Vascular Access Steal Syndrome

Overview

Vascular access steal syndrome (VASS) is a complication that can occur after the creation of an arteriovenous (AV) fistula or graft, typically used for hemodialysis in patients with end-stage renal disease. It arises when blood is diverted away (or "stolen") from the distal extremity due to preferential flow through the low-resistance AV access. This diversion results in insufficient arterial perfusion to the hand or forearm, leading to ischemic symptoms. Although uncommon, VASS can be serious and may require surgical intervention to restore adequate blood flow.

Causes

The primary cause of vascular access steal syndrome is the hemodynamic alteration induced by the creation of an AV fistula or graft. Blood preferentially flows through the artificial connection between an artery and a vein, potentially depriving distal tissues of oxygenated blood. Risk factors and contributing conditions include:

• High-flow AV fistulas or grafts

• Proximal AV access (e.g., brachial artery fistulas)

• Pre-existing peripheral arterial disease

• Diabetes mellitus or atherosclerosis

• Female gender and older age

• Use of large-caliber veins or arteries

Symptoms

Symptoms of vascular access steal syndrome usually affect the hand and may range from mild to severe, depending on the extent of ischemia. Common symptoms include:

• Coldness or cool sensation in the hand or fingers

• Pain at rest or during dialysis

• Numbness, tingling, or paresthesia

• Weakness or reduced grip strength

• Pale or bluish discoloration of the skin

• Ulcers, delayed wound healing, or gangrene in severe cases

Diagnosis

Diagnosis of VASS is based on clinical suspicion, physical examination, and confirmatory imaging studies. Diagnostic steps include:

• Clinical examination: Comparison of pulses, skin temperature, and capillary refill between the affected and unaffected limbs

• Duplex ultrasonography: To assess blood flow patterns in arteries and veins near the fistula

• Digital pressure measurements: Reduced pressures in the fingers may suggest ischemia

• Angiography: Provides detailed visualization of the arterial system and helps identify the degree of steal

Treatment

Treatment depends on the severity of symptoms and the degree of ischemia. Management options include both non-surgical and surgical approaches:

• Conservative management: Observation and monitoring in mild cases without tissue compromise

• Banding: Reduces blood flow through the AV access to improve distal perfusion

• Distal revascularization and interval ligation (DRIL): A surgical procedure that creates a bypass to restore blood flow while maintaining access function

• Revision using distal inflow (RUDI): Alters the inflow site to a more distal artery to reduce steal

• Ligation of the AV access: Reserved for severe cases when salvage of the access is not possible

Prognosis

The prognosis of vascular access steal syndrome depends on timely recognition and appropriate intervention. With early diagnosis and effective treatment, most patients experience symptom relief and preservation of hand function. However, delayed or inadequate treatment can lead to irreversible ischemic damage, including ulceration or amputation. Surgical interventions like DRIL or banding have high success rates in resolving symptoms while preserving dialysis access.