Renal artery stenosis can lead to several different clinical syndromes ranging from difficult to control hypertension to recurrent pulmonary edema (shortness of breath due to the lungs filling with fluid) to ischemic nephropathy (kidney dysfunction due to compromised arterial blood flow) and frank renal failure. Renal artery stenosis is most often due to severe atherosclerotic plaque build-up in the renal arteries (typically in those over age 50) but may be due to fibromuscular dysplasia (FMD) seen more frequently in women under the age 50. The prevalence of renal artery stenosis is increased in diabetics with high blood pressure and in those with known coronary and peripheral arterial disease. Duplex ultrasound or magnetic resonance angiography (MRA) as well as other imaging testsdcan be used to non-invasively suggest the diagnosis but the gold standard is conventional renal angiography. Catheter-based endovascular treatment options include balloon angioplasty alone (usually reserved for cases of fibromuscular dysplasia) and more commonly angioplasty with stenting both with the goal of improving blood flow to the affected kidney which may ultimately aid in long-term blood pressure control and improving kidney function.