Standardized Duplex Ultrasound-Based Protocol for Early Diagnosis of Transplant Renal Artery Stenosis: Results of a Single-Institution Retrospective Cohort Study

Abstract

Transplant renal artery stenosis (TRAS) is the most frequent vascular complication after kidney transplantation (KT) and has been associated with potentially reversible refractory hypertension, graft dysfunction, and reduced patient survival. The aim of the study is to describe the outcomes of a standardized Duplex Ultrasound- (DU-) based screening protocol for early diagnosis of TRAS and for selection of patients potentially requiring endovascular intervention. We retrospectively reviewed our prospectively collected database of KT from January 1998 to select patients diagnosed with TRAS. The follow-up protocol was based on a risk-adapted, dynamic subdivision of eligible KT patients in different risk categories (RC) with different protocol strategies (PS). Of 598 patients included in the study, 52 (9%) patients had hemodynamically significant TRAS and underwent percutaneous angioplasty (PTA) and stent placement. Technical and clinical success rates were 97% and 90%, respectively. 7 cases of restenosis were recorded at follow-up and treated with re-PTA plus stenting. Both DU imaging and clinical parameters improved after stent placement. Prospective high-quality studies are needed to test the efficacy and safety of our protocol in larger series. Accurate trial design and standardized reporting of patient outcomes will be key to address the current clinical needs.

Figure 1

Percutaneous angioplasty and stent placement for anastomotic TRAS. In all patients, a nonselective aortoiliac arteriogram was performed to exclude any preanastomotic (proximal-TRAS) inflow stenosis in the recipient arteries. The stenotic lesion was dilated with a 4.8-French angioplasty balloon catheter passed through a valved 8-French introducer sheath via a femoral approach. Where indicated, the intravascular stent (Palmaz endoprosthesis) was implanted over a stiff 0.5 mm guide wire passed carefully through the stenosis, measuring the pressure gradients. In case of hemodynamically significant stenosis, 3000–5000 U of heparin was administered intravenously and balloon dilation is performed. Balloon-size selection was based on direct measurement of the diameter of a normal nondiseased renal artery segment, as previously described (hederman). Then the bare-metal stent was inserted and left in place in the transplant renal artery after the removal of the guide wire and balloon catheter. A postangioplasty arteriogram was always obtained.