5 Years Experience With Drug Eluting and Bare Metal Stents as Primary Intervention in Transplant Renal Artery Stenosis

Interventional Management of Vascular Complications after Renal Transplantation

BACKGROUND

 Kidney transplantations are increasing due to demographic changes and are the treatment of choice for end-stage renal disease. Non-vascular and vascular complications may occur in the early phase after transplantation and at later stages. Overall postoperative complications after renal transplantations occur in approximately 12 % to 25 % of renal transplant patients. In these cases, minimally invasive therapeutic interventions are essential to ensure long-term graft function. This review article focuses on the most critical vascular complications after renal transplantation and highlights current recommendations for interventional treatment.

METHOD

 A literature search was performed in PubMed using the search terms "kidney transplantation", "complications", and "interventional treatment". Furthermore, the 2022 annual report of the German Foundation for Organ Donation and the EAU guidelines for kidney transplantation (European Association of Urology) were considered.

RESULTS AND CONCLUSION

 Image-guided interventional techniques are favorable compared with surgical revision and should be used primarily for the treatment of vascular complications. The most common vascular complications after renal transplantation are arterial stenoses (3 %-12.5 %), followed by arterial and venous thromboses (0.1 %-8.2 %) and dissection (0.1 %). Less frequently, arteriovenous fistulas or pseudoaneurysms occur. In these cases, minimally invasive interventions show a low complication rate and good technical and clinical results. Diagnosis, treatment, and follow-up should be performed in an interdisciplinary approach at highly specialized centers to ensure the preservation of graft function. Surgical revision should be considered only after exhausting minimally invasive therapeutic strategies.

KEY POINTS

  · Vascular complications after renal transplantation occur in 3 % to 15 % of patients.. · Image-guided interventional procedures should be performed primarily to treat vascular complications of renal transplantation.. · Minimally invasive interventions have a low complication rate with good technical and clinical outcomes..

CITATION FORMAT

· Verloh N, Doppler M, Hagar MT et al. Interventional Management of Vascular Complications after Renal Transplantation. Fortschr Röntgenstr 2023; DOI: 10.1055/a-2007-9649.

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 stenting with a drug-eluting stent of transplanted renal artery stenosis in a dual kidney transplanted patient

Renal transplant remains the preferred therapy for end-stage renal disease (ESRD). Given the shortage of suitable donor kidneys, use of an expanded criteria donor (ECD) allows marginal kidneys to be transplanted; albeit at risk of increased graft failure due to lower nephron mass. To reduce the risk of graft failure, double kidney transplant (DKT) is advocated, with favorable outcomes. Transplant renal artery stenosis (TRAS) is one of the most common vascular complications following renal transplant. Unlike single kidney transplants, where TRAS usually presents with fluid overload, uncontrolled hypertension, and worsening kidney functions; it may be clinically silent in DKT patients since they have two functional transplanted kidneys. We hereby report a case of TRAS in a DKT patient who had 2 years of favorable clinical outcomes following successful endovascular stenting. He however recently died of COVID-19 associated pneumonitis.

Long-term outcome of percutaneous transluminal renal angioplasty (PTRA) versus PTRA with stenting (PTRAS) in transplant renal artery stenosis

Background

Endovascular treatment is standard of care for transplant renal artery stenosis (TRAS). No study has evaluated long-term outcomes compared between percutaneous transluminal renal angioplasty (PTRA) and PTRA with stenting (PTRAS). Accordingly, this study aimed to investigate the 1-year clinical success, and short- and long-term event-free survival between PTRA and PTRAS in patients diagnosed with TRAS at Thailand’s largest national tertiary referral center.

Methods

This single-center retrospective study included kidney transplant patients treated for TRAS during January 2001 to June 2019. Clinical success was defined as (1) increase in estimated glomerular filtration rate (eGFR) > 15%, or (2) reduction in mean arterial pressure (MAP) > 15% with no decrease in antihypertensive medication, or no reduction in MAP or reduction in MAP < 15% with decrease in antihypertensive medication. Incidence of kidney transplant graft failure and transplant renal artery stenosis were also collected.

Results

Sixty-five cases of TRAS were identified from 1072 patients who underwent kidney transplantation. The majority (98.5%) had end-to-side anastomosis technique. Thirty-four patients had PTRA, while 31 patients had PTRAS. One-year clinical success according to renal outcome and BP reduction was 78.5% and 49.2%, respectively. Both renal outcome (79.4% vs. 77.4%, p = 0.845) and BP reduction (40.6% vs. 58.1%, p = 0.166) at 1 year were similar between the PTRA and PTRAS groups. Compared between PTRA and PTRAS, event-free survival for composite of kidney transplant graft failure or transplant renal artery restenosis was significantly higher for PTRAS at 1 year (82.4% vs. 100%, p = 0.025), but not significantly different at 10 years (73.5% vs. 71%, p = 0.818).

Conclusions

We demonstrated the 1-year clinical success, and short- and long-term event-free survival between PTRA and PTRAS in TRAS patients. One-year clinical success was found to be similar between groups. Event-free survival for composite of kidney transplant graft failure or transplant renal artery restenosis was significantly higher in PTRAS at 1 year, but similar between groups at 10 years.

Trial registration Thai Clinical Trials Registry, TCTR20200626002. Registered 26 June 2020—Retrospectively registered, http://www.clinicaltrials.in.th/index.php?tp=regtrials&menu=trial search&smenu = fulltext&task = search&task2 = view1&id = 6441

Intravascular ultrasound-supported percutaneous angioplasty of post-kidney transplant renal artery bifurcation stenosis

BACKGROUND

Transplant renal artery stenosis (TRAS) is an uncommon complication following renal transplantation. Its usual clinical presentation includes worsening hypertension and/or renal function, without any evidence of graft rejection. Bifurcation renal artery stenosis of the transplanted renal artery is rarely encountered.

METHODS

Percutaneous transluminal renal angioplasty (PTRA) with or without stenting is the procedure of choice to treat TRAS. We hereby describe a patient, who presented with impaired renal functions, four months following the renal transplantation. He underwent intravascular ultrasound-guided PTRA of the bifurcation lesion of TRAS.Results and conclusion: Superior renal artery had coronary drug-eluting stent implantation, while inferior renal artery and side branch of the superior renal artery had balloon angioplasty, alone. Post-intervention, the raised serum creatinine level decreased from 2.9 mg% to 1.7 mg%. The index case described the successful PTRA and stenting of the bifurcation lesion of TRAS, the technical results of which was optimized with the use of intravascular ultrasound.

Treatment of Hepatic Artery Stenosis in Liver Transplant Patients Using Drug-Eluting versus Bare-Metal Stents

Hepatic artery stenosis after liver transplant is often treated with endovascular stent placement. Our institution has adopted use of drug-eluting stents, particularly in small-caliber arteries. We aimed to compare patency rates of drug-eluting stents vs. traditional bare-metal stents. This was a single-institution, retrospective study of liver transplant hepatic artery stenosis treated with stents. Primary patency was defined as time from stent placement to resistive index on Doppler ultrasonography (<0.5), hepatic artery thrombosis, or any intervention including surgery. Fifty-two patients were treated with stents (31 men; mean age, 57 years): 15, drug-eluting stents; 37, bare-metal stents. Mean arterial diameters were 4.1 mm and 5.1 mm, respectively. Technical success was 100% (52/52). At 6 months, 1, 2, and 3 years, primary patency for drug-eluting stents was 80%, 71%, 71%, and 71%; bare-metal stents: 76%, 65%, 53%, and 46% (p = 0.41). Primary patency for small-caliber arteries (3.5–4.5 mm) with drug-eluting stents was 93%, 75%, 75%, and 75%; bare-metal stents: 60%, 60%, 50%, and 38% (p = 0.19). Overall survival was 100%, 100%, 94%, and 91%. Graft survival was 100%, 98%, 96%, and 90%. Stenting for hepatic artery stenosis was safe and effective. While not statistically significant, patency improved with drug-eluting stents compared with bare-metal stents, especially in arteries < 4.5 mm in diameter. Drug-eluting stents can be considered for liver transplant hepatic artery stenosis, particularly in small-caliber arteries.

Spontaneous recanalization of occluded transplant renal artery: a rare case report

Background

Transplant renal artery stenosis (TRAS) is a serious vascular complication that occurs after renal transplantation and can result in hypertension, renal functional impairment, and graft loss. Endovascular treatment has become the first-line treatment for TRAS because of its low invasiveness and high success rate.

Case presentation

A 23-year-old female with end-stage renal disease of unknown cause received a living-donor kidney transplantation 10 months ago. Seven months after the transplantation, her blood pressure gradually deteriorated. Magnetic resonance angiography revealed bending and stenosis of the transplant renal artery, and the patient received endovascular treatment. A digital subtraction angiography revealed significant stenosis of 95% in the proximal transplant renal artery. The guidewire could not pass through the stenotic segment of the transplant renal artery even with repeated attempts by the surgeons; as a result, the transplant renal artery became occluded, and vasodilators were ineffective. After the operation, renal function gradually worsened, so she began to receive regular dialysis. Twenty-five days later, the patient’s urine volume was significantly higher than that before, and ultrasound showed that the proximal transplant renal artery was not completely occluded. A re-intervention was performed, and the stent was placed successfully in the stenotic segment. After the operation, renal function gradually recovered, and dialysis was no longer needed.

Conclusion

Patients with iatrogenic transplant renal artery occlusion may have the possibility of spontaneous recanalization, which can help prevent the need for re-transplantation.

Endovascular treatment of an immediate postoperative transplant renal artery stenosis with a polymer free drug eluting stent

The transplant renal artery stenosis occurred up to 23% after kidney transplantation. Endovascular treatment has become the treatment of choice of this complication, but could be challenging in immediate postoperative anastomotic narrowing. We report the case of a adolescent with early renal graft artery stenosis located in the anastomosis and diagnosed 3 days after renal transplantation, with necessity of haemodialysis. This complication was treated by angioplasty on the 25th day, using a polymer free drug eluting stent with a good result. We discussed the precautions and technical features of this procedure.

Endovascular management of transplant renal artery stenosis: A single-center retrospective study

OBJECTIVES

The aim is to evaluate the efficacy and complications of percutaneous transluminal angioplasty (PTA)/stenting in the treatment of transplant renal artery stenosis (TRAS).

BACKGROUND

TRAS is a relatively rare condition, and currently, there is not enough study about interventional therapy for TRAS.

METHODS

Between April 2011 and July 2018, 33 patients with TRAS underwent interventional therapy. Analysis of parameters was as follows: technical success, pretreatment and posttreatment serum creatinine, and blood pressure, and vessel patency via ultrasound at 1, 6, and 12 months posttreatment and once a year thereafter.

RESULTS

One procedure failed. The success rate of PTA/stenting placement was 97.0%. Fourteen PTAs with 16 stents were primary interventions, with 2 stent procedures performed subsequently due to restenosis; the restenosis rate was 6.3%. During the follow-up period, two patients progressed to graft renal failure and three patients were lost to follow-up. The rest of the patients still had stable graft function and blood pressure. Compared with preoperative conditions, blood pressure and serum creatinine significantly decreased (p < .05). No treatment-related deaths or serious complications occurred.

CONCLUSIONS

PTA/stenting is a safe and effective treatment for TRAS. For selected TRAS patients, PTA or PTA with stent may achieve good therapeutic outcomes. Selecting appropriate puncture pathways may help improve the success rate and affect the operation results, and open surgery may be avoided.

Percutaneous transluminal angioplasty alone versus stent placement for the treatment of transplant renal artery stenosis

PURPOSE

The purposes of this retrospective study were to assess the efficacy of endovascular techniques for the treatment of transplant renal artery stenosis (TRAS) by analyzing technical and clinical success and to compare the results of percutaneous transluminal angioplasty (PTA) alone to those of stenting.

MATERIALS AND METHODS

A retrospective analysis was conducted on 31 patients who underwent endovascular treatment for TRAS between January 2012 and December 2017. There were 23 men and 8 women with a mean age of 60.5±14 (SD) years (range: 24-81 years). Ten patients (10/31; 32%; 8 men, 2 women; median age, 63 years) were treated with PTA alone and 21/31 (68%; 15 men, 6 women; median age, 65 years) with metallic stent placement. Several variables including serum creatinine level, glomerular filtration rate, arterial blood pressure value, antihypertensive medication obtained before and after treatment were compared. Technical success was assessed for each procedure. Clinical success was defined as a 15% drop in serum creatinine level, a decrease greater than 15% in mean blood pressure values or a decrease greater than 10% in mean blood pressure values with a reduction in the number of antihypertensive drugs needed for hypertension control.

RESULTS

Technical success was obtained in all patients [31/31; 100%; 95% confidence interval (CI): 89-100%] and clinical success in 27/31 patients (87%; 95%CI: 71-95%). Four patients (4/31; 13%; 95%CI: 5-29%) underwent repeat endovascular intervention. Mean serum creatinine level and mean arterial blood pressure values were significantly lower after treatment (177.4 and 93.8μmol/l, respectively) compared to before treatment (319.4 and 106.7μmol/l, respectively) in the stent group but not in the group treated with PTA alone (P=0.0012 and P=0.002, respectively).

CONCLUSION

The endovascular approach is safe and effective in the management of TRAS and stenting, depending on the morphology of the stenosis, should be the treatment of choice when possible.

Long-term Graft and Patient Survival after Percutaneous Angioplasty or Arterial Stent Placement for Transplant Renal Artery Stenosis: A 21-year Matched Cohort Study

Purpose To compare long-term graft and patient survival after percutaneous angioplasty (PTA) or stent placement for transplant renal artery stenosis (TRAS) with a control cohort without TRAS. Materials and Methods This is a retrospective matched cohort study of 41 patients (median age, 49 years; range, 18-72 years), including 27 male patients (median age, 48 years; range, 18-67 years) and 14 female patients (median age, 52 years; range, 24-68 years), with TRAS from December 1995 through 2016. Primary end points were death-censored graft and patient survival, compared by using log-rank test and Cox proportional regression. Secondary outcomes were improvement in renal function, blood pressure (BP), and complications. Results Twenty-four patients underwent PTA and 17 received stent placements. Ten-year graft survival was 92.1% (range, 83.2%-100%) versus 81.4% (range, 67.8%-95.3%) (P = .56), and 10-year patient survival was 89.9% (79.1%-100%) versus 84.7% (72.1%-97.5%) (P = .49), for the study and control groups, respectively. Five patients (12%) resumed dialysis in each group and a total of 17 patients died (eight in the study group and nine in the control group). Most patients died with a functioning graft (seven of eight in the study group and seven of nine in the control group). Posttreatment median systolic and diastolic BP improved by 12% and 7.4%, respectively, and serum creatinine improved by 27%. Normal systolic BP and serum creatinine level at 1 year after treatment were associated with better survival for patients (P = .04; hazard ratio [HR], 1.04; 95% confidence interval [CI]: 1.0, 1.075) and grafts (P < .001; HR, 1.02; 95% CI: 1.0, 1.027). Other covariates, including PTA versus renal stent placement, intra-arterial pressure gradient greater than 10%, diastolic BP, age at transplantation, sex, graft type, rejection, and delayed graft function, were not significant. Five patients (12.2%) had a complication (Society of Interventional Radiology class A, two of 41 [4.9%]; class B, two of 41 [4.9%]; and class D, one of 41 [2.4%]); 30-day graft loss and patient mortality were zero. Conclusion Long-term graft and patient survival after endovascular correction of transplant renal artery stenosis (TRAS) was similar to that without TRAS and most patients avoided returning to dialysis. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Dickey and Durrani in this issue.

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

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.

Short-Term Outcomes Using a Drug-Coated Balloon for Transplant Renal Artery Stenosis

BACKGROUND This study aimed to evaluate the early and mid-term outcomes of drug-coated balloon (DCB) use in patients who underwent intervention for transplant renal artery stenosis (TRAS). MATERIAL AND METHODS We retrospectively reviewed the records of TRAS patients who received endovascular therapy with DCB in our institution from March 2016 to January 2017. Statistical analysis of pre-/postoperative levels of serum creatinine (Scr), systolic blood pressure (SBP), and renal artery peak systolic velocities (PSV) were performed. RESULTS Fourteen patients presenting with TRAS, which were mostly located at the anastomosis (n=9) and transplanted artery proximal portion (n=2), were treated with DCB. Three TRAS patients with in-stent restenosis (ISR) were also included in the series. The procedure technique success rate was 100%. The mean follow-up time was 8.6 months. The Scr level decreased from 481.8 µmol/L (208.5-746.2µmol/L) pre-operation to 154µmol/L (89.1-301.2 µmol/L, p<0.01) at 1 month post-intervention. The SBP varied from 161.4 mmHg (152-173 mmHg) to 144.8 mmHg (136-154 mmHg, p<0.01). Renal artery PSV decreased from 364.1 cm/s (217.6-511.9 cm/s) to 134.9 cm/s (79.8-184.2 cm/s, p<0.01). Eleven patients finished mid-term (>6 months) follow-up. The statistical results were not significant compared to those at 1 month, although they all slightly decreased. No re-intervention was performed. CONCLUSIONS The endovascular approach to TRAS with DCB was a safe and effective treatment for restore and maintain the artery flow and renal function in short-term follow-up.