Quiz Page Answers March 2006

Article Outline

 

A 48-year-old woman with a left upper-arm brachiocephalic vein fistula access experienced several episodes of prolonged bleeding after hemodialysis. During a 7-month period, she underwent 3 percutaneous angioplasties of a long, segmental, left-cephalic vein stenosis. At the time of the last intervention, 2 overlapping 9 × 80-mm and 9 × 60-mm stents were placed across the stenosis. After 6 months, recurrent clotting of the dialyzer developed (despite heparin) and Kt/V declined (from 1.8 to 1.2). Dynamic venous pressure readings at a blood flow of 200 mL/min were 155, 163, and 169 mm Hg on 3 consecutive treatments, respectively. A fistulogram was performed (Figure 49A, Figure 49B, Figure 49C).

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• Figure 49A. 

  Plain x-ray of the stents with the humerus at 90°.

• Fibers in the stents are fractured in 2 locations (arrows), which likely is an incidental finding. However, there is stenosis at the most proximal segment of the stent (arrowhead), which likely explains the clinical presentation.

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• Figure 49B. 

  Plain x-ray of the stents with the humerus abducted to 135°.

• Fractures in the stents are evident, and the fibers are separated (arrows). This suggests that repetitive arm movement caused mechanical stress damage to the stent. The proximal stenosis is still visible (arrowhead).

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• Figure 49C. 

  X-ray of the stents after injection of radiocontrast.

• Injection of radiocontrast shows aneurysms that have formed at the sites of stent fracture (arrows).

What is your diagnosis?

With the recurrent clotting, declining Kt/V, and increasing dynamic venous pressures, one has to be concerned with a stenosis distal to the arterial anastomosis of the fistula. Given that the patient already has had a central lesion stented, one has to be concerned that stenosis has developed within the stent, at either end of the stent, or at a new location within the central vein.

Final diagnosis: Access stenosis and stent fracture.

Case provided by Ursula C. Brewster, MD, Hamid R. Mojibian, MD, John E. Aruny, MD, and Mark A. Perazella, MD, FACP, Departments of Medicine and Radiology, Yale University School of Medicine, New Haven, CT.

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