Histopathology of severe renal vascular damage in blacks

During the 1970s renal biopsies were obtained after blood pressure had been controlled in 41 black patients in Memphis who had severe hypertension plus excretory renal failure. An additional 13 binephrectomy specimens were also studied. This material yielded significant information on the state of the renal arteries--arterioles under these circumstances. Fibrinoid necrosis of the afferent glomerular arteriole and proliferative glomerulitis were not noted. Rather, the vascular lesion characterized by the accumulation of smooth muscle cells and mucopolysaccharide in the intima attended by a marked narrowing of the lumen was dominant. This lesion caused pronounced ischemia associated with obsolescence of glomeruli, atrophy, and fibrosis (end-stage kidney). This lesion has been renamed musculomucoid intimal hyperplasia as a result of changes revealed by electron microscopic and histochemical studies. Since this study the incidence of this severe vascular disease of the kidney in the same geographic area has been markedly reduced. There are a number of possible reasons for this change in incidence, but a major one appears to be improved treatment of hypertension and better compliance with antihypertensive therapy. Why such extreme changes occur in a subset of hypertensive blacks is not known. It is apparent that without improved antihypertensive treatment, this type of end-stage renal disease due to severe vascular damage will continue to be encountered.