Fibromuscular dysplasia of the renal arteries

Although renovascular hypertension is less common than primary hypertension, it is important for clinicians to recognize this clinical entity because of its distinct pathophysiology and specific therapy. It is estimated that about 5% of the overall hypertensive population have renovascular hypertension. Whereas most renovascular lesions are caused by atherosclerosis, stenosis due to fibrous dysplasia is an important disease. In children and young adults, fibromuscular dysplasia of the renal arteries is the most common cause of renovascular hypertension. This review deals with the pathology, clinical characteristics, diagnosis, and therapy of renovascular hypertension associated with fibromuscular dysplasias.     

Renovascular hypertension: an update

Renovascular hypertension, the most common remediable cause of elevated blood pressure, is a controversial topic, but most authorities agree on several principles. The absolute risk of renovascular hypertension for a specific patient can be estimated using only clinical information, thereby sparing many patients further expensive and potentially dangerous evaluations. Patients with a high absolute risk of renovascular hypertension should have angiography only if they are willing to undergo revascularization if warranted. A screening test (captopril renography, Doppler ultrasonography, magnetic resonance angiography, or computed tomography) is recommended for those with an intermediate absolute risk. Angioplasty should be offered to patients with fibromuscular dysplasia. Whether intensive medical therapy (including an angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker) for atherosclerotic renovascular hypertension is improved by angioplasty plus stent placement may be answered by ongoing studies, the largest of which may be the National Institutes of Health-funded Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial.     

Renovascular hypertension in China--report of 200 cases

Renal arteritis and fibromuscular dysplasia are two common causes of renovascular hypertension in China. The diagnostic approach now is arteriography or digital subtraction arteriography first, followed by renal vein renin assays to evaluate the functional significance. Surgical treatment is preferred if clinical status of the patients permits.     

Diagnosis and management of renovascular disease and renovascular hypertension

Renovascular disease is a common but complex disorder, the most common causes of which are fibromuscular dysplasia and atherosclerosis. Clinically, it can present as asymptomatic renal artery stenosis, renovascular hypertension, or ischemic nephropathy. Assessing the clinical index of suspicion remains essential in determining an appropriate diagnostic strategy. For diagnosis in patients with suspected fibromuscular disease, it may be reasonable to proceed directly to renal angiography; however, for most patients with suspected atherosclerotic disease, there are a number of noninvasive tests available that can aid in decision making. The choice of the most appropriate initial test should be based on patient characteristics, clinical presentation, and local expertise. Treatment options include medical, surgical, or percutaneous approaches. Generally, in patients with fibromuscular disease, percutaneous intervention provides durable improvement or cure of hypertension. In patients with atherosclerotic disease, the data are less consistent, and there does appear to be a group of patients who will respond well to medical management alone. As technology advances, the diagnostic and treatment paradigms will continue to evolve.     

Duplex scan sonography of renal artery stenosis.

Renal artery stenosis is the most common cause of potentially remediable secondary hypertension. The most common causes include atherosclerosis and fibromuscular dysplasia. Particularly the atherosclerotic form is a progressive disease that may lead to gradual and silent loss of renal functional tissue. Thus, early diagnosis of renal artery stenosis is an important clinical objective since interventional therapy may improve or cure hypertension and preserve renal function. Screening for renal artery stenosis is indicated in the suspicion of renovascular hypertension or ischemic nephropathy in order to identify patients in which an endoluminal or a surgical revascularization is advisable. In the recent years many noninvasive tests have been proposed and evaluated in the clinical practice, in alternative to arteriography. These include nuclear scan, color Doppler sonography, CT angiography and MR angiography. Sonography is usually the first diagnostic modality for the non invasive evaluation of renal vascular disease with 95% sensitivity and 90% specificity when performed in dedicated laboratories. Despite sonography is highly affected by operator dependence, and it takes a lot of time to train good operators, actually is the best screening test because it is not expensive, non invasive and accurate. When a discrepancy exists between the clinical data and the results of US, other tests are mandatory.     

Current concepts in renovascular hypertension.

Renovascular disease represents an important dimension of hypertension. Although estimates vary regarding the exact prevalence of renovascular hypertension, it is being diagnosed with increasing frequency because of refined criteria for the workup and the availability of sensitive diagnostic tests. Two major pathologic entities--atherosclerosis and fibromuscular dysplasia--account for most cases of renovascular hypertension. Once the diagnosis and clinical significance of renal artery stenosis in a hypertensive patient are established, appropriate and specific therapy should be considered. The goal is not only to treat hypertension, but to preserve and restore renal function. Although antihypertensive drug therapy may lower the blood pressure, reperfusion of the kidney (surgical, angioplasty) is a desirable long-term objective in the management of patients with renovascular hypertension. With careful selection of therapeutic choices, we are now able to render optimal care to patients with renovascular hypertension.     

Percutaneous transluminal renal angioplasty in nonatherosclerotic renovascular hypertension. Long-term results

Nineteen stenotic arteries in 16 patients with severe renovascular hypertension of nonatherosclerotic nature (fibromuscular dysplasia in 13, neurofibromatosis in 3) were treated with percutaneous transluminal renal angioplasty. The procedure was technically successful in 12 of 14 (86%) stenoses in the fibromuscular dysplasia subgroup but in only one of five (20%) lesions in the neurofibromatosis subgroup. Hypertension was abated (3 patients) or disappeared (8 patients) in 11 of the 12 (92%) patients with fibromuscular dysplasia who had a technically successful angioplasty, an effect that was sustained at latest follow-up (avg, 37 mo; range, 10-73 mo). The only complication encountered was a retroperitoneal hematoma that resolved uneventfully. Coupled with those from other centers, the results of the present study indicate that angioplasty offers a strong potential for curability in patients with renovascular hypertension caused by fibromuscular dysplasia and that percutaneous transluminal renal angioplasty should be considered the treatment of choice for the initial management of all patients with fibromuscular renovascular hypertension.     

Catheter atherectomy of intimal fibroplasia of the common iliac artery

An 18-year-old woman presented with renovascular hypertension and left lower extremity claudication. Aorto-iliac angiography showed stenotic lesions in the left renal artery and the left common iliac artery. For uncontrolled hypertension, nephrectomy was performed and histopathology of the renal artery showed intimal fibroplasia, an uncommon type of fibromuscular dysplasia. The left common iliac artery lesions were treated with directional atherectomy, which produced excellent immediate angiographic and symptomatic improvement. © 1993 Wiiey-Liss, Inc.     

A case of renovascular hypertension due to bilateral renal artery microaneurysm who succeeded in baby delivery.

We report the case of a young pregnant woman with bilateral renovascular hypertension due to renal microaneurysms from an unknown cause, who had a successful delivery. Pregnancy did not affect the disease activity even in the postpartum period. Her blood pressure was maintained within the normal range by administration of labetalol. Although the angiographic appearance of the symmetrical aneurysms in both renal artery beds from the interlobular to arcuate artery levels suggested polyarteritis nodosa of multiple microaneurysms in the bilateral interlobular arteries, the clinical features suggested other causes of renovascular hypertension, such as fibromuscular dysplasia and/or congenital microaneurysms. We were thus unable to reach a definitive diagnosis.     

Long-term experience in percutaneous transluminal dilatation of renal artery stenosis

Percutaneous transluminal dilatation was attempted in 65 patients with renovascular hypertension. In five cases (8 percent), percutaneous transluminal dilatation could not be performed for technical reasons. In the remaining 60 patients (35 with atherosclerotic stenosis and 25 with fibromuscular dysplasia), both mean systolic and diastolic pressure fell immediately after percutaneous transluminal dilatation and remained significantly lower for a period of up to five years. Cure rates after a mean control period of 21.6 months were higher in patients with fibromuscular dysplasia (50 percent) than in those with atherosclerotic stenosis (29 percent). Improvement of blood pressure was observed in 32 percent of patients with fibromuscular dysplasia and in 48 percent of patients with atherosclerotic stenosis. Follow-up angiography in 33 cases showed occlusion of the dilated artery in two patients and recurrence of slight renal artery stenosis in nine patients. Successful redilatation could be performed in five of these cases. Furthermore, renal vein renin determinations were only of limited diagnostic or prognostic value. These results document the good long-term effect of percutaneous transluminal dilatation in patients with renal artery stenosis. Percutaneous transluminal dilatation should, therefore, be the favored procedure in patients with renovascular hypertension.     

经皮肾动脉成形术治疗肾血管性高血压的近期疗效

目的 评价经皮腔内肾动脉成形术(PTRA)治疗肾血管性高压血的近期疗效及影响疗效的因素。方法22例不同病因(大动脉炎9例,纤维肌发育不良7例,动脉粥样硬化6例)的肾动脉狭窄患者接受了PFRA术。术后造影观察即时技术成功指标并复查血压,血清肌酐水平判断PTRA的临床疗效。结果 即时造影的技术成功率达95％(21/22)。术后100％的病人高血压得到改善,8例(36％)血压降至正常,14例(64％)血压状况得到改善。9例病人肾功能得到改善。无严重并发症发生。结论 以上资料提示PTRA术近期疗效良好,是一种安全有效的治疗方法。     

Etiologic factors in renovascular fibromuscular dysplasia. A case-control study

The role of several factors that have been suggested as being of etiologic importance in renovascular fibromuscular dysplasia was examined in a case-control study of 33 patients with angiographically demonstrated fibromuscular dysplasia and 61 renal transplant donor control subjects with normal renal arteries. The factors studied included use of oral contraceptive agents or markers of sex hormone dysfunction, mechanical stress to the renal artery wall, human lymphocytic antigen (HLA) type, cigarette smoking, history of hypertension for more than 5 years, and family history of cardiovascular disease. The risk of fibromuscular dysplasia was significantly (p = 0.003) increased (odds ratio = 4.1, 95% confidence interval = 1.5-10.9) among cigarette smokers. A significant (p less than 0.001) dose-response relation was noted between cigarette use and the risk of fibromuscular dysplasia developing (odds ratio = 8.6 for those who had smoked more than 10 pack-years). Personal history of hypertension more than 5 years was also associated (odds ratio = 5.0, 95% confidence interval = 1.1-22.8) with a significantly (p = 0.036) increased risk for the development of fibromuscular dysplasia. HLA-DRw6 antigen was more common in the 33 fibromuscular dysplasia patients than in the 61 renal transplant donor control subjects (odds ratio = 3.00, p = 0.067) or a second group of 934 ambulatory control subjects (odds ratio = 2.51, p = 0.031). Adjustment for cigarette smoking increased the odds ratio to 5.0 (95% confidence interval = 1.3-19.6). There was a positive though not statistically significant (odds ratio = 1.7, p = 0.175) association noted between family history of cardiovascular disease and fibromuscular dysplasia.(ABSTRACT TRUNCATED AT 250 WORDS)     

Renal artery stenosis: a cardiovascular perspective

Background Renal artery stenosis (RAS) is an important clinical entity that can lead to uncontrolled hypertension and progressive renal failure. The most common causes of RAS are atherosclerosis and fibromuscular dysplasia. Because the diagnosis of renovascular hypertension is established only when revascularization of a stenosed renal artery results in cure or improvement in patients hypertension, establishment of a causal relationship between RAS and hypertension continues to present a challenge. Therefore, a high index of suspicion is essential in the diagnosis of this condition. Methods Multiple tests, both invasive and noninvasive, are available as screening methods. Angiography remains the gold standard for diagnosis of RAS. Besides its value in establishing the diagnosis, it provides anatomic information regarding the site and severity of stenoses and appropriate revascularization strategies. Magnetic resonance angiography and duplex ultrasonography are the most promising and accurate noninvasive screening tests available, even in the presence of renal insufficiency. With advances in percutaneous transluminal angioplasty techniques, including renal artery stenting, many more patients are eligible for less invasive and effective revascularization strategies compared with the traditional surgical procedures. Results Revascularization of a stenosed renal artery is associated with preservation of renal function and better control of hypertension, unstable angina, and congestive heart failure. Because atherosclerotic RAS is associated with generalized atherosclerosis, aggressive risk factor modification and antiplatelet therapy are integral in the management of RAS regardless of the revascularization strategy. (Am Heart J 2002;143:559-64.)     

Autotransplantation and stent implantation for bilateral renal artery fibromuscular dysplasia.

A 36-yr-old male was found to have renovascular hypertension due to an occluded right renal artery and 70% stenosis in the left renal artery, caused by fibromuscular dysplasia. The right kidney was supplied by collateral blood flow, and secreted more renin than the left kidney. Two differential therapeutic approaches were taken: autotransplantation for the right kidney and percutaneous transluminal renal angioplasty followed by stent implantation for the left. The renovascular hypertension was treated with these therapies, preserving renal function in this patient.     

How to diagnose,how to treat: renal artery stenosis-diagnosis and management

Renal artery stenosis is considered to be one of the more frequent causes of secondary arterial hypertension. Through its progression renal artery stenosis can cause renal insufficiency, uncontrolled hypertension, and increased cardiovascular morbidity. A thorough clinical examination and the presence of a typical abdominal bruit may provide helpful hints to identify hypertensive patients with possible renal artery stenosis. Testing for renovascular hypertension includes renal artery imaging, assessment of its functional significance, and evaluation for possible revascularization. Renal artery stenosis secondary to fibromuscular dysplasia should be mechanically corrected. For atherosclerotic renal artery stenosis, medical management can be attempted so long as it does not cause a decline of kidney function. In patients who are candidates for renovascular revascularization, surgical intervention can be helpful in improving blood pressure control and possibly halting the progression of renal failure. Randomized controlled trials comparing direct stenting with other surgical methods are necessary to define the best revascularization strategy in patients with renovascular hypertension. A careful follow-up study after renal artery revascularization should evaluate possible benefits in halting the deterioration of chronic renal insufficiency.     

The diagnosis and management of renovascular disease: a primary care perspective. Part II. Issues in management

Renovascular disease is a complex disorder, most commonly caused by fibromuscular dysplasia and atherosclerotic disease. It usually presents in one of three forms: asymptomatic renal artery stenosis, renovascular hypertension, or ischemic nephropathy. This complexity may make diagnostic and management decisions difficult for the primary care physician. In Part I of this review (presented in the May/June 2003 issue of The JCH), the authors discussed when to consider and how to go about making a diagnosis of renovascular disease. In Part II, the authors review the management of this complex condition. There is a debate concerning the optimal treatment of patients with renovascular disease. Management options include medical, surgical, or percutaneous approaches (angioplasty and stenting). Generally in patients with fibromuscular disease, the results of surgery and percutaneous approaches appear superior. In patients with atherosclerotic disease, the data are less consistent, and there does appear to be a group of patients who will respond well to medical management. A potential management algorithm is presented.     

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.     

Renovascular hypertension in 2007: Where are we now?

Hypertension in patients with renovascular disease poses a major clinical challenge. Renal arterial disease accelerates hypertension by activation of multiple pressor systems. Although younger individuals with fibromuscular lesions often respond well to angioplasty with minor associated risks, care must be taken in cases of complex vascular anomalies, such as renal artery aneurysms. More than 85% of patients referred for revascularization have atherosclerotic renal artery stenosis; most are older patients with preexisting hypertension, diabetes, and vascular disease. The benefits of stent revascularization in this group are controversial. Antihypertensive therapy works best with drugs that block the renin-angiotensin system; however, most patients require multiple agents. Detailed analysis of the literature and small prospective trials failed to identify major benefits with renal artery angioplasty as compared with intensive drug therapy. The CORAL study and others seek to randomly assign subjects with high-grade renovascular lesions to optimal medical management with and without stenting.     

Renal Artery Stenosis: Diagnosis and Management

Renal artery stenosis is considered to be one of the more frequent causes of secondary arterial hypertension. Through its progression renal artery stenosis can cause renal insufficiency, uncontrolled hypertension, and increased cardiovascular morbidity. A thorough clinical examination and the presence of a typical abdominal bruit may provide helpful hints to identify hypertensive patients with possible renal artery stenosis. Testing for renovascular hypertension includes renal artery imaging, assessment of its functional significance, and evaluation for possible revascularization. Renal artery stenosis secondary to fibromuscular dysplasia should be mechanically corrected. For atherosclerotic renal artery stenosis, medical management can be attempted so long as it does not cause a decline of kidney function. In patients who are candidates for renovascular revascularization, surgical intervention can be helpful in improving blood pressure control and possibly halting the progression of renal failure. Randomized controlled trials comparing direct stenting with other surgical methods are necessary to define the best revascularization strategy in patients with renovascular hypertension. A careful follow-up study after renal artery revascularization should evaluate possible benefits in halting the deterioration of chronic renal insufficiency.     

Fibromuscular dysplasia

Optional statement The most common clinical manifestations of fibromuscular dysplasia (FMD) are hypertension due to renal artery involvement and transient ischemic attack or stroke due to carotid or vertebral artery involvement. Patients with renal artery FMD and hypertension should undergo primary angioplasty with the goal of curing the hypertension. If the blood pressure fails to normalize following angioplasty, the physician should institute antihypertensive medications according to the recommendations of the Joint National Committee on the Prevention, Detection, and Treatment of High Blood Pressure VII. In patients with cerebrovascular FMD, antiplatelet agents represent the cornerstone of therapy. Percutaneous angioplasty has emerged as the preferred treatment for symptomatic cerebrovascular FMD.