Fibromuscular Dysplasia: From a Rare Cause of Renovascular Hypertension to a More Frequent Systemic Arterial Disease

Abstract

Fibromuscular dysplasia (FMD) is an idiopathic, segmental, non-atherosclerotic and non-inflammatory disease, which leads to stenosis of small- and medium-sized arteries. With cerebrovascular FMD, renal artery FMD is the most frequent presentation of the disease. The prevalence of renal FMD remains elusive but an estimate of 3–5% seems reasonable. Renal artery FMD is usually diagnosed incidentally, on the occasion of a work-up for hypertension, or seldom following renal artery dissection. The typical patient with renal artery FMD is a ~50-year-old woman with hypertension, but FMD can also be diagnosed in men and at all ages of life. In children and adolescents, it is often associated with severe hypertension and cardiovascular damage. In most cases, CT-/MR-angiography may be considered as the test of choice for both screening and diagnosis of renal FMD, in association with duplex ultrasound evaluation, which provides additional hemodynamic information. In view of the high (>50%) prevalence of multivessel FMD, once a lifetime exploration of all vascular beds from brain to pelvis is recommended. Detection of cerebrovascular FMD is of particular importance, due to its high prevalence and potential dramatic consequences of complications. Smoking cessation is strongly advised. Antiplatelet treatment deserves to be considered on a case-by-case basis. In patients with hypertension, strict blood pressure control is required. Revascularization—usually by percutaneous balloon angioplasty without stenting—is justified, especially in young patients, in patients with recent onset or severe hypertension, as well as in rare cases of deterioration of renal function, in the presence of arguments in favour of a hemodynamically significant renal artery stenosis. FMD may be familial in up to 10% of cases; therefore, screening for FMD should be considered in relatives with suggestive symptoms. Finally, as patients with FMD may progress or develop complications, a lifelong yearly follow-up, tailored for each patient, is justified. The development of the US and European/International FMD registries and associated studies will undoubtedly shed new light on FMD and allow substantial progress in the understanding and management of the disease in the next decade.