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Surgical Treatment of Renal Hypertension: Results in Patients with Occlusive Lesions of Renal Arteries
TnE JouR:"L.\.L OF UROLOGY
Vol. 82. No. 4. October 1959 Printed in L'.8.A._,
Sl~RGIGAL TREAT\fENT OF RENAL HYPERTK\SIO:;\/: RESrLTS I;-J PATm:~T;.; WITH OCCLFSIVE LESIONS OF REKAL ARTERIES EUGEXE F. POliTASSE From the Departrnent of
The Claelancl Clinic fiounclation, and The Pmnlc F:. B11nts Rduw/ionol lnstil11te, Clue/and, Ohio
The most common cause of remediable renal hypertension is occlusiyr disease of the: renal artery or its major branches. Two other types of renal lrsions can he associated with hypertension: parenchyrnal diseases, sud1 as pyelonephritis or glomerulonephritis, ancl perincphritic lesions, such as traumatic hematomas, but these are not cliscuss('d in this J'(']JOrt. The use of translumbar aortography to demonstrate the arterial supply of tlw kidneys in hypertensive patients has !eel to the cliniGal recognition of tliese previously unsuspected arterial causes of renal hypertension. Prior to 1950 no h:-pcrtensivc: patit:nt at the Cleveland Clinic was suspected of having a renal arterial lesion. From 1950 through 1954, aortography was used by the urology service chiefly to clemonstrate the blood supply in various uropathies, and was utilized only occasionally in a hypertensive patient. During this period six hypertensive patients were found to have focal occhrnive disease of the renal arteries. Since January 1956, aortography has been used extensively in hypertensive patients, and through March 337 hypertensive patients were examined by this nrnthod of renal angiography. Eighty-seven were found to have occlusive disease of onr or both renal arteries, bringing the total number of cases discovered by this technique to 93. The occlusive lesion was considered to be the primary cause of hypertension in the majority of these patients, hut in ~omc the lesion was thought to be a complication of existing c:sscntial hypertension. The arterial lesions were found to be unilateral in 71 patients, ancl bilateral in 22. During this same period only 6 patients were found to have pheochromocytoma, indicating the relative freqnem:y of these two potentially curable forms of hypertension. INDICATJONS FOR RE'.'sAL ANGlOGRAPHY
Renal angiography has not been performed routinely on all hypertensive paticmts examined Head at annual meeting of American Urological Association, Inc., Atlantic City, N. J., April 20-23, Hl59.
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here. Experience ,':ioon enabled us to the basis of age, liistory, sigrrn, and eviclcncc, of abnormalities on intravcnot1s urograms, those groups of that should have rc:nal angiography the indications for renal angiography iu hn1cr. tensive patients arc: J) Disparity in length or cxcrctor:v function of the kidneys, as revealed intravenous urography. A difference of I cm. or mom in the of the kidneys of a h) pertcnsi1T. patient nrny represent atrophy of the; smalll'l' kid111cy due to vascular insufficiency; a lag in the appcar:mce of th(' radiographic medium in one , l'SJW· cially on the first film of tlw urogrnphic scnes, may indicate a difference in cxeretory again possibly due to vascular 2) Hypertension in a patient less th:m ,35 yc,a1·., of age in whom no othc;r cause fur hypertension can be found. Essential hypertension is a disem;e of the middle decades of life with a strong familial background. It should be cmplrnsizcd that tlie younger the patient, the greater the likelihood that the cause of hypertension is ascertainable. 3) Malignant hypertensive syndrome tlutt develops in a patient more than 55 yearn of agr. Again, this is not tlrn age group in which 1:bs<:Htial hypertension is expected, but is the age, when artcriosclerotic complications, among them renal hypertension, develop. 4) :N'onfamilial hypertension of ree0nt onsrt in any patient, regardless of agC', with pro. gression into the malignant 5) Hypertension that develops or worsens after an episode of Hank or abdominal pain. Infarction of part of a may have r,cc:urrecl from thrombosis of the renal artery or of :.1 branch. The method of renal angiography utilized described elsewhere!. 2 ancl will not be discussed 0
1 Poutassc, E. F., Engel, W ..). and Root, J. C Translumbar aortography. Clevelrwcl Clin. Quart., 19: 105, HJ52. 2 Pouta.sse, E. F.: Blood pressure reduction as a.n aid to renal angiography in hypertensive patients. Cleveland Clin. Quart., 22: 83, 1()55. 0
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EUGENE F. POUTASSE
in this paper. No serious eomplications from renal angiography developed in any of the hypertensive patients, or in any of the more than 200 other patients who had renal angiography prior to 1955. Measurement of function of the individual kidneys was performed on all patients who were shown to have arterial lesions by renal angiography. The findings arc reported elscwhcrc. 3 • 4 Such measurements arc of value in that they can indicate disparities of renal function between the two sides which deserve further definition with renal angiography. PATHOLOGY
The majority of the renal arterial occlusive lesions were arteriosderotie plaques, with or ,yithout superimposed thrombosis, but in about one-fifth of the patients from whom surgical specimens were obtained the stenosis was due to fibromustular subintimal proliferation. 5 Thrombosis of the renal artery without other pathologic findings in the artery was pr<'scmt in 5 patients. Small dissecting aneurysms of the renal artery or one of its major branches were found in 3 patients. These arterial lesions caused variable effects on the renal parenchyma ranging from no abnormality in a few patients to tubular atrophy, minimal to severe, focal to diffuse, in others. Compkte occlusion of a branch of the renal artery resulted in ischemic atrophy of the corresponding vascular segment of the kidney. SURGICAL TREATMJ•;NT
Surgical treatment of renal arterial lesions associated with hypertension should: 1) relieve hypertension and hypertensive vascular disease promptly and permanently, and 2) whenever possible restore normal renal function to the affected kidney. Both purposes can be achieved only after accurate definition of the arterial lesion by adequate angiography. Sixty-six of the 93 hypertensive patients with demonstrable lesions of the renal artery were selected for surgical 3 Poutasse, E. F., Donnelly, A. and Dustan, H. P.: Separated kidney function tests in hypertensive patients. Surg. Forum, 9: 826, 1958. 4 Dustan, H. P., Poutasse, E. F., Corcoran, A. C. and Page, I. H.: Significance of renal function tests in renal hypertension. Circulation, 18: 714, 1958. 5 McCormack, L. J., Hazard, J.B. and Poutasse, E. F.: Obstructive lesions of the renal artery associated with remediable hypertension. Am. J. Path., 34: 582, 1958.
treatment. Severe retinopathy was common among these patients; retinal hemorrhages and cxudates, with or without papilledema, were observed in 34. Of the 27 patients who did not undergo surgery, some died soon after the diagnosis was established, some are awaiting surgery, and some had asymptomatic hypertension and are receiving medical treatment. Thirty-nine patients had nephrectomy, and 30 had some other type of surgical procedure designed to preserve the affected kidney. More than one operation was necessary in several patients. The type of operation depended upon the nature and location of the occlusion, whether the disease was unilateral or bilateral, the degree of renal atrophy in the involved kidney, and the severity of the patient's hypertensive cardiovascular disease. Nephrectomy. Removal of the kidney with impaired arterial blood supply was perform.eel in 39 of the 66 hypertensive patients selected for surgical treatment. In general, the reasons for choosing nephrectomy were: 1) the patient was too sick with hypertensive cardiovascular disease to justify a longer or more difficult operation than nephrectomy, 2) repair of the renal artery lesion was technically unfeasible, or 3) the involved kidney showed significant atrophy from radiographic and excretory function studies, whereas the opposite kidney had good blood supply and normal function. Many of the patients in this particular group had advanced hypertensive cardiovascular disease and generalized arteriosclerosis and, as would be expected, most of the complications and deaths were attributable to these causes. Five patients died in the immediately postoperative period: two had ccrebrovascular accidents, one died of congestive heart failure, one died of myocardial infarction, and the fifth of anuria from thrombosis of the renal artery to the opposite kidney. Four died 8 months or longer after nephrectomy: two of myocardial infarction (both had remission of their hypertension, however), one of cerebrovascular accident, and the fourth of progressive hypertensive cardiovascular disease. Of the 30 living patients, 2.5 have had complete remission of their hypertension. Two had reversal of the malignant phase of hypertension and reduced blood pressure. Three patients had no change in blood pressure; two, in retrospect,
f'TIRGICAL TUEAT.MEN'T OF' HBS,\L HYPEilTEXSIO\T
developed the arteriosc:krotic plaques in one renal artery after ha,-ing had hypertension for a long period of time. 1t is not always easy to ascC'rtain the duration of a patient's hypertension or to evaluate the significance of a radio .. graphically demonstrable arterial lesion. nephrectomy. Occlusion of an accessory artery (fig. 1, A) causes atrophy of only the corresponding segment of the kidney. A. similar segmental atrophy rnrnlts from occlusion of a polar branch of the renal artery. Such lesions produce an abrupt and scn·n, form of hypertenwhieh can be cured by segmental removal of the isdwmic zone of the kidney. Two patients have been treated in this manner; one has had eomplrtc remission of hypertension for more than a ye,1r. This case report and tlrn case reports of other patients treated segmental nephrectomy will be reported in detail later. Occlusive lesions of the middle branches of the renal artrry (fig. l, B) cause atrophy or infarction of the corresponding segment of the kidney. This atroph)- is distinguislml by the fact that it extends only halfway through the depth of the kidney, because the blood supply to the opposite side of the kidney is intact. This type of segmental atrophy was found in 2 patients; the occlusive arterial lesion in the middle branch was on each occasion associated with a dissecting anPurysm. In both patients, only the block of lltrophiu renal tissue was removed by a sagittal segmental nephrectomy. One patient has had complete remission of hypertension since the operation. The other patient has had no change in blood pressure; he had a long history of hyper· tension a.nd it is beliewd that the arterial lesion 11-as a recent arteriosclerotic complication of a t~'pe that could cause later serious aggravation of his hypertension. Occlusion of one of a pair of renal arteries produces ischemic atrophy of half of the kidney, either Ragittally (fig. 1, CJ or transversely (fig. 1, , depending upon the pattern of distribution of the two renal arteries. One patient has comremission of malignant hypertension after sagittal hcrnincphrectom,v for a lesion of the type shmvn in figure 1, C. The other type of lesion, shown in figure 1, D, i~ removed readily by a transverse hcminephrectomy, as was done in one patient. However, if atrophy is not present, arterial circulation can be re-established in the partiall:v occluded arkrr using the splenic
40::i
Fro. L Diagrams adapted from ang;iograms of hypertensive patients. A, occlusion of accessor\ or polar branch of renal rtrter:v causes seg;nwntai atrophy of pole of kidney. B, occlusion of midcll(' branch causes atrophy of anterior or posteri()[' middle segment. C, occlusion of one of a of parallel renal arteries causes sagitt al D occlusion of one of two crossed renal causes transverse atrophy of half of kidne.1·. artery; this procedure was performed in one, pa tient, whose kidney has sinc;e hypertrophied and increased in excretory function (fig. 2 anrl table 1, C). Enrlartcrectomy. Removal of an eccentric arteriosclcrotic; plaque (fig. 3, opening tlw artery ancl prying loose the occluding plaque, was done on 2 patients. One later underwent trarn,for verse segmental nephrectomy (fig. J, ischcmic atrophy of the upper half of the opposite kidney; no remission of hypertension occurred, but renal function of both been preserved. The second patient wa,; on too recently for any statc1rn,nt to hn made about the cffed on his hypertension or renal function. Plaques at the orifice of the renal artery arr, eommon (fig. 3, B), and arc seen in patients with ach·ancccl atherosclerotic aorti(, disease. Endarterectomy for these lesions has been reportcd, 6 • 7 but the results of this pro., cedure have not been uniformly sur,r:c'ssful. There 6 Freeman, N. E., Leeds, 1<'. H., Elliott, W. and Roland, S. L: Thromboendartercctomy foi hypertension due to renal artery or:clusioll J.A.M.A., 156: 1077, 1954. 7 DeCamp, P. T. and Birchall, R.: Recop;uition and treatment of renal arterial stenosis associated with hypertension. Surgery, 43: l:H, 1\J58.
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EUGEi'iE F. POUTASSE
Fm. 2. Preoperative and postoperative intravenous urograms in a 30-year-old man with malignant hypertension. Angiogram B shows occlusion of first part of two of three right renal arteries. On left side there is occlusion of one of two renal arteries, similar to that shown in fig. 1, D. Splenic artery was anastomosed to this vessel. Postoperative urogram and function tests (table 1, C) show hypertrophy of this kidney. Right kidney will be removed soon. may be several reasons for this, such as uncertain status of the kidney in regard to areas of infarction, which should be removed simultaneously, and the dispersion of cholesterol emboli into the kidney at the time of the endarterectomy. I have performed what amounts to a dilatation of the aortic orifice of the renal artery in 3 patients by opening the renal artery and passing size 16 or 18F sounds through the occluded area with no real improvement in hypertension. Unfortunately, none have had followup angiographic studies to determine the postoperative
patency of the renal artery. I am convinced that it is better to perform arterial replacement by homografts or splenorcnal arterial anastomoses, if it is important to preserve the affected kidney, than to attempt endarterectomy. Excision of occluclecl segment of renal artery. Discrete occlusive lesions of the middle or distal part of the renal artery (fig. 3, C, D) can be excised and the artery repaired by end-to-end anastomosis. The kidney must be morphologically normal and show no areas of atrophy, although its excretory function may be significantly
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SURGICAL TREATMENT OF RENAL HYPERTENSION
1. Changes in renal function and blood pressure after surgical treatment of occlusive disease of renal arteries
TABLE
A. Left splenorenal arterial anastomosis for occlusion of first part of left renal artery Preop.
Rt.
altered, and the artery must be long enough to allow the ends to be joined without tension. It is possible to insert a short· homograft, but I have not found it necessary to do so thus far. This, incidentally, would increase considerably the time the kidney was deprived of arterial blood because there would be two suture lines to complete. All 6 patients who have undergone this operation now have normal blood pressure. Several in whom preoperative divided renal function studies showed depressed function of the involved kidney have had restoration of excretory function as shown by identical studies postoperatively (table 1). One of the 6 patients had simultaneous repair of the right renal artery for two occluding plaques, and removal of the opposite kidney, a contracted, duplex functionless organ. Excision and repair of the renal artery were attempted in two other patients, but technical difficulties ensued, necessitating removal of the kidney. Medial dissection and degeneration of the entire length of the renal artery were found in one patient, and immediate, recurring thrombosis on the suture line developed in the other patient. Renal arterial homografts. Arterial homografts are useful for correcting occlusion of the orifice or the first part of one or both renal arteries. This particular work was done with Dr. A. W. Humphries,* who developed and performed the operations wherein aortic or iliac artery homo* Department of Vascular Surgery.
71
Uo.,m- .... .... UN a. .... . . . . . BP ..
Left
41 5.04 2.11 413 443 64 12 210/110
GFR ...... ... V. . . . . .......
Fm. 3. A, eccentric atherosclerotic plaque suitable for endarterectomy. B, large plaque at orifice. C, symmetrical occlusion, which often occurs with fibromuscular hyperplasia. D, atherosclerotic plaque and poststenotic aneurysm. C and D, suitable for excision and repair of artery. B, arterial homografting or splenorenal arterial anastomosis required.
I
10 mo. postop.
. ....
Rt.
I
Left
44 44 2.87 3.39 424 465 32 99 145/95
B. Excision of stenotic segment of right renal artery I
I
Preop. Rt.
I
4 mo. postop.
Left
GFR. . . . .... 43 92 V . .. . . . . .... 1.52 7.62 Uo,m, . .. .. 624 421 87.9 9.6 UNa- ..... . . . BP .. . . . . . . . . . 186/112
Rt.
I
Left
56 50 4.05 3.34 511 513 66.8 I 41.5 137/81
C. Left splenorenal arterial anastomosis for bilateral renal artery disease Preop.
I
I
Rt.
I
9 mo. postop. Left
42 GFR ... ..... 31 2.34 V .. 3.19 450 Uo,m- ... ..... 441 24.6 22.8 UNa- .. ...... 220/124 BP .. . . . . . .
Rt.
I
Left
22 64 2.10 7.25 434 391 68.3 75.8 160/100
D. Excision of stenotic segment of right renal artery for bilateral renal artery disease Preop.
Rt.
GFR .... . ....
v .... . ... Uo,m- .. .... UNa- ... BP ..
I
22 mo. postop. Left
31 87 1.26 7.47 562 383 29 71.4 220/125
Rt.
I
Left
44 50 5.05 3.99 405 459 85.5 56.3 125/78
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EUGENE F. POUTASSE
Frn. 4. A, arterial homograft for occlusion of first part of ~enal artery, ~sing iliac artery. B, reversed aortic homograft for occlusion of first part of both renal arteries. grafts were used for restoration of renal circulation. The method of using iliac artery for homografts is shown in figure 4, A. A wide aortic opening must be made to insure adequate blood flow into the homograft. This operation has been done on 3 patients. The first case of correction of bilateral occlusion by this method has been reported ;8 femoral arterial homografts were used in a 2-stage operation to restore normal circulation to both kidneys. The second patient had occlusion of the orifice of the right renal artery; he died after hemorrhage from the aortic suture line on the tenth postoperative day. The third patient is of unusual interest because over a year ago he was found to have a minimal occlusive lesion of the right renal artery and complete occlusion of the left renal artery with a nonfunctioning kidney. Left nephrectomy was performed then and his hypertension remitted. Ten months later the hypertension recurred and at that time angiograms showed incomplete occlusion of the right renal artery, leaving only a thin, irregular lumen. A homograft of iliac artery was inserted and at present, 5 months postoperatively, he is doing well in all respects. The method of using aortic homografts to replace the first part of both renal arteries is shown in figure 4, B. 9 Experience has shown that the 8 Poutasse, E. F., Humphries, A. W., McCormack, L. J. and Corcoran, A. C.: Bilateral stenosis of re~al arteries and hypertension; treatment by arterial homografts. J.A.M.A., 161: 419, 1956. 9 Humphries, A. W. and Poutasse, E. F.: A
homograft should be reversed to provide a favorable take-off angle of the renal arteries. This operation has been done on 4 patients, one of ,vhom has had good health and a significant decrease in his hypertension for almost 2 years. One patient died 4 months postoperatively of progressive hypertensive vascular disease. Extensive areas of ischemic atrophy were present in his kidneys at the time of the operation. The third patient, who also had a lumbar aortic aneurysm and coronary artery disease, died of a myocardial infarction a few days after removal of the aneurysm and repair of the aorta and renal arteries. In the fourth patient the homograft thrombosed, and nephrectomy was necessary. Splenorenal arterial anastomosis. The splenic artery is readily adaptable to restore normal circulation to the left kidney. 10 , 11 It has a large caliber, is exceptionally mobile, and the proximal portion is seldom involved by atherosclerosis. It is not necessary to remove the spleen because it still receives sufficient arterial blood through the short gastric arteries (fig. 5). Of 6 patients who had this operation, the last three still have their spleens. End-to-side anastomosis of the splenic to the renal artery was clone in 2 patients (fig. 5, A). It is not necessary in this instance to divide the renal artery. End-to-end splenorenal arterial anastomosis was clone in 4 patients (fig. 5, B). The results of this operation have been remarkable. A 62-year-olcl woman who was treated 2 years ago for malignant hypertension and congestive heart failure was found to have bilateral renal arterial disease (fig. 6) with complete occlusion of the right renal artery and advanced atrophy of the kidney. The left renal artery was also completely occluded, but the kidney and reasonable excretory function were preserved by a rich collateral circulation. Two years ago left splenorenal arterial anastomosis and retechnique of arterial grafting for renal artery stenosis causing hypertension. Surg., Gynec. & Obst., 105: 764, 1957. 10 DeCamp, P. T., Snyder, C. H. and Bost, R. B.: Severe hypertension due to congenital stenosis of artery to solitary kidney; correction by splenorenal arterial anastomosis. A.M.A. Arch. Surg., 75: 1023, 1957. 11 Parton, C. W. and Nabseth, D. C.: Splenorenal arterial anastomosis in the treatment of stenosis of the renal artery: report of a case. New England J. Med., 259: 384, 1958.
SURGICAL TREATMENT OF RENAL HYPERTENSION
409
FIG. 5. A, end-to-side anastomosis of splenic artery to renal artery. Spleen receives arterial blood through short gastric arteries. B, end-to-end anastomosis, which in my experience has been more satisfactory.
FIG. 6. A, intravenous urogram in 62-year-old woman with malignant hypertension. Right kidney has atrophied. B, angiogram shows aortic disease, and complete occlusion of both renal arteries, with poststenotic filling of left renal artery via collaterals. Splenorenal arterial anastomosis and right nephrectomy were done in July 1957; the patient has had good health since then, with blood pressure 160/90 mm. Hg, and complete remission of the malignant syndrome.
moval of the right kidney were performed simultaneously. She has had complete remission of malignant hypertensive syndrome since that time. Another woman who had an occlusion of the first part of the left renal artery has had restoration of both normal blood pressure and normal renal function in the kidney for almost as long (table 1, A). A 10-year-old boy with severe hypertension recently underwent left splenorenal .arterial anastomosis which has resulted thus far
in a drop in blood pressure to practically normal levels. The other 3 patients have bilateral renal artery disease and severe hypertension. In each, the splenic artery was used to restore normal arterial pressure and flow into the left kidney. At a later date the right kidney can either be removed or receive an arterial homograft, depending on the status of the kidney and the patient's condition. One of these patients, already
410
EUGENE F. POUTASSE
briefly described in the section on segmental nephrectomy, has shown a considerable gain in function of the left kidney and is now ready to have the right kidney removed. The other 2 patients have just undergone the splenorenal arterial anastomosis and are awaiting re-evaluation. COMMENT
Renal angiography has revealed a surprisingly high incidence of occlusive disease of the renal arteries in selected hypertensive patients. As a cause of potentially remediable hypertension it now surpasses other known causes of secondary hypertension at the Cleveland Clinic. The term unilateral renal disease should be abandoned; a definitive diagnosis can and should be made in all hypertensive patients with renal disease, using appropriate roentgenographic techniques. As yet the diagnosis of occlusive disease of the renal arteries can be made only by the radiographic visualization of the renal circulation. The presence of an occlusive lesion can be suspected from the patient's history, urographic nonvisualization or smaller size of a kidney, or by the demonstration of a disparity in excretory function by separated renal function tests; but an accurate morphologic diagnosis requires angiography. It is essential to demonstrate the arterial circulation of both kidneys, because the lesions were found to be bilateral in one out of four patients. In my experience with the various techniques of renal angiography, translumbar aortography has been entirely satisfactory, practical, and economical of time. No serious complications have occurred from its use in more than 500 patients. The type and location of lesions in the renal artery, and their effect on the kidney itself, often challenge the surgeon. Although there are situations in which nephrectomy is the procedure of choice, or the only possibility, every effort should be made to discover those patients who, by reconstruction of the arterial circulation or removal of an ischemic renal segment, can be relieved of hypertension with preservation of renal tissue and function. It should be kept in mind that usually the underlying disease is some form of atherosclerosis, and that if it is not present already in the opposite kidney, it may develop later and become a clinical problem. Operations on the proximal or middle portion
of the right renal artery should be performed through a long mid-line or an anterior subcostal incision because it is essential, for reasons of safety, to have adequate exposure of the vena cava, renal veins, and aorta. The right renal artery lies behind the vena cava and renal veins, and accurate arterial surgery in this inaccessible area is difficult. The left renal artery is readily exposed through an anterior subcostal transperitoneal approach. In my experience, the human kidney usually will survive deprivation of arterial circulation for periods of as long as 30 minutes, depending on how normal the kidney is at the time of operation. Transient hyposthenuria and a reduction in function may occur. Most of the operations on the renal artery described in this paper were completed in less than 20 minutes. Some kidneys with occlusive lesions of the main renal artery have a richly developed collateral circulation which is adequate to sustain excretory function (fig. 6), but evidently the arterial pressure relationships in the kidney are insufficient to prevent renal hypertension. It is surprising to see how much reverse bleeding will occur from the distal end of the divided renal artery in some patients. Restoration of arterial pressure in these kidneys causes reduction in systemic blood pressure. Measurement of the arterial pressure distal to the occlusion in the renal artery and simultaneous comparison with the intra-aortic pressure are an integral part of the investigative work in renal hypertension at the Cleveland Clinic. There should be a measurable difference, but a statement cannot be made yet as to the minimum pressure differential necessary for the inception of renal hypertension. The method of arterial suturing depends largely on the preference of the surgeon. Both continuous and interrupted techniques were used in this series of patients. Because of the uncertainty of the eventual outcome of arterial homografts, there should be some caution about their use in young patients. The splenic artery has proved useful in restoring normal circulation to the left kidney, and it is possible that further experience will show that it is adaptable for use on the right side. Of the hypertensive patients with occlusive disease of the renal arteries who have had surgical treatment and are living, about 80 per cent
SURGICAL TREATMENT OF RENAL HYPERTENSION
now have normal blood pressure, or have residual systolic hypertension with a normal diastolic pressure. The latter situation is compatible with widespread atherosclerosis and inelasticity of the large arteries. A few patients probably developed lesions in their renal arteries as a complication of long-standing hypertension; removal of the renal factor will not cause remission of all of the hypertension. Restoration of excretory function of a kidney with a previously occluded main artery has been documented in a number of patients by comparing accurate separated renal function tests before and after arterial surgery. Some of these results are shown in table 1. For brevity, four determinations were selected: glomerular filtration rate (GFR), volume of urine in ml./min. (V), urinary osmolarity (U osm), and urinary sodium concentration (U Na). There was depression of GFR, V, and UNa in the kidney with occlusion of the main renal artery (table 1, A, B). At the time of the postoperative study there was a trend toward equalization of the GFR of the two kidneys. The urinary volume was slightly greater, the osmolarity of the urine about the same or higher, and the UNa considerably greater from the operated side. By way of contrast, the kidney with segmental atrophy from occlusion of an accessory artery or branch of the renal artery shows reduction in GFR and V, but the urine has an electrolytic composition identical to that from the opposite kidney. Removal of the area of segmental atrophy does not produce any further reduction in renal function. In patients with bilateral disease of the renal arteries considerable variation occurs in the excretory functioning of the two kidneys, depending on the relative degree of arterial occlusion and atrophy. This finding is illustrated in table 1, C, D; one patient showed little difference preoperatively in GFR, V, and UNa, compared with the other patient. The patient who had the
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left splenorenal arterial anastomosis (table 1, C) showed significant improvement in the function of that kidney (fig. 2). Meanwhile the right kidney has decreased in function as atrophy progresses. The other patient who had excision of a stenotic segment of the right renal artery (table 1, D) showed considerable improvement in the function of this kidney. The lesion in the opposite renal artery evidently has not interfered sufficiently with arterial blood flow to cause hypertension, at least within 22 months after surgery. SUMMARY
The most common cause of remediable renal hypertension is occlusive disease of the renal artery or of its major branches. From January 1955, through March 1959, 337 hypertensive patients were examined by renal angiography; 87 were found to have occlusive disease of one or both renal arteries, bringing the total number of cases at the Cleveland Clinic discovered by this technique to 93. The arterial lesions were unilateral in 71 patients and bilateral in 22. Sixty-six of the 93 hypertensive patients were selected for surgical treatment. Nephrectomy was done in 39 patients, and 30 had surgical procedures designed to preserve the affected kidney. Several patients required more than one operation. Segmental nephrectomy was performed in six, endarterectomy or dilatation of the occluded orifice of the renal artery in five, excision of the occluded arterial segment in six, renal arterial homograft in seven, and splenorenal arterial anastomosis in six. Of the patients who had surgical treatment and are living, about 80 per cent now have normal blood pressure, or have residual systolic hypertension with a normal diastolic pressure. The excretory function of a kidney with a previously occluded main artery was restored in a number of hypertensive patients by repair of the artery or splenorenal arterial anastomosis.
Vol. 82. No. 4. October 1959 Printed in L'.8.A._,
Sl~RGIGAL TREAT\fENT OF RENAL HYPERTK\SIO:;\/: RESrLTS I;-J PATm:~T;.; WITH OCCLFSIVE LESIONS OF REKAL ARTERIES EUGEXE F. POliTASSE From the Departrnent of
The Claelancl Clinic fiounclation, and The Pmnlc F:. B11nts Rduw/ionol lnstil11te, Clue/and, Ohio
The most common cause of remediable renal hypertension is occlusiyr disease of the: renal artery or its major branches. Two other types of renal lrsions can he associated with hypertension: parenchyrnal diseases, sud1 as pyelonephritis or glomerulonephritis, ancl perincphritic lesions, such as traumatic hematomas, but these are not cliscuss('d in this J'(']JOrt. The use of translumbar aortography to demonstrate the arterial supply of tlw kidneys in hypertensive patients has !eel to the cliniGal recognition of tliese previously unsuspected arterial causes of renal hypertension. Prior to 1950 no h:-pcrtensivc: patit:nt at the Cleveland Clinic was suspected of having a renal arterial lesion. From 1950 through 1954, aortography was used by the urology service chiefly to clemonstrate the blood supply in various uropathies, and was utilized only occasionally in a hypertensive patient. During this period six hypertensive patients were found to have focal occhrnive disease of the renal arteries. Since January 1956, aortography has been used extensively in hypertensive patients, and through March 337 hypertensive patients were examined by this nrnthod of renal angiography. Eighty-seven were found to have occlusive disease of onr or both renal arteries, bringing the total number of cases discovered by this technique to 93. The occlusive lesion was considered to be the primary cause of hypertension in the majority of these patients, hut in ~omc the lesion was thought to be a complication of existing c:sscntial hypertension. The arterial lesions were found to be unilateral in 71 patients, ancl bilateral in 22. During this same period only 6 patients were found to have pheochromocytoma, indicating the relative freqnem:y of these two potentially curable forms of hypertension. INDICATJONS FOR RE'.'sAL ANGlOGRAPHY
Renal angiography has not been performed routinely on all hypertensive paticmts examined Head at annual meeting of American Urological Association, Inc., Atlantic City, N. J., April 20-23, Hl59.
403
here. Experience ,':ioon enabled us to the basis of age, liistory, sigrrn, and eviclcncc, of abnormalities on intravcnot1s urograms, those groups of that should have rc:nal angiography the indications for renal angiography iu hn1cr. tensive patients arc: J) Disparity in length or cxcrctor:v function of the kidneys, as revealed intravenous urography. A difference of I cm. or mom in the of the kidneys of a h) pertcnsi1T. patient nrny represent atrophy of the; smalll'l' kid111cy due to vascular insufficiency; a lag in the appcar:mce of th(' radiographic medium in one , l'SJW· cially on the first film of tlw urogrnphic scnes, may indicate a difference in cxeretory again possibly due to vascular 2) Hypertension in a patient less th:m ,35 yc,a1·., of age in whom no othc;r cause fur hypertension can be found. Essential hypertension is a disem;e of the middle decades of life with a strong familial background. It should be cmplrnsizcd that tlie younger the patient, the greater the likelihood that the cause of hypertension is ascertainable. 3) Malignant hypertensive syndrome tlutt develops in a patient more than 55 yearn of agr. Again, this is not tlrn age group in which 1:bs<:Htial hypertension is expected, but is the age, when artcriosclerotic complications, among them renal hypertension, develop. 4) :N'onfamilial hypertension of ree0nt onsrt in any patient, regardless of agC', with pro. gression into the malignant 5) Hypertension that develops or worsens after an episode of Hank or abdominal pain. Infarction of part of a may have r,cc:urrecl from thrombosis of the renal artery or of :.1 branch. The method of renal angiography utilized described elsewhere!. 2 ancl will not be discussed 0
1 Poutassc, E. F., Engel, W ..). and Root, J. C Translumbar aortography. Clevelrwcl Clin. Quart., 19: 105, HJ52. 2 Pouta.sse, E. F.: Blood pressure reduction as a.n aid to renal angiography in hypertensive patients. Cleveland Clin. Quart., 22: 83, 1()55. 0
404
EUGENE F. POUTASSE
in this paper. No serious eomplications from renal angiography developed in any of the hypertensive patients, or in any of the more than 200 other patients who had renal angiography prior to 1955. Measurement of function of the individual kidneys was performed on all patients who were shown to have arterial lesions by renal angiography. The findings arc reported elscwhcrc. 3 • 4 Such measurements arc of value in that they can indicate disparities of renal function between the two sides which deserve further definition with renal angiography. PATHOLOGY
The majority of the renal arterial occlusive lesions were arteriosderotie plaques, with or ,yithout superimposed thrombosis, but in about one-fifth of the patients from whom surgical specimens were obtained the stenosis was due to fibromustular subintimal proliferation. 5 Thrombosis of the renal artery without other pathologic findings in the artery was pr<'scmt in 5 patients. Small dissecting aneurysms of the renal artery or one of its major branches were found in 3 patients. These arterial lesions caused variable effects on the renal parenchyma ranging from no abnormality in a few patients to tubular atrophy, minimal to severe, focal to diffuse, in others. Compkte occlusion of a branch of the renal artery resulted in ischemic atrophy of the corresponding vascular segment of the kidney. SURGICAL TREATMJ•;NT
Surgical treatment of renal arterial lesions associated with hypertension should: 1) relieve hypertension and hypertensive vascular disease promptly and permanently, and 2) whenever possible restore normal renal function to the affected kidney. Both purposes can be achieved only after accurate definition of the arterial lesion by adequate angiography. Sixty-six of the 93 hypertensive patients with demonstrable lesions of the renal artery were selected for surgical 3 Poutasse, E. F., Donnelly, A. and Dustan, H. P.: Separated kidney function tests in hypertensive patients. Surg. Forum, 9: 826, 1958. 4 Dustan, H. P., Poutasse, E. F., Corcoran, A. C. and Page, I. H.: Significance of renal function tests in renal hypertension. Circulation, 18: 714, 1958. 5 McCormack, L. J., Hazard, J.B. and Poutasse, E. F.: Obstructive lesions of the renal artery associated with remediable hypertension. Am. J. Path., 34: 582, 1958.
treatment. Severe retinopathy was common among these patients; retinal hemorrhages and cxudates, with or without papilledema, were observed in 34. Of the 27 patients who did not undergo surgery, some died soon after the diagnosis was established, some are awaiting surgery, and some had asymptomatic hypertension and are receiving medical treatment. Thirty-nine patients had nephrectomy, and 30 had some other type of surgical procedure designed to preserve the affected kidney. More than one operation was necessary in several patients. The type of operation depended upon the nature and location of the occlusion, whether the disease was unilateral or bilateral, the degree of renal atrophy in the involved kidney, and the severity of the patient's hypertensive cardiovascular disease. Nephrectomy. Removal of the kidney with impaired arterial blood supply was perform.eel in 39 of the 66 hypertensive patients selected for surgical treatment. In general, the reasons for choosing nephrectomy were: 1) the patient was too sick with hypertensive cardiovascular disease to justify a longer or more difficult operation than nephrectomy, 2) repair of the renal artery lesion was technically unfeasible, or 3) the involved kidney showed significant atrophy from radiographic and excretory function studies, whereas the opposite kidney had good blood supply and normal function. Many of the patients in this particular group had advanced hypertensive cardiovascular disease and generalized arteriosclerosis and, as would be expected, most of the complications and deaths were attributable to these causes. Five patients died in the immediately postoperative period: two had ccrebrovascular accidents, one died of congestive heart failure, one died of myocardial infarction, and the fifth of anuria from thrombosis of the renal artery to the opposite kidney. Four died 8 months or longer after nephrectomy: two of myocardial infarction (both had remission of their hypertension, however), one of cerebrovascular accident, and the fourth of progressive hypertensive cardiovascular disease. Of the 30 living patients, 2.5 have had complete remission of their hypertension. Two had reversal of the malignant phase of hypertension and reduced blood pressure. Three patients had no change in blood pressure; two, in retrospect,
f'TIRGICAL TUEAT.MEN'T OF' HBS,\L HYPEilTEXSIO\T
developed the arteriosc:krotic plaques in one renal artery after ha,-ing had hypertension for a long period of time. 1t is not always easy to ascC'rtain the duration of a patient's hypertension or to evaluate the significance of a radio .. graphically demonstrable arterial lesion. nephrectomy. Occlusion of an accessory artery (fig. 1, A) causes atrophy of only the corresponding segment of the kidney. A. similar segmental atrophy rnrnlts from occlusion of a polar branch of the renal artery. Such lesions produce an abrupt and scn·n, form of hypertenwhieh can be cured by segmental removal of the isdwmic zone of the kidney. Two patients have been treated in this manner; one has had eomplrtc remission of hypertension for more than a ye,1r. This case report and tlrn case reports of other patients treated segmental nephrectomy will be reported in detail later. Occlusive lesions of the middle branches of the renal artrry (fig. l, B) cause atrophy or infarction of the corresponding segment of the kidney. This atroph)- is distinguislml by the fact that it extends only halfway through the depth of the kidney, because the blood supply to the opposite side of the kidney is intact. This type of segmental atrophy was found in 2 patients; the occlusive arterial lesion in the middle branch was on each occasion associated with a dissecting anPurysm. In both patients, only the block of lltrophiu renal tissue was removed by a sagittal segmental nephrectomy. One patient has had complete remission of hypertension since the operation. The other patient has had no change in blood pressure; he had a long history of hyper· tension a.nd it is beliewd that the arterial lesion 11-as a recent arteriosclerotic complication of a t~'pe that could cause later serious aggravation of his hypertension. Occlusion of one of a pair of renal arteries produces ischemic atrophy of half of the kidney, either Ragittally (fig. 1, CJ or transversely (fig. 1, , depending upon the pattern of distribution of the two renal arteries. One patient has comremission of malignant hypertension after sagittal hcrnincphrectom,v for a lesion of the type shmvn in figure 1, C. The other type of lesion, shown in figure 1, D, i~ removed readily by a transverse hcminephrectomy, as was done in one patient. However, if atrophy is not present, arterial circulation can be re-established in the partiall:v occluded arkrr using the splenic
40::i
Fro. L Diagrams adapted from ang;iograms of hypertensive patients. A, occlusion of accessor\ or polar branch of renal rtrter:v causes seg;nwntai atrophy of pole of kidney. B, occlusion of midcll(' branch causes atrophy of anterior or posteri()[' middle segment. C, occlusion of one of a of parallel renal arteries causes sagitt al D occlusion of one of two crossed renal causes transverse atrophy of half of kidne.1·. artery; this procedure was performed in one, pa tient, whose kidney has sinc;e hypertrophied and increased in excretory function (fig. 2 anrl table 1, C). Enrlartcrectomy. Removal of an eccentric arteriosclcrotic; plaque (fig. 3, opening tlw artery ancl prying loose the occluding plaque, was done on 2 patients. One later underwent trarn,for verse segmental nephrectomy (fig. J, ischcmic atrophy of the upper half of the opposite kidney; no remission of hypertension occurred, but renal function of both been preserved. The second patient wa,; on too recently for any statc1rn,nt to hn made about the cffed on his hypertension or renal function. Plaques at the orifice of the renal artery arr, eommon (fig. 3, B), and arc seen in patients with ach·ancccl atherosclerotic aorti(, disease. Endarterectomy for these lesions has been reportcd, 6 • 7 but the results of this pro., cedure have not been uniformly sur,r:c'ssful. There 6 Freeman, N. E., Leeds, 1<'. H., Elliott, W. and Roland, S. L: Thromboendartercctomy foi hypertension due to renal artery or:clusioll J.A.M.A., 156: 1077, 1954. 7 DeCamp, P. T. and Birchall, R.: Recop;uition and treatment of renal arterial stenosis associated with hypertension. Surgery, 43: l:H, 1\J58.
406
EUGEi'iE F. POUTASSE
Fm. 2. Preoperative and postoperative intravenous urograms in a 30-year-old man with malignant hypertension. Angiogram B shows occlusion of first part of two of three right renal arteries. On left side there is occlusion of one of two renal arteries, similar to that shown in fig. 1, D. Splenic artery was anastomosed to this vessel. Postoperative urogram and function tests (table 1, C) show hypertrophy of this kidney. Right kidney will be removed soon. may be several reasons for this, such as uncertain status of the kidney in regard to areas of infarction, which should be removed simultaneously, and the dispersion of cholesterol emboli into the kidney at the time of the endarterectomy. I have performed what amounts to a dilatation of the aortic orifice of the renal artery in 3 patients by opening the renal artery and passing size 16 or 18F sounds through the occluded area with no real improvement in hypertension. Unfortunately, none have had followup angiographic studies to determine the postoperative
patency of the renal artery. I am convinced that it is better to perform arterial replacement by homografts or splenorcnal arterial anastomoses, if it is important to preserve the affected kidney, than to attempt endarterectomy. Excision of occluclecl segment of renal artery. Discrete occlusive lesions of the middle or distal part of the renal artery (fig. 3, C, D) can be excised and the artery repaired by end-to-end anastomosis. The kidney must be morphologically normal and show no areas of atrophy, although its excretory function may be significantly
407
SURGICAL TREATMENT OF RENAL HYPERTENSION
1. Changes in renal function and blood pressure after surgical treatment of occlusive disease of renal arteries
TABLE
A. Left splenorenal arterial anastomosis for occlusion of first part of left renal artery Preop.
Rt.
altered, and the artery must be long enough to allow the ends to be joined without tension. It is possible to insert a short· homograft, but I have not found it necessary to do so thus far. This, incidentally, would increase considerably the time the kidney was deprived of arterial blood because there would be two suture lines to complete. All 6 patients who have undergone this operation now have normal blood pressure. Several in whom preoperative divided renal function studies showed depressed function of the involved kidney have had restoration of excretory function as shown by identical studies postoperatively (table 1). One of the 6 patients had simultaneous repair of the right renal artery for two occluding plaques, and removal of the opposite kidney, a contracted, duplex functionless organ. Excision and repair of the renal artery were attempted in two other patients, but technical difficulties ensued, necessitating removal of the kidney. Medial dissection and degeneration of the entire length of the renal artery were found in one patient, and immediate, recurring thrombosis on the suture line developed in the other patient. Renal arterial homografts. Arterial homografts are useful for correcting occlusion of the orifice or the first part of one or both renal arteries. This particular work was done with Dr. A. W. Humphries,* who developed and performed the operations wherein aortic or iliac artery homo* Department of Vascular Surgery.
71
Uo.,m- .... .... UN a. .... . . . . . BP ..
Left
41 5.04 2.11 413 443 64 12 210/110
GFR ...... ... V. . . . . .......
Fm. 3. A, eccentric atherosclerotic plaque suitable for endarterectomy. B, large plaque at orifice. C, symmetrical occlusion, which often occurs with fibromuscular hyperplasia. D, atherosclerotic plaque and poststenotic aneurysm. C and D, suitable for excision and repair of artery. B, arterial homografting or splenorenal arterial anastomosis required.
I
10 mo. postop.
. ....
Rt.
I
Left
44 44 2.87 3.39 424 465 32 99 145/95
B. Excision of stenotic segment of right renal artery I
I
Preop. Rt.
I
4 mo. postop.
Left
GFR. . . . .... 43 92 V . .. . . . . .... 1.52 7.62 Uo,m, . .. .. 624 421 87.9 9.6 UNa- ..... . . . BP .. . . . . . . . . . 186/112
Rt.
I
Left
56 50 4.05 3.34 511 513 66.8 I 41.5 137/81
C. Left splenorenal arterial anastomosis for bilateral renal artery disease Preop.
I
I
Rt.
I
9 mo. postop. Left
42 GFR ... ..... 31 2.34 V .. 3.19 450 Uo,m- ... ..... 441 24.6 22.8 UNa- .. ...... 220/124 BP .. . . . . . .
Rt.
I
Left
22 64 2.10 7.25 434 391 68.3 75.8 160/100
D. Excision of stenotic segment of right renal artery for bilateral renal artery disease Preop.
Rt.
GFR .... . ....
v .... . ... Uo,m- .. .... UNa- ... BP ..
I
22 mo. postop. Left
31 87 1.26 7.47 562 383 29 71.4 220/125
Rt.
I
Left
44 50 5.05 3.99 405 459 85.5 56.3 125/78
408
EUGENE F. POUTASSE
Frn. 4. A, arterial homograft for occlusion of first part of ~enal artery, ~sing iliac artery. B, reversed aortic homograft for occlusion of first part of both renal arteries. grafts were used for restoration of renal circulation. The method of using iliac artery for homografts is shown in figure 4, A. A wide aortic opening must be made to insure adequate blood flow into the homograft. This operation has been done on 3 patients. The first case of correction of bilateral occlusion by this method has been reported ;8 femoral arterial homografts were used in a 2-stage operation to restore normal circulation to both kidneys. The second patient had occlusion of the orifice of the right renal artery; he died after hemorrhage from the aortic suture line on the tenth postoperative day. The third patient is of unusual interest because over a year ago he was found to have a minimal occlusive lesion of the right renal artery and complete occlusion of the left renal artery with a nonfunctioning kidney. Left nephrectomy was performed then and his hypertension remitted. Ten months later the hypertension recurred and at that time angiograms showed incomplete occlusion of the right renal artery, leaving only a thin, irregular lumen. A homograft of iliac artery was inserted and at present, 5 months postoperatively, he is doing well in all respects. The method of using aortic homografts to replace the first part of both renal arteries is shown in figure 4, B. 9 Experience has shown that the 8 Poutasse, E. F., Humphries, A. W., McCormack, L. J. and Corcoran, A. C.: Bilateral stenosis of re~al arteries and hypertension; treatment by arterial homografts. J.A.M.A., 161: 419, 1956. 9 Humphries, A. W. and Poutasse, E. F.: A
homograft should be reversed to provide a favorable take-off angle of the renal arteries. This operation has been done on 4 patients, one of ,vhom has had good health and a significant decrease in his hypertension for almost 2 years. One patient died 4 months postoperatively of progressive hypertensive vascular disease. Extensive areas of ischemic atrophy were present in his kidneys at the time of the operation. The third patient, who also had a lumbar aortic aneurysm and coronary artery disease, died of a myocardial infarction a few days after removal of the aneurysm and repair of the aorta and renal arteries. In the fourth patient the homograft thrombosed, and nephrectomy was necessary. Splenorenal arterial anastomosis. The splenic artery is readily adaptable to restore normal circulation to the left kidney. 10 , 11 It has a large caliber, is exceptionally mobile, and the proximal portion is seldom involved by atherosclerosis. It is not necessary to remove the spleen because it still receives sufficient arterial blood through the short gastric arteries (fig. 5). Of 6 patients who had this operation, the last three still have their spleens. End-to-side anastomosis of the splenic to the renal artery was clone in 2 patients (fig. 5, A). It is not necessary in this instance to divide the renal artery. End-to-end splenorenal arterial anastomosis was clone in 4 patients (fig. 5, B). The results of this operation have been remarkable. A 62-year-olcl woman who was treated 2 years ago for malignant hypertension and congestive heart failure was found to have bilateral renal arterial disease (fig. 6) with complete occlusion of the right renal artery and advanced atrophy of the kidney. The left renal artery was also completely occluded, but the kidney and reasonable excretory function were preserved by a rich collateral circulation. Two years ago left splenorenal arterial anastomosis and retechnique of arterial grafting for renal artery stenosis causing hypertension. Surg., Gynec. & Obst., 105: 764, 1957. 10 DeCamp, P. T., Snyder, C. H. and Bost, R. B.: Severe hypertension due to congenital stenosis of artery to solitary kidney; correction by splenorenal arterial anastomosis. A.M.A. Arch. Surg., 75: 1023, 1957. 11 Parton, C. W. and Nabseth, D. C.: Splenorenal arterial anastomosis in the treatment of stenosis of the renal artery: report of a case. New England J. Med., 259: 384, 1958.
SURGICAL TREATMENT OF RENAL HYPERTENSION
409
FIG. 5. A, end-to-side anastomosis of splenic artery to renal artery. Spleen receives arterial blood through short gastric arteries. B, end-to-end anastomosis, which in my experience has been more satisfactory.
FIG. 6. A, intravenous urogram in 62-year-old woman with malignant hypertension. Right kidney has atrophied. B, angiogram shows aortic disease, and complete occlusion of both renal arteries, with poststenotic filling of left renal artery via collaterals. Splenorenal arterial anastomosis and right nephrectomy were done in July 1957; the patient has had good health since then, with blood pressure 160/90 mm. Hg, and complete remission of the malignant syndrome.
moval of the right kidney were performed simultaneously. She has had complete remission of malignant hypertensive syndrome since that time. Another woman who had an occlusion of the first part of the left renal artery has had restoration of both normal blood pressure and normal renal function in the kidney for almost as long (table 1, A). A 10-year-old boy with severe hypertension recently underwent left splenorenal .arterial anastomosis which has resulted thus far
in a drop in blood pressure to practically normal levels. The other 3 patients have bilateral renal artery disease and severe hypertension. In each, the splenic artery was used to restore normal arterial pressure and flow into the left kidney. At a later date the right kidney can either be removed or receive an arterial homograft, depending on the status of the kidney and the patient's condition. One of these patients, already
410
EUGENE F. POUTASSE
briefly described in the section on segmental nephrectomy, has shown a considerable gain in function of the left kidney and is now ready to have the right kidney removed. The other 2 patients have just undergone the splenorenal arterial anastomosis and are awaiting re-evaluation. COMMENT
Renal angiography has revealed a surprisingly high incidence of occlusive disease of the renal arteries in selected hypertensive patients. As a cause of potentially remediable hypertension it now surpasses other known causes of secondary hypertension at the Cleveland Clinic. The term unilateral renal disease should be abandoned; a definitive diagnosis can and should be made in all hypertensive patients with renal disease, using appropriate roentgenographic techniques. As yet the diagnosis of occlusive disease of the renal arteries can be made only by the radiographic visualization of the renal circulation. The presence of an occlusive lesion can be suspected from the patient's history, urographic nonvisualization or smaller size of a kidney, or by the demonstration of a disparity in excretory function by separated renal function tests; but an accurate morphologic diagnosis requires angiography. It is essential to demonstrate the arterial circulation of both kidneys, because the lesions were found to be bilateral in one out of four patients. In my experience with the various techniques of renal angiography, translumbar aortography has been entirely satisfactory, practical, and economical of time. No serious complications have occurred from its use in more than 500 patients. The type and location of lesions in the renal artery, and their effect on the kidney itself, often challenge the surgeon. Although there are situations in which nephrectomy is the procedure of choice, or the only possibility, every effort should be made to discover those patients who, by reconstruction of the arterial circulation or removal of an ischemic renal segment, can be relieved of hypertension with preservation of renal tissue and function. It should be kept in mind that usually the underlying disease is some form of atherosclerosis, and that if it is not present already in the opposite kidney, it may develop later and become a clinical problem. Operations on the proximal or middle portion
of the right renal artery should be performed through a long mid-line or an anterior subcostal incision because it is essential, for reasons of safety, to have adequate exposure of the vena cava, renal veins, and aorta. The right renal artery lies behind the vena cava and renal veins, and accurate arterial surgery in this inaccessible area is difficult. The left renal artery is readily exposed through an anterior subcostal transperitoneal approach. In my experience, the human kidney usually will survive deprivation of arterial circulation for periods of as long as 30 minutes, depending on how normal the kidney is at the time of operation. Transient hyposthenuria and a reduction in function may occur. Most of the operations on the renal artery described in this paper were completed in less than 20 minutes. Some kidneys with occlusive lesions of the main renal artery have a richly developed collateral circulation which is adequate to sustain excretory function (fig. 6), but evidently the arterial pressure relationships in the kidney are insufficient to prevent renal hypertension. It is surprising to see how much reverse bleeding will occur from the distal end of the divided renal artery in some patients. Restoration of arterial pressure in these kidneys causes reduction in systemic blood pressure. Measurement of the arterial pressure distal to the occlusion in the renal artery and simultaneous comparison with the intra-aortic pressure are an integral part of the investigative work in renal hypertension at the Cleveland Clinic. There should be a measurable difference, but a statement cannot be made yet as to the minimum pressure differential necessary for the inception of renal hypertension. The method of arterial suturing depends largely on the preference of the surgeon. Both continuous and interrupted techniques were used in this series of patients. Because of the uncertainty of the eventual outcome of arterial homografts, there should be some caution about their use in young patients. The splenic artery has proved useful in restoring normal circulation to the left kidney, and it is possible that further experience will show that it is adaptable for use on the right side. Of the hypertensive patients with occlusive disease of the renal arteries who have had surgical treatment and are living, about 80 per cent
SURGICAL TREATMENT OF RENAL HYPERTENSION
now have normal blood pressure, or have residual systolic hypertension with a normal diastolic pressure. The latter situation is compatible with widespread atherosclerosis and inelasticity of the large arteries. A few patients probably developed lesions in their renal arteries as a complication of long-standing hypertension; removal of the renal factor will not cause remission of all of the hypertension. Restoration of excretory function of a kidney with a previously occluded main artery has been documented in a number of patients by comparing accurate separated renal function tests before and after arterial surgery. Some of these results are shown in table 1. For brevity, four determinations were selected: glomerular filtration rate (GFR), volume of urine in ml./min. (V), urinary osmolarity (U osm), and urinary sodium concentration (U Na). There was depression of GFR, V, and UNa in the kidney with occlusion of the main renal artery (table 1, A, B). At the time of the postoperative study there was a trend toward equalization of the GFR of the two kidneys. The urinary volume was slightly greater, the osmolarity of the urine about the same or higher, and the UNa considerably greater from the operated side. By way of contrast, the kidney with segmental atrophy from occlusion of an accessory artery or branch of the renal artery shows reduction in GFR and V, but the urine has an electrolytic composition identical to that from the opposite kidney. Removal of the area of segmental atrophy does not produce any further reduction in renal function. In patients with bilateral disease of the renal arteries considerable variation occurs in the excretory functioning of the two kidneys, depending on the relative degree of arterial occlusion and atrophy. This finding is illustrated in table 1, C, D; one patient showed little difference preoperatively in GFR, V, and UNa, compared with the other patient. The patient who had the
411
left splenorenal arterial anastomosis (table 1, C) showed significant improvement in the function of that kidney (fig. 2). Meanwhile the right kidney has decreased in function as atrophy progresses. The other patient who had excision of a stenotic segment of the right renal artery (table 1, D) showed considerable improvement in the function of this kidney. The lesion in the opposite renal artery evidently has not interfered sufficiently with arterial blood flow to cause hypertension, at least within 22 months after surgery. SUMMARY
The most common cause of remediable renal hypertension is occlusive disease of the renal artery or of its major branches. From January 1955, through March 1959, 337 hypertensive patients were examined by renal angiography; 87 were found to have occlusive disease of one or both renal arteries, bringing the total number of cases at the Cleveland Clinic discovered by this technique to 93. The arterial lesions were unilateral in 71 patients and bilateral in 22. Sixty-six of the 93 hypertensive patients were selected for surgical treatment. Nephrectomy was done in 39 patients, and 30 had surgical procedures designed to preserve the affected kidney. Several patients required more than one operation. Segmental nephrectomy was performed in six, endarterectomy or dilatation of the occluded orifice of the renal artery in five, excision of the occluded arterial segment in six, renal arterial homograft in seven, and splenorenal arterial anastomosis in six. Of the patients who had surgical treatment and are living, about 80 per cent now have normal blood pressure, or have residual systolic hypertension with a normal diastolic pressure. The excretory function of a kidney with a previously occluded main artery was restored in a number of hypertensive patients by repair of the artery or splenorenal arterial anastomosis.