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.     

The diagnosis and management of renovascular disease: a primary care perspective. Part I. Making the diagnosis

Renovascular disease is a complex disorder, the most common causes of which are fibromuscular dysplasia and atherosclerotic disease. It usually presents in one of three forms: asymptomatic renal artery stenosis, renovascular hypertension, or ischemic nephropathy. This complexity often makes diagnostic and management decisions difficult. This review will be presented in two parts. In Part I, the authors will discuss when to consider and how to go about making the diagnosis. In Part II (in a future issue of The JCH ), the authors discuss the management of renovascular disease. The clinical index of suspicion remains paramount in setting the diagnostic strategy. Although it is subject to certain limitations, conventional contrast angiography is usually considered the gold standard in confirming the diagnosis. In addition, there are a number of available noninvasive tests that can aid in decision making. These tests can be divided into those that detect the anatomic presence of a stenosis and those that identify the functional consequences of the renal artery obstruction.
No one study is appropriate for every patient. A diagnostic algorithm is proposed at the conclusion of this review.     

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.     

Clinical insights into the diagnosis and management of atherosclerotic renal artery disease

Atherosclerotic renovascular disease (ARVD) is an increasingly common contributor to hypertension and renal failure. However, not all patients with an identified obstructive atherosclerotic renal artery stenosis will have clinical improvement, even after successful percutaneous intervention. As such, there remains extensive controversy regarding optimal diagnostic and treatment strategies. Part of this controversy is the result of a paucity of well-designed prospective, randomized clinical trials, but the complex nature of the disorder and the heterogeneity of patients presenting with possible ARVD make simple diagnostic and treatment paradigms difficult to develop. This narrative review describes the latest observations concerning the prevalence, pathogenesis, natural history, diagnostic studies, and treatment options for suspected ARVD. Hopefully, this knowledge will improve the ability of clinicians to weigh risks and benefits and determine the best strategy in individual patients.     

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.     

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.     

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.     

Early results of percutaneous renal artery angioplasty in patients with renovascular hypertension

The authors report early results of percutaneous transluminal angioplasty of renal arteries in 28 patients. This method of treatment of renovascular hypertension is applicable in certain cases, mostly in patients with fibromuscular hyperplasia and in arteriosclerotic renal artery disease. Early good and very good hypotensive results were obtained in 27 cases (96.4%).     

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.     

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 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.     

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.     

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.     

Aktuelle Strategien in der Therapie der Nierenarterienstenose

Severe renal artery stenosis may cause renovascular hypertension; in case of bilateral narrowing or in a stenotic solitary kidney, renal insufficiency (ischemic kidney disease) or rarely pulmonary flush edema may occur. Renal artery stenosis may be treated by revascularization, using either percutaneous (balloon angioplasty, stenting) or less common open surgical procedures, both with excellent primary patency rates. However, randomized trials of renal artery angioplasty or stenting have failed to demonstrate a longer-term benefit with regard to blood pressure control and renal function over medical management alone (except for fibromuscular disease). Furthermore, endovascular procedures are associated with substantial risks. It has not yet been demonstrated that renal revascularization leads to a prolongation of event-free survival. Careful patient selection is essential to maximize the potential benefit.     

Difficult cases in heart failure. Percutaneous transluminal septal myocardial ablation in the management of hypertrophic obstructive cardiomyopathy

Hypertrophic cardiomyopathy is a complex genetic condition with a heterogeneous clinical course. Some patients remain asymptomatic throughout life while others develop one or more of the adverse clinical consequences including symptoms of congestive heart failure with exertional dyspnea and functional disability (usually with preserved left ventricular systolic function), atrial fibrillation, or sudden cardiac death. Because of this heterogenicity in the clinical presentations, management of patients with hypertrophic cardiomyopathy includes a wide range of pharmacologic therapies as well as invasive approaches. In recent years, nonsurgical catheter-based treatment of hypertrophic cardiomyopathy has been increasingly used in the management of a subset of these patients. The authors present a case of percutaneous transluminal septal myocardial ablation in a patient with hypertrophic cardiomyopathy who was symptomatic despite maximal medical treatment.     

Fibromuscular dysplasia involving coronary arteries--a case report

The authors report a young patient with fibromuscular dysplasia involving multivessels including coronary arteries. If young patients have chest pain on effort, fibromuscular dysplasia of coronary arteries must be considered. As fibromuscular dysplasia is a chronic progressive disease and some cases progress rapidly in a few months, careful follow-up and comprehensive medical management may be necessary in such patients.     

Renovascular hypertension update

Hypertension detected in patients with renovascular disease poses a major clinical challenge. The rapid expansion of noninvasive imaging, effective antihypertensive drug therapy, and endovascular interventional procedures combine to make optimal management a moving target. Renal arterial disease accelerates the development of hypertension associated with activation of multiple pressor systems and accelerated target organ injury. Younger individuals with fibromuscular lesions often respond well to renal revascularization with minor associated risks. Care must be taken in cases of complex vascular anomalies, such as renal artery aneurysms. Atherosclerotic renal artery stenosis is detected more commonly than ever before and affects more than 85% of patients referred for revascularization. Most are older patients with long-standing hypertension, diabetes, and pre-existing complications of vascular disease. The benefits of extensive workup and intervention in this group of patients are controversial. Antihypertensive drug therapy is most effectively achieved with drugs that block the reninangiotensin system, but most require multiple agents. Selection of patients for renal revascularization in this group is far more controversial than with fibromuscular disease. Several small trials failed to identify major benefits with renal artery angioplasty as compared to closely monitored drug therapy, although crossover rates from medical to interventional arms were high. The Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) seeks to randomly assign subjects with proven, high-grade renal artery lesions to optimal medical management with and without stenting. This important trial employs distal embolic protection to prevent deterioration of renal function. Understanding the optimal role for renal revascularization depends heavily upon the successful conduct of such trials.     

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.     

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.     

Ischemic renal disease: revascularization or conservative treatment?

Ischemic nephropathy is recognized as a distinct cause of renal insufficiency and it is defined as a significant reduction in glomerular filtration rate in patients with hemodynamically significant renovascular occlusive disease. We argue the epidemiologic and clinical manifestations of atherosclerotic renovascular disease, and we evaluate the pronostic agents. Published studies of the outcome of revascularization for renal-artery stenosis have been excellent, offering a durable patency and functional improvement but they have had numerous limitations. The atherosclerosis is a systemic disease and it provides the general prognosis of patients. We conclude that ischemic renal disease is a nephropathy of smoker men, with proteinuria excretion similar to nephropathy with unilateral stenosis. The age of patients is the clinical feature that decide the treatment: surgery, angioplasty/stent or medical management. Comparative analysis of percutaneous transluminal angioplasty and operation for renal revascularization and medically treated patients have proved that the advanced chronic renal insufficiency is associated with an unfavourable response of treatment of the ischemic nephropathy. But, in this nephropathy the revascularization can be the better therapy for selected patients. The revascularization with angioplasty/stent for patients with unilateral renal stenosis and chronic renal insufficiency has a doubtful effectiveness, as the chronic renal failure is result of nephroangiosclerosis.