James C. Hunt

Renovascular hypertension. Mechanisms, natural history and treatment.

Hypertension with atheromatous or fibromuscular renal artery stenosis was studied prospectively in 214 cases for 7 to 14 years. After 3 months or less of medical management proved unsuccessful, 100 patients, were submitted to surgical management. At latest follow-up examination, 84 of these survived and 51 were normotensive without medication. The survivors included 26 of 37 with artheromatous stenosis and 58 of 63 with fibromuscular stenosis. Medical management was continued in the other 114 patients (except for 16 transferred after 6 months to 5 years to surgical care but are not reported on here). Of these 114 patients, 44 had atheromatous disease, of whom 10 were surviving with medication at latest follow-up examination (7 others having been transferred to surgical management); and 70 had fibromuscular stenosis, of whom 49 survived with continuing medication (9 others having been transferred to surgery). At the latest follow-up study (December 1972), 55 of the 214 patients had died. Myocardial infarction, stroke and renal failure were the most common causes of death. Renal artery stenosis may be demonstrated by current angiographic techniques. Functional significance of proved lesions can be determined by renal vein renin activity, differential renal function study or demonstration of a systolic-diastolic or continuous abdominal bruit; and it can be suggested by intravenous urography and isotope renography. In carefully selected patients, definite amelioration or long-term relief of existing hypertension may be accomplished by appropriate surgical management; in the severe cases thus managed, the mortality rate appears to be decidedly reduced.

Renal venous renin activity: Enhancement of sensitivity of lateralization by sodium depletion☆

Abstract The predictive value of significant lateralization of renal venous renin activity (ratio of 1.5 or greater between the value from the affected or more severely affected kidney and the value from the contralateral kidney) with respect to the results of surgical treatment of renovascular hypertension was assessed in 60 patients followed up postoperatively for 6 to 30 months. Studies of renal venous renin activity in 26 patients with normal levels of sodium intake disclosed lateralization in 8 (all in improved condition after surgery) and non-lateralization in 18 (17 in improved and 1 in unimproved condition after surgery). Results were correctly predicted in 9 patients (35 percent). Studies in 41 patients with reduced sodium intake showed lateralization in 33 (all in improved condition) and nonlateralization in 8 (4 in improved and 4 in unimproved condition after surgery). Results were correctly predicted in 37 patients (90 percent). Seven patients were studied on both regimens. Sodium depletion increased the sensitivity of the renal venous renin activity measurement for determining a functionally significant presser kidney in renovascular hypertension.

Renal Function in Donors and Recipients of Renal Allotransplantation: Radioisotopic Measurements

Excerpt In patients with renal allografts, serial determinations of renal function are of prognostic significance. Trends in renal function may be considered as reflecting a balance between effecti...

Radioisotopic renography. Diagnosis of renal arterial disease in hypertensive patients.

Sodium ortho-iodohippurate (Hippuran) I131 renography has been performed by a standardized technic in patients with renal artery stenosis, pyelonephritis, primary aldosteronism, pheochromocytoma, and renal tubular acidosis with nephrocalcinosis, as well as in patients in whom the hypertension was apparently not secondary. Fifty of 94 patients studied were found to have abnormal renograms.In patients with renal artery stenosis, all of 37 patients studied had values on the renogram that were outside the range for normal subjects. Although the renographic findings were not considered diagnostic of renal artery stenosis, certain abnormalities of the renogram were commonly observed in the presence of such lesions. When a unilateral delay in the appearance of maximal radioactivity was associated with delayed disappearance ot the medium, renal artery stenosis was frequently observed. Less pronounced differences in the function of the two kidneys were observed in patients with bilateral renal artery stenosis. A state of antidiuresis was often found helpful in the detection of less severe differences in renal function.In patients with predominantly unilateral pyelonephritis, the renographic abnormalities were qualitatively consistent with the degree of impairment of renal function. Bilateral abnormalities were observed in two patients who had bilateral parenchymal disease. The abnormalities on the renogram did not permit distinction between renovascular and renal parenchynal disease. Pyelonephritis associated with obstructive uropathy revealed findings highly suggestive of renal artery stenosis. Distinction from renovascular lesions could be determined with the aid of urographic studies.Only three of 44 patients with essential hypertension had abnormal renograms. The renograms, normal and abnormal, revealed essentially equal function of the two kidneys. The patients with abnormal renograms were not found by other technics to have evidence of secondary hypertension.The patients who were found to have pheochromocytoma and primary aldosteronism had normal isotope renograms. The patient with renal tubular acidosis and nephrocalcinosis had a bilaterally abnormal renogram and severe impairment of total renal function.The presence of a normal isotope renogram, as performed in our laboratory, is considered strong evidence against the existence of a renal or renovascular cause for secondary hypertension.

Hypertension and renal artery stenosis: Serial observations on 54 patients treated medically

Medical treatment of hypertension was undertaken in 54 selected patients with arteriographically proved stenosis of the renal artery (32 with atheromatous and 22 with fibromuscular lesions). At follow‐up study (average, 20.3 months), 65 per cent of 49 surviving patients were normotensive on a regimen of common antihypertensive drugs in usual doses. There also was improvement in the hypertensive changes noted in the optic fundus. In 13 patients, additional cardiovascular episodes complicated the hypertensive disease and 5 of these patients had died. The frequent long duration of hypertension and frequent bilateral involvement of the renal arteries necessitate caution in recommending surgical treatment when: (1) the situation technically demands nephrectomy; (2) there are renovascular lesions in the absence of significant hypertension; (3) arteriographic and renal function data are discordant; and (4) there is associated severe symptomatic cardiovascular disease, old age, or other infirmities.

Serial renal function and angiographic observations in idiopathic fibrous and fibromuscular stenoses of the renal arteries.

Abstract Fifty-five hypertensive patients with angiographically demonstrable idiopathic fibrous and fibromuscular stenoses of the renal arteries were restudied an average of 34.3 months later, at which time 32 patients were normotensive with medical and surgical management. Nineteen showed progression: 12 of the 40 with multifocal type, 6 of the 13 with focal and tubular types, 1 of the 2 with bilateral dissecting aneurysms. In 2 additional patients renal ostial atherosclerosis developed. Ten patients had postoperative progression of ipsilateral fibromuscular stenoses. One patient had fibromuscular lesions of the celiac and hepatic arteries, and 2 patients had coincidental similar stenoses in the iliac arteries. Twenty-one patients had diminished renal function that in some was due to restenosis of a graft, progression of main renal arterial stenosis, or intrarenal arteriolosclerosis. The renal function of 2 patients improved. The high incidence of progression of fibrous and fibromuscular stenoses dictates careful patient selection for medical and surgical management and follow-up study.

Diagnosis and management of renovascular hypertension

Abstract The clinical history is seldom helpful in establishing a diagnosis of renovascular hypertension. Symptoms are not different from those accompanying hypertension due to other causes, except for the occasional pain associated with a renovascular accident. Generally, the age and sex of patients reveal a much higher incidence of fibromuscular lesions in young women and of atheromatous lesions in older men. In a surgically treated group of 100 patients with apparent renovascular hypertension, 37 gave a family history of significant hypertension. Long duration of the elevation of blood pressure is so common among patients with renovascular hypertension that we have not been able to use recency to distinguish the cause of hypertension. Physical findings may be distinctly helpful in establishing a diagnosis. If hypertension is of one years known duration, or longer, and parenchymal renal disease and adrenal causes have been excluded, the physician should strongly suspect renovascular hypertension when examination of the optic fundus reveals severe retinal arteriolar narrowing and focal constriction without significant chronic hypertensive sclerosis. A continuous bruit over the lateral upper region of the abdomen virtually confirms the presence of functionally significant severe renal artery stenosis. Systolic-diastolic bruits of high frequency (pitch), long duration and lateral location should also be considered as strongly suggestive of a renovascular lesion even if screening procedures such as urography or isotope renography reveal no significant differences of renal size or function. The combination of isotope renography and excretory urography can produce comparative estimates of mass and function of the separate kidneys. Neither procedure alone will permit a diagnosis of renal artery stenosis, and therefore the results of each should be considered as normal or abnormal rather than as positive or negative. Severe unilateral renal artery stenosis, or stenosis more severe on one side than the other, is commonly associated with a smaller renal size and renographic abnormality on that side; but these procedures may indicate that the kidneys are of equal size and have equal function even though the patient has surgically remediable hypertension. Despite improvement in screening procedures, renal artery stenosis can be diagnosed only by renal arteriography. The significance of these lesions should be confirmed by differential renal function studies or renal venous renin activity determination, or both, before surgical management is undertaken. The severity of stenosis is a deciding factor both in establishing the diagnosis and in determining the treatment. Hypertension caused by slight or moderate stenosis commonly responds favorably to medical management. We consider operation in such cases only if control of blood pressure by medical means proves unsatisfactory or if deterioration of renal function is demonstrated by clearances of inulin and paraaminohippurate. The location and type of stenosing lesions dictate the choice of operative technic. Atheromatous stenosis occurs far more commonly in the aorta and proximal portion of the renal artery than in the main artery, and rarely is located in the primary branches; hence endarterectomy, plastic repair, or bypass procedures usually are feasible. Fibromuscular dysplasia occurs almost exclusively in the distal three fourths of the main renal artery or its primary branches. Many of these distal lesions are not suited to surgical correction. However, when the morphologic and functional characteristics of the renovascular lesions are carefully analyzed preoperatively, and when technics and surgical therapy are appropriate to the problem at hand, atheromatous and fibromuscular stenosis can often be successfully repaired or bypassed. Nephrectomy (partial or total) may be necessary, however, for atheromatous lesions (because of severe ischemic atrophy with interstitial fibrosis or renal infarction) or fibromuscular lesions (because of involvement of the branch arteries or renal infarction). Our experience with the frequent necessity of nephrectomy when lesions of the branch arteries are demonstrated arteriographically in patients with fibromuscular dysplasia has often caused us to undertake medical antihypertensive therapy, at least on a trial basis, and reconsider operation subsequently if control of blood pressure is unsatisfactory or if renal function deteriorates.

Sodium Intake and Hypertension: A Cause for Concern

Cardiovascular disease is the leading cause of death worldwide. Hypertension--the leading cause of heart attack, stroke, and kidney failure--occurs in more than 20% of adults in most modern societies. Hypertensive patients have defective sodium metabolism. From childhood throughout adult life most acculturated peoples consume 10 to 20 g of salt daily and have more obesity. Populations with low blood pressure are more active, leaner, and consume a diet low in sodium and high in potassium; however, when members of these groups are exposed to western diets, blood pressure increases with age and hypertension occurs. Drug treatment to control blood pressure prevents deaths. Conservative management, including low-sodium, high-potassium diets, restores normal blood pressure in more than half of hypertensive patients. More information on the cause and mechanisms of this condition is needed, but our primary concern is for improved nutrition and drug treatment to prevent hypertension-related cardiovascular deaths.

Functional Characteristics of the Separate Kidneys in Hypertensive Man

1. 1. Functional studies of the separate kidneys were undertaken in 165 hypertensive patients who had previously undergone excretory urography. Of these, 150 had isotope renography and 147 had renal arteriography. Complications consisted of acute or recurrent pyelonephritis in 4 patients; all responded promptly to appropriate chemotherapy. 2. 2. In 17 hypertensive patients with dominantly unilateral atrophie pyelonephritis, mean values revealed markedly diminished urine volume (54%), clearances of inulin and paraaminohippuric acid (PAH) (65 and 62%), and reabsorption of filtered sodium (1.5%) and water (1.6%) for the diseased kidney. Concentrations of sodium, PAH, and inulin and osmolality of the urine from the diseased side were usually slightly to moderately diminished. In two patients data on urine volume and sodium concentration met criteria for a positive Howard test. 3. 3. Patients with apparent essential hypertension had only minor differences between the kidneys in all parameters studied. The range of differences in those with essential hypertension and aberrant arteries was somewhat greater; however, mean differences were minimal except for greater clearances of inulin and PAH which correlated well with greater renal mass. 4. 4. Of 102 patients with stenosing lesions of the renal arteries, 53 had unilateral and 49 had bilateral obstruction. In patients with unilateral severe renal artery stenosis urine volume and sodium concentration were diminished along with usually diminished clearances of inulin and PAH on the involved side (mean values − 79, − 53, − 47 and − 47%, respectively). Urine osmolality was usually increased as were concentrations of inulin and PAH, the latter two usually by more than 100 per cent. The percentage reabsorption of filtered sodium and water was markedly increased on the involved side (mean values 3.1 and 2.6%, respectively). Patients with unilateral severe renal artery stenosis and aberrant renal arteries differed only in that the mean value for sodium concentration in the urine was only slightly diminished on the involved side (6%). Patients with unilateral renal artery stenosis and partial renal infarction usually could not hyperconcentrate urine on the involved side. Urine volume, sodium concentrations, and osmolality were diminished; however, inulin and PAH concentrations were slightly but consistently increased. When stenosis was severe on one side and mild on the other, functional characteristics were similar to those observed with unilateral stenosis, except for more variable sodium concentrations and osmolality. When stenosis was bilateral and equally severe, significant differences in functional characteristics were seldom observed. Patients with mild or moderate stenosis (less than 50% narrowing of the renal artery) seldom had more than slight differences in functional characteristics. 5. 5. With arteriographically demonstrated renal artery stenosis, (a) increased reabsorption of filtered sodium and water by 1 per cent or more on the involved side, a positive Howard test, and increased osmolality characterized functionally significant lesions and were not seen in essential hypertension; (b) differences in inulin and PAH concentrations largely reflected differences in water reabsorption; and (c) when sodium concentrations were greater on the involved side (negative Howard test), a high incidence of either a branch artery lesion, multiple arteries to the involved kidney, bilateral main artery stenosis, or partial renal infarction was observed.

Management of hypertension of renal origin

Abstract Studies as clinically warranted were accomplished in more than 2,000 patients seen from January 1964 through December 1968 because of hypertension and suspected or proved renal disease. Data from the clinical history, physical examination, laboratory investigation and results of surgical or medical treatment are reported for 100 cases each of 5 entities—glomerulonephritis, pyelonephritis, renal cyst, renal tumor and apparent primary hypertension with renal disease. Comparison is made with data included from 100 cases of renal artery stenosis and hypertension. Female patients numbered 286, and predominated in the groups with renal artery stenosis and with pyelonephritis. Ages ranged from 6 to 81 years. Hypertension was less severe in the groups with renal tumor or cyst. Hypertensive changes of the retinal arterioles were more severe in the group with renal artery stenosis and in the group with primary hypertension, and renal function was more severely impaired with glomerulonephritis and primary hypertension. Surgical treatment was given 234 patients, 71 of whom later had normal blood pressures without medical treatment. For 366 patients medical treatment was primary; 125 of these usually maintained diastolic blood pressure of less than 90 mm Hg. Sodium restriction proved a valuable part of conservative management in most cases. Dialysis or transplantation, or both, were required for 49 patients. In the 600 cases, 507 patients are alive 2 to 13 years after initial examination, and 93 have died.