Clinical benefit from any revascularization procedure will be the net gain due to reperfusion of the ischemic organ balanced against the risk of a procedural complication. The same is true for renal artery ischemia caused by atherosclerotic or, less commonly, fibromuscular dysplasia (FMD) lesions (Fig. 52-1). Recent clinical trials have attempted to determine the benefit of revascularization but have been seriously hampered by difficulty in defining a threshold for an ischemia producing renal artery stenosis (RAS).
A. Selective left renal artery angiography from the right radial access using a 5-Fr, 125-cm-long multipurpose catheter. Note there is a moderately severe proximal stenosis present (arrow). B. Selective right renal artery angiography from the right femoral artery with a 5-Fr internal mammary catheter. Note the appearance of “stacked coins” (arrow) diagnostic of fibromuscular dysplasia (FMD).
Renal ischemia due to an obstruction of the renal artery causes 3 well-described clinical scenarios: (1) renovascular hypertension, (2) ischemic nephropathy, and (3) cardiac destabilization syndromes such as sudden-onset pulmonary edema, decompensated heart failure, and acute coronary syndromes. Helping to identify patients with these clinical manifestations of renal ischemia who also have anatomically suitable lesions for treatment is the purpose of this chapter. The primary method of revascularization for renal artery stenosis is endovascular, not open surgery. Open surgery is rarely performed today and usually accompanies another related open surgical procedure on the abdominal aorta, for example.
PREVALENCE OF RENAL ARTERY STENOSIS
The prevalence of renal artery stenosis (RAS) depends on the population examined. In a Medicare population (mean age, 77 years), screening renal ultrasound duplex studies demonstrated greater than 60% RAS in 6.8% of patients.1 There were almost twice as many males (9.1%) as females (5.5%; P = .053), and there were no racial differences (Caucasian, 6.9%; African American, 6.7%) in the prevalence of RAS. Among the general hypertensive population, RAS is the most common (2%-5%) secondary cause of hypertension. An autopsy series of patients older than 50 years found RAS (≥50%) in 27% of patients, and this rate increased to 53% if there was a history of diastolic hypertension >100 mm Hg. Among patients entering dialysis treatment, 10% to 15% have RAS as the cause of end-stage renal disease.2 Approximately 25% of elderly patients with renal insufficiency have unsuspected RAS.
RAS is predominantly due to atherosclerosis in the adult population, with FMD being more common in younger females.3 RAS is more common in patients who have atherosclerosis involving any other vascular bed. In patients undergoing cardiac catheterization for suspected coronary artery disease, the prevalence of RAS ranges from 25% to 30%, whereas peripheral arterial disease or abdominal aortic aneurysm is associated with RAS in 30% to 40% of ...