Transplant renal artery stenosis: outcome after percutaneous intervention

Percutaneous transluminal interventions of transplant renal artery stenosis: A case series study

Introduction

and importance: Transplant renal artery stenosis (TRAS) is a well-recognized vascular complication after kidney transplant that can lead to graft loss, when it is diagnosed early and treated appropriately it may prevent kidney damage and related systemic squeals.

Case presentation

This case-series represents our center experience in managing TRAS using percutaneous transluminal angioplasty [either balloon angioplasty (PTA) or stent placement (PTAS)] in 11 patients.

Clinical discussion

All treated patients experienced immediate total recovery of renal function and normalization of arterial blood pressure without any drug or reducing the number of drugs used; no complications related to the intervention were reported.

Conclusion

PTA or PTAS of TRAS can be considered safe and effective when it diagnosed and treated early.

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Transplant renal artery stenosis is a vascular complication after kidney transplant that can lead to graft loss.

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When it is diagnosed and treated appropriately it prevents kidney damage and systemic sequelae.

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Endovascular intervention is the treatment of choice for Transplant renal artery stenosis or other arterial complications that may compromise the transplant kidney vitality.

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Percutaneous transluminal angioplasty either balloon angioplasty or stent placement is considered safe and effective.

New onset hypertension after transplantation

It has been reported that up to 90% of organ transplant recipients have suboptimal blood pressure control. Uncontrolled hypertension is a well-known culprit of cardiovascular and overall morbidity and mortality. In addition, rigorous control of hypertension after organ transplantation is a crucial factor in prolonging graft survival. Nevertheless, hypertension after organ transplantation encompasses a broader range of causes than those identified in non-organ transplant patients. Hence, specific management awareness of those factors is mandated. An in-depth understanding of hypertension after organ transplantation remains a debatable issue that necessitates further clarification. This article provides a comprehensive review of the prevalence, risk factors, etiology, complications, prevention, and management of hypertension after organ transplantation.

Rescue of an asymptomatic arterial occlusion after kidney transplant

Arterial injury leading to vascular occlusion is a rare complication of kidney transplantation that requires urgent intervention to salvage the kidney and prevent graft loss. Occasionally, the recipient iliac vessels may be injured, resulting in acute ischaemia of the lower extremity in addition to loss of blood flow to the kidney transplant. In the case presented here, a 58-year-old man with chronic kidney disease secondary to IgA nephropathy underwent pre-emptive deceased donor renal transplantation complicated by an external iliac artery (EIA) dissection proximal to the transplant anastomosis. However, as a result of retrograde blood flow from collateral vessels, perfusion of the kidney and right lower extremity was initially preserved and early diagnosis was made after post-transplant ultrasound. This report reviews the aetiology, clinical features and therapeutic options for arterial injuries post-transplant. This case also highlights the importance of post-transplant vigilance and the value of routine postoperative ultrasound imaging.

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.

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.

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

Hypertension in Kidney Transplant Recipients: Where Are We Today?

PURPOSE OF REVIEW

Cardiovascular disease is the leading cause of death and allograft loss among kidney transplant recipients, and hypertension is an independent risk factor for cardiovascular morbidity of this patient population. The etiology of hypertension is multifactorial, including pre-transplant volume overload, post-transplant recipient and donor-associated variables, and transplant-specific causes (immunosuppressive medications, allograft dysfunction and surgical complications such as transplant artery stenosis).

RECENT FINDINGS

No randomized controlled trials have assessed the optimal blood pressure targets and explored the best antihypertensive regimen for kidney transplant recipients. According to the large observational studies, it is reasonable to achieve a blood pressure goal of equal to or less than 130/80 mmHg in the long-term follow-up for minimizing the cardiovascular morbidity. The selection of antihypertensive agents should be based on the patient's co-morbidities; however, the initial choice could be calcium channel blockers especially in the first few months of transplantation. In patients with cardiovascular indications of renin-angiotensin-aldosterone system inhibition, given the well-described benefits in diabetic and proteinuric patients, it is reasonable to consider the use of renin-angiotensin-aldosterone system inhibitors. There is a need for future prospective trials in the transplant population to define optimal blood pressure goals and therapies.

Physical activity in elderly kidney transplant patients with multiple renal arteries

INTRODUCTION

Kidney transplantation (KT) is the gold standard for treatment of patients with end- stage-renal disease. To expand the donor reserve, it is necessary to use marginal/suboptimal kidneys.

METHODS

We retrospectively evaluated the short/long-term outcome of 34 KT elderly patients who received allografts with vascular abnormalities (MRA group), in comparison with 34 KT patients who received a kidney with a single renal artery (SRA group) pair-matched by age, length of time on dialysis, comorbidity and donor age.

RESULTS

All participants completed the International Physical Activity Questionnaire at KT, and then 4, 8, and 12 weeks after transplantation. Our data indicate that kidney with vascular anatomical variants may be successfully transplanted, since the overall rate of surgical complications was 20.6% in the SRA group and 17.6% in the MRA group and that the 5-year survival rate after KT was 100% in both groups.

CONCLUSIONS

The data also underline that individualized physical activity programs induced similar excellent results in both groups, improving physical capacities, arterial pressure, lipid metabolism, insulin sensitivity, quality of life and physical and mental status.

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.

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.

Patient Selection for Kidney Transplant

The incidence of end-stage renal disease has continued to increase. Similarly, the number of patients living with a functioning renal allograft has also increased. Transplantation has improved with advances in surgical techniques, immunosuppression, and better control of comorbid conditions. Transplantation is transformative and offers the greatest potential for restoring a healthy, productive, and durable life to appropriately selected patients. This article describes factors to address in selection of renal transplant candidates and discusses commonly encountered perioperative events. Paramount to selecting appropriate candidates is the collaboration between a multidisciplinary team focused on a systematic process guided by protocols and common practices.

Endovascular Treatment of Transplant Renal Artery Stenosis: Evaluation of Postoperative Outcomes and Risk Factors for Recurrence

Angioplasty with or without stenting has become a well-established procedure to treat transplant renal artery stenosis (TRAS). We evaluated our experience on postoperative outcomes following the intervention and identified potential predictive factors of TRAS recurrence. Consecutive patients who underwent endovascular treatment of TRAS were retrospectively reviewed. The study end points were the technical success, 30-day postoperative complications, and the estimated glomerular filtration rate (eGFR). Thirty-two patients underwent endovascular treatment for TRAS. The technical success rate was 96.6%. Complications were observed for 7 (21.9%) patients: 4 had a dissection, 2 a pseudoaneurysm, and 1 (3.1%) patient developed an acute pulmonary edema. The mean eGFR significantly increased at 7 days, 3 months, and 6 months postintervention (43.1, 44.9, and 44.3 vs 33.9 mL/min/1.73 m2 preoperatively, P < .05). The TRAS recurrence was observed in 7 (21.9%) patients. These patients had significantly higher preoperative peak systolic velocity and systolic rise time (5 vs 4 m/s, P = .0383 and 103 vs 80 milliseconds, P = .0148, respectively). Endovascular treatment of TRAS is associated with high technical success and significant improvement in renal function. Further studies are required to confirm predictive factors of TRAS recurrence following endovascular treatment.

ACR Appropriateness Criteria® Renal Transplant Dysfunction

Renal transplantation is the treatment of choice in patients with end-stage renal disease because the 5-year survival rates range from 72% to 99%. Although graft survival has improved secondary to the introduction of newer immunosuppression drugs and the advancements in surgical technique, various complications still occur. Ultrasound is the first-line imaging modality for the evaluation of renal transplants in the immediate postoperative period and for long-term follow-up. In addition to depicting many of the potential complications of renal transplantation, ultrasound can also guide therapeutic interventions. Nuclear medicine studies, CT, and MRI are often helpful as complementary examinations for specific indications. Angiography remains the reference standard for vascular complications and is utilized to guide nonsurgical intervention. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Evaluation of the efficacy and safety of endovascular management for transplant renal artery stenosis

OBJECTIVES

To evaluate the safety and efficacy of endovascular intervention with angioplasty and stent placement in patients with transplant renal artery stenosis.

METHODS

All patients diagnosed with transplant renal artery stenosis and graft dysfunction or resistant systemic hypertension who underwent endovascular treatment with stenting from February 2011 to April 2016 were included in this study. The primary endpoint was clinical success, and the secondary endpoints were technical success, complication rate and stent patency.

RESULTS

Twenty-four patients with transplant renal artery stenosis underwent endovascular treatment, and three of them required reinterventions, resulting in a total of 27 procedures. The clinical success rate was 100%. All graft dysfunction patients showed decreased serum creatinine levels and improved estimated glomerular filtration rates and creatinine levels. Patients with high blood pressure also showed improved control of systemic blood pressure and decreased use of antihypertensive drugs. The technical success rate of the procedure was 97%. Primary patency and assisted primary patency rates at one year were 90.5% and 100%, respectively. The mean follow-up time of patients was 794.04 days after angioplasty.

CONCLUSION

Angioplasty with stent placement for the treatment of transplant renal artery stenosis is a safe and effective technique with good results in both the short and long term.

Combined Percutaneous Transrenal and Transfemoral Endovascular Recanalization and Angioplastic Reconstruction of a Disrupted Transplant Renal Artery Stent: A Novel Salvage Technique

Renal artery stenosis is the most common vascular complication following renal transplantation. Percutaneous endovascular transluminal angioplasty with stenting is the treatment of choice for clinically significant renal artery stenosis. The authors present a case describing a novel combined transrenal parenchyma and transfemoral approach to repairing a disrupted transplant renal artery stent. The patient's allograft renal artery stenosis was initially managed via the standard percutaneous approach, but during follow-up the stent became disrupted and crushed, causing partial occlusion of the renal artery. This was manifested by persistently elevated serum creatinine values, lower extremity edema, and four-medication hypertension. After a failed traditional percutaneous transfemoral attempt, the authors were able to successfully access the renal arterial system via a combined transrenal and transfemoral approach, using an upper-pole artery through the renal parenchyma. This transrenal approach used a 3 Fr system, allowing the authors to get a wire across the stent, which they were previously unable to do. With wire access, they performed a balloon angioplastic reconstruction to restore the stent's patency, resulting in a reduction in serum creatinine, lower extremity edema, and blood pressure. This technique avoided a potentially difficult reoperative repair without immediate complication and provides a method for vascular access to the renal arterial system in select patients.

Interventional Therapy for Transplant Renal Artery Stenosis Is Safe and Effective in Preserving Allograft Function and Improving Hypertension

Purpose:

To evaluate the outcomes of percutaneous intervention (PI) for transplant renal artery stenosis (TRAS).

Materials and Methods:

Doppler ultrasonography was used as the screening tool, and angiography was the diagnostic method for TRAS. The indications for PI were (1) a reduction in lumen diameter of >50% or (2) a mean pressure gradient of >15 mm Hg. Technical success was assessed immediately after the procedure. The short-term results of stenosis were evaluated by serum creatinine (Scr) levels and blood pressure (BP). The long-term results were assessed by graft survival and renal function.

Results:

From October 2009 to July 2015, a total of 660 patients had kidney transplantation and 22 cases underwent PI. The technical success was 100%. The mean Scr level preintervention was 321.6 ± 167.2 (range, 171.3-862.0) μmol/L, and it decreased to 145.3 ± 44.7 (range, 74.3-260.8) μmol/L 1 month postintervention ( P < .001). Blood pressure was also improved at 1 month postintervention, as assessed by systolic (157.0 ± 13.0 vs 131.0 ± 11.0 mm Hg, P < .001), diastolic (95.0 ± 5.0 vs 77.0 ± 9.0 mm Hg, P < .001), and mean arterial pressure (116.0 ± 7.0 vs 95.0 ± 9.0 mm Hg, P < .001). The patency rate was 100%, 91.7%, and 85.7% at 1, 3, and 12 months, respectively. The secondary patency rate was 100%. Graft survival was 100% during follow-up. There was no significant deterioration in graft function or BP ( P > .05) postintervention when compared to posttransplantation.

Conclusions:

Percutaneous intervention for TRAS is safe and results in significant improvement both in allograft function and in BP.

Artery Stenosis of the Renal Graft: Experience of a Center of Northeastern Brazil

BACKGROUND

Transplant renal artery stenosis (TRAS), the most common vascular complication after transplant (Tx), leads to resistant hypertension, impaired renal function, and even loss of the graft. The purpose of the study was to investigate the prevalence and factors associated with TRAS in northeastern Brazil.

METHODS

The study was conducted as a retrospective case-control study in a population of Tx recipients in a renal Tx center in northeastern Brazil. Demographic and clinical characteristics of the recipients and donors, data related to the surgery, laboratory data, and number of anti-hypertensive drugs were assessed. Statistical analysis was performed with the use of SPSS 17.0.

RESULTS

A total of 494 of 529 recipients were assessed, of which 24 had TRAS. The prevalence of TRAS was 4.8%. Twelve patients (50%) were men with a mean age of 46.7 ± 13.5 years. The mean time of diagnosis was 89.9 days after Tx. The risk factors associated with TRAS were number of anti-hypertensive drugs ≥2 (odds ratio, 17.0; confidence interval, 4.1 to 70.4; P = .001) and grafting with 2 or more arteries (odds ratio, 8.9; confidence interval, 1.4 to 56.6; P = .021). There was a significant reduction in mean systolic blood pressure (147.1 ± 23.7 to 127.8 ± 15.2 mm Hg, P = .001) and diastolic blood pressure (86.6 ± 13.0 to 77.6 ± 9.4 mm Hg, P = .001) after TRAS repair and in serum creatinine (2.8 ± 2.4 to 1.9 ± 1.8 mg/dL, P = .04).

CONCLUSIONS

Grafts with 2 or more arteries are associated with TRAS, as well as patients who use a higher number of anti-hypertensive drugs. TRAS repair was associated with improved blood pressure control and renal function.

Renal Transplant Arterial Stenosis Treated With Bare-Metal Versus Drug-Eluting Stents: Comparison of Treatment Outcomes

INTRODUCTION

This study aims to evaluate outcomes of bare-metal stents (BMS) versus drug-eluting stents (DES) in patients who undergo stenting for transplant renal arterial stenosis.

MATERIALS AND METHODS

We retrospectively reviewed records of renal transplantation patients who underwent transplant renal arterial stenting from September 2009 to September 2013. All stents greater than 5 mm were excluded to allow for equivalent comparison between the DES and BMS groups. Statistical comparisons were performed using a two-tailed Fischer exact test, and analysis of continuous variables was analyzed using a one-way analysis of variance.

RESULTS

The final study population included a total of 18 patients who received either BMS or DES (11 and 7 patients, respectively) for transplant renal arterial stenosis. The most common indications for stenting were increasing creatinine level and abnormal Doppler velocities. There were more re-interventions with BMS (n = 4/11) than DES (n = 0/7), but the trend was not statistically significant (P = .12). Three patients who received BMS had a clinically significant decrease in blood pressure versus 4 in the DES group (P = .33). Six patients who received BMS had a clinically significant decrease in creatinine level versus 3 in the DES group (P = 1.0).

CONCLUSION

There is an absolute but not statistically significant difference in the incidence of restenosis requiring repeat intervention between the BMS and DES groups. No difference was detected in clinical success as measured by decreases in blood pressure or creatinine. Future larger studies are needed to corroborate these findings.

Transplant renal artery stenosis: The impact of endovascular management and their outcomes

Introduction:

Transplant renal artery stenosis (TRAS) is a well-known vascular complication of renal transplantation. The aim of this analysis was to assess the short and midterm outcomes of endovascular therapy to salvage transplant kidney.

Methods:

We retrospectively analyzed our transplant database from 2000 to 2015. Percutaneous transluminal angioplasty/stenting was done in 24 patients (22 men and two women) with significant TRAS. The mean age was 59 ± 12 years. The parameters analyzed were: Technical success, pre- and post-treatment serum creatinine and number of antihypertensive drugs before and after treatment and vessel patency on Doppler ultrasonography at 3 and 6 months.

Results:

Overall incidence of TRAS in this study was 5.06%. Incidence of TRAS following live donor transplantation was 4.68% while that in deceased donors was 11.5%. Technical success was 100%. There were no periprocedural deaths. Renal function was improved from 2.32 ± 0.5 mg/dL to 1.72 ± 0.3 mg/dL (P < 0.001) and number of antihypertensive medications after the procedure was reduced from 2.9 ± 0.7 to 2 ± 0.6 (P < 0.001) at 6 months follow-up. One patient developed restenosis within 5 months (4.2%). Clinical success at 6 months follow-up was 79.2%.

Conclusions:

Endovascular treatment of TRAS has high technical success with minimal complications. It also provides satisfactory clinical success with improvement in overall transplant renal function and renovascular hypertension in early follow-up.

Successful endovascular treatment of transplant intrarenal artery stenosis in renal transplant recipients: Two case reports

Transplant renal artery stenosis (TRAS) is a relatively rare complication after renal transplantation. The site of the surgical anastomosis is most commonly involved, but sites both proximal and distal to the anastomosis may occur, as well. Angioplasty is the gold standard for the treatment of the stenosis, especially for intrarenal lesions. We report two cases of intrarenal TRAS and successful management with angioplasty without stent placement. Both patients were male, 44 and 55 years old respectively, and they presented with elevated blood pressure or serum creatinine within three months after transplantation. Subsequently, they have undergone angioplasty balloon dilatation with normalization of blood pressure and serum creatinine returning to baseline level. Percutaneous transluminal balloon renal angioplasty is a safe and effective method for the treatment of the intrarenal TRAS.

Iatrogenic-related transplant injuries: the role of the interventional radiologist

As advances in surgical techniques and postoperative care continue to improve outcomes, the use of solid organ transplants as a treatment for end-stage organ disease is increasing. With the growing population of transplant patients, there is an increasing need for radiologic diagnosis and minimally invasive procedures for the management of posttransplant complications. Typical complications may be vascular or nonvascular. Vascular complications include arterial stenosis, graft thrombosis, and development of fistulae. Common nonvascular complications consist of leaks, abscess formation, and stricture development. The use of interventional radiology in the management of these problems has led to better graft survival and lower patient morbidity and mortality. An understanding of surgical techniques, postoperative anatomy, radiologic findings, and management options for complications is critical for proficient management of complex transplant cases. This article reviews these factors for kidney, liver, pancreas, islet cell, lung, and small bowel transplants.

Assessment and management of hypertension in transplant patients

Hypertension in renal transplant recipients is common and ranges from 50% to 80% in adult recipients and from 47% to 82% in pediatric recipients. Cardiovascular morbidity and mortality and shortened allograft survival are important consequences of inadequate control of hypertension. In this review, we examine the epidemiology, pathophysiology, and management considerations of post-transplant hypertension. Donor and recipient factors, acute and chronic allograft injury, and immunosuppressive medications may each explain some of the pathophysiology of post-transplant hypertension. As observed in other patient cohorts, renal artery stenosis and adrenal causes of hypertension may be important contributing factors. Notably, BP treatment goals for renal transplant recipients remain an enigma because there are no adequate randomized controlled trials to support a benefit from targeting lower BP levels on graft and patient survival. The potential for drug-drug interactions and altered pharmacokinetics and pharmacodynamics of the different antihypertensive medications need to be carefully considered. To date, no specific antihypertensive medications have been shown to be more effective than others at improving either patient or graft survival. Identifying the underlying pathophysiology and subsequent individualization of treatment goals are important for improving long-term patient and graft outcomes in these patients.

Renal Transplant Complications: Diagnostic and Therapeutic Role of Radiology

Kidney was the first and is the most frequently transplanted organ. Despite improved surgical techniques and transplantation technology, complications do occur and, if left untreated, may lead to catastrophic consequences. Renal transplantation complications may be vascular (eg, renal artery and vein stenosis and thrombosis, arteriovenous fistula, and pseudoaneurysms); urologic (eg, urinary obstruction and leak, and peritransplantation fluid collections, including hematoma, seroma, lymphocele, and abscess formation); and nephrogenic, including acute tubular necrosis, graft rejection, chronic allograft nephropathy, and neoplasm. Early diagnosis and treatment of these complications are paramount to prevent graft failure and other significant morbidities to the patients. Radiology plays a pivotal role in the diagnosis and treatment of these complications, with minimally invasive percutaneous techniques. In this article, we reviewed renal transplantation anatomy, a wide range of complications that may occur after renal transplantation surgery, typical imaging appearances of the complications on varies imaging modalities, and percutaneous interventional techniques that are used in their treatment.

Endovascular interventions for managing vascular complication of renal transplantation

Renal transplantation is a well-established treatment for patients with end-stage renal disease. Although the procedure is commonly undertaken with a high rate of initial technical success, a low but significant risk of vascular complications can develop and ultimately threaten the transplanted kidney. Complications include transplant renal artery stenosis, extraparenchymal and intraparenchymal pseudoaneurysm and arteriovenous fistula formation, and stenosis of native iliac arteries due to aortoiliac occlusive disease. Historically, open surgical correction of these complications has been associated with high morbidity and the risk of graft loss. Endovascular approaches are better tolerated by renal transplantation patients and are used increasingly for management of vascular complications associated with kidney transplantation. We review the contemporary diagnosis and treatment of these complications using endovascular techniques.

Complications of transplantation. Part 1: renal transplants

Vascular complications after solid-organ transplantation are not uncommon and may lead to graft dysfunction and ultimately graft loss. A thorough understanding of the surgical anatomy, etiologies, and types of vascular complications, their presentation, and the options for management are important for managing these complex patients. This article reviews the basic surgical anatomy, vascular complications, and endovascular management options of vascular complications in patients with renal transplants.

Ultrasonographic features of kidney transplants and their complications: an imaging review

Renal transplantation is the treatment of choice for managing patients with end-stage kidney disease. Being submitted to a very serious surgical procedure, renal transplant recipients can only benefit from follow-up imaging and monitoring strategies. Ultrasound is considered as the principal imaging test in the evaluation of renal transplants. It is an easily applied bedside examination that can detect possible complications and guide further imaging or intervention. In this imaging review, we present essential information regarding the sonographic features of healthy renal transplants, detailing the surgical technique and how it affects the sonoanatomy. We focus on various complications that occur following renal transplantation and their sonographic features by reviewing pertinent literature sources and our own extensive imaging archives.

[Percutaneous thrombus aspiration in renal artery stenosis after renal transplantation]

We describe the case of a patient with chronic renal failure under hemodialysis for five years who, after renal transplantation, developed acute renal failure and hypertension refractory to medical therapy. Given the clinical and imaging (renal ultrasound and computed tomography) suspicion of renal artery graft thrombosis, invasive angiography was performed, which confirmed the diagnosis. The therapeutic approach consisted of percutaneous thrombus aspiration and subsequent balloon angioplasty of the entire artery, followed by stent implantation in a second procedure. The clinical course was uneventful with improvement of renal function and normalization of blood pressure. The case highlights the importance of percutaneous intervention in the management of patients with vascular complications after transplantation, with successful application of a procedure normally used in the setting of acute myocardial infarction - percutaneous thrombus aspiration and implantation of a drug-eluting vascular stent.

Close to transplant renal artery stenosis and percutaneous transluminal treatment

Purpose. To evaluate the efficacy of percutaneous transluminal angioplasty (PTA) in the management of arterial stenosis located close to the allograft anastomosis (close-TRAS). Materials and Methods. 31 patients with renal transplants were admitted to our institution because of persistent hypertension and impairment of transplant renal function and underwent angiography for vascular investigation. 27 were diagnosed suffering from transplant renal artery stenosis (TRAS), whereas 4 had severe iliac artery stenosis proximal to the transplant anastomosis (Prox-TRAS). 3 cases of TRAS coexisted with segmental renal arterial stenosis, whereas 3 other cases of TRAS were caused by kinking and focal stenosis in the middle of the transplanted renal artery. Results. Angioplasty and stenting were successfully applied to all patients with iliac artery stenosis as well as to those with TRAS and segmental artery stenosis. Two of three patients with kinking were well treated with angioplasty and stenting, whereas one treated only with angioplasty necessitated surgery. No major procedure-related complications appeared, and the result was decrease of the serum creatinine level and of the blood pressure. Conclusions. PTA is the appropriate initial treatment of TRAS and close-TRAS, with low morbidity and mortality rates, achieving improvement of graft function and amelioration of hypertension.

Transluminal angioplasty of transplanted renal artery stenosis: a review of the literature for its safety and efficacy

Transplant renal artery stenosis (TRAS) is a well-known cause of posttransplant hypertension accompanied by possible graft dysfunction and is potentially curable when is diagnosed early. Colour Doppler Ultrasonography (CDU) is the screening procedure of choice in most studies whereas some centers employ Magnetic Resonance Angiography (MRA), if available. Although both CDU and MRA can arouse suspicion of disease in less symptomatic cases, angiographic techniques are essential for confirmation of TRAS. Percutaneous Transluminal Angioplasty (PTA) is a good and widespread therapeutic approach for the treatment of TRAS due to its acceptable complication rate and high technical success rate. The purpose of this paper is to assess the safety and efficacy of PTA in the treatment of TRAS, to compare the long-term outcomes between different reports, and to examine the role of PTA with stenting in inhibiting recurrence of the disease.

Hypertension in kidney transplant recipients

Arterial hypertension is frequently observed in renal transplant recipients. Its pathogenesis is multifactorial in most cases. Calcineurin inhibitors (CNI) can increase peripheral vascular resistance by inducing arteriolar vasoconstriction and can cause extracellular fluid expansion by reducing the glomerular filtration rate (GFR), activating the renin-angiotensin system (RAS), and by inactivating the atrial natriuretic peptide. Glucocorticoids can impair urinary water and salt excretion. Poor graft function can lead to increased extracellular volume and inappropriate production of renin. Native kidneys, older age of the donor and transplant renal artery stenosis (TRAS) may also contribute to the development of hypertension. Arterial hypertension not only can increases the risk for cardiovascular events but can also deteriorate renal allograft function. A number of studies have shown that the higher the levels of blood pressure are, the higher is the risk of graft failure. On the other hand, a good control of blood pressure may prevent many cardiovascular and renal complications. Appropriate lifestyle modification is the first step for treating hypertension. Calcium channel blockers (CCB) and renin-angiotensin system (RAS) inhibitors are the most frequently used antihypertensive agents, but in many cases, a combination of these and other drugs is required to obtain good control of hypertension.

High-resolution 3D contrast-enhanced MRA with parallel imaging techniques before endovascular interventional treatment of arterial stenosis

This study aimed to evaluate the efficacy of high-resolution 3D contrast-enhanced magnetic resonance angiography (3D CE MRA) with parallel imaging techniques for the diagnosis of various arterial stenoses and its value for planning endovascular interventional treatment. Thirty-five patients underwent 3D CE MRA before endovascular interventional treatment. Numbers of patients were as follows: clinically documented renal artery stenosis (n = 10), renal transplant artery stenosis (n = 1), carotid artery stenosis (n = 12), iliac artery stenosis (n = 11) and femoro-popliteal artery stenosis (n = 1). A total of 39 arterial segments were treated. The depiction of various arterial stenoses was evaluated. The degree and length of the stenoses were compared and analyzed between 3D CE MRA and digital subtraction angiography (DSA). The accuracy of MRA in depicting lesion characteristics (ulceration, eccentricity, post-stenotic dilatation) was reviewed. The overall value of 3D CE MRA in planning interventional treatment was determined. The quality of 3D CE MRA in the demonstration of various arterial stenoses was judged excellent or good. A strong correlation was noted between 3D CE MRA and DSA regarding severity and length of stenosis. The accuracy of 3D CE MRA in depicting lesion characteristics was good. 3D CE MRA overestimated three severe iliac artery stenoses. Except in these three segments, the value of 3D CE MRA analysis was judged high. 3D CE MRA was found to be better than DSA in revealing the distal reconstitution and occluded segment in cases of iliac artery stenosis. 3D CE MRA is accurate in demonstrating the relevant anatomy necessary to plan endovascular interventional treatment for patients with arterial stenosis.

Vascular complications in renal transplantation: a single-center experience in 1367 renal transplantations and review of the literature

Renal transplantation is the treatment of choice for end-stage renal disease. Vascular complications in renal transplantation are not uncommon and may often lead to allograft loss. The most common vascular complications are transplant renal artery stenosis, transplant renal artery thrombosis, transplant renal vein thrombosis, biopsy-induced vascular injuries, pseudoaneurysm formation, and hematomas. Transplant renal artery and vein thrombosis have an early onset and a dramatic clinical manifestation and usually lead to allograft loss. In contrast, transplant renal artery stenosis has better treatment possibilities, whereas the rest do not occur so often. In our institution, 1367 renal transplantations were performed from September 1980 to April 2005. During this period, we encountered 38 major vascular complications leading to graft loss and 19 transplant renal artery stenoses with successful treatment in the majority of cases. According to these data, we can conclude that renal transplantation is a safe therapeutic procedure for renal failure.

Contrast enhanced MR angiography with parallel imaging in the early period after renal transplantation

PURPOSE

To evaluate renal allograft vessels in the early period after kidney transplantation with three-dimensional (3D) contrast-enhanced MR angiography (3D CE MRA) using a parallel imaging technique.

MATERIALS AND METHODS

Sixty-three consecutive patients were examined with 3D CE MRA and integrated SENSE technique (Sensitivity Encoding) 2 to 21 days after renal transplantation. MR angiography studies were analyzed for the presence of arterial stenosis. The degree of renal transplant artery stenosis was graded qualitatively as <50% = mild, 50-70% = moderate, 70-99% = severe, and occlusion. Four patients (6.3%) with moderate (n = 1) or severe (n = 3) arterial stenoses on CE MRA underwent selective intra-arterial digital subtraction angiography. In two patients, selective intravenous digital subtraction angiography (DSA) was performed.

RESULTS

Twenty-seven (42.9%) of the 63 patients had normal CE MR angiograms, 29 (46%) showed mild, 3 patients (4.8%) moderate, and 4 patients (6.3%) severe stenoses of the donor artery. In three patients, the severe stenosis of the graft artery was confirmed by surgery or intra-arterial DSA. One patient with suspicion of severe arterial stenosis on MRA had moderate vessel narrowing on DSA. Twelve months after kidney transplantation, serum creatinine levels were not significantly different in patients with mild and moderate stenoses from those without (P > 0.19) but significantly different from those with severe stenoses (P < 0.05).

CONCLUSION

The incidence of mild and moderate vessel narrowing at the arterial anastomosis is unexpectedly high in the early period after kidney transplantation and is most likely due to surgery-related tissue edema.

Salvage of hyperacute renal transplant hypoperfusion with stent placement: a case report

The authors report on a patient who underwent renal artery stent placement 6 hours after transplantation due to acute hypoperfusion of the transplant, which was diagnosed with intraoperative Doppler ultrasonography. Extensive atherosclerotic disease of the cadaveric transplant renal artery necessitated endarterectomy before creation of the anastomosis, and no further surgical options were considered feasible by the transplant surgeon. Six hours after the transplantation, percutaneous transluminal renal angioplasty and stent placement were performed, resulting in restoration of normal arterial flow and rescue of allograft function.

Drug-eluting stent insertion in the treatment of in-stent renal artery restenosis in three renal transplant recipients

Percutaneous transluminal angioplasty (PTA) with or without stent insertion is the treatment of choice in transplant renal artery stenosis. However, in-stent restenosis occurs in as many as 13% of patients after PTA and stent insertion. This article describes three patients with recurrent transplant renal artery in-stent stenosis who were treated with paclitaxel-eluting stents. In two patients, the transplant renal artery remained patent after insertion of the drug-eluting stent (DES), and one patient required balloon angioplasty 7 months after the DES was inserted.

Posttransplant diabetes and hypertension: pathophysiologic insights and therapeutic rationale

New-onset diabetes after transplantation and hypertension are very common after renal transplantation and are associated with adverse graft and cardiovascular outcomes. A thorough understanding of the unique factors that operate in renal transplant recipients is essential for the proper evaluation and management of these important disorders. This review outlines the pathogenesis, diagnostic workup, and therapeutic rationale for diabetes and hypertension after transplantation.