I was pleased to read Dr. Abuelo's excellent summary of the vascular causes of renal failure [1]. In clinical practice, many of these causes are rare and easily forgotten or overlooked. I emphasize the importance of microvascular disease that affects the renal arterioles. I have observed this condition to be among the most common causes of renal failure progressing to end-stage renal disease. Unfortunately, this entity is not mentioned in most nephrology or internal medicine journals and texts and was not discussed by Dr. Abuelo.

Microvascular renal disease is commonly present in patients with a medical history consistent with diffuse vascular disease (that is, previous coronary event, carotid artery disease, peripheral vascular disease, and so forth). Clinical presentation resembles that of patients with hypertensive nephrosclerosis, except that patients have a history of minimal or no hypertension. An increasing serum creatinine level is associated with an unremarkable urinalysis other than variable amounts of urinary protein, which can approach 1 to 2 g/d. When done, renal biopsy shows a histologic profile typical of that seen in hypertensive nephrosclerosis. Evidence of arteriolar vascular disease can also often be seen on biopsy. As with hypertensive nephrosclerosis, patients with what I refer to as "atherosclerotic nephrosclerosis" often progress rapidly to end-stage renal disease. Similarly, the long-term survival of patients receiving dialysis is often compromised as a result of their coincidental diffuse vascular involvement.

Microvascular renal disease leading to atherosclerotic nephrosclerosis is a common clinical entity. Because of the lack of available information in the nephrology and internal medicine literature, the condition is often a vague and misunderstood cause of renal failure. Both its apparently increasing incidence (as patients enjoy increased survival after interventions are given to treat vascular disease) and poor prognosis point to a need for further discussion of these complications.