Fibromuscular dysplasia of the renal arteries: what do we know in 2024? / Dysplasie fibromusculaire des artères rénales : que savons-nous en 2024 ?

Fibromuscular dysplasia (FMD) is a rare nonatherosclerotic, noninflammatory vascular disease affecting mostly renal and carotid arteries and is the second most frequent cause of renal artery stenosis. The symptomatology is dominated by arterial hypertension due to the frequent involvement of the renal arteries and depends on the location of the lesions. Most of the cases are middle-aged women of Caucasian origin. There are two subtypes based on angiographic aspect: multifocal FMD (80% of the cases) and focal FMD (rarer with a more balanced sex ratio). Angioplasty of the renal arteries is generally disappointing with less than 50% cure of hypertension. It appears necessary to improve our knowledge of the FMD and to optimize the selection of eligible patients for revascularization with transdisciplinary collegial therapeutic decision.

La dysplasie fibromusculaire (DFM) est une maladie rare caractérisée par des sténoses segmentaires non artérioscléreuses, non inflammatoires, des artères de moyens calibres, touchant surtout les artères rénales et les carotides. Elle constitue la seconde cause de sténoses des artères rénales. La symptomatologie dépend de la localisation des lésions et est dominée par l'hypertension artérielle (HTA) en raison de l'atteinte fréquente des artères rénales. Cette pathologie touche majoritairement les femmes caucasiennes d'âge moyen. Il en existe deux sous-types, basés sur l'aspect angiographique : la DFM multifocale (80 % des cas) et la DFM focale (plus rare, sex ratio plus équilibré). Les résultats des prises en charge interventionnelles s'avèrent globalement décevants avec moins de 50 % de guérison de l'HTA. Il est nécessaire d'améliorer nos connaissances sur la physiopathologie de la DFM et d'optimiser la sélection des patients éligibles à une revascularisation par une prise de décision thérapeutique collégiale, en réunion de concertation pluridisciplinaire.

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

BACKGROUND: This study evaluated the long-term effects of percutaneous intervention in children and adolescents with transplant renal artery stenosis (TRAS). METHODS: Twenty patients had significant stenosis (>50%) and underwent percutaneous transluminal angioplasty (PTA/stenting) (TRAS group-intervention); 14 TNS (non-significant group -control) patients did not have significant stenosis (≤50%) and were treated clinically. The combined primary endpoints were death from all causes and late graft failure. The secondary endpoints were serum creatinine (SCr), systolic blood pressure (SBP), and diastolic blood pressure (DBP). RESULTS: No statistically significant difference was found between TRAS-Intervention(N = 20) and TNS groups-Control (N = 14) for these clinical parameters: deaths, 1 (5.0%) vs. 0 (0.0%) (p = 1.000) and graft loss, 4 (20.0%) vs. 2 (14.3%) (p = 1.000). For the secondary endpoints, after 1 month and 1 year the values of SCr, SBP, and DBP were similar between the two groups but not statistically significant. DISCUSSION: In the TRAS group (intervention), the stent implantation was beneficial for treating refractory hypertension and reducing blood pressure (BP) in children and adolescents. Despite the outcomes being similar in the two groups, it can be inferred that the patients in the TRAS group (intervention) would have had a worse outcome without the percutaneous intervention. CONCLUSION: TRAS treatment with stenting can be considered for children and adolescents. Because the sample in the present study comprised of only a specific population, further studies are needed for generalization. TRIAL REGISTRATION: The trial was registered at clinictrials.gov with trial registration number NCT04225338.

Open bypass revascularisation for endovascular-resistant transplant renal artery stenosis secondary to mechanical renal artery kinking.

Transplant renal artery stenosis (TRAS) represents a significant vascular complication subsequent to renal transplantation. This pathology is associated with grave implications including graft dysfunction and mortality. Early identification and therapeutical intervention are imperative for preserving graft longevity and achieving optimal clinical outcomes. We detail the case of a male in his 20s, following renal transplantation, who encountered recurrent TRAS, aetiologically linked to mechanical arterial kinking. Initial management using endovascular techniques yielded insufficient resolution. Consequently, the persistence of endovascular-resistant stenosis necessitated a surgical bypass intervention using the great saphenous vein, granting a 2-year period devoid of restenosis. The existing literature emphasises the indispensability of discerning the appropriate juncture for transitioning from endovascular to surgical management in TRAS cases. The robustness and durability of bypass grafts present an efficacious therapeutical strategy in contemporaneous practice.

Transplant Renal Artery Stenosis: A Case Report and Literature Review.

Transplant renal artery stenosis is the most common vascular complication that occurs following kidney transplantation and can lead to graft dysfunction and even its loss. The present report describes A patient with endstage renal disease who underwent living related renal transplantation. He had oliguria and creatinine rise in the post-operative course but all doppler ultrasonography (DUS) during the 2 months post-operation for the renal graft showed a normal mean resistive index in the graft renal artery. Hemodialysis treatment started and continued for 4.5 months. On post-operative day 137, because of the patient's anuria and resistant hypertension, another DUS carried out and reported evidence that suggested arterial stenosis. A computed tomographic (CT) renal angiogram showed a small filling defect in the proximal graft artery that was highly suggestive for transplant renal artery stenosis (TRAS). Following angiography revealed a short linear stenosis. Endovascular intervention and stent placement were performed successfully for the patient on post-operative day 139. This case was initially diagnosed as ongoing acute rejection for which he received antirejection therapy without any significant improvement. After percutaneous transluminal angioplasty (PTA), serum creatinine trended down and urine output improved within 12 h, and they were stable at one-year follow up with a good renal function. It was noteworthy that, despite after a 4.5-month delay in diagnosis and maintenance need for dialysis, the patient responded to endovascular treatment and the graft function became normalized. Our case demonstrates that graft can be saved even if renal artery stenosis is diagnosed after several months of dialysis and diagnosis of end stage renal disease post transplantation.

A Case Report of Concurrent Transplant Renal Artery Stenosis, Renal Cell Carcinoma, and Papillary Thyroid Cancer After Renal Transplantation: A Literature Review.

BACKGROUND: Kidney transplantation is the preferred treatment option for eligible patients with end-stage renal disease. With advanced transplantation technology and novel immunosuppressive agents, kidney transplant recipients survive significantly longer. However, the chance of developing malignant tumors has increased, posing a serious challenge to the survival of transplanted kidneys and patients. CASE PRESENTATION: We report a male patient (the patient's informed consent has been obtained) who underwent kidney transplantation 23 years ago. Subsequently, he developed transplant renal artery stenosis, primary renal clear cell carcinoma, and papillary thyroid cancer. The narrowed blood vessels were dilated through percutaneous transluminal angioplasty, and the malignant tumor was removed surgically. Currently, antirejection drugs are regularly taken, and the transplanted kidney function is good. The patient is satisfied with his living conditions. CONCLUSIONS: Hypertension that is difficult to control after kidney transplantation should be suspected as a possibility of graft vascular stenosis. When B-ultrasound cannot accurately diagnose it, magnetic resonance angiography should be used as early as possible to clarify the diagnosis and relieve the stenosis before graft dysfunction. Transplantation patients have a high incidence of malignant tumors after surgery, and the risk increases with the prolongation of the disease course. The focus should be on symptomatic treatment of related diseases, and antirejection drugs can be reduced or not reduced as appropriate.

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.

A Rare Case of Focal Renal Fibromuscular Dysplasia Treated With Angioplasty: A Case Report.

BACKGROUND: Fibromuscular dysplasia is an idiopathic, segmental, nonatherosclerotic, noninflammatory vascular disease that can lead to arterial stenosis, tortuosity, occlusion, aneurysms, and dissection. Fibromuscular dysplasia is a rare cause of hypertension that can easily be missed. To date, there has been no definitive treatment for fibromuscular dysplasia. CASE REPORT: In this report, we present an uncommon case of renovascular hypertension in a 21-year-old non-white female with a 3-year history of hypertension secondary to fibromuscular dysplasia involving bilateral renal arteries. Computed tomography angiography during the arterial phase revealed distal focal narrowing of the right main renal artery, distal focal narrowing of the left main renal artery, and proximal focal narrowing of the left accessory lower renal artery. Percutaneous balloon dilatation of the stenotic lesion was performed successfully up to 1 year After the procedure, the arterial blood pressure was within the normal range (110/70 to 125/75 mmHg) without medication. After 1 year of follow-up, CTA revealed re-stenosis in left main renal artery without clinical symptoms and normal blood pressure. Repeated procedure was done successfully. CONCLUSIONS: This case report highlights the difficulty in the diagnosis and treatment of focal fibromuscular dysplasia in young non-white female patients. Computerized tomographic angiography is a useful tool for identifying the cause and showing the benefit of percutaneous transluminal renal angioplasty treatment for this rare entity, as an early percutaneous angioplasty intervention may have a clinical cure for hypertension.

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.

Takayasu's arteritis presenting as acute STEMI.

An 18-year-old man with past medical history of secondary arterial hypertension diagnosed at age 15 presented with an abdominal magnetic resonance imaging (MRI) that exhibited left renal artery stenosis.

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).

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.

Endovascular Treatment of Transplant Renal Artery Stenosis: A Single-Center Retrospective Cohort Study.

OBJECTIVES: Endovascular therapy is the most common treatment for transplant renal artery stenosis; however, its long-term outcomes remain controversial, with no uniform standard for percutaneous transluminal angioplasty versus percutaneous transluminal stenting. MATERIALS AND METHODS: We retrospectively analyzed 26 patients with transplant renal artery stenosis who underwent endovascular therapy. We evaluated long-term efficacy of endovascular therapy and the reasonable choice of treatment. RESULTS: Serum creatinine increased significantly at onset of transplant renal artery stenosis (113.88 ± 37.573 before vs 279.31 ± 94.98 µmol/L during stenosis; P1 < .001), and endovascular therapy had a good short-term effect (279.31 ± 94.98 during stenosis vs 139.54 ± 124.40 µmol/L at 2 weeks posttreatment; P2 = .002). Long-term efficacy of endovascular therapy was stable (139.54 ± 124.40 at 2 weeks posttreatment vs 150.69 ± 180.72 at 6 months vs 161.58 ± 174.49 µmol/L at last follow-up; P3 > .05). Blood pressure increased significantly at onset of transplant renal artery stenosis (126.65 ± 16.11 before vs 159.62 ± 25.84 mm Hg during stenosis; P1 < .001). Moreover, the short-term effect of endovascular therapy was good (159.62 ± 25.84 during stenosis vs 128.73 ± 14.22 mm Hg at 2 weeks posttreatment; P2 < .001). Long-term effects remained stable (128.73 ± 14.22 at 2 weeks posttreatment vs 131.15 ± 14.55 at 6 months vs 138.50 ± 16.82 mm Hg at last follow-up; P3 > .05). Peak systolic velocity decreased significantly after endovascular therapy (176.6 ± 67.93 during stenosis vs 114.24 ± 67.93 cm/s at 2 weeks posttreatment; P < .001). CONCLUSIONS: Endovascular therapy is effective in transplant renal artery stenosis treatment and has a low incidence of complications. Percutaneous transluminal angioplasty should be performed routinely during endovascular therapy. After dilation, if stenosis remains >25% or retracted, then percutaneous transluminal stenting is recommended. Otherwise, percutaneous transluminal angioplasty is preferred.

[An Unusual Complication in 3 Cases: Renal��Subcapsular Hematoma Following Percutaneous Angioplasty]. / ���� Olguda Nadir Bir Komplikasyon: Perk��tan Anjioplasti Sonras�� Renal Subkaps��ler Hematom.

Renal artery stenosis is the leading cause of secondary hypertension. Percutaneous treatment options are safe and e���ective but can, in rare cases, entail possible complications such as renal subcapsular hematoma. Awareness of such complications will enable better management. Although post-intervention subcapsular hematomas are believed to occur secondary to wire perforation, in this report, we present 3 cases demonstrating reperfusion injury ���ndings rather than wire perforation.

Ultra-Low-Dose Contrast Using Transluminal Renal Angioplasty: The ULTRA Study.

BACKGROUND: Although severe atherosclerotic renal artery stenosis (ARAS) is a predictor of future cardiovascular events, large trials have not shown the benefits of percutaneous transluminal renal angioplasty (PTRA). This study aimed to validate the safety and efficacy of PTRA using low-concentration digital subtraction angiography (LC-DSA) in patients with severe ARAS and advanced chronic kidney disease (CKD). MATERIALS AND METHODS: This prospective study was conducted between August 2018 and October 2021. Eighteen patients with 20 lesions, CKD stage 3b or worse, and significant renal artery stenosis were included and underwent PTRA using ultra-low-dose contrast medium. The primary endpoint was a change in renal function based on serum creatinine (sCr) level. RESULTS: The mean sCr level significantly improved from 3.34 ± 1.8 mg/dL pre-PTRA to 2.48 ± 1.19 mg/dL at 1 month post-PTRA (P = .02). The mean amount of contrast used was 8.3 ± 3.9 mL per vessel. More severe stenosis and rapid deterioration of renal function before treatment were associated with improved kidney function. No cardiovascular or renal complications such as stroke or contrast-induced nephropathy were observed during the 30-day period. CONCLUSIONS: PTRA using an ultra-low-dose contrast medium is safe and provides acceptable results.

Use of Intravascular Lithotripsy in Heavily Calcified Renal Artery Stenosis: A Case Report.

Heavily calcified arterial lesions are difficult to treat in an endovascular manner with conventional techniques due to limited arterial compliance. Intravascular lithotripsy offers a novel minimally invasive therapeutic option through endovascular emission of acoustic waves, fracturing calcium deposits and facilitating lesion dilation. We present the case of a successful application of the Shockwave intravascular lithotripsy system (IVL®, Shockwave Medical Inc) in a heavily calcified stenosis of the right renal artery in a patient with a coral reef aorta.

"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.

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.

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.