Ischemic nephropathy: where are we now?

Identification and reversing the loss of kidney function beyond occlusive disease of the renal arteries poses a major clinical challenge. Recent studies indicate that atherosclerotic renal artery stenosis develops as a function of age and is commonly associated with other microvascular disease, including nephrosclerosis and diabetic nephropathy. The risks of renal artery stenosis are related both to declining kidney function and to accelerated cardiovascular disease, with increased morbidity and mortality. Newer drugs, including agents that block the renin-angiotensin system, have improved the level of BP control for renovascular hypertension. Progressive renovascular disease during medical therapy can produce refractory hypertension, congestive heart failure, and renal failure with tubulointerstitial fibrosis. Recent studies indicate a complex interplay of oxidative stress, endothelial dysfunction, and activation of fibrogenic cytokines as a result of experimental atherosclerosis and renal hypoperfusion. Advances in imaging and interventional devices offer major new opportunities to prevent progressive loss of kidney function. Recent series indicate that although 25 to 30% of patients with impaired renal function can recover glomerular filtration after revascularization, many have no apparent change in kidney function and 19 to 25% experience a significant loss of kidney function, in some cases as a result of atheroemboli. To select patients who are most likely to benefit from vascular intervention, clinicians should understand the pathophysiology of developing ischemic nephropathy and the potential hazards of revascularization in the setting of diffuse atherosclerotic disease. Further research should be directed toward identification of critical disease, regulation of fibrogenesis, and the interaction with other atherosclerotic processes.