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Findings: Contrast injection of the left leg AV graft with images obtained over the left iliac venous system (Image #1) reveals a high-grade stenosis of the left iliac venous system at the junction of the common and external iliac veins. This is in proximity to the surgical clips and is presumed to be at the site of venous anastomosis of the failed renal transplant. The lesion was angioplastied with a 14 mm diameter balloon. Post angioplasty there was marked improvement in luminal diameter (Image #2). The patient's left lower extremity edema improved dramatically. However, the patient returned six months later with recurrent leg swelling and follow-up venogram (Image #3) revealed recurrent stenosis at the angioplasty site. Therefore, a 14 mm diameter self-expanding metallic stent was deployed at the stenotic site. This resulted in marked improvement in luminal diameter (Image #4). The patient's lower extremity edema resolved and he remains asymptomatic over one year later.
Diagnosis: Venous stenosis following renal allograft and AV graft placement.
Discussion: AV graft failure is commonly due to thrombosis secondary to venous stenoses. Primary patency rates at one year may be as low as 50%. In those patients who develop venous stenoses, approximately 60% occur at the venous anastomosis, 30% occur within the graft and the remaining 10% usually occur within several cm of the venous anastomosis. In this patient, however, the stenosis occurred somewhat further upstream at the site of prior renal transplant vein anastomosis. Presumably, the previous surgery in this location rendered this vein more susceptible to injury following graft placement and arterialization of venous flow. This patient nicely illustrates that while venous angioplasty is technically simple, long-term results are somewhat disappointing. Grafts treated with angioplasty alone have a six month patency of approximately 60% and a one year patency of only approximately 40%. With stent placement, patency rates approaching 80% at six months have been achieved. In this patient the indication for treatment was not graft failure but rather symptomatic venous obstruction which was undoubtedly compounded by the presence of a graft in this extremity.
References:
Vorwerk D, et al. Venous Stenosis and Occlusion in Hemodialysis Shunts:
Follow-up Results of Stent Placement in Sixty-Five Patients. Radiology 1995; 195:140-146.
Gray RJ, et al. Use of Wallstents for Hemodialysis Access - Related Venous Stenoses
and Occlusions Untreatable With Balloon Angioplasty. Radiology 1995; 195:479-484.
Valji K. Transcatheter Treatment of Thrombosed Hemodialysis Access Grafts.
AJR 1995; 164:823-829.
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