Kidney Intrinsic Mechanisms as Novel Targets in Renovascular Hypertension.

Almost a hundred years have passed since obstruction of the renal artery has been recognized to raise blood pressure. By now chronic renovascular disease (RVD) due to renal artery stenosis is recognized as a major source of renovascular hypertension and renal disease. In some patients, RVD unaccompanied by noteworthy renal dysfunction or blood pressure elevation may be incidentally identified during peripheral angiography. Nevertheless, in others, RVD might present as a progressive disease associated with diffuse atherosclerosis, leading to loss of renal function, renovascular hypertension, hemodynamic compromise, and a magnified risk for cardiovascular morbidity and mortality. Atherosclerotic RVD leads to renal atrophy, inflammation, and hypoxia but represents a potentially treatable cause of chronic renal failure because until severe fibrosis sets in the ischemic kidney, it retains a robust potential for vascular and tubular regeneration. This remarkable recovery capacity of the kidney begs for early diagnosis and treatment. However, accumulating evidence from both animal studies and randomized clinical trials has convincingly established the inadequate efficacy of renal artery revascularization to fully restore renal function or blood pressure control and has illuminated the potential of therapies targeted to the ischemic renal parenchyma to instigate renal regeneration. Some of the injurious mechanisms identified as potential therapeutic targets included oxidative stress, microvascular disease, inflammation, mitochondrial injury, and cellular senescence. This review recapitulates the intrinsic mechanisms that orchestrate renal damage and recovery in RVD and can be harnessed to introduce remedial opportunities.

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.

Cardiovascular outcomes improve in children with renovascular hypertension following endovascular and surgical interventions.

BACKGROUND: Renovascular hypertension (RenoVH) is a cause of hypertension in children. A common cause of RenoVH is renal artery stenosis which acts by reducing blood supply to renal parenchyma and activating the renin-angiotensin-aldosterone axis, often leading to cardiac remodelling. This longitudinal observational study aims to describe occurrence of cardiovascular changes secondary to RenoVH and also any improvement in cardiac remodelling after successful endovascular and/or surgical intervention. METHODS: All patients with RenoVH referred to our centre, who received ≥ 1 endovascular intervention (some had also undergone surgical interventions) were included. Data were collected by retrospective database review over a 22-year period. We assessed oscillometric blood pressure and eight echocardiographic parameters pre- and post-intervention. RESULTS: One hundred fifty-two patients met inclusion criteria and had on average two endovascular interventions; of these children, six presented in heart failure. Blood pressure (BP) control was achieved by 54.4% of patients post-intervention. Average z-scores improved in interventricular septal thickness in diastole (IVSD), posterior Wall thickness in diastole (PWD) and fractional shortening (FS); left ventricular mass index (LVMI) and relative wall thickness (RWT) also improved. PWD saw the greatest reduction in mean difference in children with abnormal (z-score reduction 0.25, p < 0.001) and severely abnormal (z-score reduction 0.23, p < 0.001) z-scores between pre- and post-intervention echocardiograms. Almost half (45.9%) had reduction in prescribed antihypertensive medications, and 21.3% could discontinue all antihypertensive therapy. CONCLUSIONS: Our study reports improvement in cardiac outcomes after endovascular + / - surgical interventions. This is evidenced by BP control, and echocardiogram changes in which almost half achieved normalisation in systolic BP readings and reduction in the number of children with abnormal echocardiographic parameters. A higher resolution version of the Graphical abstract is available as Supplementary information.

Nonatherosclerotic Renovascular Hypertension.

Renovascular hypertension (RVH) is a secondary form of high blood pressure resulting from impaired blood flow to the kidneys with subsequent activation of the renin-angiotensin-aldosterone system. Often, this occurs due to abnormally small, narrowed, or blocked blood vessels supplying one or both kidneys (ie: renal artery occlusive disease) and is correctable. Juxtaglomerular cells release renin in response to decreased pressure, which in turn catalyzes the cleavage of circulating angiotensinogen synthesized by the liver to the decapeptide angiotensin I. Angiotensin-converting enzyme then cleaves angiotensin I to form the octapeptide angiotensin II, a potent vasopressor and the primary effector of renin-induced hypertension. The effects of angiotensin II are mediated by signaling downstream of its receptors. Angiotensin receptor type 1 is a G-protein-coupled receptor that activates vasoconstrictor and mitogenic signaling pathways resulting in peripheral arteriolar vasoconstriction and increased renal tubular reabsorption of sodium and water which promotes intravascular volume expansion. Angiotensin II stimulates the adrenal cortical release of aldosterone, which promotes renal tubular sodium reabsorption, resulting in volume expansion. Angiotensin II acts on glial cells and regions of the brain responsible for blood pressure regulation increasing renal sympathetic activation. Angiotensin II simulates the release of vasopressin from the pituitary which stimulates thirst and water reabsorption from the kidney to expand the intravascular volume and cause peripheral vasoconstriction (increased sympathetic tone). All of these mechanisms coalesce to increase arterial pressure by way of arteriolar constriction, enhanced cardiac output, and the retention of sodium and water.

Influence of Intestinal Barrier on Alleviating an Increase in Blood Pressure by Sodium Alginate Intake in 2-Kidney, 1-Clip Renovascular Hypertensive Rats.

Sodium alginate (SALG) is a substance derived from brown seaweed that has been shown to reduce blood pressure (BP). However, its effects on renovascular hypertension caused by 2-kidney, 1-clip (2K1C) are not yet clear. Previous research suggests that hypertensive rats have increased intestinal permeability, and that SALG improves the gut barrier in inflammatory bowel disease mouse models. Therefore, the goal of this study was to determine whether the antihypertensive effects of SALG involve the intestinal barrier in 2K1C rats. Rats were fed either a 1.0% SALG diet or a control diet for six weeks after being subjected to 2K1C surgery or a sham operation. The systolic BP was measured weekly, and the mean arterial BP was measured at the end of the study. Intestinal samples were taken for analysis, and plasma lipopolysaccharide (LPS) levels were measured. The results showed that BP in 2K1C rats was significantly higher than in SHAM rats when fed CTL, but not when fed SALG. The gut barrier in 2K1C rats was improved by SALG intake. Plasma LPS levels also differed depending on the animal model and diet. In conclusion, dietary SALG may alleviate 2K1C renovascular hypertension by altering the gut barrier.

Atherosclerotic renovascular disease: a clinical practice document by the European Renal Best Practice (ERBP) board of the European Renal Association (ERA) and the Working Group Hypertension and the Kidney of the European Society of Hypertension (ESH).

Atherosclerotic renovascular disease (ARVD) is the most common type of renal artery stenosis. It represents a common health problem with clinical presentations relevant to many medical specialties and carries a high risk for future cardiovascular and renal events, as well as overall mortality. The available evidence regarding the management of ARVD is conflicting. Randomized controlled trials failed to demonstrate superiority of percutaneous transluminal renal artery angioplasty (PTRA) with or without stenting in addition to standard medical therapy compared with medical therapy alone in lowering blood pressure levels or preventing adverse renal and cardiovascular outcomes in patients with ARVD, but they carried several limitations and met important criticism. Observational studies showed that PTRA is associated with future cardiorenal benefits in patients presenting with high-risk ARVD phenotypes (i.e. flash pulmonary oedema, resistant hypertension or rapid loss of kidney function). This clinical practice document, prepared by experts from the European Renal Best Practice (ERBP) board of the European Renal Association (ERA) and from the Working Group on Hypertension and the Kidney of the European Society of Hypertension (ESH), summarizes current knowledge in epidemiology, pathophysiology and diagnostic assessment of ARVD and presents, following a systematic literature review, key evidence relevant to treatment, with an aim to support clinicians in decision making and everyday management of patients with this condition.

Renovascular Hypertension with Progressive Atherosclerotic Renal Artery Stenosis in an Elderly Patient with Known Fibromuscular Dysplasia: A Case Report.

BACKGROUND Atherosclerotic renal artery stenosis (ARAS) and renovascular fibromuscular dysplasia (FMD) are 2 of the most common etiologies of renovascular hypertension. They have different pathophysiologies, risk factors, presentations, and treatment options. However, as our population ages, it can become increasingly common to see patients who previously had FMD who develop ARAS at an advanced age, indicated by recurrent renovascular hypertension. CASE REPORT We present a case of a 66-year-old female patient who, in 2007, had presented with uncontrolled hypertension. She underwent magnetic resonance angiography and was found to have bilateral FMD, for which she received balloon angioplasty to a severe lesion on the mid-right renal artery and subsequently had normalization of blood pressures and resolution of symptoms. In 2021 she returned with uncontrolled hypertension while being treated with 3 antihypertensives. Bilateral renal arteriography revealed new severe ostial stenosis of the left renal artery and a patent right renal artery in which balloon angioplasty was performed 14 years ago. Based on the angiographic pattern of this new left RAS, we concluded this lesion was caused by atherosclerosis. The left ostial lesion was treated with a bare-metal stent and the patient was continued on antihypertensive medication and statin; at follow-up 4 months later, her blood pressures had normalized. CONCLUSIONS This case features a patient who developed severe ARAS with underlying history of bilateral renal artery FMD. Clinicians need to be aware that in patients with FMD, worsening renovascular hypertension at an advanced age could indicate the development of new hemodynamically significant ARAS. These patients need repeat diagnostic testing and treatment with medial optimization with or without endovascular revascularization in the appropriate clinical setting.

Stent-Graft Placement for Radiation-Induced Abdominal Aortic Stenosis after Renal Autotransplantation.

Renovascular hypertension (RVH) is a common cause of secondary hypertension. However, there have been no reports on RVH due to radiation-induced abdominal aorta stenosis after renal autotransplantation. A 27-year-old woman with a history of neuroblastoma treated by radiation therapy and RVH treated with renal autotransplantation presented with hypertension and dyspnea. At age 19, she had experienced hypertensive heart failure due to RVH from radiation-induced left renal artery stenosis and had undergone renal autotransplantation involving the extraction of her left kidney. Her systolic blood pressure (BP) was well-controlled but had increased progressively. She was diagnosed with hypertensive heart failure and admitted to hospital. Although her dyspnea soon subsided after treatment, her BP remained high. Renal artery ultrasound revealed no obvious stenosis. The ankle brachial pressure index (ABI) showed a significant bilateral decrease to 0.71/0.71 (right/left) from 0.94/0.95 eight years before. Magnetic resonance angiography and aortic angiography revealed severe stenosis in the abdominal aorta, and the systolic pressure gradient of intra-aortic blood flow, distal and proximal to a stenotic lesion, was 58 mmHg. These arterial stenoses in the irradiated area were highly suggestive of radiation-induced vasculopathy. She finally underwent an endovascular VIABAHN VBX balloon-expandable stent-graft placement for this radiation-induced abdominal aorta stenosis, which resolved the pressure gradient. After the procedure, her ABI improved to 0.91/0.88 and her BP was well-controlled. This is the first case of successful stent-graft placement for RVH after renal autotransplantation due to radiation-induced abdominal aorta stenosis as a consequence of neuroblastoma.

Endovascular Versus Medical Management of Atherosclerotic Renovascular Disease: Update and Emerging Concepts.

Atherosclerotic renovascular disease is the most frequent cause of renovascular hypertension and its prevalence increases with age and in specific subset of patients, such as those with end-stage chronic kidney disease, heart failure, and coronary artery disease. Besides hypertension, atherosclerotic renovascular disease is responsible for several clinical manifestations, including life-threatening conditions, such as recurrent flash pulmonary edema, rapidly progressive chronic kidney disease, or acute kidney injury. Atherosclerotic renovascular disease is usually part of a more diffuse atherosclerotic process and requires a combination therapy including antihypertensive, antiplatelet and lipid-lowering agents, as well as optimization of antidiabetic treatment, if needed. Besides medical therapy, percutaneous renal angioplasty was supposed to be the most effective therapy for atherosclerotic renovascular disease, by leading to blood flow restoration. However, despite an apparently solid rationale, several randomized clinical trials failed to confirm the favorable effects of percutaneous renal angioplasty on blood pressure control, kidney function, cardiovascular and renal outcomes, previously reported in observational, retrospective and single-center cohorts, switching off the enthusiasm for this procedure. Several studies' limitations may partly account for this failure, including heterogeneity of diagnostic techniques, overestimation of the degree of renal artery stenosis, inappropriate timing of revascularization, multiple protocol revisions, frequent crossovers, and most importantly exclusion of patients at higher likelihood to respond to angioplasty. The purpose of this review is to summarize studies' potential weaknesses and provide guidance to the clinician for identification of patients who may benefit most from revascularization.

Prevalence and clinical characteristics of renovascular hypertension associated with fibromuscular dysplasia in China.

OBJECTIVES: The aim of this study was to investigate the clinical characteristics of renal artery fibromuscular dysplasia (FMD) in patients in China and identify the cure rate of hypertension after angioplasty. METHODS: Consecutive hypertensive patients with renal artery stenosis caused by FMD who underwent catheter-based angiography, and were followed at two Chinese referral centres, were retrospectively analysed. All patients underwent a detailed investigation, including demographic characteristics, clinical characteristics, biochemical sampling, Doppler ultrasonography of carotid arteries, magnetic resonance angiography (MRA) of the intracranial artery, and CTA or MRA of the abdominal artery and catheter-based renal angiography. Patients were routinely followed up at 1 month, 6 months and every year after the procedure. RESULTS: Among 245 study participants, with a mean diagnosed age of 26.9 ±â€Š9.9 years, 137 (55.9%) were women, and 38 (15.5%) were children. All patients were diagnosed with hypertension at a mean age of 23.4 ±â€Š8.4 years. There were 73.5% focal and 15.2% multivessel cases. Aneurysms, arterial dissections and total occlusions were found in 21.6, 4.1 and 12.2% of patients, respectively. Patients with multifocal FMD were older (26.0 vs. 23.7 years, P  = 0.021) and more often female (70.8 vs. 50.6%, P  = 0.004). Among children with renal FMD, 55.2% were men, and 86.8% were focal. After a median follow-up of 7.0 years, multifocal FMD had a higher cure rate of hypertension than focal FMD after revascularization (71.7 vs. 55.8%, P  = 0.032). CONCLUSION: In a cohort of mostly young Chinese patients, the prevalence of hypertension associated with renal FMD is similar in both sexes. Focal FMDs were more frequent than the multifocal ones and, after angioplasty, were associated with a worse blood pressure outcome.

Long-term outcomes of angioplasty for pediatric renovascular hypertension: A single-center experience.

OBJECTIVES: We used single-center data to evaluate the long-term outcome of percutaneous transluminal angioplasty (PTA) for pediatric renovascular hypertension (RVH) and to analyze the factors that influence effectiveness. METHODS: We retrospectively evaluated 33 pediatric RVH patients (18 boys; mean age: 9.1 ± 4 years, range: 2-16) who underwent PTA from January 2007 to December 2019. 15 patients had Takayasu arteritis (TA) and 18 were non-TA. The median follow-up from the initial PTA was 69 months (range: 12-157; IQR: 25.5-89). RESULTS: The technical success rate of 52 PTA procedures was 90.4% in 33 children. Renal artery stents were implanted in two patients, external guidewires were used in two patients, and a drug-coated balloon was used in only one patient. The overall effective rate of PTA was 63.6%, including cured 39.4% and improved 24.2%, at the end of follow-up. Overall clinical outcomes were not statistically different between the TA and non-TA groups (p = 0.316), nor were cure rates (p = 0.072). 15 patients received reintervention due to restenosis after the first successful PTA; the interval was 2-56 months (median: 12 months). Four patients received reintervention due to a failed PTA. A total of four patients received open surgery. Binary logistics regression analysis showed that stenosis length and residual stenosis rate were strongly correlated with effective PTA (p = 0.045, p = 0.044). CONCLUSIONS: As a primary treatment for pediatric RVH, PTA can achieve satisfactory results, which are influenced by lesion length and residual stenosis rate.

Utilizing 3D printing to facilitate surgical in-situ paediatric renal artery aneurysm repair for refractory hypertension.

Renal artery aneurysmal (RAA) disease is a rare, but potentially life-threatening cause of renovascular disease presenting with hypertension. Conventional management involves aneurysmal excision followed by renal auto-transplantation. We present the management of a 13-year-old girl with complex multiple saccular aneurysmal disease of the left renal artery with hilar extension and symptomatic hypertension. We used 3D printing to print a patient-specific model that was not implanted in the patient but was used for surgical planning and discussion with the patient and their family. Endovascular options were precluded due to anatomical complexities. Following multi-disciplinary review and patient-specific 3D printing, she underwent successful in-situ RAA repair with intraoperative cooling, without the need for auto-transplantation. 3D printing enabled appreciation of aneurysmal spatial configuration and dimensions that also helped plan the interposition graft length needed following aneurysmal excision. The models provided informed multidisciplinary communications and proved valuable during the consent process with the family for this high-risk procedure. To our knowledge, this is the first reported case utilizing 3D printing to facilitate in-situ complex repair of RAA with intra-hilar extension for paediatric renovascular disease.

A Nine-year-old Boy with Renovascular Hypertension: Knowing Where to Look.

Renal artery entrapment (RAE) by hypertrophic diaphragmatic crura is an extremely rare cause of renovascular hypertension (RVH). Here, we report the case of a 9-year-old boy diagnosed with RVH caused by right RAE by a hypertrophic diaphragmatic crus and successfully managed with close medical monitoring. Diagnosis of this entity is easily overlooked if the optimal views are not obtained during imaging, which depends on a high index of suspicion. We would like to remind clinicians to keep this rare condition in mind when evaluating children with RVH.