A Study of the Angiographic Appearance of the Kidney in an Aging Normotensive Population

Abstract

That intrarenal vessels undergo morphologic changes in the presence of systemic hypertension has been well documented by microangiographic, histologic, and in vitro as well as in vivo arteriographic studies (3–5, 8, 9, 12). Conflicting evidence exists, however, as to whether or not similar morphologic changes occur in the patient who is both normotensive and free of primary renal disease. Meaney et al. (9) studied injection specimens of 13 normotensive persons, all of whom had normal-appearing arterial trees except for 1 patient with polyarteritis nodosa in whom interlobar arterial aneurysms were seen. Contrariwise, similar studies by Virtama et al. (12) and Greenblatt (4) describe interlobar and arcuate arterial abnormalities similar to those seen in hypertension in some of their specimens from normotensive individuals. A precise understanding of the effect of aging on the development and incidence of arterial abnormalities in the normotensive population was not obtained from previous studies. Such information would be of importance in assessing the clinical significance of arteriographie abnormalities demonstrated in normotensive as well as hypertensive patients undergoing selective renal arteriography. This study was undertaken, therefore, to determine if intrarenal arterial abnormalities usually associated with hypertension also occurred in a normotensive population free of renal disease and, if so, to determine if the abnormalities were age-related in their incidence. Materials and Methods The results of this study are based on information derived from the arterial appearances on radiographs of kidneys removed at autopsy and injected with a barium gel mixture. The study was limited to specimens derived from those subjects whose blood pressure during life was documented clearly to be below 90 mm Hg diastolic and whose clinical history and pathologic (including histologic) examination revealed no evidence of primary renal disease such as pyelonephritis, glomerulonephritis, any form of arteritis, hydronephrosis, or arterial embolization. In order to minimize leakage of the injected material over the surface of the kidney, the organ was removed from the body with the perinephric fat and capsule intact; a cannula was then inserted and secured into the renal artery or arteries. Barium gel5 was injected into the arterial tree through an injection apparatus which permitted control of the injection pressure by a hand pump and manometer. Pressure was maintained at a level approximately 20 mm Hg higher than the systolic pressure of the individual recorded during life. Hardening of the contrast medium gel occurred within twenty minutes after injection, at which time perirenal fat was dissected from the specimen and radiographs were obtained. Kodak mammographic film (SO-378) was used. Exposures were obtained at 65 kV and 300 mAs using a large focal spot.