Clinical diagnosis of hypertensive nephrosclerosis

Priscilla Kincaid-Smith

Department of Pathology, University of Melbourne, Grattan Street, Parkville, Victoria, Australia

Sir,

In response to this article I would like to offer some data on the rarity with which hypertension causes renal failure in Melbourne.

In the early years of renal transplantation bilateral nephrectomy was carried out routinely prior to transplantation. This gave me a unique opportunity to study the pathology in the kidney in all patients presenting with end-stage renal failure between 1963 and 1972 [1]. The definitive pathological diagnosis in these patients is shown in Table 1Go. Many would also have had a histological diagnosis made on renal biopsy prior to nephrectomy but all kidneys were available for study prior to transplantation.


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No patient was admitted to chronic dialysis at that time. All were transplanted so that Table 1Go includes all 130 patients presenting with end-stage renal failure over this period.

Table 1Go shows that only two of 130 patients had hypertension as a cause of renal failure. Both had presented with malignant hypertension and severely impaired renal function. They had pathological features of malignant nephrosclerosis [2] in which there was no doubt that the occlusive vascular lesions caused the renal failure. Two further patients were diagnosed clinically as having hypertension as the cause of renal failure, however, one showed bilateral cortical necrosis, the other multiple bilateral major renal artery lesions.

How does this fit in with the extraordinary figures of end-stage renal disease due to hypertensive nephrosclerosis causing renal failure in 29% of new patients in the US and in 36.8% of new black patients?

Hypertensive nephrosclerosis in American blacks, described by Fogo and co-workers [3], showed well marked interstitial fibrosis and focal and segmental glomerular lesions. The extent of the glomerular lesions did not correlate with the vascular lesions. Blood vessels, although showing lesions, did not show the type of lesion which deprives nephrons of their blood supply which is the presumed cause of renal failure in so called hypertensive nephrosclerosis.

I have had a very wide experience of renal disease, renal pathology and renal failure over 50 years. I am still looking for my first case of vascular lesions of benign nephrosclerosis causing renal failure.

References

  1. Kincaid-Smith P. The prevention of renal failure. In: Villarreal H, ed. Proceedings of the Fifth International Congress of Nephrology Mexico. S. Karger, Basel, 1972: 100–118
  2. Kincaid-Smith P, McMichael J, Murphy EA. The clinical course and pathology of hypertension with papilloedema (malignant hypertension). QJ Med 1958; 27(105): 117–153
  3. Fogo A, Breyer JA, Smith MC et al. Accuracy of the diagnosis of hypertensive nephrosclerosis in African Americans: a report from the African American Study of Kidney Disease (AASK) Trial. AASK Pilot Study Investigators. Kidney Int 1997; 51: 244–252[ISI][Medline]

 

Reply

R. Zatz

Renal Division, Department of Clinical Medicine, University of São Paulo Medical School, São Paulo, Brazil

Sir,

We wish to thank Dr Kincaid-Smith for her remarks and the Editor for giving us a chance to reply to them. We do not believe there is an unsurmountable contradiction between the present American and European data and those described by Dr Kincaid-Smith in her letter. It is quite likely that this apparent conflict originates from the very different conditions under which these data were obtained. We would like to emphasize here some of these differences: (i) Dr Kincaid-Smith's data pertain to a 10-year period that started 37 years ago. At those days, anti-hypertensive therapy was far from standardized, the efficiency of treatment was limited and the very realization that hypertension constituted a cardiovascular risk factor was quite recent. As a consequence, most hypertensive patients would likely die from cardiovascular events before advanced hypertensive-related renal disease became manifest. In fact, hypertensive nephrosclerosis started to stand out as a presumed cause of ESRD only in the early 1980s, coinciding with a steady increase in the mean age of new dialysis patients [1,2]. The conspicuous absence of diabetic nephropathy in Dr Kincaid-Smith's table reinforces the view that the epidemiologic profile of renal disease has changed substantially in the last decades. Accordingly, diabetic nephropathy and `nephrosclerosis or hypertension' were diagnosed as primary diseases in 14% and 9%, respectively, of new dialysis patients in Australia in 1991 (2). (ii) Dr Kincaid-Smith's series refers specifically to patients that received renal allografts during that period. Since according to her no patient was admitted to chronic dialysis, those patients not receiving transplants must have died of renal failure. Unless we have access to autopsy data obtained during the same period, we cannot be certain that the cohort receiving renal transplants was representative of the overall ESRD population. For instance, it is reasonable to suppose that patients with ages 60 or above, precisely those in which the prevalence of hypertensive nephrosclerosis is expectedly higher, would have a higher chance of dying before undergoing transplantation surgery.

Based on our own data and in those reported by several others, we believe that hypertensive nephrosclerosis does exist as an independent cause of ESRD, although we realize that the profile of ESRD changes continuously with time, as well as with geographic and socioeconomic factors, as pointed out in our Editorial Comment [3]. New biopsy-based studies are still needed to clarify this controversial question.

References

  1. US Renal Data System. USRDS 1997 Annual Data Report. Bethesda, MD. U.S. Department of Health and Human Services, National Institutes of Diabetes and Digestive and Kidney Disease. 1997
  2. D'Amico G. Comparability of the different registries on renal replacement therapy. Am J Kid Dis 1995; 25: 113–118[ISI][Medline]
  3. Caetano EP, Zatz R, Praxedes JN. The clinical diagnosis of hypertensive nephrosclerosis—how reliable is it? Nephrol Dial Transplant 1999; 14: 288–290[Free Full Text]