In their recent review of atherosclerotic renovascular disease, Rimmer and Gennari [1] point out that hypertension is not a sensitive marker of renal artery stenosis. Several studies were cited showing that among normotensive persons undergoing angiography for nonrenal indications, an important minority have anatomically significant renal artery stenosis. The important issue here, however, is not whether renal artery stenosis can occur in the absence of hypertension, but rather whether renal artery narrowing can be severe enough to cause renal failure without raising blood pressure. In the study by Harding and colleagues [2], in which 15% of 1235 patients undergoing coronary angiography were found to have unsuspected radiographically significant renal artery stenosis, the mean serum creatinine level was normal in patients with unilateral and those with bilateral disease. This finding suggests that, in the absence of hypertension, many of these angiographically significant renal artery lesions may be functionally insignificant.

As Rimmer and Gennari point out, the risks associated with diagnostic and therapeutic intervention are not trivial in those persons most likely to be affected by atherosclerosis. In deciding whether to intervene invasively in normotensive patients with vascular disease and renal failure, it would be very helpful to know if renal artery stenosis ever causes clinically important renal failure without causing hypertension.