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Midaortic syndrome (MAS) is a rare condition characterized by stenosis of the abdominal aorta with or without the involvement of branch vessels. The majority of cases are thought to be idiopathic though MAS has been associated with a number of conditions including granulomatous vasculitis, neurofibromatosis-1 (NF-1), Alagille Syndrome, fibromuscular dysplasia (FMD), and Williams syndrome. Patients typically present with hypertension due to decreased renal perfusion. Less common presentations include renal insufficiency, heart failure, claudication, stroke, and abdominal pain. Imaging modalities help establish the diagnosis of MAS including duplex ultrasound, computed tomography angiography (CTA), magnetic resonance angiography (MRA), and angiography. Initial therapy focuses on medical management with antihypertensives prior to intervention. Invasive interventions are indicated when there is evidence of end organ damage or dysfunction such as decreased renal function, poorly growing kidneys, cerebrovascular accident, left ventricular hypertrophy or frank cardiac failure. Endovascular interventions may assist in diagnosis and may treat some lesions although reintervention rates are high. Most patients require some type of surgical intervention, and a variety of surgical options are available based on anatomic findings. Renal revascularization may be accomplished by renal artery bypass, autotransplantation, or renal artery reconstruction. Aortic lesions may be repaired using patch angioplasty or aortoaortic bypass. Mesenteric arteries do not typically require reconstruction as they are rarely symptomatic. More novel options include the use of tissue expanders to lengthen the aorta to allow for primary aortic reconstruction (TESLA) or the use of the meandering mesenteric artery as an autologous aortic bypass graft (MAGIC)., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Renal artery stenosis is a potentially reversible cause of hypertension, and transcatheter techniques are essential to its treatment. Angioplasty remains a first-line treatment for stenosis secondary to fibromuscular dysplasia. Renal artery stenting is commonly used in atherosclerotic renal artery stenosis, although recent trials have cast doubts upon its efficacy. Renal denervation is a promising procedure for the treatment of resistant hypertension, and in the future, its indications may expand., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The spectrum of pediatric vascular pathology differs from the adult population and it varies greatly to include congenital and acquired disorders. Although catheter-directed angiography remains the gold standard, most vascular conditions in the child can be adequately diagnosed with magnetic resonance angiography, computed tomographic angiography, or duplex/Doppler ultrasonography with only a few exceptions, such as intrarenal arterial stenosis, small vessel vasculitides, and visceral vascular malformations. The advancement of catheter and wire technology has made it increasingly possible for complex arterial interventions to be performed in children, including embolization, angioplasty with stent insertion, thrombolysis, and endovascular neurological procedures. More angiographic procedures are being performed with the aim of also being therapeutic. Special considerations in children include the use of appropriate equipment and adequate dosing of contrast and of the various medications used during angiography, particularly in patients less than 15 kg in weight. This article will focus on the management of renovascular hypertension, liver transplant hepatic arterial intervention, and the use of carbon dioxide gas as a contrast agent in the child., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Atherosclerotic renal artery stenosis (ARAS) is the most common cause of renal artery stenosis in the adult population. ARAS may result in progressive renal impairment, renovascular hypertension, and/or cardiac disturbance syndromes. Because medical therapy does not affect the progressive nature of this disease process, more aggressive treatments are needed to definitively treat ARAS. When performed correctly, renal artery stenting has been shown to stabilize or improve renal function and/or renovascular hypertension in 65-70% of carefully selected patients with ARAS. Therefore, percutaneous renal artery stenting should be considered the primary treatment for patients with symptomatic ARAS., (Copyright 2010 Elsevier Inc. All rights reserved.)

Hypertension produced by renal artery occlusive disease is an important secondary form of hypertension. Clinicians commonly encounter forms of renal arterial disease of varying severity, many of which are of little hemodynamic significance when first detected. Experimental studies emphasize that transient activation of the renin-angiotensin-aldosterone system is necessary for initiation of renovascular hypertension. At some point, angiotensin II activates additional mechanisms responsible for sustained increased blood pressure including sodium retention, endothelial dysfunction, and vasoconstriction related to production of reactive oxygen species. Widespread application of agents that block the renin-angiotensin system, including angiotensin-converting enzyme inhibitors and angiotensin-receptor blockers, render many patients with unilateral renal arterial disease manageable primarily by medical means for many years. In the setting of high a priori likelihood of renovascular disease, recognizing the potential for disease progression during medical therapy and individually evaluating the risks and benefits of renal revascularization are important tasks. Recent prospective studies show limited, but real, benefit regarding blood pressure control for patients with atherosclerotic disease. Whether earlier renal revascularization offers benefits regarding improved morbidity and mortality from cardiovascular end point reduction is an important question to be addressed in multicenter, prospective, randomized trials. Our paradigm stresses the fact that patients with renovascular hypertension require intensive blood pressure control and cardiovascular risk factor intervention, both before and after revascularization. Hence, management of such patients requires close attention and periodic review regarding restenosis and progression of vascular disease.

Renal artery stenosis (RAS) is a significant cause of secondary hypertension, the progression of which can lead to renal insufficiency, uncontrolled hypertension, and even end-stage renal disease. The 2 most common forms of RAS are atherosclerotic renovascular disease and fibromuscular dysplasia (FMD). Atherosclerosis accounts for 90% of all cases of RAS and generally affects an elderly population. Conversely, FMD accounts for approximately 10% of all RAS cases and is described as affecting a younger population. Four cases of FMD in individuals older than 70 years are presented, in a period of 1 year at 1 facility. This case series calls into question the previously reported low prevalence of FMD in elderly persons. It is conceivable that renal artery investigation might be denied an elderly patient thought to have atherosclerotic disease. Because conventional angioplasty is considered the treatment of choice for patients with FMD because of the high response rate for uncontrolled hypertension, the prevalence of FMD in the elderly population should be reevaluated to detect and treat this population accordingly.

Pediatric renovascular hypertension is an uncommon but important clinical problem. Atherosclerosis is rare in children, who typically suffer from fibromuscular dysplasia, neurofibromatosis type 1, Williams syndrome, or certain other rare conditions. Children with renovascular disease often have involvement of other arteries including the aorta and mesenteric and cerebral vessels. The pediatric interventional radiology service has a vital role in the diagnosis, evaluation, and treatment of renovascular hypertension. Renal vein renin sampling appears to be more useful in children than in adults, because their arterial disease is more often bilateral and segmental. Diagnostic angiography is still superior to less-invasive methods of imaging the renal arteries, especially the smaller branches. Interventional options include angioplasty, stenting, and ethanol ablation. Angioplasty is almost always technically successful and usually gives a worthwhile clinical improvement. Stenting is only used in children when angioplasty fails. Ethanol embolization may be appropriate in children with focal renin-producing areas that are untreatable by angioplasty.

Atherosclerotic renal vascular disease is being recognized more frequently in an elderly patient population with chronic kidney disease. It also is much easier to diagnose and treat, at this time, because of the wide availability of coronary angiography and other radiologic imaging studies. In general, patients with atherosclerotic ischemic renal vascular disease are much sicker than the usual ESRD patient with more cardiac comorbidity and higher mortality rates. It is important to determine whether the lesions in the renal artery are physiologically significant before performing an intervention. The interventions are often risky with significant morbidity. Nephrologists should guide their colleagues to follow prudent courses of action. There are no evidence-based guidelines in this area.

Childbearing is important to women with renal disease, but pregnancy has generally been regarded as very high risk in these women. In this review, an attempt is made to clarify the nature and severity of those risks in the settings of chronic renal insufficiency and end-stage renal disease, including dialysis patients and transplant recipients. Hypertension is the most common life-threatening problem in all three groups. A wide range of antihypertensive medications have been used, with angiotensin-converting enzyme inhibitors the only drugs absolutely contraindicated because of their association with neonatal anuria, pulmonary hypoplasia, and neonatal death. Women with serum creatinine levels of 1.4 mg/dL or greater are at risk for accelerated loss of renal function compared with women who don't become pregnant. Transplant recipients have a risk for loss of renal function similar to controls as long as renal function is well preserved. The frequency of conception is decreased in women with renal insufficiency and markedly decreased in dialysis patients (0.5% per year). Return of fertility is the rule in transplant recipients. Exposure to immunosuppressive drugs, including prednisone, azathioprine, cyclosporine, and tacrolimus, has not been associated with an increase in congenital anomalies. These drugs, particularly cyclosporine, have been associated with small-for-gestational-age babies. Transplant recipients are at risk for infections that have implications for the fetus, including cytomegalovirus, herpes simplex, and toxoplasmosis. All groups have an increased risk for prematurity and intrauterine growth restriction. The percentage of pregnancies resulting in surviving infants in women with renal insufficiency and transplant recipients ranges from 70% to 100%. For women who conceive after starting dialysis, the likelihood of a surviving infant is approximately 50%.

Patients with fibromuscular dysplasia (FMD) and hypertension are frequently treated with percutaneous transluminal renal angioplasty (PTRA). Because the goal of this procedure is the cure of hypertension, we reviewed the outcomes of 23 consecutive patients undergoing this procedure to determine factors associated with cure. Twelve (52.2%) of the patients were taking no antihypertensive medications at 6 months and were classified as cured. Using logistic regression, we found three variables to be independently associated with cure: level of systolic blood pressure before intervention (P = 0.02), duration of hypertension (P = 0.03), and age (P = 0.03). Younger patients with milder hypertension of a shorter duration were most likely to be cured. Analysis of the regression equation predicts that some patients with an extremely low chance of cure might be managed with a trial of medical therapy, because FMD is unlikely to progress to renal failure.

To evaluate the efficacy of balloon-expandable (Palmaz) stents in the treatment of atheromatous renal artery stenosis, prospective placement of stents in 24 arteries in 20 patients was performed over an 18-month period. Indications were hypertension in 18 patients and renal insufficiency (serum creatinine > 1.5 mg/dL) in 11, and all lesions failed conventional transluminal angioplasty. Technical success was achieved in 96% of cases. Hypertension benefit was noted in 77% of patients followed for 6 months (n = 13) and 67% of patients at 1 year (n = 8). Improvement in serum creatinine was seen in 71% (n = 7) and 100% (n = 3) of azotemic patients evaluated at 6 and 12 months, respectively. Six-month angiographic patency was identified in 13 of 16 treated sites. Renal artery stent placement resulted in one asymptomatic segmental branch occlusion; there were no other procedural complications. In conclusion, renal artery stent placement is a technically and clinically effective treatment for hypertension and azotemia due to renal artery stenosis.

Contemporary patients requiring renal revascularization often have diffuse atherosclerosis, and increasingly undergo intervention for salvage of renal function rather than control of hypertension alone. Risk-benefit analyses and outcome data are difficult to obtain, since few reports have analyzed a modern, unselected series of consecutive patients subjected to renal revascularization by surgical as well as interventional techniques. We reviewed our 5-year experience with 76 consecutive renal revascularizations in 63 patients. Indications for intervention were hypertension and renal salvage, 60 percent (n = 38); hypertension, 24 percent (n = 15); renal salvage, 9.5 percent (n = 6); and other, 6.5 percent (n = 4). Ninety-four percent (n = 59) of patients had atherosclerotic occlusive disease of the renal arteries. Percutaneous transluminal angioplasty (PTA) was initially performed on 18 renal arteries in 16 patients, of whom 56 percent (n = 9) subsequently required surgical reconstruction. Fifty-eight surgical reconstructions were performed in 56 patients and consisted of aortorenal bypass (n = 27), aortorenal endarterectomy (n = 18), and extra-anatomic bypass (n = 13). Concomitant aortic replacement was required in 57 percent (n = 32) of patients. Preoperative risk factors and operative indications did not differ between the PTA and surgical reconstruction groups. Morbidity and mortality rates associated with PTA were 33 percent and 4.8 percent, respectively, while for surgical treatment the morbidity rate was 7 percent and the mortality rate 5.3 percent (P = NS). Functional improvement was achieved in 74 percent of surgically treated patients compared with 22 percent of PTA-treated patients (P < 0.01). Actuarial renal artery primary patency at 48 months was 81 percent for the surgery group and 17 percent for the PTA group (P < 0.01). Aortorenal bypass, endarterectomy, and extra-anatomic bypass were equally efficacious (P > 0.05). The results of surgical reconstruction are excellent, offering more durable patency and functional improvement than PTA, without increased risk. The operation should be tailored to fit the individual patient's disease, since the results of endarterectomy and bypass procedures are equivalent.

Renovascular hypertension is one of the more common causes of secondary hypertension. The true prevalence of this condition is not known, because only a selected few with hypertension are considered for thorough diagnostic work-up. The higher incidence figures come from centers with a special interest in this disease. The ability of a clinician to detect renovascular hypertension has improved substantially, thanks to the advances in radiology. The predominant mechanism of blood pressure elevation from renal ischemia is activation of the renin-angiotensin system. Clinically, the pathological lesions that cause renal artery stenosis are atherosclerosis and fibromuscular dysplasia; the former is typically seen in older men, and the latter is typically found in young women. Suspicion of the presence of renovascular disease should prompt the physician to obtain appropriate screening and confirmatory tests. Once diagnosed, the management of patients with renovascular hypertension requires a carefully planned multidisciplinary approach to offer the patient a best possible therapeutic option, with surgical revascularization or balloon angioplasty, or chronic medical therapy. However, these options are not mutually exclusive. The best long-term results are obtained with surgical therapy. Although balloon angioplasty is being increasingly used perhaps as the preferred initial therapeutic procedure for many patients with renal artery stenosis, long-term results comparable with surgery are not yet available. The ideal rational therapy for patients with renal artery stenosis is reperfusion of the ischemic kidney either by surgical correction or by balloon dilation. The aim is not only to improve the blood pressure control, but also to prevent and at times to reverse renal failure. Although effective antihypertensive drugs have become available, the role of medical management of renovascular hypertension is shrinking and should be limited to patients who have contraindications to or unwilling to undergo corrective procedures to relieve renal ischemia.

The clinical setting that suggests transplant renal artery stenosis, its various forms, and the involvement of the renin-angiotensin system in its pathogenesis has been reviewed. Both captopril-enhanced renography and pulse duplex Doppler ultrasound are useful noninvasive screening tests for renal artery stenosis. Some form of angiography remains essential in defining the extent of the lesion and in planning therapy. Percutaneous transluminal angioplasty is the first-line therapy for most cases. Open surgical repair provides the most definitive treatment but has greater morbidity. Medical therapy alone is appropriate in patients with significant chronic allograft rejection or other comorbidities that preclude intervention for the renal artery stenosis.

Pediatric interventional radiology offers new treatment options not possible a few years ago. Interventional radiologists treat not only certain causes of hemorrhage but also symptomatic arteriovenous malformations, renovascular hypertension, and portal hypertension. Interventionalists help maintain liver and renal transplants, increasing transplant patient survival. In addition to these selected disorders and types of radiological intervention, specific procedures such as thrombolysis, transjugular intrahepatic portosystemic shunts, and maintenance of hemodialysis access are discussed.

Renal arteriography remains the only study to identify and define correctly both location and extent of renal artery stenosis. Because other studies do not adequately identify all children who have renal artery disease, it is reasonable to perform renal arteriography in those children with severe hypertension who do not have another readily identifiable cause for their hypertension. On the other hand, in children with less profound elevation of blood pressure in whom there is no other definable cause, it is possible to defer renal angiography. In these children with mild or moderate hypertension, studies such as the captopril 99mTc-DTPA scan or intravenous digital subtraction angiography may identify those for whom arteriography is more likely to have abnormal results.

The first reports of surgically curable hypertension in the late 1930s led to enthusiasm among clinicians for removing kidneys with arterial stenosis in hypertensive patients. The development of vascular surgical techniques in the 1950s made it possible to achieve successful renal revascularization in many of these cases. However, the cause and effect relationship between a stenotic renal artery lesion and hypertension was poorly understood and many patients treated surgically had no improvement of blood pressure postoperatively. Continued experience in this field during the past two decades has significantly improved our understanding of the natural history and functional significance of renovascular disorders. Patients with renovascular hypertension can now be identified with a high degree of accuracy and successful renal revascularization is possible in most cases. Nevertheless, multiple factors must be weighed in determining whether medical or surgical therapy is more appropriate for a given patient. These include the causal relationship of renovascular disease to hypertension, the adequacy of blood pressure control with medical therapy, the natural history of untreated renovascular disease with particular regard for the risk of sustaining impaired renal function, the medical condition of the patient, the morbidity and results of surgical therapy, and the availability of other therapeutic options such as percutaneous transluminal dilatation.

Percutaneous transluminal renal angioplasty (PTRA) is a low risk, cost-effective procedure with a high degree of technical and therapeutic success in most categories of renovascular hypertension (RVH) when performed at experienced centers. The role of radiology in screening and diagnosis is discussed with special attention to renal vein sampling for renin assay (RVR) and digital subtraction angiography (DSA). The results of PTRA are compared with surgery. At New York Hospital, PTRA is the procedure of first choice in fibromuscular dysplasia, unilateral nonostial atheroma, arteritis, renal transplantation, and pediatrics. In patients with bilateral and ostial atherosclerotic disease and/or azotemia, the choice between surgery or PTRA depends on the surgical risk category of the patient.

During the last 3 yr a large number of patients with renal artery stenosis have undergone attempted treatment of their stenosis by the technique termed percutaneous transluminal angioplasty or dilatation (PTD) using the balloon tipped catheter developed by Gruntiz. A number of publications have documented that this technique is reasonably safe and effective in renal artery lesions due to fibromuscular disease (FMD), atherosclerosis (AS), or prior surgery such as renal artery bypass or transplantation. Although initially many of the patients that were treated were felt to be poor surgical risks, many patients have now been treated who were excellent candidates for renal artery bypass. The cumulative experience argues that PTD should be the first treatment tried in any patient with significant renal artery stenosis causing hypertension. It should be noted that the cumulative experience is not based on any controlled trial and therefore may well be biased. Nevertheless, I will present this argument based on the published data and our own experience at Indiana University. This argument pertains to any patient with incomplete renal artery occlusion who has a functionally significant stenosis (determined by renal vein renin sampling) and who is a good surgical candidate. Those patients who are at high risk for major surgery will obviously be best treated by PTD or medical management. The argument has four major points: safety, effectiveness, cost analysis, and availability.

Percutaneous transluminal angioplasty is a nonsurgical treatment for vascular disease. It is relatively safe and economical and may be an alternative, or an adjunct, to surgery, or may be helpful where no surgical alternative exists. Percutaneous transluminal angioplasty is applicable to nearly every system, except the carotid bifurcation plaque.

Surgery has been used to treat renal vascular hypertension for almost 50 years. The reason for the many apparent discrepancies in the literature on effectiveness and risk have become clear only in the past decade. The results are poorest and the risk is greater, not surprisingly, in patients with advanced atherosclerosis involving many vascular beds. The results are much better in fibromuscular disease, both in terms of effectiveness and risk. Angioplasty has been available for a much shorter time, but a reasonable picture of the short-term effectiveness and the risk is emerging. The risk is substantially lower than that of surgery. The results are again best in fibromuscular disease. In atherosclerotic disease, the results are especially poor for the most common lesion, that involving the renal artery ostium. Medical therapy before the development of captopril was often difficult and often unsatisfactory. Since the development of converting-enzyme inhibition, medical therapy is an important option. In the early experience, reflecting the severity of the hypertension, the frequency with which azotemia was present, and the high dose of captopril used, the adverse reaction rate was substantial. In one study, none of 133 patients with unilateral renal arterial disease and an intact contralateral kidney developed renal failure. Among 136 patients with bilateral disease or a solitary kidney, renal failure occurred in 15 and led to discontinuation of therapy in 12. If surgery or angioplasty are contraindicated, one can modify the therapeutic goal.(ABSTRACT TRUNCATED AT 250 WORDS)

It is now possible to accurately identify patients with renovascular hypertension who need renal angioplasty or revascularization. Evaluation does not require hospitalization and begins with the determination of an ambulatory plasma renin activity (PRA) indexed against sodium excretion and a captopril test. Subsequently differential renal vein renins with matching inferior vena caval (IVC) renins are measured often with converting enzyme inhibition. Identifying criteria are as follows: (1) high PRA indexed against sodium excretion, (2) hypersecretion of renin following captopril administration, (3) absence of renin secretion from the contralateral kidney, and (4) an ipsilateral renal vein renin increment at least 50% greater than the matching IVC renin. Patients who meet the criteria are admitted for percutaneous transluminal renal angioplasty.