Background: Transplant Renal Artery Stenosis (TRAS) is a recognized complication resulting in graft dysfunction and post-transplant hypertension. Non-nephrotoxic imaging modalities such as ultrasonography are effective diagnostically, though definitive intervention historically requires vascular angiography with contrast agents. This presents a clinical challenge due to potential nephrotoxic effects of iodinated contrast agents in the setting of pre-existing graft dysfunction. CO2 angiography, which lacks nephrotoxic properties, is a potential alternative agent in the treatment of transplant renal artery stenosis.

Methods: Patients with suspected transplant renal artery stenosis diagnosed by non-invasive imaging modalities (ultrasonography, MRI, or both) underwent CO2 angiography in a vascular hybrid suite with definitive treatment with angioplasty alone, or angioplasty and drug-eluting stent placement. Clinical findings, Creatinine at baseline, time of procedure, early post procedure, and long-term nadir were reviewed.

Results: Of 113 transplants, 6 patients were identified to have potential TRAS who underwent CO2 angiography. 5 of 6 patients had stenosis of the proximal renal artery adjacent to the anastomosis, and 1 patient had an intimal dissection of the native external iliac artery with a web overlying the ostium of the renal artery. Of the 5 patients with TRAS, 4 were cadaveric grafts and 1 was a living donor. Diagnosis was made 3-7 months post-transplant. 3 of 5 presented with rising Cr, worsening htn, and peripheral edema. 1 presented with rising Cr and htn, and 1 presented with hypertensive emergency as the sole symptom. 2 of 5 patients were treated with PTA alone; 1 restenosed in the first month, and 1 remains with a baseline Cr at 8 months. 3 of 5 were treated initially with PTA and drug-eluting stent placement, as well the pt with restenosis. All 4 maintain a baseline Cr. Of the 6 procedures for treatment of TRAS, 5 demonstrated rapid improvement in renal function within 48 hours of intervention. The patient with intimal dissection and web underwent PTA to alleviate the obstructive component.

Conclusion: CO2 angiography is a safe, nephrotoxic-free contrast modality for the endovascular management of TRAS. Best patency rates are with PTA/stent placement.

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