Surgery at Harbor-UCLA Medical Center. He is also Co-Chair of the College of Applied Anatomy and a Professor of Surgery at UCLA's David Geffen School of Medicine. He completed his undergraduate degree in Biology at Loyola Marymount University and earned his medical degree from UCLA. He then completed his residency in General Surgery at UCLA-Harbor Medical Center followed by a fellowship in Vascular Surgery at the Mayo Clinic. Resources: Rutherford Chapters (10th ed.): 174, 175, 177, 178 Prior Holding Pressure episode on AV access creation: https://www.audiblebleeding.com/vsite-hd-access/ The Society for Vascular Surgery: Clinical practice guidelines for the surgical placement and maintenance of arteriovenous hemodialysis access: https://www.jvascsurg.org/article/S0741-5214%2808%2901399-2/fulltext KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update: https://pubmed.ncbi.nlm.nih.gov/32778223/ Outline: Steal Syndrome Definition & Etiology Steal syndrome is an important complication of AV access creation, since access creation diverts arterial blood flow from the hand. Steal can be caused by multiple factors—arterial occlusive disease proximal or distal to the AV anastomosis, high flow through the fistula at the expense of distal arterial perfusion, and failure of the distal arterial networks to adapt to this decreased blood flow. Incidence and Risk Factors The frequency of steal syndrome is 1.6-9%1,2, depending on the vessels and conduit choice Steal syndrome is more common with brachial and axillary artery-based accesses and nonautogenous conduits. Other risk factors for steal syndrome are peripheral vascular disease, coronary artery disease, diabetes, advanced age, female sex, larger outflow conduit, multiple prior permanent access procedures, and prior episodes of steal.3,4 Long-standing insulin-dependent diabetes causes both medial calcinosis and peripheral neuropathy, which limits arteries’ ability to vasodilate and adjust to decreased blood flow. Patient Presentation, Symptoms, Grading Steal syndrome is diagnosed clinically. Symptoms after AVG creation occurs within the first few days, since flow in prosthetic grafts tend to reach a maximum value very early after creation. Native AVFs take time to mature and flow will slowly increase overtime, leading to more insidious onset of symptoms that can take months or years. The patient should have a unilateral complaint in the extremity with the AV access. Symptoms of steal syndrome, in order of increasing severity, include nail changes, occasional tingling, extremity coolness, numbness in fingertips and hands, muscle weakness, rest pain, sensory and motor deficits, fingertip ulcerations, and tissue loss. There could be a weakened radial pulse or weak Doppler signal on the affected side, and these will become stronger after compression of the AV outflow. Symptoms are graded on a scale specified by Society of Vascular Surgery (SVS) reporting standards:5 Workup Duplex ultrasound can be used to analyze flow volumes. A high flow volume (in autogenous accesses greater than 800 mL/min, in nonautogenous accesses greater than 1200 mL/min) signifies an outflow issue. The vein or graft is acting as a pressure sink and stealing blood from the distal artery. A low flow volume signifies an inflow issue, meaning that there is a proximal arterial lesion preventing blood from reaching the distal artery. Upper extremity angiogram can identify proximal arterial lesions. Prevention Create the AV access as distal as possible, in order to preserve arterial inflow to the hand and reduce the anastomosis size and outflow diameter. SVS guidelines recommend a 4-6mm arteriotomy diameter to balance the need for sufficient access flow with the risk of steal. If a graft is necessary, tapered prosthetic grafts are sometimes used in patients with steal risk factors, using the smaller end of the graft placed at the arterial anastomosis, although this has not yet been proven to reduce the incidence of steal. Indications for Treatment Intervention is recommended in lifestyle-limiting cases of Grade II and all Grade III steal cases. If left untreated, the natural history of steal syndrome can result in chronic limb ischemia, causing gangrene with loss of digits or limbs. Treatment Options Conservative management relies on observation and monitoring, as mild cases of steal syndrome may resolve spontaneously. Inflow stenosis can be treated with endovascular intervention (angioplasty with or without stent) Ligation is the simplest surgical treatment, and it results in loss of the AV access. This is preferred in patients with repetitive failed salvage attempts, venous hypertension, and poor prognoses. Flow limiting procedures can address high volumes through the AV access. Banding can be performed with surgical cutdown and placement of ...
