Primary hypertension — how does it cause renal failure?

Classically it is stated that the kidney, apart from being the 'villain ' with respect to the pathogenesis of essential or primary hypertension, may also be its 'victim ' [1]. But is there really a clear-cut relationship between primary hypertension and renal insufficiency? The magnitude of the problem The incidence of end-stage renal failure has risen progressively on both sides of the Atlantic, primarily because of the increased number of elderly patients with diabetes and hypertension. According to the United States Renal Data System, between 1983 and 1987 the incidence of end-stage renal failure generally rose by 5.7 % per year, while that ascribed to hyperten-sion increased by 8.3 % per year. In Europe end-stage renal failure caused by hypertension was the admission diagnosis in approximately 20 % of patients [2,3]. Thus primary hypertension is an important cause of end-stage renal failure. Since malignant hypertension has become rare it is obvious that patients with so-called 'benign ' (a complete misnomer) primary hypertension, often mild to moderate, must develop progressive renal failure as well. What renal lesions are found in primary hypertension? So-called hypertensive nephrosclerosis is the principal lesion found in uncomplicated hypertension by renal biopsy or at autopsy. So-called nephro(angio) sclerosis of preglomerular arterioles and even more so of inter-lobular and interarcuate arteries exhibit two features: (i) arteriolar hyalinosis, and (ii) medial hypertrophy leading to fibroplastic intimal thickening with medial wasting. This is accompanied by ischaemic parenchy-mal damage with atrophy and replacement type of fibrosis [4]. Correspondence and offprint requests to: Pietro Zucchelli, Malpigh