15th July 2024

Background

Disease of the renal arteries is an increasingly common cause of renal impairment and renal hypertension, particularly in the Western world. Reduced renal perfusion results in the upregulation of the renin-angiotensin-aldosterone system, contributing to hypertension.

There are two main types of renovascular disease:

• Atherosclerosis related renal artery stenosis (most common; 90%)
• Fibromuscular dysplasia (9%)

More rarely, renal artery dissection or embolism may give rise to the same clinical picture.  Moderate renal artery stenosis may be asymptomatic, but hypertension will eventually develop as the condition progresses.

Atherosclerosis related renal artery stenosis

This is predominantly seen in older patients who are also likely to have systemic atherosclerosis.  Patients are likely to have other associated risk factors such as hypertension, diabetes mellitus, ischaemic heart disease, a smoking history or peripheral vascular disease.  Similar to other forms of atherosclerotic disease, mild to moderate stenosis may present with little or no symptoms. In contrast, more severe disease may present with flash pulmonary oedema, hypertension and/or decline in renal function.

Fibromuscular dysplasia

Fibromuscular dysplasia (FMD) is an idiopathic, non-inflammatory, non-atherosclerotic disease affecting the fibrous layers of the arterial walls. FMD has the propensity to affect any vascular bed but medium sized renal and cerebral arteries are the most commonly affected. Multifocal FMD causes a ‘string of bead’ appearance on magnetic resonance angiography or computed tomographic angiography, which corresponds to areas of vascular stenosis alongside areas of ‘bulging.’  A typical patient is a female between the ages of 16 and 50 with early onset or unexplained hypertension. Other symptoms depend on the distribution of vascular beds involved, for example, pulsatile tinnitus or chest pain.