Outcomes of endovascular treatment of renal arterial stenosis in transplanted kidneys

Retrospective analysis of percutaneous intervention of the renal artery in transplanted kidneys in children and adolescents at a tertiary public hospital

BACKGROUND

This study evaluated the long-term effects of percutaneous intervention in children and adolescents with transplant renal artery stenosis (TRAS).

METHODS

Twenty patients had significant stenosis (>50%) and underwent percutaneous transluminal angioplasty (PTA/stenting) (TRAS group-intervention); 14 TNS (non-significant group -control) patients did not have significant stenosis (≤50%) and were treated clinically. The combined primary endpoints were death from all causes and late graft failure. The secondary endpoints were serum creatinine (SCr), systolic blood pressure (SBP), and diastolic blood pressure (DBP).

RESULTS

No statistically significant difference was found between TRAS-Intervention(N = 20) and TNS groups-Control (N = 14) for these clinical parameters: deaths, 1 (5.0%) vs. 0 (0.0%) (p = 1.000) and graft loss, 4 (20.0%) vs. 2 (14.3%) (p = 1.000). For the secondary endpoints, after 1 month and 1 year the values of SCr, SBP, and DBP were similar between the two groups but not statistically significant.

DISCUSSION

In the TRAS group (intervention), the stent implantation was beneficial for treating refractory hypertension and reducing blood pressure (BP) in children and adolescents. Despite the outcomes being similar in the two groups, it can be inferred that the patients in the TRAS group (intervention) would have had a worse outcome without the percutaneous intervention.

CONCLUSION

TRAS treatment with stenting can be considered for children and adolescents. Because the sample in the present study comprised of only a specific population, further studies are needed for generalization.

TRIAL REGISTRATION

The trial was registered at clinictrials.gov with trial registration number NCT04225338.

Zero-contrast PTRA and stenting for child with TRAS: A case report

BACKGROUND

Kidney transplantation is often complicated by TRAS, and PTRA can effectively treat it. However, PTRA is not appropriate for patients with CKD because iodinated contrast agent may induce nephropathy.

METHODS

This article reports about a 14-year-old boy with a history of kidney transplantation complicated by RAS. He initially underwent percutaneous balloon dilation to relieve the stenosis. One and half a year after dilation, he received zero-contrast PTRA and stenting under the guidance of external and IVUS with reference to previous PAG image.

RESULTS

After successful stent implantation, the cross-sectional area of the renal artery lumen was significantly increased.The blood pressure and level of creatinine also decreased and kept stable during follow-up.

CONCLUSION

This report suggests the feasibility of external ultrasound and IVUS guided, zero-contrast PTRA in patients with poor renal function or iodinated contrast allergy.

Assessment and management of transplant renal artery stenosis. A literature review

BACKGROUND

transplant renal artery stenosis (TRAS) following kidney transplantation is a possible cause of graft failure. This review aimed to summarize the evidence about physiopathology, diagnosis and early and late effectiveness of the endovascular treatment (EVT), including angioplasty and stenting procedures.

METHODS

a literature research was performed using Pubmed, Scopus and the Cochrane Library databases (January 2000 to September 2020) according to PRISMA guidelines. Studies were included if they describe EVT, percutaneous transluminal angioplasty or stent placement of TRAS, published in English and with a minimum of ten patients.

RESULTS

56 studies were included. TRAS incidence ranges from 1% up to 12% in transplanted kidneys. The TRAS risk factors were: elderly donor and recipient, cytomegalovirus match status, Class II Donor Specific Antibodies (DSA), expanded donor criteria, delayed graft functioning and other anatomical and technical factors. The highest frequency of TRAS presentation is after 3-6 months after kidney transplantation. The most frequent localization of stenosis was para-anastomotic (ranging from 25% to 78%). In 9 studies, all patients were treated by percutaneous transluminal angioplasty (PTA), in 16 studies all patients received percutaneous transluminal stenting (PTS) and in 21 series patients received either PTA or PTS. The Twelve months patency rates after EVT ranged from 72% to 94%. The overall complication rate was 9%, with pseudoaneurysms and hematomas as most frequent complications.

CONCLUSION

TRAS can be successfully and safely treated through an endovascular approach. Stent delivery seems to guarantee a higher patency rate compared to simple angioplasty, however further studies are needed to confirm these results.

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.

Diagnosis and spontaneous healing of asymptomatic renal allograft extra-renal pseudo-aneurysm: A case report

BACKGROUND

Transplant renal artery stenosis is a relatively frequent vascular complication after transplantation. However, extra-renal pseudo-aneurysms (EPSAs) are rare after transplantation; they can be life-threatening and usually need open surgical repair. We discuss the diagnosis and spontaneous healing of an asymptomatic renal allograft EPSA caused by renal artery anastomotic stenosis, which was diagnosed in a timely manner and managed by conservative treatments.

CASE SUMMARY

We present a 37-year-old male patient diagnosed with a renal allograft EPSA caused by renal artery anastomotic stenosis due to multiple atherosclerotic plaques with ultrasonographic examination 6 mo post transplantation. The stenosis rate of 90% and the EPSA were verified by computed tomography angiography. The diagnosis was further confirmed with digital subtraction angiography. Percutaneous transluminal angiography was conducted, and a metallic stent was successfully implanted at the stenosed site of the main renal artery trunk. No further intervention for the EPSA was undertaken due to the difficulty of stenting and the risk of bleeding; regular ultrasonographic follow-ups were recommended. The stenosis was significantly relieved immediately after stent implantation and the EPSA was healed spontaneously by completely filling with hypo-echoic thrombosis 8 mo after stenting.

CONCLUSION

Ultrasonography combined with a high-frequency linear probe can detect vascular complications post renal transplantation at an early stage and improve prognosis.