Double kiss mini-crush technique to treat complex recurrent renal artery in-stent restenosis.

The double-kiss mini-crush (DKMC) technique has been successfully deployed in the past for the treatment of complex coronary lesions even for left main lesions. Our case report consists of a proof-of-principle that the DKMC technique can be successfully translated as well to the field of complex renal artery lesions. Insightful thinking out-of-the "coronary" box in concert with skillful off-label application of coronary stenting procedures may open the gate for unprecedented opportunities for the treatment of difficult-to-tackle in-stent restenosis in the renal circulation.

Interventions for renal artery stenosis: Appraisal of novel physiological insights and procedural techniques to improve clinical outcome.

Randomized clinical trials failed to show additional benefit of renal artery stenting on top of medical therapy. Instead of writing an obituary on renal artery stenting, we try to explain these disappointing results. A transstenotic pressure gradient is needed to reduce renal perfusion and to activate the renin-angiotensin-aldosterone system. In only a minority of patients included in trials, a transstenotic pressure gradient is measured and reported. Like the coronary circulation, integration of physiological lesion assessment will allow to avoid stenting of non-significant lesions and select those patients that are most likely to benefit from renal artery stenting. Renal artery interventions are associated with peri-procedural complications. Contemporary techniques, including radial artery access, no-touch technique to engage the renal ostium and the use of embolic protection devices, will minimize procedural risk. Combining optimal patient selection and meticulous technique might lead to a netto clinical benefit when renal artery stenting is added to optimal medical therapy.

Percutaneous Transluminal Renal Angioplasty for Pediatric Hypertension Secondary to Total Renal Artery Occlusion.

PURPOSE: To assess the feasibility and effectiveness of percutaneous transluminal renal angioplasty (PTRA) for pediatric renovascular hypertension (RVH) secondary to total renal artery occlusion (RAO). MATERIALS AND METHODS: From 2011 to 2021, 13 pediatric patients with RVH confirmed with 14 renal artery occlusions were reviewed. The mean age was 11.2 years (range, 4-16 years). Nine occlusions involved main artery occlusion, and 5 involved branch occlusion. Blood pressure ratio (BPR) was defined as the ratio of the actual measured blood pressure (BP) value to the 95th percentile value adjusted for age, sex, and height. RESULTS: PTRA was performed in 9 patients (9/13, 69%). Technical success was achieved in 5 patients (5/9, 56%), with stent placement in 2 children (2/9, 22%). During the 12-month follow-up, restenosis was identified in both of the stent-receiving patients at the 12-month follow-up visit (2/9, 22%). Mean systolic BPR decreased from 1.20 (SD ± 0.07) to 0.96 (SD ± 0.06; P = .003), mean diastolic BPR decreased from 1.19 (SD ± 0.07) to 0.95 (SD ± 0.08; P = .005), and the number of medications required decreased from 3.8 (SD ± 0.8) to 2.4 (SD ± 0.9; P = .052) after PTRA. Subsequent to PTRA, the mean glomerular filtration rate of the occluded kidney improved from 19.5 mL/min (SD ± 12.3) to 36.3 mL/min (SD ± 10.8; P = .007), and the mean longitudinal dimension of the affected kidneys significantly increased from 8.2 cm (SD ± 1.5) to 9.2 cm (SD ± 1.7; P = .006). CONCLUSIONS: Endovascular treatment is often feasible for pediatric patients with RAO, results in acceptable BP control, and preserves renal function.

Risks and benefits of renal artery stenting in fibromuscular dysplasia: Lessons from the ARCADIA-POL study.

INTRODUCTION: Although renal stenting is the standard revascularization method for atherosclerotic renal artery stenosis (RAS) (FMD-RAS), stenting in fibromuscular dysplasia (FMD) RAS is usually limited to periprocedural complications of angioplasty and primary arterial dissection. The main aim of the study was to retrospectively analyze the immediate and long-term results of renal stenting versus angioplasty in patients with FMD. METHODS: Of 343 patients in the ARCADIA-POL registry, 58 patients underwent percutaneous treatment due to FMD-RAS (in 70 arteries). Percutaneous transluminal renal angioplasty (PTRA) was performed as an initial treatment in 61 arteries (PTRA-group), whereas primary stenting was undertaken in nine arteries (stent-group). Stent-related complications were defined as: in-stent restenosis > 50% (ISR); stent fracture; under-expansion; or migration. RESULTS: In the PTRA-group, the initial restenosis rate was 50.8%. A second procedure was then performed in 22 arteries: re-PTRA (12 arteries) or stenting (10 arteries). The incidence of recurrent restenosis after re-PTRA was 41.7%. Complications occurred in seven of 10 (70%) arteries secondarily treated by stenting: two with under-expansion and five with ISR. In the stent-group, stent under-expansion occurred in one case (11.1%) and ISR in three of nine stents (33.3%). In combined analysis of stented arteries, either primarily or secondarily, stent-related complications occurred in 11/19 stenting procedures (57.9%): three due to under-expansion and eight due to ISRs. Finally, despite several revascularization attempts, four of 19 (21%) stented arteries were totally occluded and one was significantly stenosed at follow-up imaging. CONCLUSION: Our study indicates that renal stenting in FMD-RAS may carry a high risk of late complications, including stent occlusion. Further observational data from large-scale registries are required.

Endovascular Treatment for Transplant Renal Artery Stenosis: 10 Years' Experience from a Single Center.

INTRODUCTION: Transplant renal artery stenosis (TRAS) is a common post-renal transplant complication. Although endovascular treatment is widely used to treat TRAS, previous research has been limited by small sample sizes. This article aimed to present the clinical outcomes of endovascular treatment for TRAS in a large sample. METHODS: Between January 2010 and December 2019, this study included patients with TRAS who were admitted to our center. All patients' clinical symptoms, comorbidities, imaging data, treatment, and follow-up results were reviewed retrospectively. RESULTS: Seventy two patients participated in this study. The median time between renal transplantation and TRAS was 5.25 months. Out of 72 patients, 55 (76.4%) received balloon dilatation in conjunction with stent deployment, 10 (13.9%) received drug-coated balloon dilatation alone, and 7 (9.7%) received balloon dilatation alone. The median follow-up period was 27 months. Primary patency rates were 100%, 81.8%, 74.5%, 64.6%, and 61.8% at 1, 3, 6, 12, and 24 months. A total of 23 patients were found to have restenosis during follow-up, with 6 (26.1%) requiring reintervention and none remaining restenosis after the second treatment. In the subgroup analysis of the three types of stenosis, patients with transplant renal stenosis at the anastomosis had a significantly higher rate of primary patency. Between endovascular treatments, the primary patency rate, postoperative creatinine clearance, and mean systolic blood pressure did not differ significantly. CONCLUSION: Endovascular treatment resulted in favorable short-term patency as well as effective relief of renal dysfunction and renal hypertension in TRAS patients.

Graft survival after percutaneous transluminal renal stenting for transplant renal artery stenosis (TRAS) is worse compared to matched cadaveric grafts without TRAS.

OBJECTIVES: Transplant renal artery stenosis (TRAS) is now recognized as a curable disease with a good prognosis if intervention occurs in the early stage. However, the mid-term outcomes of TRAS when treated by percutaneous transluminal angioplasty with stent placement have yet to be fully elucidated. The purpose of this study was to compare mid-term graft and patient survival of TRAS group with a control group. PATIENTS AND METHODS: Ninety-two patients were diagnosed of TRAS between January 2016 and January 2022 in our center. Fifty-six pairs of recipients with grafts from the same donor were selected as a study group with TRAS and a control group without TRAS, respectively. All donor kidneys were from deceased organ donation rather than living donors. The primary endpoints were graft and patient survival. The secondary outcomes were changes in renal graft function. RESULTS: The mean follow-up time for the TRAS group was 43.6 months, while the mean follow-up time for the control group was 45.3 months. In the TRAS group, the age of patients ranged from 11 to 62 years with 39 males and 17 females. In the control group, the age of patients ranged from 18 to 67 years with 40 males and 16 females. In the TRAS group, there were more patients with diabetic nephropathy as the primary renal disease compared to the control group (5/56 vs 0/56), and the incidence of acute rejection was higher in the TRAS group than in the control group (12/56 vs 3/56). Eight patients in the TRAS group and one patient in the control group experienced graft loss (p = .019). Four patients in the TRAS group and four patients in the control group died with functional renal allograft during the follow-up time (p = .989). The levels of eGFR did not differ significantly between the two groups in the first three years after kidney transplant (p > .05). Patients in the TRAS group had worse graft functionality (eGFR, 44.96 ± 18.9 vs 54.9 ± 19.6 mL/min) in the fourth year when compared with the control group (p = .01). CONCLUSIONS: The graft function deteriorated faster, and graft survival was lower in the TRAS group treated by stent placement when compared with a control group without TRAS over the mid-term.

Proximal Renal Artery Stenosis Presenting as Uncontrolled Hypertension.

Presentation: We present a case of 50-year-old lady who present with 1-month history of uncontrolled hypertension. Diagnosis: Magnetic resonance angiography showed stenosis of the left renal artery just beyond the ostium extending over approximately 7mm in length. Computed tomography angiography show focal narrowing of the proximal renal artery just distal to vessel origin, approximately 60% stenosis. Treatment: Anti-hypertensive medication was initiated in the ward. She was referred to vascular surgeon for renal bypass. Discussion: Renal artery stenosis is common cause of hypertension but may go unrecognised. The focus of this case is on the evaluation and necessity for a complete evaluation of the patient who is presenting with uncontrolled hypertension. To rule out renal artery stenosis, patient should be examined using CT-angiography or, if possible, arteriography.

The Effect of Endovascular Treatment of Renal Artery Stenoses on Coexistent Aneurysms Associated with Fibromuscular Dysplasia.

PURPOSE: Endovascular data on patients with coexistent renal artery stenosis (RAS) and renal artery aneurysm (RAA) caused by fibromuscular dysplasia (FMD) are scarce, and the outcomes from RAS-specific treatment on RAA remain unclear. This study aimed to evaluate the safety and effectiveness of RAS-specific endovascular management in patients with coexisting RAA caused by FMD. MATERIALS AND METHODS: Clinical and endovascular data on 19 patients with coexistent RAS and RAA caused by FMD who underwent RAS-specific endovascular therapy were analyzed prospectively. An RAA located within 10 mm of the RAS was defined as a stenosis-related RAA (SRAA), and long-term outcomes were evaluated. RESULTS: Nineteen patients (24 RASs and 30 RAAs) underwent endovascular therapy. Twenty-one RASs were treated with balloon angioplasty alone, whereas 3 RASs were treated with stent implantation. None of the RAAs were treated directly. During an average of 4.2 years ± 3.2 of follow-up, systolic and diastolic blood pressures decreased from 183.0 mm Hg ± 19.5 and 120.2 mm Hg ± 19.0 to 127.9 mm Hg ± 10.3 and 80.9 mm Hg ± 6.9, respectively; the number of antihypertensive medications reduced from 1.7 ± 1.0 to 0.8 ± 0.3 (for all, P < .001). The serum creatinine level remained stable. The maximum diameter of all RAAs decreased from 14.6 mm ± 9.7 to 11.3 mm ± 8.4 (P < .001). There was a significant difference in the improvement rate of the maximum diameter between SRAAs (65.0%, 13 of 20) and non-SRAAs (20.0%, 2 of 10) (P = .019). CONCLUSIONS: RAS-specific endovascular therapy is safe and effective and possibly aids in preventing RAA progression in patients with FMD with coexistent RAS and RAA.

Drug-coated balloon for treatment of non-atherosclerotic renal artery stenosis-a multi-center study.

INTRODUCTION: Renal artery stenosis (RAS) is a significant reason for secondary hypertension. Impaired renal function and subsequent cardiopulmonary dysfunction could also occur. Patients of non-atherosclerotic RAS has a relatively young age and long life expectancy. Revascularization with percutaneous transluminal angioplasty (PTA) is a viable treatment option. However, restenosis is unavoidable which limits its use. Drug-coated balloon (DCB) has been proven to be effective in restenosis prevention in femoropopliteal arterial diseases and in patients with renal artery stenosis. And PTA for Renal artery fibromuscular dysplasia is safe and clinically successful. Therefore, we could speculate that DCB might have potential efficacy in non-atherosclerotic RAS treatment. METHODS AND ANALYSIS: This will be a randomized multi-center-controlled trial. Eighty-four eligible participants will be assigned randomly in a 1:1 ratio to the control group (plain old balloon, POB) and the experimental group (DCB). Subjects in the former group will receive balloon dilatation alone, and in the latter group will undergo the DCB angioplasty. The DCB used in this study will be a paclitaxel-coated balloon (Orchid, Acotec Scientific Holdings Limited, Beijing, China). Follow-up visits will be scheduled 1, 3, 6, 9, and 12 months after the intervention. Primary outcomes will include controlled blood pressure and primary patency in the 9-month follow-up. Secondary outcomes will include technical success rate, complication rate, and bail-out stenting rate. TRIAL REGISTRATION: ClinicalTrials.gov (number NCT05858190). Protocol version V.4 (3 May 2023).

"Coexistence of IgA nephropathy and renal artery stenosis in Takayasu arteritis: case report and literature review".

Although Takayasu arteritis (TAK) is a form of large vessel vasculitis, complications of glomerulonephritis have occasionally been observed, with mesangial proliferative glomerulonephritis as the most common. The aim of this work was to present a case-based review regarding the association of glomerulonephritis and IgA nephropathy (IgAN) with TAK. A literature search was carried out using the PubMed and Scopus databases for articles published in English, and the Ichu-shi Web for Japanese. A 34-year-old Japanese man was evaluated for proteinuria, and IgAN was diagnosed by renal biopsy. Simultaneously, aortic wall thickening and right renal artery stenosis confirmed a coexisting TAK. Prednisolone and methotrexate improved both diseases, and percutaneous transluminal renal angioplasty resulted in right renal artery reopening. Our case and literature review revealed that membranous proliferative glomerulonephritis and IgAN are common in eastern Asia, while focal segmental glomerulosclerosis and mesangial proliferative glomerulonephritis are common in other regions. The incidence of IgAN is higher in TAK cases and is mostly reported in Asia. Abdominal aortic involvement and renal artery stenosis are common in cases with preceding TAK. IgAN could be related to the cytokine network involving interleukin-6, suggesting the usefulness of tocilizumab in patients with TAK accompanied by IgAN. The type of glomerulonephritis complicated with TAK differs among regions, and patients with TAK are more likely to experience IgAN than the healthy population.

Abdominal arterial lesions associated with antiphospholipid antibodies: a comparative cross-sectional magnetic resonance angiography study.

OBJECTIVE: Case reports and small case series suggest that stenotic lesions of the renal, coeliac and mesenteric arteries may occur in the antiphospholipid syndrome (APS) resulting in clinical consequences such as hypertension and abdominal angina. The objective was to determine the prevalence of stenotic lesions in arteries arising from the middle aorta in patients with antiphospholipid antibodies (aPL) compared with healthy, hypertensive and atherosclerotic controls. METHODS: In a cross-sectional comparative radiological study using magnetic resonance angiography (MRA), we assessed five groups of subjects for the prevalence of stenotic lesions in arteries arising from the middle aorta: APS/aPL positive, healthy renal donors, patients with hypertension, patients with atherosclerosis defined radiologically and patients with systemic lupus erythematosus and vasculitis who were negative for aPL. All subjects underwent MRA in suspended respiration and images were assessed by two senior radiologists blinded to the clinical details. RESULTS: In the atherosclerosis group, vascular stenotic lesions were more prevalent (71%) than in any other group (P ≤0.000002). The prevalence of all stenotic lesions in aPL positive patients (33%) was significantly higher than in the renal donors (18%) and hypertensive patients (19%) (P ≤0.009). Renal artery stenosis was significantly more prevalent in aPL positive patients than in renal donors (P ≤0.0006) but similar to the prevalence in hypertensive patients. Coeliac and/or mesenteric lesions were significantly more common in aPL positive patients vs hypertensive patients (P ≤0.001). Stenoses did not correlate with traditional risk factors. CONCLUSION: Arterial stenotic lesions in arteries arising from the middle aorta were highly prevalent in atherosclerotic subjects and were more common in aPL-positive patients than in hypertensive patients and healthy renal donors.

Insights from intravascular pressure measurement of renal artery revascularization in patients with fibromuscular dysplasia: The DYSART study.

OBJECTIVE: The indication of percutaneous renal transluminal angioplasty (PTRA) in fibromuscular dysplasia (FMD) is mainly based on renal artery stenosis (RAS) due to atherosclerosis criteria, which are not specific to FMD. Consequently, the selection of patients who could benefit from this treatment and its effectiveness remain uncertain. The aims of this study were to: (1) report the effects of PTRA guided by trans-stenotic pressure measurements on hypertension 7 months after treatment; (2) assess the impact of pressure measurement to guide treatment efficacy in comparison to visual angiographic parameters; and (3) evaluate the reproducibility and accuracy of the stenosis measurement using a 4F catheter in comparison to a pressure guidewire. METHODS: This prospective multi-centric study analyzed 24 patients with hypertension with RAS due to FMD that required PTRA. Clinical, duplex ultrasound, and angiographic indices were collected, and patients were followed up for 7 months (±1 month). Angiographic indices were measured twice both by a pressure guidewire and a 4F catheter. Assessment of procedural and clinical success of angioplasty was performed for all patients. RESULTS: Twenty-three patients (96%) had procedural success (considered as a post-PTRA translesional systolic gradient ≤10 mmHg or reduced by at least 80%) with a significant decrease in the systolic gradient after angioplasty (26.50 mmHg; [interquartile range, 16.75-38.75] vs 0.00 [interquartile range, 0.00-2.00]; P < .01). Three patients (12%) had complications, including two renal artery dissections and one partial renal infarction. Twenty-one patients (88%) were clinical responders to angioplasty at follow-up. Visual stenosis assessment showed a poor correlation with systolic gradient measurement before and after PTRA (R from -0.05 to 0.41; P = 0.06-0.82). High correlations were found between pressure measurements made by a 4F catheter and guidewire (R from 0.64 to 0.89; P ≤ .003). CONCLUSIONS: In patients selected by clinical indicators and duplex ultrasound, reaching a translesional systolic gradient ≤10 mmHg or reduced by at least 80% after angioplasty, promotes a high success rate for PTRA in hypertension due to FMD RAS.

Perfusion and oxygenation in allografts with transplant renal artery stenosis: Evaluation with functional magnetic resonance imaging.

BACKGROUND: Transplant renal artery stenosis (TRAS) has been shown to reduce kidney perfusion leading to post-operative hypertension. We aimed to measure the perfusion and oxygenation changes in TRAS with arterial spin labeling (ASL) and blood oxygen level-dependent (BOLD) imaging, respectively. METHODS: In this single-center prospective study, a total of seven patients with TRAS and seven age- and sex-matched normal kidney transplant recipients underwent both ASL and BOLD imaging. Moreover, measurements of ASL and BOLD were also performed in five patients after successful angioplasty for TRAS. RESULTS: Allograft cortical perfusion as measured by ASL in the TRAS group was significantly decreased as compared with normal control group (129.9 ± 46.6 ml/100 g vs. 202.4 ± 47.7 ml/100 g, P = .01). Interestingly, allograft oxygenation as indicated by R2* derived from BOLD in both the cortex (16.42 ± 1.90 Hz vs. 18.25 ± 4.34 Hz, P = .33) and the medulla (30.34 ± 2.35 Hz vs. 30.43 ± 6.85 Hz, P = .97) showed no statistical difference between the TRAS and normal control group. In addition, both cortical and medullary oxygenation remained unchanged despite significantly improved cortical perfusion in those undergone successful angioplasty. CONCLUSION: Cortical and medullary oxygenation were preserved in the presence of reduced allograft perfusion in clinically significant TRAS. Prospective larger studies are needed to conclusively establish perfusion and oxygenation changes in TRAS.

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.

Treatment of Severe Renal Artery Stenosis with Acute Kidney Injury Requiring Hemodialysis by Percutaneous Transluminal Renal Angioplasty and Stent Implantation.

PURPOSE: To evaluate the outcomes of percutaneous transluminal renal angioplasty with stent implantation (PTRAS) among patients with renal artery stenosis (RAS) who become dialysis-dependent due to acute deterioration of renal function. MATERIALS AND METHODS: This was a single-center retrospective cohort study of all PTRAS procedures performed from 2003 to 2019 in a referral hospital. A total of 109 procedures were performed in 92 patients. Eleven patients (12%) presented with anuric acute kidney injury (AKI) secondary to high-grade RAS (defined as intraluminal stenosis above 70% per angiography) and underwent PTRAS after starting hemodialysis. Data collected included demographic parameters, medical background, creatinine, blood pressure, indication for intervention, procedure characteristics, adverse events, and long-term data including dialysis treatment and mortality. Among the dialysis-dependent AKI group, outcome measures were defined based on the postprocedural improvement in kidney function and discontinuation of dialysis. RESULTS: Following PTRAS, 8 of 11 patients (73%) demonstrated improved kidney function and were able to discontinue dialysis. The median time on dialysis was 18 days (range, 2-35 days) before PTRAS and 4.5 days (range, 1-24 days) to recovery of kidney function after the time of intervention. CONCLUSIONS: Patients with atherosclerotic RAS who develop RAS-related AKI may benefit from PTRAS even after several weeks of anuria and dialysis dependence.

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-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: Fifty-six 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. CONCLUSIONS: 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.

Pediatric Renal Artery Stenosis: A 19-Year Experience in Management and Outcomes at a Tertiary Pediatric Hospital.

BACKGROUND: Renal artery stenosis (RAS) is an uncommon cause of pediatric hypertension. Guidelines for workup and management have not been established. The most widely reported etiology of the pediatric renovascular disease has been fibromuscular dysplasia; however, other etiologies including middle aortic syndrome (MAS) and vasculitides have been described. We reviewed cases of radiologically identified pediatric RAS and describe etiologies, management, and long-term clinical outcomes in our patients. METHODS: Reports for duplex ultrasound, computed tomography angiography, magnetic resonance imaging, and conventional angiography from an academic children's hospital between 2000 and 2019 were evaluated. Positive reports for RAS were confirmed by a vascular surgeon and a radiologist. Demographics, indications for evaluation, management, and long-term clinical outcomes were documented. Data are summarized as count (n), geometric mean, median, or standard deviation as appropriate. Univariate differences between treatment cohorts were analyzed using Chi-squared tests for categorical variables. Nonparametric paired Wilcoxon signed-rank test and Mann-Whitney U-test were used for the analysis of paired ordinal or continuous data. A statistical analysis was performed with SPSS software (SPSS Inc., Chicago, IL) with significance defined at a P < 0.05 level. RESULTS: Imaging for suspected RAS was performed on 984 children. Of the 38 patients with positive imaging for RAS, 60.5% were idiopathic, 31.5% (n = 12) had concomitant congenital/systemic comorbidity, and 21.0% (n = 8) had RAS and concomitant aortic pathology. Fibromuscular dysplasia only accounted for 13.2% (n = 5) of patients. Regarding management, 34.2% (n = 13) underwent invasive intervention, 23.7% (n = 9) underwent endovascular intervention alone, and 10.5% (n = 4) underwent endovascular plus surgical intervention. Conservative management was performed for 65.8% (n = 25) of patients at a long-term follow-up (33.8 months), 34.2% (n = 13) requiring only lifestyle changes, and 31.6% (n = 12) requiring only medical management. CONCLUSIONS: Pediatric RAS is a low-frequency disease and long-term outcomes have been under-reported. The incidence of associated aortic pathology in our intervention cohort appears higher than that was previously reported. A long-term follow-up demonstrated that up to 65.8% of patients could be managed successfully with conservative therapy.

Safety and Efficacy of Drug Eluting Stents for Treatment of Transplant Renal Artery Stenosis.

BACKGROUND: Transplant renal artery stenosis (TRAS) after renal transplantation is a common cause of graft dysfunction and failure. Endovascular intervention in the form of percutaneous transluminal angioplasty (PTA) and stenting has rapidly become the dominant treatment modality for the TRAS. There is a paucity of clinical data on the use of drug-eluting stent (DES) for TRAS. We investigated the outcomes of patients with clinically significant TRAS undergoing DES placement. METHODS: A retrospective review of patients with clinically significant TRAS undergoing PTA with DES placement from June 2014 to April 2021 was conducted. Patients treated for TRAS exhibited uncontrolled hypertension and/or unexplained allograft dysfunction. Patient demographics, procedural details, and follow-up outcomes were collected. Primary endpoints were the in-stent primary patency and graft survival. Secondary endpoints were freedom from reintervention, primary-assisted patency, and access-related complications. RESULTS: Thirteen TRAS in 12 patients with graft function alteration were treated with DES. The median age was 57 years (interquartile range (IQR), 48-63 years), and 9 (70%) patients were male. The median follow-up was 9 months (IQR, 4-52 months). The most common comorbidity was hypertension (100%), coronary artery disease (83%), and diabetes. The median time from deceased donor transplant to intervention was 5.8 months (IQR, 3.5-6.7 months). TRAS was most commonly found at the juxta-ostial segment (77%). The procedure was performed with carbon dioxide angiography with minimal amount of iodinated contrast (median, 3 mL) under local anesthesia in 9 (69%), and general anesthesia in 4 (31%) patients. The median stent diameter was 4.5 mm (IQR, 4-5 mm), and the median stent length was 15 mm (IQR, 15-18 mm). No intraoperative complications occurred. The rates of stenosis-free primary patency of the DES and graft survival were 76% and 100%, respectively. All 3 reinterventions for restenosis resulted from the kinking of the transplant renal artery proximal to the DES, which were treated by extending the stent more proximally 1-2 mm into the external iliac artery. There were no access-related complications. The median time to reintervention was 0.9 months (range, 0.23-2 months). Freedom from reintervention and primary-assisted patency were 76% and 100%, respectively. CONCLUSIONS: Our study demonstrates that DES is a safe and effective treatment modality in patients with TRAS at short to mid-term follow-up. As all reinterventions after DES were performed due to kinking of the transplant renal artery proximal to the stent, bridging of the DES 1-2 mm into the external iliac artery is recommended.

Renal Artery Stenosis due to Entrapment.

BACKGROUND: Common etiologies of renovascular occlusive disease include atherosclerosis disease, developmental fibrotic conditions such as fibromuscular dysplasia, and vasculitis. Extrinsic compression of the renal artery is a rarely reported phenomenon but can lead to similar clinical manifestations. METHODS: We report recent experience with 2 patients who presented with extrinsic renal artery compression due to entrapment. Diagnosis was made with a constellation of findings on computed tomography angiography, dynamic duplex sonography, and catheter angiography. Both patients had hypertension and 1 had downstream subsegmental renal infarcts. The patients, both with right-sided renal artery entrapment, were treated with open surgical decompression. Exposure was achieved via extended Kocher maneuver followed by mobilization of the right kidney and, in 1 patient, detachment of the right lobe of liver to allow circumferential exposure of the proximal right renal artery to the aorta. All entrapping tissue was circumferentially released. RESULTS: Both operations were uncomplicated. Intraoperative sonography was used to confirm luminal patency of the released segments. Follow-up of renal artery duplex in both patients demonstrated resolution of dynamic compression. Renal artery peak systolic velocity and accelerations indices were all within normal limits. In both patients, improvement in blood pressure control was noted and discontinuation of anticoagulation was possible in the patient who had recurrent episodes of renal infarct. CONCLUSIONS: Extrinsic compression of renal artery by diaphragmatic crura is rare but should be considered in younger patients or otherwise any patients with no vascular risk factors when renovascular hypertension workup yields no demonstrable intrinsic disease. A high index of suspicion should be raised when an anomalously high origin of the renal artery or proximity to the diaphragmatic crura is seen on cross-sectional imaging. Work-up should include dynamic imaging to assess compression of renal arteries during expiration. Open surgical or laparoscopic decompression of the involved renal arteries can be curative.

Outcomes Following the Endovascular Treatment of Renal Artery Stenosis Caused by Fibromuscular Dysplasia: A Systematic Review and Meta-Analysis.

OBJECTIVE: Renal artery revascularization has been performed to improve blood pressure control and to cure hypertension in patients with renal artery fibromuscular dysplasia (RAFMD). We herein conducted a systematic review and meta-analysis of studies assessing outcomes associated with the treatment of hypertensive RAFMD patients via endovascular angioplasty in order to offer an up-to-date overview of the relative costs and benefits of this approach to revascularization in RAFMD patients. METHODS: We systematically searched the PubMed and Embase databases and the Cochrane Central Register for Controlled Trials to identify relevant studies published as of January 15, 2020. Key outcomes of interest in these studies included technical success, the incidence of perioperative complications, cure rates, and overall improvement rates. RESULTS: In total, we identified 36 relevant studies of 1916 total repairs conducted in 1191 patients. Of these included studies, 33 were retrospective, while 3 were prospective. The overall technical success rate across these studies was 94.3%. Rates of total, major, and minor complications in these pooled studies were 12.9%, 4.6%, and 7.4%, respectively. Pooled rates of cured hypertension and improved hypertension following angioplasty, defined according to study-specific criteria, were 37.0% [95% CI: 27.0%-47.0%] and 80.0% [95% CI: 75.0% to 84.0%], respectively, although these rates varied highly among studies. Cure rates for studies used current clinical definitions for substantial variations across studies. Cure rates in studies using current definitions of cured hypertension (blood pressure <140/90 mm Hg without treatment) were just 18.1% following angioplasty. Cure rates fell markedly with increasing mean patient age (OR associated with an increase in mean age of 10 years: -0.24 [95% CI: -0.44 to -0.04, P = 0.019] and with mean known duration of hypertension (OR associated with an increase in mean hypertension duration of 5 years: -0.09 [95% CI: -0.12 to -0.05, P = 0.001]). CONCLUSIONS: These findings suggest that endovascular treatment yielded moderate benefits to RAFMD patients, with substantial variation across studies. The blood pressure outcome was strongly influenced by patient age.