Renal artery stenosis in kidney transplants

Transplant renal artery stenosis: Study of incidence using doppler ultrasound, risk factors and analysis is effect in graft outcomes

INTRODUCTION AND OBJECTIVES

Transplant renal artery stenosis (TRAS) is a vascular complication after kidney transplantation which estimated incidence is 13%. It could cause refractory arterial hypertension, kidney dysfunction and premature death in transplant recipients.

METHODS

We carried out a retrospective study including every patient who underwent renal transplantation between 2014 and 2020. They were evaluated with a systematic post-transplant renal Doppler ultrasound. To identify independent risk factors for transplant renal artery stenosis we performed a multivariate analysis.

RESULTS

Seven hundred twenty-four kidney transplants were included, 12% ​​were living donors and 88% were deceased donors. The mean age was 54.8 in recipients and 53 in donors. Transplant renal artery stenosis was diagnosed in 70 (10%) recipients, the majority in the first 6 months after surgery. 51% of patients with transplant renal artery stenosis were managed conservatively. The multivariate analysis showed diabetes mellitus, graft rejection, arterial resuture and donor body mass index as independent risk factors for transplant renal artery stenosis. Survival of the grafts with transplant renal artery stenosis was 98% at 6 months and 95% at two years.

CONCLUSIONS

The systematic performance of Doppler ultrasound in the immediate post-transplant period diagnosed 10% of transplant renal artery stenosis in our cohort. Despite the above risk factors, an adequate monitoring and treatment could avoid the increased risk of graft loss in patients with transplant renal artery stenosis.

Evidence-Based Complementary Benefit of the Vascular Surgeon Among the Team of Renal Transplantation; a Single Center Experience

BACKGROUND

In a kidney transplant tertiary referral center; we compared 3 operating team configurations of different surgical specialties to highlight the effect of the operating surgeon's specialty on various operative details and procedural outcome.

METHODS

A total of 50 cases of living donor transplantations were divided into 3 main groups according to the operating surgeons' specialty, the first group (A) includes 12 patients exclusively operated on by urologists with advanced training in transplantation, the second group (B) includes 35 patients operated by combined surgical specialties; a urologist and a vascular surgeon both with advanced transplantation training, and a third group (C) includes 3 cases where the transplant operation commenced with operating urologists as in group (A) but required intraoperative urgent notification of a vascular surgeon to manage unexpected intraoperative technical difficulties or major complications. Cases were studied according to operative details, anastomosis techniques, ischemia times, total procedure time, recovery of urinary output, intensive care unit (ICU) stay, postoperative surgical complications and serum creatinine level for up to 3 years of follow-up.

RESULTS

Study of operative details revealed that total duration of graft ischemia was significantly shorter in group (B) and significantly longer in group (C) (P value 0.001), Total procedural duration also varied significantly between the 3 groups, group (B) being the shortest while group (C) was the longest (P value less than 0.001). Technically; group (A) used only end to end arterial anastomosis as a standard technique, while group (B) used both end-to-end and end-to-side anastomoses as required per each case. End to side anastomosis in group (B) yielded better immediate graft response in the form of change in color, texture, earlier and more profuse postoperative urine volumes (P value 0.025). Furthermore, anastomosis to common and external iliac arteries (group B) yielded earlier and higher urine volumes than the internal iliac artery (P values 0.024 and 0.031 respectively). Group (B) recorded significantly less postoperative perigraft hematomas and lymphoceles compared to the other 2 groups. Equal rates of urine leaks, ICU stay, creatinine levels, patient and grafts survival rates among groups (A) and (B), while postoperative recovery and ICU stay duration were more lengthy in the complicated group (C).

CONCLUSIONS

A vascular surgeon operating in a transplantation team would deal comfortably and efficiently with various vascular related challenges and complications, thus avoiding unnecessary time waste, complications and costs.

Renal Artery Stenosis in Living Donor Kidney Transplantation: A Rare Cause of "Flash Edema"

Transplant renal artery stenosis (TRAS) is a well-recognized vascular complication after kidney transplantation, with an incidence ranging from 1% to 23%. TRAS often presents with clinical features such as refractory hypertension, de novo hypertension, allograft dysfunction, and the presence of a bruit over the graft. A rare manifestation of TRAS is flash pulmonary edema. Here, we present a case of a 37-year-old male who received a living donor kidney. Four years after the transplant, he presented with acute kidney injury, hypertensive crisis, and flash pulmonary edema. Initially, methylprednisolone pulses were administered due to suspicion of acute rejection, which was later ruled out after a kidney graft biopsy. Computed tomography angiography showed findings suggesting stenosis or thrombus in the renal artery. The patient developed sudden acute pulmonary edema, requiring hemodialysis, with notable clinical improvement. Subsequently, stent placement was performed without complications, resulting in the complete recovery of renal function and effective blood pressure control. The incidence of renal artery stenosis is higher in living donor kidney transplantation, mainly due to technical complexities during surgery. Acute presentations, such as flash edema, are exceptionally rare but can occur years after transplantation. Prompt intervention can lead to favorable outcomes.

Successful management of proteinuria in recurrent immunoglobulin A nephropathy after deceased donor kidney transplantation: A case report

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is the most common type of primary glomerulonephritis, and recurrent IgAN is common after kidney transplantation (KT). Owing to the differences in various biopsy protocols and follow-ups in each study, the recurrence rate varies from 9.7% to 46%. Although the relapse rates are high, there is no definitive treatment for IgAN recurrence.

METHODS

We present a case of successful management of proteinuria in recurrent IgAN after deceased donor KT. A 60-year-old man diagnosed with IgAN 20 years prior, who progressed to end-stage renal disease, underwent deceased donor KT 5 years prior and was admitted to our hospital with progressively increasing proteinuria.

RESULTS

The pathological examination of the kidney biopsy specimen revealed recurrent IgAN. High-dose steroid treatment was initiated, and the patient was discharged while maintaining steroid treatment. However, outpatient follow-up showed that proteinuria did not decrease while steroids were maintained. Therefore, an angiotensin receptor blocker was administered after explaining its benefits to the patient. After the addition of angiotensin receptor blocker, proteinuria continued to decrease.

CONCLUSION

This case report highlights the importance of using renin-angiotensin system inhibitors with supportive care in cases of suspected of recurrent IgAN after KT. It also emphasizes the need to prescribe renin-angiotensin system inhibitors when steroid therapy is unsuccessful in cases of recurrent IgAN after KT.

Pseudoaneurysm and Renal Artery Stenosis Post-renal Transplant: A Rare Presentation

We report the case of a 51-year-old gentleman who underwent living renal transplantation in Pakistan for end-stage renal disease one and a half years ago. He presented to our hospital with renal artery stenosis and an extra-renal pseudoaneurysm at the anastomotic site of the transplanted kidney. This can cause graft dysfunction and hypertension due to impairment of arterial perfusion in the transplanted kidney. Treatment with percutaneous transluminal angioplasty and covered stenting of the pseudoaneurysm and stenosis improved kidney function and hypertension.

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.

Use of absorbable hemostat bolster for prevention of donor renal artery kinking in kidney transplant

Transplant renal artery stenosis due to mechanical kinking is a rare but significant complication in kidney transplantation that can lead to graft dysfunction due to graft hypoperfusion, delayed graft function, or even global kidney infarction. When detected during surgery, re-anastomosis is usually performed after re-clamping, which inevitably prolongs the warm ischemia time, and increases the possibility of primary graft non-function. In this report, we describe a novel, noninvasive surgical technique whereby the donor renal artery is padded with absorbable hemostatic material (i.e., Surgicel) bolster, placed below the middle third of the renal artery in recipients who were found to have mechanical kinking during the implantation procedure. The bolster technique was used in 12 kidney transplant recipients who were found to have kinking of the donor artery during the primary surgery. After pillowing the renal artery with absorbable hemostatic bolster, no residual kinking was observed intra-operatively, and good allograft perfusion was confirmed with no Doppler ultrasound evidence of renal artery stenosis confirmed at 1 week, 1 month, and 1 year after transplantation.

Cardiovascular Risk after Kidney Transplantation: Causes and Current Approaches to a Relevant Burden

Background. Cardiovascular disease is a frequent complication after kidney transplantation and represents the leading cause of mortality in this population. Material and Methods. We searched for the relevant articles in the National Institutes of Health library of medicine, transplant, cardiologic and nephrological journals. Results. The pathogenesis of cardiovascular disease in kidney transplant is multifactorial. Apart from non-modifiable risk factors, such as age, gender, genetic predisposition and ethnicity, several traditional and non-traditional modifiable risk factors contribute to its development. Traditional factors, such as diabetes, hypertension and dyslipidemia, may be present before and may worsen after transplantation. Immunosuppressants and impaired graft function may strongly influence the exacerbation of these comorbidities. However, in the last years, several studies showed that many other cardiovascular risk factors may be involved in kidney transplantation, including hyperuricemia, inflammation, low klotho and elevated Fibroblast Growth Factor 23 levels, deficient levels of vitamin D, vascular calcifications, anemia and poor physical activity and quality of life. Conclusions. The timely and effective treatment of time-honored and recently discovered modifiable risk factors represent the basis of the prevention of cardiovascular complications in kidney transplantation. Reduction of cardiovascular risk can improve the life expectancy, the quality of life and the allograft function and survival.

Complex Vascular Reconstruction of an En Bloc Pediatric Kidney Damaged during Organ Procurement

En bloc pediatric kidney (EBPK) allografts are a potential solution to expand the organ donor pool; however, EBPK transplantation has been traditionally considered suboptimal due to concerns of perioperative vascular and urologic complications. Accidental organ or vasculature injury during harvest is not uncommon; however, this does not necessarily mean that the organ should be discarded. Careful vascular reconstruction can be performed using donor vascular grafts, salvaging the organ without stenosis or thrombosis of the vessels. We report an extensive vascular reconstruction of the right renal artery, aorta, and inferior vena cava of a damaged EBPK allograft using a donor pediatric aorta vascular patch with the goal of avoiding postoperative vascular complications.

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.

Long-term clinical outcomes of patients with nonsignificant transplanted renal artery stenosis

Background

Transplant renal artery stenosis (TRAS) is the main vascular complication of kidney transplantation. For research and treatment purposes, several authors consider critical renal artery stenosis to be greater than 50%, and percutaneous intervention is indicated in this scenario. However, there are no reports in the current literature on the evolution of patients with less than 50% stenosis.

Method

This retrospective study included data from all patients who underwent kidney transplantation and were suspected of having TRAS after transplantation with stenosis under 50% independent of age and were referred for angiography at a single centre between January 2007 and December 2014.

Results

During this period, 6,829 kidney transplants were performed at Hospital do Rim, 313 of whom had a clinical suspicion of TRAS, and 54 of whom presented no significant stenosis. The average age was 35.93 years old, the predominant sex was male, and most individuals (94.4%) underwent dialysis before transplantation. In most cases in this group, transplants occurred from a deceased donor (66.7%). The time between transplantation and angiography was less than one year in 79.6% of patients, and all presented nonsignificant TRAS. Creatinine levels, systolic blood pressure, diastolic blood pressure and glomerular filtration rate improved over the long term. The outcomes found were death and allograft loss.

Conclusion

Age, sex and ethnic group of patients were factors that did not interfere with the frequency of renal artery stenosis. The outcomes showed that in the long term, most patients evolve well and have improved quality of life and kidney function, although there are cases of death and kidney loss.

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.

Role of hypertension in kidney transplant recipients

Cardiovascular events are one of the leading causes of mortality in kidney transplant recipients. Hypertension is the most common comorbidity accompanying chronic kidney disease, with prevalence remaining as high as 90% even after kidney transplantation. It is often poorly controlled. Abnormal blood pressure profiles, such as masked or white-coat hypertension, are also extremely common in these patients. The pathophysiology of blood pressure elevation in kidney transplant recipients is complex and includes transplantation-specific risk factors, which are added to the traditional or chronic kidney disease-related factors. Despite these observations, hypertension management has been an under-researched area in kidney transplantation. Thus, relevant evidence derives either from studies in the general population or from small trials in kidney transplant recipients. Based on the relevant guidelines in the general population, lifestyle modifications should probably be applied as the first step of hypertension management in kidney transplant recipients. The optimal pharmacological management of hypertension in kidney transplant recipients is also not clear. Dihydropyridine calcium channel blockers are commonly used as first line agents because of their lack of adverse effects on the kidney, while other antihypertensive drug classes are under-utilised due to fear of the possible haemodynamic consequences on renal function. This review summarizes the existing data on the pathophysiology, diagnosis, prognostic significance and management of hypertension in kidney transplantation.

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.

Acute Page kidney after angioplasty in kidney transplant allografts

Acute Page kidney (APK) in kidney transplantation is a rare entity often related to interventional techniques. Percutaneous angioplasty remains an exceptional cause of APK. Herein we describe the clinical course and outcome of APK following percutaneous angioplasty for transplant renal artery stenosis in four kidney transplant recipients, where external compression of the graft was caused by subcapsular haematomas. All patients were treated with surgical drainage, after which two cases recovered baseline kidney function, one developed advanced chronic kidney disease and one remained dialysis-dependent. To our knowledge, the present series is the largest to describe APK in kidney allografts after percutaneous angioplasty.

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.

The Association Between Macroscopic Arteriosclerosis of the Renal Artery, Microscopic Arteriosclerosis, Organ Discard, and Kidney Transplant Outcome

Supplemental Digital Content is available in the text.

Background.

During organ retrieval, surgeons estimate the degree of arteriosclerosis and this plays an important role in decisions on organ acceptance. Our study aimed to elucidate the association between macroscopic renal artery arteriosclerosis, donor kidney discard, and transplant outcome.

Methods.

We selected all transplanted and discarded kidneys in the Netherlands between January 1, 2000, and December 31, 2015, from deceased donors aged 50 y and older, for which data on renal artery arteriosclerosis were available (n = 2610). The association between arteriosclerosis and kidney discard, the relation between arteriosclerosis and outcome, and the correlation between macroscopic and microscopic arteriosclerosis were explored.

Results.

Macroscopic arteriosclerosis was independently associated with kidney discard (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.02-1.80; P = 0.03). Arteriosclerosis (any degree) was not significantly associated with delayed graft function (OR, 1.16; 95% CI, 0.94-1.43; P = 0.16), estimated glomerular filtration rate 1-y posttransplant (B, 0.58; 95% CI, –2.07 to 3.22; P = 0.67), and long-term graft survival (hazard ratio, 1.07; 95% CI, 0.86-1.33; P = 0.55). There was a significant association between mild arteriosclerosis and primary nonfunction (OR, 2.14; 95% CI, 1.19-3.84; P = 0.01). We found no correlation between macroscopic and histological arteriosclerosis, nor between histological arteriosclerosis and transplant outcome.

Conclusions.

Macroscopic arteriosclerosis of the renal artery was independently associated with kidney discard and somewhat associated with primary nonfunction posttransplant. However, there was no effect of arteriosclerosis on delayed graft function, estimated glomerular filtration rate at 1 y, or long-term graft survival. Our results are valid only after inevitable exclusion of discarded kidneys that had on average more arteriosclerosis. Hence, conclusions should be interpreted in the light of this potential bias.

Successful Endovascular Treatment for Very-Late-Onset and Acute Progressive Multiple Transplant Renal Segmental Artery Stenoses: A Case Report

PURPOSE

To report the endovascular treatment for acute progressive and very-late-onset multiple segmental small-artery stenoses in transplanted kidney parenchyma presenting with rapidly deteriorating renal function and refractory hypertension in a 65-year-old man.

CASE REPORT

Nineteen years ago, the patient received a living renal transplant via end-to-end anastomosis of the right internal iliac artery for kidney failure caused by chronic glomerulonephritis. His transplant renal function (creatinine: 0.9 mg/dL) and blood pressure were stable for 18 years. Then rapid worsening of renal function (creatinine: 2.5 mg/dL) and refractory hypertension occurred. Magnetic resonance angiography and renal angiography showed multiple small segmental artery stenoses in the transplanted kidney. At the 1-month follow-up consultation, total occlusion of 2 branches traversing the inferior pole of the kidney was observed, revealing acute progression of artery stenosis. Balloon angioplasty was successfully performed on those branches; renal function improved (creatinine: 1.3 mg/dL), and blood pressure was sufficiently controlled.

CONCLUSIONS

This is a rare case that revealed very-late-onset multiple segmental renal artery stenoses with acute progression in the transplant kidney. Even multiple small segmental artery stenoses can reduce transplant renal function in the chronic phase and progress rapidly. Early percutaneous transluminal angioplasty may thus be feasible and important for preventing graft loss.

Management of the patient who has had a kidney transplant in the medical assessment unit

The number of people with kidney transplants has increased rapidly over the last 20 years. They are often medically complex and have a significant need for both routine and urgent care. Patients who have received a kidney transplant can be challenging to manage in the medical assessment unit. They are vulnerable to infections and acute kidney injury; disease presentation and course may be atypical and they are at risk of rapid deterioration. This review describes a systematic approach to their assessment and management and highlights specific considerations to be borne in mind.

Allograft dysfunction and parenchymal necrosis associated with renal artery stenosis and perigraft hematoma after kidney transplantation

Transplant renal artery stenosis (TRAS) is one cause of allograft dysfunction. TRAS causes parenchymal necrosis and graft insufficiency. Herein, we report the case of a 40-year-old female with end-stage renal disease due to immunoglobulin A nephropathy, who underwent kidney transplantation with her elder sister. The surgery was successful and the allograft showed primary graft function. At postoperative day (POD) 2, urine output decreased sharply. We checked a non-enhanced abdominal computed tomography scan which showed subcapsular and pelvic cavity hematomas. She underwent hematoma removal surgery with renal upper polar capsulotomy. Bleeding control was successful, but her serum creatinine was 5.4 mg/dL. At POD 25, abdomen magnetic resonance angiography showed significant stenosis at the anastomosis site between the graft renal artery and the recipient’s internal iliac artery. Then, percutaneous transluminal angioplasty was implemented. Significant stenosis (>80%) was detected at the anastomotic site and a 5-mm stent was inserted at stenotic lesion with post-stent balloon angioplasty using a 5-mm balloon catheter. The renal arterial diameter and blood flow were normalized. At postoperative 5 months, a 99mTc dimercaptosuccinic acid scan showed multiple focal radioisotope defects. At 54 months after renal transplantation, her serum creatinine level was 4.0 mg/dL and her glomerular filtration rate was 13 mL/min/1.73 m². Hence, we report that TRAS can cause parenchymal necrosis and allograft dysfunction.

Approach and Management of Hypertension After Kidney Transplantation

Hypertension is one of the most common cardiovascular co-morbidities after successful kidney transplantation. It commonly occurs in patients with other metabolic diseases, such as diabetes mellitus, hyperlipidemia, and obesity. The pathogenesis of post-transplant hypertension is complex and is a result of the interplay between immunological and non-immunological factors. Post-transplant hypertension can be divided into immediate, early, and late post-transplant periods. This classification can help clinicians determine the etiology and provide the appropriate management for these complex patients. Volume overload from intravenous fluid administration is common during the immediate post-transplant period and commonly contributes to hypertension seen early after transplantation. Immunosuppressive medications and donor kidneys are associated with post-transplant hypertension occurring at any time point after transplantation. Transplant renal artery stenosis (TRAS) and obstructive sleep apnea (OSA) are recognized but common and treatable causes of resistant hypertension post-transplantation. During late post-transplant period, chronic renal allograft dysfunction becomes an additional cause of hypertension. As these patients develop more substantial chronic kidney disease affecting their allografts, fibroblast growth factor 23 (FGF23) increases and is associated with increased cardiovascular and all-cause mortality in kidney transplant recipients. The exact relationship between increased FGF23 and post-transplant hypertension remains poorly understood. Blood pressure (BP) targets and management involve both non-pharmacologic and pharmacologic treatment and should be individualized. Until strong evidence in the kidney transplant population exists, a BP of <130/80 mmHg is a reasonable target. Similar to complete renal denervation in non-transplant patients, bilateral native nephrectomy is another treatment option for resistant post-transplant hypertension. Native renal denervation offers promising outcomes for controlling resistant hypertension with no significant procedure-related complications. This review addresses the epidemiology, pathogenesis, and specific etiologies of post-transplant hypertension including TRAS, calcineurin inhibitor effects, OSA, and failed native kidney. The cardiovascular and survival outcomes related to post-transplant hypertension and the utility of 24-h blood pressure monitoring will be briefly discussed. Antihypertensive medications and their mechanism of actions relevant to kidney transplantation will be highlighted. A summary of guidelines from different professional societies for BP targets and antihypertensive medications as well as non-pharmacological interventions, including bilateral native nephrectomy and native renal denervation, will be reviewed.

Intra-arterial computed tomography angiography with ultra-low volume of iodine contrast and stent implantation in transplant renal artery stenosis in terms of contrast-induced kidney injury - a preliminary report

PURPOSE

Traditional digital subtraction angiography is still regarded as the gold standard in the diagnostics of transplant renal artery stenosis (TRAS). However, this procedure requires a high volume of iodine contrast medium for optimal visualisation of the renal artery. The aim of this study was to analyse both the usefulness and the safety of intra-arterial computed tomography angiography (IA-CTA) with ultra-low-volume iodine contrast administration in the diagnostic and therapeutic management of TRAS in patients with impaired renal transplant function.

MATERIAL AND METHODS

Thirty-three patients with a suspicion of TRAS based on Doppler-ultrasound and clinical setting underwent IA-CTA with ultra-low iodine contrast volume. A special, author-elaborated CTA protocol was used. The volume of 8-18 ml of diluted iodine contrast medium was administered through a catheter with the tip placed 2 cm below the aortic bifurcation.

RESULTS

In six patients the CTA examinations revealed TRAS in three configurations: in the anastomosis, in the trunk (critical and high-grade), or in both sections. Stenoses were treated with primary stenting obtaining favourable anatomical outcome. No intervention-related complications were observed. No contrast-induced acute kidney injury was diagnosed in this study. Mean serum creatinine concentration was 2.93 ± 0.89 mg/dl at the baseline and 2.89 ± 1.73 mg/dl and 2.17 ± 0.51 mg/dl after three and seven days from IA-CTA, respectively.

CONCLUSIONS

Intra-arterial CTA with ultra-low volume of iodine contrast seems to be a safe and reliable diagnostic tool to detect and assess TRAS in the aspect of stent implantation. Application of this imaging modality eliminates the need for a high volume of iodine contrast and thus does not adversely influence renal transplant function.

Diagnosis and Treatment of Renal Artery Stenosis in China in the Era of Donation After Cardiac Death

Background

The aim of this study was to investigate the clinical features and treatment strategies of transplant renal artery stenosis (TRAS) with kidneys from donation after cardiac death (DCD).

Material/Methods

We collected the clinical data of donors and recipients of single-center DCD-induced TRAS from January 2015 to June 2017.

Results

All the 8 cases of TRAS were from hypertensive cerebrovascular accident DCD-originated kidneys. The mean donor age was 53.5 (45~57) years, with mean BMI 27.8 (26.4~32.3) kg/m², atherosclerosis index 5.8 (4.9~7.0), and renal atherosclerotic plaque. Clinical features of TRAS were: refractory hypertension with elevated serum creatinine >50%, and negative urine protein and occult blood. Ultrasound of transplanted kidneys showed renal blood flow index 0.49 (0.43~0.55). Angiography confirmed the diagnosis of renal artery trunk or secondary branch stenosis. There were 2 cases of moderate stenosis and 6 cases of severe stenosis. Six patients underwent stent implantation and 2 patients underwent balloon dilatation. Seven patients had serum creatinine recovery after interventional therapy during follow-up. The transplanted kidney of 1 patient ruptured 6 h after interventional therapy and was then resected.

Conclusions

The incidence of TRAS with hypertensive cerebrovascular accident DCD-originated kidneys is relatively high, which is a warning to kidney transplant physicians. Digital subtraction angiography (DSA) is the most reliable diagnostic means of TRAS and can be performed concurrently with intervention therapy. If the donor has severe atherosclerosis, plaques that are visible to the unaided eye in the renal artery trunk should be removed as completely as possible.

Outcomes of endovascular treatment of renal arterial stenosis in transplanted kidneys

Objective

To evaluate the effectiveness and outcomes of endovascular treatment of TRAS with PTA.

Materials and Methods

We searched our prospectively collected database looking at cases of TRAS between January 2005-December 2011. CCT was the gold-standart for diagnosis of TRAS. Parameters analysed comprised technical aspects, arterial blood pressure variation, and renal function. A minimum follow-up of 24 months was considered.

Results

Of the 2221 renal transplants performed in the selected period, 22 (0.9%) patients were identified with TRAS. Fourteen (63.6%) were male and mean age was 377±14.8years (12-69). Kidney graft was from deceased donnors in 20 (80%) cases. On doppler evaluation, mean blood flow speed after transplantation, at TRAS diagnosis and after TAP was 210.6±99.5, 417±122.7 and 182.5±81.6mL/sec, respectively (p<0.001). For SBP and DBP, there was a significant difference between between pre-intervention and all post-treatment time points (p<0.001). After 1 month of the procedure, there was stabilization of the Cr level with a significant difference between mean Cr levels along time (p<0.001). After a mean follow-up of 16±4.2 (3-24) months, overall success rate was 100%.

Conclusions

Endovascular treatment with PTA/stenting is a safe and effective option for managing TRAS, ensuring the functionality of the graft and normalization of blood pressure and renal function.

Optical coherence tomography in varying aetiologies of renal artery stenosis: a case series

Background

Renal artery stenosis (RAS) is a common cause of secondary hypertension. The most common aetiology is atherosclerosis; however, other causes like fibromuscular dysplasia (FMD) and Takayasu arteritis (TA) are also frequently encountered. The lesion characteristics and its response to percutaneous intervention depend upon the aetiology of RAS. Optical coherence tomography (OCT) is an excellent imaging modality to analyse coronary lesions during percutaneous coronary interventions. The data regarding the utility of OCT in renal artery imaging is limited, consisting of a few case reports.

Case summary

We hereby report four cases of RAS, each of different aetiology (atherosclerotic, FMD, post-transplant, and TA), who underwent OCT imaging of the renal artery along with percutaneous renal angioplasty.

Discussion

The advantages of OCT imaging include demonstration of the arterial wall, pathological features of the disease, and to guide percutaneous interventions. The major limitation of OCT is its lower imaging depth, which may render imaging of large vessels difficult.

Risk factors for transplant renal artery stenosis after live donor transplantation

Background

Renal transplant surgeons are making increasing use of live donor kidneys with multiple renal arteries. This study aimed to identify independent risk factors for the development of transplant renal artery stenosis (TRAS) in the modern era of complex arterial reconstruction for multiple vessels.

Methods

Multivariable logistic regression analysis with a stepwise variable deletion model was used to identify risk factors for the development of TRAS in a consecutive series of live donor kidney transplants.

Results

Of 506 kidney transplants, 19 (3·8 per cent) had evidence of significant TRAS on CT angiography. Functional TRAS, defined by improvement in BP control or renal function after correction of a stenosis by angioplasty, occurred in 13 of 506 patients (2·6 per cent). Independent risk factors for TRAS were: use of an explanted internal iliac artery graft from the recipient (odds ratio (OR) 4·95; P = 0·020) and total ischaemia time (OR 1·82; P = 0·010). TRAS was associated with a lower 5-year allograft survival rate (79 versus 88·7 per cent; P = 0·020) but only one graft loss was attributed directly to TRAS. The 5-year allograft survival rate after internal iliac artery grafting was 86 per cent.

Conclusion

Although use of an internal iliac artery graft is an independent risk factor for TRAS after live donor kidney transplantation, this technique is still a useful option for complex arterial reconstruction.

Vascular complications in kidney transplant recipients

Vascular complications are a significant source of morbidity and mortality among renal transplant recipients. Imaging using ultrasound, CT, and MRI plays a key role in diagnosing such complications. This review focuses on the major vascular complications of renal grafts, which include transplant renal arterial and venous stenoses, arterial and venous thromboses, arteriovenous fistulas, and pseudoaneurysms. Etiology, diagnostic modalities useful for diagnosis, and imaging appearance will be presented.

Endovascular treatment of transplant renal artery stenosis based on hemodynamic assessment using a pressure wire: a case report

Background

Transplant renal artery stenosis (TRAS) is a serious complication after renal transplantation, leading to hypertension, deterioration in renal function, and/or graft loss. The incidence of TRAS reportedly varies from 1 to 23%, depending on its definition or diagnostic tools. The hemodynamic definition or therapeutic indication of TRAS is unclear.

Case presentation

A 66-year-old man with a history of diabetes, chronic kidney disease, and angina presented with a 2-week history of dyspnea and leg edema. He had undergone living-donor kidney transplantation for end-stage renal disease secondary to diabetic nephropathy 7 years earlier. He developed acute deterioration in renal function after the administration of an angiotensin II receptor blocker and required emergency hospitalization owing to acute congestive heart failure with pulmonary edema. A vasodilator and loop diuretics were administered following his admission, and the patient’s symptoms resolved quickly. Further investigation, including magnetic resonance angiography and ultrasonography, revealed severe stenosis of the transplant renal artery. Renal arteriography and pressure gradient measurement using a 0.014-inch pressure wire were performed. The systolic pressure gradient was 40 mmHg, and the resting Pd/Pa ratio (ratio of mean distal to lesion and mean proximal pressures) was 0.90 without hyperemia. Hemodynamically significant stenosis was suspected. Intravascular ultrasonography revealed vessel shrinkage in the stenotic area, suggestive of the end-to-end anastomosis site. Pre-dilation using a 4-mm balloon, implantation of a 6-mm self-expandable stent, and post-dilatation using a 5-mm balloon were performed. Although the moderate stenosis persisted angiographically, the systolic pressure gradient dropped to 20 mmHg with the mean systolic pressure ratio increased to 0.95, which was considered an acceptable result. One month after the procedure, the patient’s renal function and blood pressure control had significantly improved.

Conclusions

Hemodynamic assessment using a pressure wire is useful in determining the appropriate therapeutic indication and endpoint of endovascular treatment of TRAS.

Detection of transplant renal artery stenosis with contrast-enhanced ultrasound

Transplant renal artery stenosis (TRAS) is a vascular complication occurring during the first 2 years after kidney transplantation, with an incidence and a prevalence ranging from 1% to 23%, and from 1.5% to 4%, respectively. Detection of TRAS is the key, since most stenoses may progress to renal graft loss, however it may be difficult to detect due to its nonspecific clinical manifestations. Although Doppler ultrasound has become a primary imaging technique, digital subtraction angiography (DSA) remains the gold standard for diagnosing TRAS. We present a case of delayed graft function following kidney transplantation complicated by a lateral by-pass with prosthesis upstream and downstream of renal anastomosis, TRAS criteria were unclear using Doppler ultrasound, contrast-enhanced computed tomography-scan, and DSA. Only contrast-enhanced ultrasound (CE-US), observing a delayed and pulsating contest impregnation of renal parenchyma, supported the hypothesis of TRAS that was confirmed by the measurement of trans-anastomosis pressure gradient during DSA.

Transplant renal artery stenosis caused by the stretch of an artey branch: a case report and literature review

Background

Renal transplant is the preferred treatment option for these patients with end-stage renal disease. Transplant renal artery stenosis (TRAS) is one of the most common and serious vascular complications after renal transplantation, and most of the TRAS occurred in the anastomosis. The complication must be diagnosed and treated timely, otherwise the function of transplanted kidney may be losed.

Case presentation

A 46-year-old male with end-stage renal disease of unknown cause received a cadaveric renal transplant one year ago. Although three antihypertensive medications were administrated, his blood pressure gradually increased to 190/120 mmHg 3 weeks posttransplantation. Also the level of creatinine increased to 194 μmol/L.Color Doppler ultrasonography indicated a decreased resistance index (RI) in intrarenal arteries and increased blood flow of the transplant renal artery, therefore, a vascular complication of TRAS was suspected. Arteriography was performed and demonstrated TRAS caused by stretch of an artery branch, and the TRAS occurred in the distal site of the anastomosis instead of the anastomosis. Percutaneous transluminal bare stent implantation treatment was successfully performed. Satisfactory clinical efficacy with improvement in transplant renal function and renovascular hypertension was achieved after the interventional treatment.

Conclusion

To our knowledge this is the first reported case of TRAS caused by stretch of an artery branch. When refractory hypertension and allograft dysfunction are presented posttransplantation, TRAS should be suspected. Color Doppler ultrasonography as a non-invasive examination may provide some valuable information, three-dimention CT can be useful for further diagnosis, but is seldom necessary. Arteriography provides the definitive diagnosis of TRAS. Percutaneous transluminal stent implantation treatment of TRAS has high success rate with minimal invasion and complications. When an artery branch situated on the stenosis, a bare stent rather than covered stent is the preferred choice.

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.

Peri- and Postsurgical Evaluations of Renal Transplant

Renal transplantation is the best treatment of choice for patient with chronic renal insufficiency because it provides better quality of life and longer survival. Survival rates for grafts and patients have improved over the recent decades because of significant evolution of surgical techniques and immunosuppressive treatment. However, renal transplantation is still associated with several complications, which may result in poor outcome. Cause of allograft dysfunction, which occurs in the early or late post-transplantation period, should be recognized immediately, so that it can be managed correctly. Surgical complications are rare and include renal artery stenosis, vascular thrombosis, hematoma, ureteral obstruction, urinary leak, hematoma, lymphocele, and perinephric fluid collections. Parenchymal complications, which are histopathologically categorized according to Banff classification, include antibody-mediated rejection, T-cell mediated rejection, interstitial fibrosis and tubular atrophy, calcineurin inhibitors, acute tubular injury, and others. Detection of changes in the allograft function is an important task in the appropriate management of complications. Although first-line imaging tool in the recognition of complications is ultrasonography, radionuclide imaging is a modality capable of assessing graft function qualitatively and quantitatively. Sequential renal scintigraphy is of particular importance in the differential diagnosis of complications, which need prompt and accurate management. Renal scintigraphy within 24-48 hours of transplantation surgery is recommended to serve as a baseline for comparison when functional impairment develops. In addition, studies have shown that early renal scintigraphy has a predictive value for the short-term and long-term graft outcomes. This article focuses in the main complications after renal transplantation, their imaging findings, and the role of renal scintigraphy.

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.

Three-Dimensional Computed Tomography Reconstruction in Transplant Renal Artery Stenosis

OBJECTIVES

Transplant renal artery stenosis is a frequently recognized complication of kidney transplant procedures. A single-center retrospective study was conducted to examine the use of 3-dimensional computed tomography reconstruction in diagnosing transplant artery stenosis.

MATERIALS AND METHODS

During 2013 at our center, 86 patients underwent kidney transplant. All patients underwent ultrasonographic analyses. Patients with clinically suspected transplant renal artery stenosis were examined by 3-dimensional computed tomography reconstruction and were treated with endovascular approaches or medically managed.

RESULTS

Ten patients were diagnosed with transplant renal artery stenosis by 3-dimensional computed tomography reconstruction. No evidence of contrast-induced nephrotoxicity was observed. Nine of the 10 patients underwent percutaneous transluminal angio-plasty, whereas the remaining patient was treated conservatively. Procedural success rate was 100%. Patients were followed for a mean period of 20 ± 3 months. Blood pressure improved from a mean of 163/90 to 132/73 mm Hg at the end of the follow-up period. In the 9 patients who underwent angioplasty, serum creatinine improved from 198 ± 24 to 134 ± 16 μmol/L at the end of the follow-up period. The cystatin C level in some patients declined after interventional therapy.

CONCLUSIONS

Three-dimensional computed tomography reconstruction is a safe choice for patients who present with increased serum creatinine levels and refractory hypertension. Percutaneous transluminal angioplasty is the preferred therapeutic technique for transplant renal artery stenosis.

Transplant renal artery stenosis: Evaluation with contrast-enhanced ultrasound

OBJECTIVE

To assess the efficacy of contrast-enhanced ultrasound (CEUS) in depicting transplant renal artery stenosis (TRAS).

MATERIALS AND METHODS

Seventy-eight patients (56 men and 22 women; aged 36±12.2years) who were suspected of TRAS due to either Doppler ultrasound (DUS) abnormalities or difficult control of blood pressure and/or persistent deterioration of renal function were enrolled to perform CEUS. The reference standard for the TRAS diagnoses was computed tomography angiography (CTA). The diagnostic performance of DUS and CEUS parameters was assessed by the area under the receiver operating characteristic curve (AUC).

RESULTS

TRAS was diagnosed in 32 out of 78 cases by CTA. The AUC, accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of CEUS in predicting TRAS were 0.92, 92.3%, 87.5%, 95.7%, 93.3%, and 91.7%, respectively. CEUS rectified 13 (28.3%) false-positive cases on DUS, which were confirmed by CTA. Compared to DUS parameters, CEUS showed the highest AUC, statistically significant differences of AUC were found (P=0.006-0.039), except for that of the PSV ratio in the main transplant renal artery to that in interlobar artery (PSV-ratio) (AUC: 0.92 versus 0.86, P=0.422). However, CEUS showed a significantly higher specificity (95.7% versus 76.1%, P=0.008) and the same sensitivity compared to PSV-ratio.

CONCLUSIONS

CEUS is superior to DUS in depicting TRAS. Moreover, our results suggest that CEUS might potentially be used as a noninvasive tool to spare many patients from unnecessary CTA.

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.

Unique Considerations When Managing Hypertension in the Transplant Patient

For the select fortunate recipients of organ transplants, transplantation affords the rare opportunity for a new life. Given the scarcity of organs for transplantation, it is imperative that the health of transplant recipients be optimized in order to fully benefit from this gift of life. Unfortunately, hypertension is highly prevalent in the transplant population and it is considered a major cardiovascular risk factor contributing to mortality and morbidity in this population. In this chapter, we expound on the epidemiology, unique pathophysiology, evaluation, and management of hypertension as it pertains to the solid organ transplant recipient. In addition, a brief commentary is made on the subject of hypertension following living kidney donation, and practical aspects of management of hypertension in the solid organ recipient are summarized at the end of the chapter.

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.

Revascularization of Kidney Allograft after Renal Artery Occlusion Secondary to Angioplasty

Arterial thrombosis causing complete occlusion is a rare event in the natural history of a transplanted allograft; an incidence of 1.4% has been reported. This condition usually results from technical problems, hyperacute rejection, severe atherosclerosis, or injury to donor or recipient arteries. The treatment of choice is transplant nephrectomy. We report a case of renal artery occlusion after a therapeutic radiological procedure and subsequent salvaging of the graft. The case report shows that an aggressive surgical approach toward restoring circulation is worth the effort.

Management of Hypertension in Solid-Organ Transplantation

Posttransplant hypertension is a major risk factor for cardiovascular disease and chronic renal allograft dysfunction. A significant number of transplant recipients suffer from posttransplant hypertension in part because of corticosteroid and calcineurin inhibitor use. Although the optimal blood pressure range and the antihypertensive agents of choice in the transplant population have not been determined, the guidelines for blood pressure control in the general population can be extrapolated to the transplant population. The choice of an antihypertensive regimen should be tailored on the basis of the individual patient's risk factors and comorbidities.

Evaluation of the Vascular Surgical Complications of Renal Transplantation

BACKGROUND

Renal transplantation is the treatment of choice of end-stage renal failure. However, vascular surgical complications can compromise the functional prognosis of the transplant or even be life threatening in the short term. Since few data are available in the literature, the objective of this study was to evaluate the vascular surgical complications of renal transplantation.

METHODS

In a retrospective and monocentric study, the records of all the patients receiving a kidney transplant between January 2008 and December 2014 were reviewed. The demographic data and the follow-up of the patients who presented a vascular surgical complication in relation to their transplant were collected. Minor, intermediate, or major vascular complications were defined according to the need for monitoring, reoperation, or the risk of transplant loss or a life-threatening situation. Predictive factors of vascular complications were also looked for.

RESULTS

Mean age was 50.9 ± 15.0 years, and 312 kidney transplants were carried out (205 men). Fifty vascular surgical complications (16.0%) were found. Among them, 23 vascular complications (7.4%) were major, including 6 (1.9%) which required transplantectomy, after 4 arterial thromboses (1.3%), 1 early venous thrombosis (0.3%), and 1 injury of the inferior vena cava (0.3%). Twelve complications (3.8%) were minor. Surgical revision was necessary in 76% of the vascular complications (n = 38). The average follow-up of the transplanted population was 37.4 ± 24.0 month, 268 kidney transplants (85.8%) were functional and 21 patients (6.7%) returned to dialysis. Surgical complications were more frequent when the recipient had hypertension (P = 0.02, OR = 2.5; 95% CI [1.1-6.1]), in case of right kidney transplant (P = 0.0004, OR = 3.1; 95% CI [1.6-5.8]) and when the kidney hilum consisted of at least arteries (P = 0.02, OR = 10.0; 95% CI [1.3-34]). Male gender (P = 0.03, OR = 0.5; 95% CI [0.3-0.9]) as well as the choice of the common iliac arterial (P = 0.001, OR = 0.4; 95% IC [0.2-0.7]) and venous (P = 0.002, OR = 0.3; 95% IC [0.2-0.8]) axes to carry out the vascular anastomoses appeared as protective factors.

CONCLUSIONS

The vascular surgical complications of kidney transplantation, especially thromboses, can be serious and lead to transplant loss. The expertise of vascular surgeons finds its place here and makes it possible to maintain low rates of vascular complications and loss of transplants.