Impending rupture of an arteriovenous fistula aneurysm

Hemodialysismedium

A 57-year-old man on hemodialysis presents immediately after dialysis with a painful, enlarged arteriovenous fistula. The fistula has enlarged progressively over several weeks, and after his last few treatments he needed 7–10 minutes of compression for hemostasis. Staff cannulate with 16-gauge needles using the rope-ladder technique. He takes apixaban for atrial fibrillation. The arterial anastomosis of the left arm fistula is expanded and pulsatile, and the overlying skin is blanched and tight with several needle puncture sites. What is the best next step?

  1. A.Avoid cannulation of expanded area
  2. B.Urgent surgical referralCorrect
  3. C.Duplex Doppler ultrasound of expanded area
  4. D.Ultrasound-guided manual compression

Explanation

The next best step is urgent surgical referral. This patient has a rapidly enlarging, painful, pulsatile aneurysmal segment of his fistula with thin, shiny, blanched, and tight overlying skin, recent prolonged bleeding after needle removal, and anticoagulation with apixaban. These are recognized warning signs of impending rupture: skin thinning or blanching, ulceration or eschar, spontaneous or prolonged bleeding from cannulation sites, and rapid expansion. Rupture of a high-flow fistula can cause exsanguination within minutes. The KDOQI 2019 vascular access guideline identifies such features as indications for urgent surgical evaluation, and management typically involves aneurysmorrhaphy, plication, resection with interposition grafting, or ligation, with a temporary catheter if needed. Imaging can be obtained as part of surgical planning, but it should not delay referral. Outflow stenosis, which raises intra-access pressure and contributes to both aneurysm growth and prolonged bleeding, should be sought and treated at the same time. Ultrasound-guided compression is used to thrombose iatrogenic femoral pseudoaneurysms after arterial catheterization. Compressing an expanding fistula aneurysm under thin skin risks thrombosing the access and does not address the threatened rupture. Duplex ultrasound helps distinguish true aneurysm from pseudoaneurysm, measure size and wall thickness, and identify thrombus or outflow stenosis. It is useful, but with skin changes signaling imminent rupture, surgical assessment takes priority and can include imaging. Avoiding cannulation of the dilated segment is appropriate preventive practice, and repeated cannulation of the same area is a cause of aneurysm formation. However, once overlying skin is compromised and the segment is enlarging rapidly, avoidance alone does not remove the risk of rupture.

Why each option

A.
Avoiding cannulation of dilated segments prevents enlargement, but it cannot remove rupture risk once overlying skin is blanched, tight, and the aneurysm is expanding.
B.
Correct. Rapid enlargement, pain, prolonged post-needle bleeding, and blanched tight skin over a pulsatile aneurysm on apixaban signal impending rupture needing urgent surgery.
C.
Duplex imaging characterizes aneurysm size, thrombus, and outflow stenosis, but with skin changes signaling imminent rupture it must not delay surgical assessment.
D.
Ultrasound-guided compression treats iatrogenic femoral pseudoaneurysms; compressing an expanding fistula aneurysm under compromised skin risks access thrombosis without removing rupture risk.

Reference: Lok CE, Am J Kidney Dis 2020 (KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update); Mudoni A, Clin Kidney J 2015 (aneurysms and pseudoaneurysms in dialysis access)

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