Fibromuscular Dysplasia of Renal and Carotid Arteries

We report here two cases of fibromuscular dysplasia (FMD). The first case describes an asymptomatic 75-year-old man with FMD of the right internal carotid artery. The second case reports a 17-year-old man who presented with arterial hypertension caused by FMD of the left renal artery and was subsequently successfully treated by angioplasty. FMD is a rare nonatherosclerotic, noninflammatory angiopathy, which can involve almost every arterial vascular bed. It is a less common cause of stenosis of renal and carotid arteries. FMD can present with arterial hypertension when it involves renal arteries or with ischemic stroke or transient ischemic attack when the disease affects the carotid or vertebral arteries. Many cases are asymptomatic and may be discovered incidentally. Percutaneous transluminal angioplasty should be used in patients with a stenosis of the renal artery causing arterial hypertension. On the contrary, conservative therapy should be chosen in patients with asymptomatic and extensive lesions of the carotid arteries.     

Renal artery stenosis and ambulatory blood pressure monitoring: A case report and review of the literature

Renal artery stenosis (RAS) is a prevalent cause of secondary hypertension. Elderly patients with atherosclerosis and young women with fibromuscular dysplasia (FMD) are particularly at risk. Blood pressure screening is often key to this diagnosis, although the reliability of clinical screening has been questioned, and ambulatory blood pressure monitoring (ABPM) likely offers superior ability to diagnose poorly controlled hypertension. In patients with RAS, medical management should be the primary means of therapy; however, in a select group of these patients, renal revascularization may be considered, and has been shown to reduce blood pressure and stabilize chronic kidney disease. In this report, we present a patient diagnosed with RAS due to FMD, found to have significant hypertension via ABPM, and treated successfully with percutaneous renal artery angioplasty; importantly, continuous 24‐hr ambulatory monitoring after pressure gradient guided renal angioplasty confirmed reduction in blood pressure.     

Atherosclerotic renal artery stenosis

Opinion statement The clinical diagnosis of renal artery stenosis relies on a high index of suspicion and confirmation by noninvasive imaging modalities. There are three distinct clinical syndromes associated with renal artery stenosis: renin-dependent hypertension, essential hypertension, and ischemic nephropathy. Clinical features that should heighten suspicion for renal artery stenosis include abrupt-onset or accelerated hypertension at any age, unexplained acute or chronic azotemia, azotemia induced by angiotensin-converting enzyme (ACE) inhibitors, asymmetric renal dimensions, and congestive heart failure with normal ventricular function. Patients with true renin-dependent (renovascular) hypertension are typically young or middle-age women with renal fibromuscular dysplasia (FMD). Initial therapy for renovascular hypertension associated with FMD is an ACE inhibitor; refractory hypertension responds readily to balloon angioplasty without stenting. Elderly patients with generalized atherosclerosis and hypertension often have atherosclerotic renal artery stenosis (ARAS); hypertension in these patients is usually not renin dependent (ie, essential hypertension). Hypertension alone, even if treated with multiple medications, is not a compelling indication for renal artery revascularization; these patients should be treated aggressively with antihypertensive medical therapy. Renal artery revascularization with stenting may be considered for refractory severe hypertension, and would be expected to improve blood control and modestly reduce medication requirements. Renal revascularization rarely cures hypertension in patients with ARAS. Patients with ARAS, hypertension, and end-organ injury should be considered for renal revascularization. Manifestations of end-organ injury include nonischemic pulmonary edema; hypertensive crisis associated with acute coronary syndrome, aortic dissection, or neurologic impairment; and renal insufficiency. Ischemic nephropathy is best treated before the development of advanced renal failure. The best candidates for revascularization are those with baseline serum creatinine less than 2.0 mg/dL, bilateral renal artery stenosis, normal renal resistive indices, no proteinuria, and one or more manifestations of end-organ injury. In these patients, renal revascularization is best accomplished by stenting, although surgical revascularization may be considered in patients with concomitant severe aortic aneurysmal or occlusive disease.     

Fibromuscular dysplasia of renal arteries: percutaneous revascularization based on hemodynamic assessment with a pressure measurement guidewire.

Fibromuscular dysplasia (FMD) leading to renal artery stenosis and hypertension is one of the most common treatable causes of secondary hypertension. However, frequently it can be difficult to judge the anatomical severity of a stenotic lesion with various noninvasive and invasive imaging modalities. We present two patients with poorly controlled hypertension and FMD affecting the renal arteries, in whom there were no anatomically significant stenoses by renal magnetic resonance angiography or selective renal artery angiography. Utilizing a 0.014' high fidelity micromanometer tipped PressureWire XT (Radi, Reading, MA), to measure intravascular pressure gradients throughout the diseased renal arteries, we identified physiologically significant stenoses, and successfully treated both patients with percutaneous transluminal angioplasty.     

Percutaneous vascular interventions in renal artery diseases

Renal artery stenosis (RAS) is a progressive manifestation of atherosclerosis. It is associated with hypertension and progressive renal failure. Noninvasive testing includes renal artery duplex, computed tomographic angiography (CTA) and magnetic resonance angiography (MRA). Percutaneous transluminal renal angioplasty and stenting (PTRAS) is indicated for significant atherosclerotic RAS while percutaneous transluminal renal angioplasty (PTRA) is indicated for fibromuscular dysplasias (FMD) associated with the proper clinical indications. PTRAS is associated with a high technical success rate and an acceptable adverse event and restenosis rate. PTRAS appears to improve control of hypertension and renal preservation. All patients should be followed clinically and with periodic duplex ultrasonography. Restenosis is treated with repeat angioplasty and occasionally stenting. Current and future areas of investigation will involve distal protection and drug eluting stents.     

Renal artery stenosis

Opinion statement Fibromuscular dysplasia (FMD) and aortoarteritis are the most frequent causes of secondary hypertension induced by renal artery stenosis (RAS). Revascularization of this disease entity usually cures arterial hypertension. Demographic evolution leads to an increasing incidence of atherosclerotic RAS, one of the major causes of end-stage renal failure. Furthermore, atherosclerotic RAS leads to deterioration of primary hypertension, progression of atherosclerosis manifestation such as occlusive and aneurysmatic peripheral artery disease, and chronic or acute organ damage such as left ventricular hypertrophy and recurrent flash pulmonary edema. Despite the lack of sufficiently powered randomized controlled trials, each hemodynamically relevant RAS (eg, ≥ 70%) should be considered for stent angioplasty in patients without end-stage ischemic nephropathy or limited life expectancy due to concomitant disease (eg, cancer). Drug-eluting stents will probably reduce the overall low in-stent restenosis rate of 10% to 20%. Interventions in patients with dialysis-dependent end-stage nephropathy are left to appropriate clinical study protocols.     

Revascularisation of renal artery stenosis caused by fibromuscular dysplasia: effects on blood pressure during 7-year follow-up are influenced by duration of hypertension and branch artery stenosis

Fibromuscular dysplasia (FMD) mainly affects renal arteries. Percutaneous transluminal renal angioplasty (PTRA) and surgery are effective treatments, but long-time follow-up is lacking. Retrospective follow-up for 7.0+/-4.7 years of 69 consecutive patients (age 44+/-13 years) treated for hypertension due to FMD, 59 patients underwent PTRA and eight patients surgery. In two patients no PTRA was performed. Technical success was achieved in 56 (95%) patients undergoing PTRA and all eight undergoing surgery. After successful PTRA, both systolic and diastolic blood pressures (SBP and DBP) had decreased at discharge (from 174+/-33/100+/-13 to 138+/-19/80+/-15 mmHg; P<0.0001), and remained lower at 1 month, 1 year, and last follow-up after 7.0+/-4.7 years (140+/-25/83+/-12 mmHg; P<0.0001). Serum-creatinine had decreased both at 1 year (from 84+/-28 to 75+/-13 micromol/l; P=0.0030) and last follow-up (75+/-16 micromol/l; P=0.0017). The number of antihypertensive drugs decreased (from 2.3+/-1.2 before PTRA to 1.4+/-1.3 at discharge and at 1 month; P<0.0001, and 1.6+/-1.5 at last follow-up; P=0.0011). SBP decreased more after PTRA among patients with FMD only in the main renal artery than in those with branch artery involvement (43+/-29 vs 20+/-41 mmHg; P=0.0198). Beneficial effects on BP, creatinine and antihypertensive drugs also occurred after surgery. Patients on antihypertensive drugs at last follow-up had longer hypertension duration before PTRA than those without (5.9+/-7.7 vs 1.8+/-4.1 years; P=0.0349). Cure was achieved in 16 (24%), improvement in another 26(39%), and benefit in 42(63%). In conclusion, renal artery FMD, PTRA and surgery have beneficial long-term effects, negatively affected by hypertension duration and branch artery involvement.     

Treatment of hypertension associated with renal arterial occlusive disease

Renal artery stenosis is a common cause of diastolic hypertension. Recent development of arterial reconstructive technics provides the opportunity to cure most patients with renovascular hypertension and to salvage the involved kidney or kidneys.

Resectional therapy provides a second type of treatment when definitive arterial reconstruction is impossible.

Patch graft angioplasty and renal artery bypass are the two most satisfactory technical means of renal revascularization.

Selection of patients with renal artery stenosis for revascularization is primarily a matter of exclusion. Specific contraindications include cerebrovascular insufficiency and coronary artery disease. Eighty per cent of 140 patients having renal revascularization procedures were cured of hypertension.     

Diffuse fibromuscular dysplasia successfully treated with scoring balloon angioplasty in a 3-year-old boy

In children, up to 10% of the cases of arterial hypertension may be caused by a renovascular disease. The etiology of this renovascular disease is most of the time due to a fibromuscular dysplasia (FMD), which causes a noninflammatory intimal-medial fibroplasia leading to luminal compromise. Percutaneous transluminal angioplasty of FMD is a worldwide-accepted treatment modality for this serious arterial disease with, so far, good safety and long-term efficacy data. Once FMD involves several arterial compartments leading to symptoms the outcomes are poor. Herein we report the case of a 3½-year-old boy with severe arterial hypertension and abdominal angina due to a diffuse multivisceral FMD involvement, successfully managed by a percutaneous angioplasty approach using a new balloon catheter for plaque modulation.     

Fibromuscular dysplasia: a rare disease that can mimic vasculitis

Fibromuscular dysplasia (FMD) is an uncommon angiopathy that occurs mainly in young to middle-aged female individuals. It is an idiopathic, segmental, non-inflammatory and non-atherosclerotic vascular disease leading to stenosis of small- and medium-sized arteries. Clinical manifestations are determined by the artery involved, most commonly hypertension (renal artery) and stroke (carotid artery). When FMD affects multiple vascular beds, it may mimic a systemic vasculitis. Here, we present the case of a young female patient with FMD. The patient had a clinical history of bilateral internal carotid artery dissection that required surgical repair. Since a systemic vascular disease was suspected, abdominal angiography was done, showing evidence of a ??string of beads?? appearance involving the distal two-thirds of the right renal artery. This lesion is considered to be pathognomonic of the medial FMD that accounts for 70?C95% of all cases of FMD. Two years later, a new magnetic resonance angiography confirmed the ??string of beads?? appearance of the middle to distal part of the right renal artery, with significant hemodynamic stenosis that was successfully dilated with percutaneous transluminal angioplasty.     

Page kidney: Rare cause of acute kidney injury after complicated renal artery angioplasty

The authors present a case of a patient who experienced a rare complication after attempted renal angioplasty and stenting, Page kidney. This patient presented with new onset hypertension secondary to bilateral renal artery stenosis and was referred for revascularization given hypertension refractory to medical management. The right renal artery underwent successful angioplasty and stenting; however, the left renal artery experienced recoil stenosis. Post‐procedure the patient developed acute kidney injury secondary to Page kidney from subcapsular and extracapsular hematoma. This was managed conservatively with transfusions and the hematoma and acute kidney injury self‐resolved over the next 4 months. This case highlights the importance of revascularization for refractory hypertension secondary to hemodynamically significant bilateral renal artery stenosis, the rare complication of Page kidney with attempted revascularization of renal artery stenosis and the involvement of a hypertension specialist in the decision of revascularization of renal artery stenosis.     

Atherosclerotic renal artery disease

Atherosclerotic renal artery stenosis may present with hypertension, renal failure (ischemic nephropathy), or congestive heart failure. The prevalence of renal artery stenosis is increasing in patients with other manifestations of atherosclerosis. The diagnosis is being made more frequently due to better screening tests such as duplex ultrasound and magnetic resonance angiography. Renal artery stenosis is discovered incidentally during imaging studies performed for other reasons. Revascularization should be performed using angioplasty and stenting in patients who have hypertension that cannot be adequately controlled with medications, in patients with severe bilateral renal artery stenosis or stenosis to a solitary functioning kidney and in patients with congestive heart failure when no other clear cut cause can be found.     

Clinical significance of cerebral aneurysm in renovascular hypertension due to fibromuscular dysplasia: two cases in siblings

Two cases, in siblings, of renovascular hypertension caused by fibromuscular dysplasia (FMD) of the renal artery associated with cerebral aneurysms are reported. Both of the cases were found to have cerebral aneurysm, as well as multiple stenotic or occluded lesions in arteries such as renal, mesenteric, celiac, and internal carotid arteries. One case died of subarachnoid hemorrhage and the other case was successfully operated on for the aneurysm. This report suggests that FMD should be considered to be a systemic angiopathy including the cerebral artery, as well as the renal artery. Thus, cerebral angiography is recommended to detect the association with cerebral aneurysm, at least, in cases with multiple lesions of FMD. Occurrence of FMD in siblings also indicates that a genetic factor might be involved in the pathogenesis of FMD.     

Dilation of renal artery stenosis after administration of losartan.

Transluminal angioplasty with a balloon catheter is effective to dilate renal artery stenosis (RAS) caused by fibromuscular dysplasia (FMD), but lesions resistant to the angioplasty exist. In this report, we describe the case of a young woman with RAS of FMD that was difficult to dilate even by cutting-balloon angioplasty. To facilitate the formation of a smooth intimal covering at the site of angioplasty, we administered losartan, an angiotensin receptor blocker, for 4 months after the angioplasty. Although re-stenosis was detected at 5 months after the angioplasty, the normotensive state continued without antihypertensives and the re-stenosis gradually dilated afterwards. The present case suggests the possibility of remodeling the renal artery during the normotensive state by administering losartan after the angioplasty.     

Renal Artery Stent Placement: Indications and Results

Although revascularization of renal artery stenosis (RAS) from fibromuscular dysplasia (FMD) generally yields satisfying outcomes, traditional approaches to revascularization for atherosclerotic renal artery stenosis (ARAS) have been suboptimal because of the invasiveness, relatively high perioperative morbidity and mortality rates of surgery, and the low rates of technical success and long-term patency with percutaneous renal balloon angioplasty (PTA). Endovascular stents have been deployed for failed PTA (unsatisfactory results or complications) and treatment of restenotic lesions. Compared to PTA, primary stenting of ostial ARAS gives superior technical success rates greater than 95% and improved long-term patency. Curing hypertension after RAS revascularization is rare (< 10%). Improved control with fewer medications is a more realistic goal. Renal function as judged by serum creatinine improves in 20% to 30%, stabilizes in 40% to 60%, and deteriorates in 20% to 30% of patients whose renal function is impaired initially. One study demonstrated successful stenting slowed the rate of progression of renal failure in 89% of patients whose serum creatinine was less than 400 mol/L. Complications of renal artery stenting may be substantial, though procedure-related mortality is low. Patient selection for renal revascularization remains controversial. Those with renovascular disease and uncontrolled hypertension, progressive renal failure, or recurrent flash pulmonary edema should be carefully considered for renal artery stenting in experienced centers.     

Assessment of renal artery fibromuscular dysplasia: Angiography,intravascular ultrasound (with virtual histology), and pressure wire measurements

Fibromuscular dysplasia (FMD) of the renal arteries is classically associated with secondary hypertension in younger individuals, which may be treatable and even curable by percutaneous transluminal renal angioplasty. Angiography of these renal arteries oftendisplays “beaded” luminal abnormalities. The angiographic findings, however, may not accurately reflect the severity or precise location of the intraluminal obstruction. We present a case of an older individual with longstanding hypertension and FMD, in whom the use of a coronary pressure wire and intravascular ultrasound enabled precise localization and treatment of the hemodynamically significant stenosis. Virtual histology of FMD in the renal vasculature is also reported. © 2008 Wiley‐Liss, Inc.     

Successfully treated "accelerated" renovascular hypertension with intravascular stenting.

A 76-year-old man developed progressive renal dysfunction with refractory hypertension. Bilateral renal artery stenosis due to atherosclerosis was revealed. Both the hypertension and renal dysfunction were improved by percutaneous transluminal renal angioplasty with stenting. Based on the rapidly progressive elevation of plasma renin activity and the improvement of both renal dysfunction and hypertension after stenting, this was considered a case of "accelerated" renovascular hypertension. There have been an increasing number of patients with bilateral renal artery stenosis due to atherosclerosis. The present case reminds us that a rapid progression of renal dysfunction suggests, in addition to besides rapidly progressive glomerulonephritis with crescent formation, bilateral renal artery stenosis, the incidence of which is on the rise. In the present case, angioplasty with stenting was effective for blood pressure control and preservation of renal function.     

Fibromuscular Dysplasia Affecting a Two‐Branched Renal Artery in a Patient With a Solitary Kidney: Case Presentation

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory arterial disease, commonly involving the renal arteries. Here we report a case of a 16‐year‐old Chinese male who was found to have severe hypertension with proteinuria for 2 years. Computed tomography showed absence of the left kidney and enlargement of the right kidney. Subsequent angiography confirmed the above findings and revealed narrowing of both the upper and lower branches of the right renal artery caused by FMD. These combined lesions are very rare, and individuals affected are at increased risk of renal dysfunction if left untreated. Treatment with percutaneous balloon angioplasty is the first choice in such a patient and usually results in optimal outcomes.     

Nierenarterienstenosen

Renal artery stenosis can be caused by a variety of diseases but atherosclerotic renal artery stenosis (ARAS 60–90%) and fibromuscular dysplasia are the two most frequent entities. Only 1% of hypertensive patients develop renal artery stenosis and correction of stenosis will not automatically improve blood pressure or renal function. If such an improvement occurs, renovascular hypertension or renovascular azotemia can be retrospectively diagnosed. Up to now randomized controlled trials have failed to show a benefit of angioplasty in patients with ARAS compared to medicinal treatment alone. All patients with renal artery stenosis should receive optimal medical treatment to treat hypertension and prevent progression of atherosclerotic disease. Expert opinions based on uncontrolled trials recommend angioplasty in patients with ARAS and unexplained flash pulmonary edema, refractory heart failure, uncontrollable hypertension and progressive renal failure. The results of further randomized controlled trials are eagerly awaited.     

Complementary roles of color-flow duplex imaging and intravascular ultrasound in the diagnosis of renal artery fibromuscular dysplasia: should renal arteriography serve as the "gold standard"?

OBJECTIVES: The purpose of this study was to compare color-flow duplex imaging (CFDI), intravascular ultrasound (IVUS), and renal arteriography in diagnosing renal artery (RA) fibromuscular dysplasia (FMD) and correlating with the hemodynamic response to balloon angioplasty (BA) in patients with drug-resistant hypertension. BACKGROUND: Renal arteriography is generally regarded as the gold standard for diagnosing RA FMD. The observation that CFDI and IVUS depicted endoluminal abnormalities suggestive of RA FMD in some patients with normal renal arteriograms prompted comparison of these modalities in a consecutive series of patients. METHODS: Twenty hypertensive patients with CFDI suggestive of RA FMD (mid-to-distal flow derangement and velocity augmentation) underwent renal arteriography, IVUS, and BA, with both immediate and long-term blood pressure (BP) response assessment. RESULTS: All patients were women, aged 31 to 86 years (mean 62 years). On IVUS, various endoluminal defects (eccentric ridges; fluttering membranes; spiraling folds) were depicted at locations predicted by CFDI and were uniformly identified at sites where arteriography depicted classic evidence of FMD (8 patients). However, similar defects were detected by IVUS when angiography was borderline (7 patients) or normal (5 patients). Balloon angioplasty eliminated (16 patients) or reduced (4 patients) the IVUS findings and lowered systolic BP in all (mean reduction 53 mm Hg, p < 0.0001). This reduction was maintained during follow-up of 4 to 22 (mean 13) months (mean reduction 44 mm Hg, p < 0.0001), independent of baseline angiographic appearance. CONCLUSIONS: Both CFDI and IVUS depict the blood flow and endoluminal abnormalities of RA FMD. Balloon angioplasty eliminates or improves IVUS findings and produces substantial, sustained BP reduction, an effect that is independent of baseline arteriographic appearance, calling into question the legitimacy of arteriography as the diagnostic gold standard.