Endovascular Treatment of Transplant Renal Artery Stenosis: A Systematic Review and Meta-analysis

OBJECTIVE

Endovascular treatment through either percutaneous transluminal angioplasty (PTA) alone or stenting has been previously used as a treatment for transplant renal artery stenosis (TRAS). This review aimed to investigate the results of endovascular treatment for renal artery stenosis in transplanted kidneys as compared with the outcomes of interventions, medical management, and graft survival in non-TRAS patients.

METHODS

A systematic review of PubMed, Google Scholar, Cochrane, and Scopus was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines in which studies that reported outcomes of the treatment of TRAS via the endoluminal approach were identified, and their results were meta-analyzed.

RESULTS

Fifty-four studies with a total of 1522 patients were included. A significant reduction of serum creatinine level was found, favoring the stenting group, with a mean difference of 0.68 mg/dL (95% confidence interval (CI), 0.17-1.19; Z=2.60, p=0.0009). Comparison of pre- and post-intervention values of any intervention revealed a significant decrease in overall serum creatinine level (0.65 mg/dL; 95% CI, 0.40-0.90; Z=5.09, p=0.00001), overall blood pressure, with a mean difference of 11.12 mmHg (95% CI, 7.29-14.95; Z=5.59, p=0.00001), mean difference in the use of medications (0.77; 95% CI, 0.29-1.24; p=0.002), and peak systolic velocity (190.05; 95% CI, 128.41-251.69; p<0.00001). The comparison of serum creatinine level between endovascular interventions and best medical therapy favored endovascular intervention, with a mean difference of 0.23 mg/dL (95% CI, 0.14-0.32; Z=5.07, p<0.00001). Graft survival was similar between the treated patients and those without TRAS (hazard ratio, 0.98; 95% CI, 0.75-1.28; p=0.091). The overall pooled success rate was 89%, and the overall complication rate was 10.4%, with the most prevalent complication being arterial dissection.

CONCLUSION

The endovascular treatment of TRAS improves graft preservation and renal function and hemodynamic parameters. PTA + stenting appears to be a more effective option to PTA alone in the stabilization of renal function, with additional benefits from decreased restenosis rates. Further high-quality studies could expand on these findings.

Endovascular treatment for transplant renal artery stenosis: A retrospective cohort study

Transplant renal artery stenosis (TRAS) is the most common (1%-23%) vascular complication following kidney transplantation. The aim of this study was to review our experience with an endovascular approach to treat TRAS.We retrospectively reviewed kidney transplant recipients who underwent percutaneous transluminal angioplasty (PTA) due to TRAS in our institute from January 2009 to December 2015. We analyzed the patient's baseline characteristics, postoperative renal function, blood pressure evolution, and the number of pre- and post-procedure antihypertensive drugs.A total of 21 patients (15 men, 6 women) were treated with the endovascular technique. The predominant presentation was graft dysfunction (76.2%). Stenosis or hemodynamic kinking was located at the anastomosis in 7 (33.3%) patients, proximal to the anastomosis in 13 (61.9%) patients, and distal the anastomosis in 1 (4.8%) patient. PTA without stent placement was performed in 7 patients (33.3%), and PTA with stent placement was performed in 14 patients (67.7%). Serum creatinine levels demonstrated no difference between the pre-procedure level and that on discharge day (1.61 mg/dl [0.47-3.29 mg/dl] vs 1.46 mg/dl [0.47-3.08 mg/dl]; P = .33). The glomerular filtration rate also showed no difference between the pre-procedure value and that on discharge day (53.6 ml/min [22.4-145.7 ml/min] vs 57.0 ml/min [17.56 -145 ml/min]; P = .084). Systolic blood pressure and diastolic blood pressure (DBP) varied from 137 mm Hg (120-160 mm Hg) and 84 mm Hg (70-100 mm Hg) pre-procedure to 129 mm Hg (90-150 mm Hg) and 79 mm Hg (60-90 mm Hg) at discharge, respectively (P = .124 and P = .07). The number of antihypertensive medications significantly decreased from 1.5 (0-6) pre-procedure to 0.5 (0-2) at discharge (P = .023). In our study, there were no technical failures, procedure-related complications or deaths. During the follow-up period, the free-from-reintervention rate was 100%, and graft failures occurred in 2 patients (9.5%) due to rejection.Endovascular procedures for TRAS show a high technical success rate with a low complication rate and a low reintervention rate. PTA showed a trend toward a positive impact on lowering serum creatinine, systolic blood pressure, and diastolic blood pressure and improving estimated glomerular filtration rate, and the number of antihypertensive medications could be significantly reduced after this procedure.

Diagnosis and Treatment of Early Transplant Renal Artery Stenosis: Experience From a Center in Eastern China

Few studies have focused on the clinical characteristics of transplant renal artery stenosis (TRAS) with early onset. Sixteen cases diagnosed with TRAS in our center from January 2014 to August 2018 were retrospectively analyzed. Sixteen transplant patients without TRAS were selected as controls. The median diagnostic time for TRAS was 47.5 days after transplantation. No significant difference was observed between the TRAS group and the control group. The serum creatinine level (Scr), estimated glomerular filtration rate, systolic/diastolic blood pressure, graft artery peak systolic velocity (PSV), and resistive index of intersegmental artery (RI-ISA) between the 2 groups were (5.55 ± 3.49) and (1.89 ± 0.85) mg/dL; (17.83 ± 14.94) and (49.39 ± 19.96) mL/min; (143.50 ± 9.49)/(86.14 ± 7.38) and (130.38 ± 18.86)/(82.81 ± 12.52) mm Hg; (3.39 ± 1.57) and (1.31 ± 0.51) m/s; and (0.51 ± 0.10) and (0.67 ± 0.13), respectively. All showed statistical significance except the diastolic blood pressure. The Scr, estimated glomerular filtration rate, systolic/diastolic blood pressure, graft artery PSV, and RI-ISA in the TRAS group prior and after treatment were (5.55 ± 3.49) and (3.20 ± 1.50) mg/dL; (17.83 ± 14.94) and (25.60 ± 13.29) mL/min; (143.50 ± 9.49)/(86.14 ± 7.38) and (128.07 ± 16.16)/(75.71 ± 7.56) mm Hg; (3.39 ± 1.57) and (2.00 ± 1.04) m/s; and (0.51 ± 0.10) and (0.61 ± 0.10); all showed statistical significance. Receiver operating characteristic analysis showed an area under curve of 0.8616 for PSV and 0.8535 for RI-ISA in diagnosing TRAS. Patients with TRAS in our center showed a unique characteristic of early onset. The most prominent clinical symptom of TRAS is increasing Scr level instead of refractory hypertension. Screening of color Doppler flow imaging with a graft artery PSV >2.5 m/s and RI-ISA <0.5 could yield a preliminary diagnosis of TRAS. Percutaneous transluminal angioplasty/stenting could effectively improve allograft function as well as color Doppler flow imaging indexes.