Congenital Malformation of the Renal Artery, a Cause of Hypertension

Abstract

The causal relationship of renal pathology to arterial hypertension is not yet clearly defined. The classic experiments of Goldblatt (10) convincingly demonstrated that interference with the renal arterial blood flow through one or both kidneys in the experimental animal can result in sustained hypertension. Goldblatt (11, 12) presents formidable evidence to show that such experimental hypertension bears a striking similarity to essential hypertension in man and suggests that the mechanisms in the two may be identical. There is, however, a large body of opinion which is strongly opposed to this point of view. Indeed, Smith (24), Goldring (13), and Thompson and Smithwick (26) insist that, with the possible exception of pyelonephritic and pyonephrotic atrophy, urologic disease does not increase the incidence of hypertension, nor is renal disease more common in the hypertensive than in the normotensive population. Be that as it may, there is general agreement that there are at least certain forms of renal disease which definitely represent the exact human counterpart of the experimental renal hypertension of Goldblatt. Such cases are those in which, for one reason or another, there is a marked reduction, but not a complete suppression, of the arterial blood flow through one or both kidneys. While the actual mechanism is not definitely understood, it is generally assumed that a relatively ischemic kidney elaborates a pressor substance which acts as a humoral hypertensive agent. The occasional cases of unilateral renal disease in which removal of the diseased kidney alleviates or cures the hypertensive state, lend support to this theory. These cases comprise a very small but nevertheless an important segment of all cases of hypertension in man. The most obvious instances in this category are the lesions which reduce the renal blood flow directly by mechanical narrowing of the lumen of the main renal artery. Such mechanical narrowing may be caused by thrombosis, arteriosclerotic plaques, aneurysm, neoplasm, or congenital anomaly. Congenital malformation of the renal artery, producing hypertension by the Goldblatt mechanism, is undoubtedly a rare entity. Yet, it probably occurs more often than it is actually found or even suspected. Careful search of the literature reveals a remarkable paucity of reported examples, and none has appeared, as far as we could discover, in the roentgenologic literature. In 1954, Howard et al. (17), reporting on 6 hypertensive patients with unilateral renal disease, described a case (Case 3) of a thirty-nine-year-old man from whom a non-functioning left kidney was removed. Pathologic examination of the specimen disclosed that the main renal artery was absent and in its place several small arteries entered the hilus of the kidney.