Arteriovenous Access Hemodialysis Graft Pseudoaneurysm

Clinical History

A 78-year-old female suffering from end-stage chronic renal failure, treated with haemodialysis, was referred to the emergency department with pain and swelling at the site of the arteriovenous access graft.

Imaging Findings

We present a case of a 78-year-old female suffering from end-stage chronic renal failure, treated with haemodialysis, who was referred to the emergency department with pain and swelling at the site of the arteriovenous access graft. A CT angiography was performed to assess the cause of the upper arm swelling and the patency of the arteriovenous access graft. A large haematoma with fluid-fluid level and a focal outpounching of contrast media in the graft wall showed (Fig. 1), suggesting the formation of a pseudoaneurysm at the puncture site. Vessel view reconstruction showed the exact site of the pseudoaneurysm (Fig. 2). VRT shows the arteriovenous straight access graft, the pseudoaneurysm and the brachial artery and axillary vein anastomotic sites (Fig. 3).

Discussion

Maintenance of vascular access in patients with long term haemodialysis is the most common cause of hospitalisation. Various vascular access methods for haemodialysis have been used over the years. Currently the majority of long term haemodialysis accesses are polytetrafluoroethylene (PTFE) grafts placed primarily in the upper extremity. These grafts are however not immune to complications. Among the most common are: thrombosis, infection, venous aneurysm, pseudoaneurysm formation and subcutaneous infiltration with resultant haematoma. However the most common cause of graft failure is progressive stenosis at the venous anastomosis. Patients undergoing dialysis carry a high risk of arterial complications due to the use of large caliber needles, systemic heparinisation and repeated cannulations of a surgically created arteriovenous fistula. Pseudoaneurysms are rare complications (<5%) and often associated with wellworn haemodialysis grafts and their development is due to the concurrence of several events including; degradation of the PTFE graft material, insufficient haemostasis of a cannulation site, and the presence of a haemodynamically significant stenosis downstream from the cannulation site. Inadequate compression of a cannulation site can lead to persistent bleeding and the formation of a perigraft haematoma. The coexistence of a distal stenosis can increase intragraft pressure, force blood into the perigraft hematoma, and create a persistent communication between the haematoma and graft lumen. Continued bidirectional blood flow leads to the formation of a perigraft cavity or pseudoaneurysm.

Differential Diagnosis List

Final Diagnosis

Arteriovenous Access Graft Pseudoaneurysm

URL:	https://www.eurorad.org/case/8040
DOI:	10.1594/EURORAD/CASE.8040
ISSN:	1563-4086