Surgical Treatment of Renovascular Hypertension
Wallace
6. Chung, MD, CM, FRCS(C),
Anthony J. Salvian,
MD, Vancouver,
FACS, Vancouver, BC
In 1934 Goldblatt et al [I] published a classic paper in which they described the effect on blood pressure of partially occluding one renal artery in the dog. This discovery suggested the possibility of controlling hypertension by nephrectomy in patients with unilateral renal disease. Three years later the first planned nephrectomy was performed as a therapeutic tool in the treatment of hypertension. After an experience of over 20 years, Smith [2] reported the results of 575 nephrectomies in hypertensive patients suspected of having unilateral impairment of renal function. A significant reduction in blood pressure was recorded in only 26 per cent of the patients. Subsequently it was concluded that nephrectomy for hypertension should not be performed in all types of renal disease, and that reversible renal hypertension is primarily arterial in origin. In 1954 Freeman et al 131 described the first renal artery repair for renovascular hypertension. Since then, with the advent of rapid sequence intravenous pyelography, improvement of arteriographic techniques, and refinement of split renal function and renal vein renin studies, the surgical success rate has improved steadily [4,5]. The purpose of this paper is to present our experience with renovascular surgery and to confirm the fact that satisfactory surgical results are mainly dependent on careful selection of patients. Material
and Methods
In the 15 year period from 1962 to 1976,50 patients with renovascular hypertension were operated on. There were 37 women and 13 men, with an overall mean age of 38 years. The 20 patients with underlying arteriosclerosis had a mean age of 50 years whereas the 27 patients with fibromuscular hyperplasia had a mean age of 36 (Table I). Three other miscellaneous conditions consisted of a fibrous band, stenosis of arterial anastomoses in a renal transplant, and From the Department of Surgery, University of British Columbia, and the Vancouver General Hospital, Vancouver, BC. Reprint requests should be addressed to Wallace B. Chung. MD, Department of Surgery, Vancouver General Hospital, Vancouver, BC V5.Z LM9. Presented at the 50th Annual Meeting of the Pacific Coast Surgical Association, Yosemite National Park, California, February 19-22. 1979.
Volume 139, July 1979
BC
a hypertrophied renal artery.
sympathetic
ganglion
compressing
the
Symptoms. The symptoms initiating investigation were present an average of ‘27 months with a range of 2 months to 20 years. The most common were headache, visual disturbances, and fatigue. Of interest was the fact that 19 patients were completely asymptomatic and were found to be hypertensive while being examined for another condition. Patient Selection. The selection of patients for renal artery surgery was carried out in two stages: general and specific. In general screening, history and physical examination are very important. Besides ruling out other possible causes of hypertension, they may reveal specific clues pointing to a renal artery lesion as the cause. The history is usually one of recent onset of severe hypertension, more commonly in a young woman without a strong family history of hypertension. In our series, the mean diastolic pressure preoperatively in the hospital with medical therapy was 115 mm Hg and the mean age of the 27 female patients with fibromuscular hyperplasia was 36 years. Furthermore, even in patients in whom arteriosclerosis was the cause of renal artery stenosis, the mean age was only 50 years. Only 16 per cent of the patients had a positive family history of hypertension. Physical examination, besides demonstrating high blood pressure, may also indicate the presence of an epigastric bruit a little off the midline. In contrast to many investigators, we believe that the bruit is a very important and significant sign that is present in the majority of patients with renal artery stenosis and must be sought for carefully. Characteristically, it is biphasic, consisting of a highpitched systolic and a lower-pitched diastolic component. In all patients in whom this bruit was heard, none had negative results on arteriography. If the history and physical examination suggest a possible renal cause of hypertension, we proceed to more specific diagnostic tests TABLE I
Etiologic Factors
Etiologic Factor
Total
Men
Women
Mean Age (yr)
Arteriosclerosis Fibromuscular hyperplasia Miscellaneous
20 27
12 0
8 27
50 36
3
1
2
17
143
Chung and Salvian
consisting of rapid sequence intravenous pyelography, renal arteriography, and split renal function or renal vein renin studies, or both. Rapid Sequence Intravenous Pyelography. This study involves dehydrating the patient, injecting a contrast medium intravenously, and taking roentgenograms every minute for 5 minutes and at 10 and 15 minutes. Since the
Figure 1. Fibromuscular hyperplasia in a 4 1 year old woman as seen on a selective renal arteriogram. No significant stenosis was found.
Figure 2, Same 41 year old woman, in whom a selective arteriogram taken during a Valsalva maneuver demonstrafed significant sfenosis.
144
test is one of comparison, it is useless in patients with bilateral disease or with only one kidney. In unilateral renal artery stenosis, comparison of the ischemic kidney to the normal kidney reveals certain characteristics. First is the loss of parenchyma. Not only is the affected kidney shorter, but the cortex is also thinner. Secondly, in the early films, there is delay in the appearance of the dye, and in the late films, delay in excretion of the contrast medium, resulting in hyperconcentration. In a small number of cases, notching of the renal pelvis and ureter may be due to arterial collateral formation. This test was undertaken in 40 patients and the results were considered positive in 35 and negative in 5. Aortography and Renal Arteriography. This technique is the most diagnostic test of renal artery stenosis. It is usually carried out transfemorally, allowing for aortography and bilateral selective renal arteriography. The aortographic part of the procedure is vital since the character of the adjacent aorta from which the graft is to originate must be known. In addition, it will reveal possible abnormal sites of origin of the renal artery or even multiple renal arteries. The renal artery is occasionally folded on itself. We have found that in order not to miss some less obvious stenoses, the artery must be “unfolded” by the Valsalva maneuver (Figures 1 and 2). In our series, all patients had preoperative angiography. Four patients had bilateral disease and two patients had solitary kidneys. Split Renal Function Tests. Even though arteriography may have demonstrated a stenotic renal artery, evidence that it is the cause of hypertension is still inconclusive. It is known that 30 per cent of aortograms taken to investigate peripheral vascular disease show significant renal artery stenosis, yet the patients are normotensive [6]. It therefore remains with other tests to determine whether a renal artery stenosis is significant in producing renal ischemia and hence hypertension. In our early experience, we relied predominantly on the split renal function test of Howard. The test is dependent on the fact that in an ischemic kidney with functioning tubules, there is an exaggerated reabsorption of water and sodium. In addition, with the decrease in urinary volume, there is an increase in concentration of urinary phenolsulfonphthalein (PSP) and creatinine. The criteria of significant renal ischemia expressed as a ratio of the ischemic kidney divided by the normal kidney are the volume less than 0.5, the sodium less than 0.85, and the PSP and creatinine more than 1.85. This test was carried out in 21 patients and the results were positive in all cases. Renal Vein Renin Assay. In view of the technical difficulties and frequent complications of split renal function tests, we turned to renal vein renin determinations in the later cases. Decreased flow to the kidney activates the renin-angiotensin system in the juxtaglomerular complex, resulting in increased secretion of renin from the ischemic kidney and decreased renin production from the normal side. Comparing the abnormal kidney to the normal kidney, a ratio of 1.4 or more is considered positive. Seven patients had the assays carried out. Six had positive results and one equivocal.
The American Journal of Surgery
Renovascular
TABLE II
Results
Operative
Management
Technically, to overcome the Goldblatt phenomenon, either vascular reconstruction or, if that is impossible, nephrectomy could be performed. In our 50 patients, 54 surgical procedures were carried out, consisting of 37 saphenous vein aortorenal bypass vein grafts, 6 Teflon @ bypass grafts, 3 saphenous patch grafts, 2 thromboendarterectomies, and 6 nephrectomies. Four of the nephrectomies were carried out as the primary procedure and two were performed after vascular procedures failed. There was no operative mortality in the 54 operations. A detailed description of operative techniques is beyond the scope of this paper. However, from our experience, several points should be emphasized. The type of reconstruction depends on the preference of the surgeon. However, it is our impression that the saphenous vein, if available and used in the bypass principle, offers the greatest flexibility and may be adaptable in many situations (Figure 3). So often, not only is the renal artery beyond the stenosis small, but also the lesions of fibromuscular hyperplasia may extend into the primary branches. In these situations, only the saphenous vein with its softness and pliability will allow placement of the smallest bites with the finest sutures to “wedge” open a narrowed bifurcation or a primary branch. In this critical area of anastomosis, we found the careful and meticulous placement of sutures greatly facilitated by the use of
Volume 138, July 1979
Results Related to Pathologic Findings Arteriosclerosis
Fibromuscular Hyperplasia
Miscellaneous
Total
Good Improved Poor
15 5 0
18 7 2
3 0 0
36 12 2
Total
20
27
3
50
TABLE Ill
Figure 3. A saphenous vein graft with a genffe curve from the aorta (on right), crossing over theinferior vena cava to the renal artery. Note the venous gratl enters the renal artery at an acute angle.
Hypertension
Results Related to Number of Positive Tests
No. of Positive Tests
No. of Patients
Good
4 3 2 1
17 16 12 5
14 13 8 1
3 3 3 3
0 0 1 1
Total
50
36
12
2
Results improved
Poor
a head light and a loup with a 4 times magnification. Thromboendarterectomy seems to be most suitable in some very localized arteriosclerotic lesions. However, our only case of acute thrombosis and renal infarction occurred with this type of procedure. We believe that the thinned out area of renal artery after thromboerdarterectomy is prone to kinking and thrombosis. If the procedure is selected, we reinforce the area with a saphenous vein patch graft. Results
In evaluating the results we have applied the definition of clinical response as follows: good, if the diastolic blood pressure is 90 mm Hg or less with no antihypertensive medication; improved, if the diastolic blood pressure is between 90 and 1.10 mm Hg with no or minimal antihypertensive medication; poor, if the diastolic blood pressure remains above 110 mm Hg or if large doses of antihypertensive medication are required for control. On the basis of these criteria, 36 patients or 72 per cent had a good response, 12 or 24 per cent were improved, and 2 or 4 per cent were unimproved. The follow-up period of the group with a good response ranged from 18 months to 16 years with an average of 34 months. That in the improved group ranged from 18 months to 11 years with an average of 42 months. When we considered the surgical response in relation to pathologic findings (Table II), we found that of the 20 arteriosclerotic patients, 15 had good results and 5 were improved. Of the 27 patients with fibromuscular hyperplasia, 17 had good results, 8 were improved, and 2 were unimproved.
145
Chung and Salvian
TABLE IV
Results Related to Diagnostic Criteria
Results
Bruit
Intravenous Pyelographv
Good Improved Poor
25 6 0
27 7 1
Angioaraphv 35 10 1
Split Renal Function Tests
Renin Assays
16 5 0
5 1 0
It is also of interest to consider the surgical response in relation to the four diagnostic criteria, that is, physical findings of a bruit, rapid sequence intravenous pyelography, arteriography, and the split renal function test, renal vein renin assay, or both (Table III). Seventeen patients had positive responses to all four criteria, and all responded to surgery with 14 cured and 3 improved. Sixteen patients had three of four positive criteria, and they also responded favorably to surgery with 13 cured and 3 improved. Twelve patients had two of four positive criteria. Eight were cured, three were improved, and one was unimproved. Five patients had only one positive criterion. Only one was cured, three were improved, and one was unimproved. Taking the tests individually, the specific bruit was heard in 31 patients. Of these, 25 had good response and 6 were improved (Table IV). Rapid sequence intravenous pyelography was performed in 40 patients with 35 positive results. Twenty-seven had good response, 7 had improved response, and 1 poor response. Of the five patients with negative results, three had good response, one had improved response, and one poor response. Renal angiography was performed in all patients and 46 showed unilateral renal artery stenosis. Of these, 35 had good results, 10 were improved, and 1 was unchanged. Four patients had bilateral stenosis. Two patients had reconstruction of both arteries with good results. Two patients had only the worse side done: one was improved and one was unchanged. Split renal function tests, renal vein renin assays, or both were performed in 28 patients with 27 positive results. All 27 patients responded favorably, with good results in 21 and improvement in 6. Conclusions
Fifty patients were diagnosed as having renovascular hypertension on the basis of history, a specific abdominal bruit, rapid sequence intravenous pyelography, renal arteriography, and split renal function tests, renal vein renin assays, or both. Fifty-four procedures, consisting of 37 saphenous vein aortorenal bypass grafts, 6 Teflon aortorenal bypass grafts,
146
3 saphenous vein patch grafts, 2 thromboendarterectomies, and 6 nephrectomies, were carried out. There was no operative mortality. The patients were followed up a mean period of 38 months. The results showed a cure rate of 72 per cent and an improved rate of 24 per cent. Those patients having three or more positive diagnostic criteria showed a cure rate of 82 per cent and an improvement rate of 18 per cent. From a review of the current literature and our own experience, we believe that reconstructive vascular surgery or nephrectomy, when performed for the proper indications and by a technically experienced surgeon, not only is safe but also will yield excellent results. References 1. Goldblatt M, Lynch J, Hanzal RF, Summerville WW: Studies on experimental hypertension. J Exp Med 59: 347, 1934. 2. Smith H: Unilateral nephrectomy in hypertensive disease. J Ural 76: 685, 1956. 3. Freeman NE, Leeds FH, Elliot WG, Roland SI: Thromboendarterectomy for hypertension due to renal artery occlusion. JAMA 156: 1077, 1954. 4. DeBakey ME, Morris GC, Morgen RD, Crawford ES, Cooley DA: Lesions of the renal artery. Surgical technic and results. Am JSurg 107: 84, 1964. 5. Foster JH, Richard HD, Pinkerton JA, Rhamy RK: Ten years experience with surgical management of renovascular hypertension. Ann Surg 177: 755, 1973. 6. Eyler WR, Clark MD, Garman JE, Rian RL, Meininger DE: Angiography of the renal areas including a comparative study of renal arterial stenoses in patients with and without hypertension. Radiology 78: 879, 1962.
Discussion
John E. Connolly (Irvine, CA): Before giving my own opinions on the surgical treatment of renovascular hypertension, I would like to ask Dr. Chung three questions: (1) Did any of your patients have associated disease such as an abdominal aneurysm or aortoiliac occlusive disease that was corrected simultaneously? (2) Did any of your patients have bilateral renal artery stenosis? (3) Did you measure and correlate pressure gradients at the time of operation? I believe that three groups of patients are most likely to carry an increased chance that their hypertension is due to renovascular lesions. Group 1 are those who are in the first decade of life. Group 2 are women in whom hypertension develops before age 45 and who are not on the pill. I noted that Dr. Cbung’s series had an abnormally large number of cases of fibromuscular hyperplasia as opposed to most series which consist primarily of group 3 patients, who are those who are over age 50 and have arteriosclerosis as the cause of the lesion. In this third and larger group the important clue is the recent onset of hypertension. We have all had experience with rapid intravenous pyelography or hypertensive intravenous pyelography as a screening procedure, but we should remember that the results are positive in only 70 per cent in most series and
The American Journal 01 Surgery
Renovascular
in less than 50 per cent in patients with fibromuscular hyperplasia. Likewise, split function tests and renal vein renin assays give at least 10 per cent false-negative results. Therefore, aortography is highest on my list of diagnostic tests. Aortography, however, is indicated only if the patient being evaluated would be an operative candidate if a lesion was found. For instance, most patients over 65 would not be surgical candidates unless their hypertension was malignant and uncontrollable, and thus that type of patient should not be subjected to aortography. Despite all these screening tests, including aortography, in certain cases we may not know if we can alleviate the hypertension until we have obtained direct gradients at the operating table. 1 have backed out of several cases when no gradient was demonstrable even though our so-called screening tests indicated that a gradient would be present. When a gradient is present, I prefer, as do the investigators, to perform end-to-side saphenous vein bypass generally. If significant bilateral stenoses are present, the technique of crossclamping the aorta, opening it directly, and performing endarterectomy, as described by Wylie, is the procedure of choice. Since arteriosclerotic renal lesions originate in the aorta, their entire renal tail can be removed in this manner. The safest place to clamp the aorta for this procedure is at the diaphragm above the celiac axis, after which the aorta can be clamped below the renal vessels and opened longitudinally. If you are worried about the ischemit renal time, you can put some ice slush in the abdomen to lower the kidney temperature and to avoid having to rush the endarterectomy. This technique will permit you to endarterectomize all of the renal orifices. In some cases as many as five renal arteries may need to be endarterectomized to cure the hypertension. Finally, 1 would like to mention some historical facts of the first successful case alluded to by Dr. Chung. The patient was a 48 year old patient who was referred by an internist in Sacramento to Dr. Norman Freeman of San Francisco, whom many of you knew. This was in 1951 when Dr. Freeman was working at the Franklin Hospital in San Francisco. This patient was sent to him because of the socalled Leriche syndrome, that is, claudication and sexual impotence. The patient also had hypertension. Aortography performed retrograde through a carotid artery demonstrated aortoiliac occlusive disease and stenosis of one renal artery. Freeman recognized that the hypertension might be secondary to the Goldblatt phenomenon, but I do not believe he had any plans to do anything about it. Dr. Sam Roland, who was a contemporary of mine, was a urology resident at Franklin Hospital then and subsequently told me the following story. He was scrubbing at a sink alongside Dr. Freeman and asked him what he was doing that day. Dr. Freeman replied he was going to perform aortoiliac endarterectomy. Sam said, “Does the patient have hypertension?” Norman said, “Yes, he does.” Sam said, “Maybe he has the Goldblatt phenomenon. Why don’t you clean the renal artery out also?” Freeman said,
Volume 138, July 1979
Hypertension
“I had thought about that possibility. How would you do it?” He said, “I would suggest that you reach into the renal orifice with a right angle clamp when you have the aorta open and pull that plug out.” According to Sam, that is how Norman Freeman happened to do the first case. That first patient was operated on in 1952 and reported on in the Journal of the American Medical Association in 1954. Dr. Frank Leeds, Freeman’s associate, recently told me that the patient lived until 1975, free of hypertension. Finally, it might be of interest to report that the preoperative pyelogram on this first successful case showed nothing abnormal. Richard Ang Lim (Santa Barbara, CA): I want to ask Dr. Chung one question, and that is whether he has seen renal systolic hypertension. Five months ago, I operated on a 67 year old retired, diabetic female anesthesiologist who 1 year previously was found to have hypertensive encephalopathy. The internists tried to treat her with all kinds of medications, including blocking agents, diuretics, and others, and they all failed to control the hypertension. The unusual feature of this case was the persistent systemic hypertension. She had systolic hypertension of 260 to 280 mm Hg with a normal diastolic pressure of about 70 to 80. This is rather rare because we did research on it and talked to people, and nobody has seen this phenomenon associated with renal stenosis. There is bilateral disparity with the rapid sequence intravenous pyelographic screening test. Renal angiography subsequently confirmed a 95 per cent stenosis of the right renal artery. The renin differential test shows a 51 ratio, far higher than the acceptable ratio for diagnosis of renal hypertension. With all of this evidence, therefore, we discussed the problem with her and then operated on her 5 months ago. At surgery we performed aortorenal bypass with a gortex graft. The patient’s systolic pressure returned to normal, medication was discontinued, and she continues to do very well at this point. Nicholas A. Halasz (San Diego, CA): We who perform transplantations have a good model for this because the transplanted kidney’s artery can develop stenosis tprobably from rejection) and produce renovascular hypertension. We learned that these kidneys, in addition to producing hypertension, may have marked deterioration of function and will mimic rejection. The creatinine clearances decrease to 20,15, even 10 ml with a kidney that is perfectly viable. Using this as an example, we have looked carefully at a number of patients who have end-stage renal disease and are being considered for transplantation. A number of these patients, three in the last 5 years, functionally had a solitary kidney with severe stenosis. Therefore, I would like to emphasize that in a patient with one bad kidney and one that, may be good, arteriography is indicated. W. B. Chung (closing): I agree with all Dr. Connolly has said. It is obvious that our series contains a highly selected
147
Chung and Salvian
group of patients who are younger than those in most reported series. As such, they have less associated vascular disease. As a matter of fact, only two patients have asymptomatic carotid bruits, two have angina, and three have peripheral vascular disease. We have not measured the gradient across the stenosis. I believe the correlation of this test to postoperative results has not been absolute. When the many preoperative tests we mentioned indicate renal ischemia, we proceed with bypass. Dr. Connolly’s comment on false-positive and falsenegative results is well taken and is why we depend on a battery of tests rather than on just one or two. An example is our results with rapid sequence intravenous pyelography. Five of these tests were reported as having negative results, yet of these five patients three were cured and two were improved. I cannot comment on thromboendarterectomy through
148
the aorta as we have not used this ingenious procedure. Certainly the reported technical results are very good. Dr. Lim’s case is indeed extraordinary with extremely high systolic pressure and normal diastolic pressure. All of our patients have high diastolic as well as high systolic pressures. The fact that Dr. Lim’s patient was cured by renal artery reconstruction must indicate that the problem was renovascular in origin. Dr. Halasz’s comment on the deterioration of renal function in a transplanted kidney due to renal artery stenosis is important. We had one such patient in our series. I always consider that renal artery stenosis has two deleterious effects on the patient. The first of course is hypertension, but the second, of equal importance, is gradual deterioration of renal function and ultimate renal infarction. The latter possibility, which is often forgotten in our preoccupation with hypertension, should also be considered in renovascular surgery.
The American Journal of Surgery
Wallace
6. Chung, MD, CM, FRCS(C),
Anthony J. Salvian,
MD, Vancouver,
FACS, Vancouver, BC
In 1934 Goldblatt et al [I] published a classic paper in which they described the effect on blood pressure of partially occluding one renal artery in the dog. This discovery suggested the possibility of controlling hypertension by nephrectomy in patients with unilateral renal disease. Three years later the first planned nephrectomy was performed as a therapeutic tool in the treatment of hypertension. After an experience of over 20 years, Smith [2] reported the results of 575 nephrectomies in hypertensive patients suspected of having unilateral impairment of renal function. A significant reduction in blood pressure was recorded in only 26 per cent of the patients. Subsequently it was concluded that nephrectomy for hypertension should not be performed in all types of renal disease, and that reversible renal hypertension is primarily arterial in origin. In 1954 Freeman et al 131 described the first renal artery repair for renovascular hypertension. Since then, with the advent of rapid sequence intravenous pyelography, improvement of arteriographic techniques, and refinement of split renal function and renal vein renin studies, the surgical success rate has improved steadily [4,5]. The purpose of this paper is to present our experience with renovascular surgery and to confirm the fact that satisfactory surgical results are mainly dependent on careful selection of patients. Material
and Methods
In the 15 year period from 1962 to 1976,50 patients with renovascular hypertension were operated on. There were 37 women and 13 men, with an overall mean age of 38 years. The 20 patients with underlying arteriosclerosis had a mean age of 50 years whereas the 27 patients with fibromuscular hyperplasia had a mean age of 36 (Table I). Three other miscellaneous conditions consisted of a fibrous band, stenosis of arterial anastomoses in a renal transplant, and From the Department of Surgery, University of British Columbia, and the Vancouver General Hospital, Vancouver, BC. Reprint requests should be addressed to Wallace B. Chung. MD, Department of Surgery, Vancouver General Hospital, Vancouver, BC V5.Z LM9. Presented at the 50th Annual Meeting of the Pacific Coast Surgical Association, Yosemite National Park, California, February 19-22. 1979.
Volume 139, July 1979
BC
a hypertrophied renal artery.
sympathetic
ganglion
compressing
the
Symptoms. The symptoms initiating investigation were present an average of ‘27 months with a range of 2 months to 20 years. The most common were headache, visual disturbances, and fatigue. Of interest was the fact that 19 patients were completely asymptomatic and were found to be hypertensive while being examined for another condition. Patient Selection. The selection of patients for renal artery surgery was carried out in two stages: general and specific. In general screening, history and physical examination are very important. Besides ruling out other possible causes of hypertension, they may reveal specific clues pointing to a renal artery lesion as the cause. The history is usually one of recent onset of severe hypertension, more commonly in a young woman without a strong family history of hypertension. In our series, the mean diastolic pressure preoperatively in the hospital with medical therapy was 115 mm Hg and the mean age of the 27 female patients with fibromuscular hyperplasia was 36 years. Furthermore, even in patients in whom arteriosclerosis was the cause of renal artery stenosis, the mean age was only 50 years. Only 16 per cent of the patients had a positive family history of hypertension. Physical examination, besides demonstrating high blood pressure, may also indicate the presence of an epigastric bruit a little off the midline. In contrast to many investigators, we believe that the bruit is a very important and significant sign that is present in the majority of patients with renal artery stenosis and must be sought for carefully. Characteristically, it is biphasic, consisting of a highpitched systolic and a lower-pitched diastolic component. In all patients in whom this bruit was heard, none had negative results on arteriography. If the history and physical examination suggest a possible renal cause of hypertension, we proceed to more specific diagnostic tests TABLE I
Etiologic Factors
Etiologic Factor
Total
Men
Women
Mean Age (yr)
Arteriosclerosis Fibromuscular hyperplasia Miscellaneous
20 27
12 0
8 27
50 36
3
1
2
17
143
Chung and Salvian
consisting of rapid sequence intravenous pyelography, renal arteriography, and split renal function or renal vein renin studies, or both. Rapid Sequence Intravenous Pyelography. This study involves dehydrating the patient, injecting a contrast medium intravenously, and taking roentgenograms every minute for 5 minutes and at 10 and 15 minutes. Since the
Figure 1. Fibromuscular hyperplasia in a 4 1 year old woman as seen on a selective renal arteriogram. No significant stenosis was found.
Figure 2, Same 41 year old woman, in whom a selective arteriogram taken during a Valsalva maneuver demonstrafed significant sfenosis.
144
test is one of comparison, it is useless in patients with bilateral disease or with only one kidney. In unilateral renal artery stenosis, comparison of the ischemic kidney to the normal kidney reveals certain characteristics. First is the loss of parenchyma. Not only is the affected kidney shorter, but the cortex is also thinner. Secondly, in the early films, there is delay in the appearance of the dye, and in the late films, delay in excretion of the contrast medium, resulting in hyperconcentration. In a small number of cases, notching of the renal pelvis and ureter may be due to arterial collateral formation. This test was undertaken in 40 patients and the results were considered positive in 35 and negative in 5. Aortography and Renal Arteriography. This technique is the most diagnostic test of renal artery stenosis. It is usually carried out transfemorally, allowing for aortography and bilateral selective renal arteriography. The aortographic part of the procedure is vital since the character of the adjacent aorta from which the graft is to originate must be known. In addition, it will reveal possible abnormal sites of origin of the renal artery or even multiple renal arteries. The renal artery is occasionally folded on itself. We have found that in order not to miss some less obvious stenoses, the artery must be “unfolded” by the Valsalva maneuver (Figures 1 and 2). In our series, all patients had preoperative angiography. Four patients had bilateral disease and two patients had solitary kidneys. Split Renal Function Tests. Even though arteriography may have demonstrated a stenotic renal artery, evidence that it is the cause of hypertension is still inconclusive. It is known that 30 per cent of aortograms taken to investigate peripheral vascular disease show significant renal artery stenosis, yet the patients are normotensive [6]. It therefore remains with other tests to determine whether a renal artery stenosis is significant in producing renal ischemia and hence hypertension. In our early experience, we relied predominantly on the split renal function test of Howard. The test is dependent on the fact that in an ischemic kidney with functioning tubules, there is an exaggerated reabsorption of water and sodium. In addition, with the decrease in urinary volume, there is an increase in concentration of urinary phenolsulfonphthalein (PSP) and creatinine. The criteria of significant renal ischemia expressed as a ratio of the ischemic kidney divided by the normal kidney are the volume less than 0.5, the sodium less than 0.85, and the PSP and creatinine more than 1.85. This test was carried out in 21 patients and the results were positive in all cases. Renal Vein Renin Assay. In view of the technical difficulties and frequent complications of split renal function tests, we turned to renal vein renin determinations in the later cases. Decreased flow to the kidney activates the renin-angiotensin system in the juxtaglomerular complex, resulting in increased secretion of renin from the ischemic kidney and decreased renin production from the normal side. Comparing the abnormal kidney to the normal kidney, a ratio of 1.4 or more is considered positive. Seven patients had the assays carried out. Six had positive results and one equivocal.
The American Journal of Surgery
Renovascular
TABLE II
Results
Operative
Management
Technically, to overcome the Goldblatt phenomenon, either vascular reconstruction or, if that is impossible, nephrectomy could be performed. In our 50 patients, 54 surgical procedures were carried out, consisting of 37 saphenous vein aortorenal bypass vein grafts, 6 Teflon @ bypass grafts, 3 saphenous patch grafts, 2 thromboendarterectomies, and 6 nephrectomies. Four of the nephrectomies were carried out as the primary procedure and two were performed after vascular procedures failed. There was no operative mortality in the 54 operations. A detailed description of operative techniques is beyond the scope of this paper. However, from our experience, several points should be emphasized. The type of reconstruction depends on the preference of the surgeon. However, it is our impression that the saphenous vein, if available and used in the bypass principle, offers the greatest flexibility and may be adaptable in many situations (Figure 3). So often, not only is the renal artery beyond the stenosis small, but also the lesions of fibromuscular hyperplasia may extend into the primary branches. In these situations, only the saphenous vein with its softness and pliability will allow placement of the smallest bites with the finest sutures to “wedge” open a narrowed bifurcation or a primary branch. In this critical area of anastomosis, we found the careful and meticulous placement of sutures greatly facilitated by the use of
Volume 138, July 1979
Results Related to Pathologic Findings Arteriosclerosis
Fibromuscular Hyperplasia
Miscellaneous
Total
Good Improved Poor
15 5 0
18 7 2
3 0 0
36 12 2
Total
20
27
3
50
TABLE Ill
Figure 3. A saphenous vein graft with a genffe curve from the aorta (on right), crossing over theinferior vena cava to the renal artery. Note the venous gratl enters the renal artery at an acute angle.
Hypertension
Results Related to Number of Positive Tests
No. of Positive Tests
No. of Patients
Good
4 3 2 1
17 16 12 5
14 13 8 1
3 3 3 3
0 0 1 1
Total
50
36
12
2
Results improved
Poor
a head light and a loup with a 4 times magnification. Thromboendarterectomy seems to be most suitable in some very localized arteriosclerotic lesions. However, our only case of acute thrombosis and renal infarction occurred with this type of procedure. We believe that the thinned out area of renal artery after thromboerdarterectomy is prone to kinking and thrombosis. If the procedure is selected, we reinforce the area with a saphenous vein patch graft. Results
In evaluating the results we have applied the definition of clinical response as follows: good, if the diastolic blood pressure is 90 mm Hg or less with no antihypertensive medication; improved, if the diastolic blood pressure is between 90 and 1.10 mm Hg with no or minimal antihypertensive medication; poor, if the diastolic blood pressure remains above 110 mm Hg or if large doses of antihypertensive medication are required for control. On the basis of these criteria, 36 patients or 72 per cent had a good response, 12 or 24 per cent were improved, and 2 or 4 per cent were unimproved. The follow-up period of the group with a good response ranged from 18 months to 16 years with an average of 34 months. That in the improved group ranged from 18 months to 11 years with an average of 42 months. When we considered the surgical response in relation to pathologic findings (Table II), we found that of the 20 arteriosclerotic patients, 15 had good results and 5 were improved. Of the 27 patients with fibromuscular hyperplasia, 17 had good results, 8 were improved, and 2 were unimproved.
145
Chung and Salvian
TABLE IV
Results Related to Diagnostic Criteria
Results
Bruit
Intravenous Pyelographv
Good Improved Poor
25 6 0
27 7 1
Angioaraphv 35 10 1
Split Renal Function Tests
Renin Assays
16 5 0
5 1 0
It is also of interest to consider the surgical response in relation to the four diagnostic criteria, that is, physical findings of a bruit, rapid sequence intravenous pyelography, arteriography, and the split renal function test, renal vein renin assay, or both (Table III). Seventeen patients had positive responses to all four criteria, and all responded to surgery with 14 cured and 3 improved. Sixteen patients had three of four positive criteria, and they also responded favorably to surgery with 13 cured and 3 improved. Twelve patients had two of four positive criteria. Eight were cured, three were improved, and one was unimproved. Five patients had only one positive criterion. Only one was cured, three were improved, and one was unimproved. Taking the tests individually, the specific bruit was heard in 31 patients. Of these, 25 had good response and 6 were improved (Table IV). Rapid sequence intravenous pyelography was performed in 40 patients with 35 positive results. Twenty-seven had good response, 7 had improved response, and 1 poor response. Of the five patients with negative results, three had good response, one had improved response, and one poor response. Renal angiography was performed in all patients and 46 showed unilateral renal artery stenosis. Of these, 35 had good results, 10 were improved, and 1 was unchanged. Four patients had bilateral stenosis. Two patients had reconstruction of both arteries with good results. Two patients had only the worse side done: one was improved and one was unchanged. Split renal function tests, renal vein renin assays, or both were performed in 28 patients with 27 positive results. All 27 patients responded favorably, with good results in 21 and improvement in 6. Conclusions
Fifty patients were diagnosed as having renovascular hypertension on the basis of history, a specific abdominal bruit, rapid sequence intravenous pyelography, renal arteriography, and split renal function tests, renal vein renin assays, or both. Fifty-four procedures, consisting of 37 saphenous vein aortorenal bypass grafts, 6 Teflon aortorenal bypass grafts,
146
3 saphenous vein patch grafts, 2 thromboendarterectomies, and 6 nephrectomies, were carried out. There was no operative mortality. The patients were followed up a mean period of 38 months. The results showed a cure rate of 72 per cent and an improved rate of 24 per cent. Those patients having three or more positive diagnostic criteria showed a cure rate of 82 per cent and an improvement rate of 18 per cent. From a review of the current literature and our own experience, we believe that reconstructive vascular surgery or nephrectomy, when performed for the proper indications and by a technically experienced surgeon, not only is safe but also will yield excellent results. References 1. Goldblatt M, Lynch J, Hanzal RF, Summerville WW: Studies on experimental hypertension. J Exp Med 59: 347, 1934. 2. Smith H: Unilateral nephrectomy in hypertensive disease. J Ural 76: 685, 1956. 3. Freeman NE, Leeds FH, Elliot WG, Roland SI: Thromboendarterectomy for hypertension due to renal artery occlusion. JAMA 156: 1077, 1954. 4. DeBakey ME, Morris GC, Morgen RD, Crawford ES, Cooley DA: Lesions of the renal artery. Surgical technic and results. Am JSurg 107: 84, 1964. 5. Foster JH, Richard HD, Pinkerton JA, Rhamy RK: Ten years experience with surgical management of renovascular hypertension. Ann Surg 177: 755, 1973. 6. Eyler WR, Clark MD, Garman JE, Rian RL, Meininger DE: Angiography of the renal areas including a comparative study of renal arterial stenoses in patients with and without hypertension. Radiology 78: 879, 1962.
Discussion
John E. Connolly (Irvine, CA): Before giving my own opinions on the surgical treatment of renovascular hypertension, I would like to ask Dr. Chung three questions: (1) Did any of your patients have associated disease such as an abdominal aneurysm or aortoiliac occlusive disease that was corrected simultaneously? (2) Did any of your patients have bilateral renal artery stenosis? (3) Did you measure and correlate pressure gradients at the time of operation? I believe that three groups of patients are most likely to carry an increased chance that their hypertension is due to renovascular lesions. Group 1 are those who are in the first decade of life. Group 2 are women in whom hypertension develops before age 45 and who are not on the pill. I noted that Dr. Cbung’s series had an abnormally large number of cases of fibromuscular hyperplasia as opposed to most series which consist primarily of group 3 patients, who are those who are over age 50 and have arteriosclerosis as the cause of the lesion. In this third and larger group the important clue is the recent onset of hypertension. We have all had experience with rapid intravenous pyelography or hypertensive intravenous pyelography as a screening procedure, but we should remember that the results are positive in only 70 per cent in most series and
The American Journal 01 Surgery
Renovascular
in less than 50 per cent in patients with fibromuscular hyperplasia. Likewise, split function tests and renal vein renin assays give at least 10 per cent false-negative results. Therefore, aortography is highest on my list of diagnostic tests. Aortography, however, is indicated only if the patient being evaluated would be an operative candidate if a lesion was found. For instance, most patients over 65 would not be surgical candidates unless their hypertension was malignant and uncontrollable, and thus that type of patient should not be subjected to aortography. Despite all these screening tests, including aortography, in certain cases we may not know if we can alleviate the hypertension until we have obtained direct gradients at the operating table. 1 have backed out of several cases when no gradient was demonstrable even though our so-called screening tests indicated that a gradient would be present. When a gradient is present, I prefer, as do the investigators, to perform end-to-side saphenous vein bypass generally. If significant bilateral stenoses are present, the technique of crossclamping the aorta, opening it directly, and performing endarterectomy, as described by Wylie, is the procedure of choice. Since arteriosclerotic renal lesions originate in the aorta, their entire renal tail can be removed in this manner. The safest place to clamp the aorta for this procedure is at the diaphragm above the celiac axis, after which the aorta can be clamped below the renal vessels and opened longitudinally. If you are worried about the ischemit renal time, you can put some ice slush in the abdomen to lower the kidney temperature and to avoid having to rush the endarterectomy. This technique will permit you to endarterectomize all of the renal orifices. In some cases as many as five renal arteries may need to be endarterectomized to cure the hypertension. Finally, 1 would like to mention some historical facts of the first successful case alluded to by Dr. Chung. The patient was a 48 year old patient who was referred by an internist in Sacramento to Dr. Norman Freeman of San Francisco, whom many of you knew. This was in 1951 when Dr. Freeman was working at the Franklin Hospital in San Francisco. This patient was sent to him because of the socalled Leriche syndrome, that is, claudication and sexual impotence. The patient also had hypertension. Aortography performed retrograde through a carotid artery demonstrated aortoiliac occlusive disease and stenosis of one renal artery. Freeman recognized that the hypertension might be secondary to the Goldblatt phenomenon, but I do not believe he had any plans to do anything about it. Dr. Sam Roland, who was a contemporary of mine, was a urology resident at Franklin Hospital then and subsequently told me the following story. He was scrubbing at a sink alongside Dr. Freeman and asked him what he was doing that day. Dr. Freeman replied he was going to perform aortoiliac endarterectomy. Sam said, “Does the patient have hypertension?” Norman said, “Yes, he does.” Sam said, “Maybe he has the Goldblatt phenomenon. Why don’t you clean the renal artery out also?” Freeman said,
Volume 138, July 1979
Hypertension
“I had thought about that possibility. How would you do it?” He said, “I would suggest that you reach into the renal orifice with a right angle clamp when you have the aorta open and pull that plug out.” According to Sam, that is how Norman Freeman happened to do the first case. That first patient was operated on in 1952 and reported on in the Journal of the American Medical Association in 1954. Dr. Frank Leeds, Freeman’s associate, recently told me that the patient lived until 1975, free of hypertension. Finally, it might be of interest to report that the preoperative pyelogram on this first successful case showed nothing abnormal. Richard Ang Lim (Santa Barbara, CA): I want to ask Dr. Chung one question, and that is whether he has seen renal systolic hypertension. Five months ago, I operated on a 67 year old retired, diabetic female anesthesiologist who 1 year previously was found to have hypertensive encephalopathy. The internists tried to treat her with all kinds of medications, including blocking agents, diuretics, and others, and they all failed to control the hypertension. The unusual feature of this case was the persistent systemic hypertension. She had systolic hypertension of 260 to 280 mm Hg with a normal diastolic pressure of about 70 to 80. This is rather rare because we did research on it and talked to people, and nobody has seen this phenomenon associated with renal stenosis. There is bilateral disparity with the rapid sequence intravenous pyelographic screening test. Renal angiography subsequently confirmed a 95 per cent stenosis of the right renal artery. The renin differential test shows a 51 ratio, far higher than the acceptable ratio for diagnosis of renal hypertension. With all of this evidence, therefore, we discussed the problem with her and then operated on her 5 months ago. At surgery we performed aortorenal bypass with a gortex graft. The patient’s systolic pressure returned to normal, medication was discontinued, and she continues to do very well at this point. Nicholas A. Halasz (San Diego, CA): We who perform transplantations have a good model for this because the transplanted kidney’s artery can develop stenosis tprobably from rejection) and produce renovascular hypertension. We learned that these kidneys, in addition to producing hypertension, may have marked deterioration of function and will mimic rejection. The creatinine clearances decrease to 20,15, even 10 ml with a kidney that is perfectly viable. Using this as an example, we have looked carefully at a number of patients who have end-stage renal disease and are being considered for transplantation. A number of these patients, three in the last 5 years, functionally had a solitary kidney with severe stenosis. Therefore, I would like to emphasize that in a patient with one bad kidney and one that, may be good, arteriography is indicated. W. B. Chung (closing): I agree with all Dr. Connolly has said. It is obvious that our series contains a highly selected
147
Chung and Salvian
group of patients who are younger than those in most reported series. As such, they have less associated vascular disease. As a matter of fact, only two patients have asymptomatic carotid bruits, two have angina, and three have peripheral vascular disease. We have not measured the gradient across the stenosis. I believe the correlation of this test to postoperative results has not been absolute. When the many preoperative tests we mentioned indicate renal ischemia, we proceed with bypass. Dr. Connolly’s comment on false-positive and falsenegative results is well taken and is why we depend on a battery of tests rather than on just one or two. An example is our results with rapid sequence intravenous pyelography. Five of these tests were reported as having negative results, yet of these five patients three were cured and two were improved. I cannot comment on thromboendarterectomy through
148
the aorta as we have not used this ingenious procedure. Certainly the reported technical results are very good. Dr. Lim’s case is indeed extraordinary with extremely high systolic pressure and normal diastolic pressure. All of our patients have high diastolic as well as high systolic pressures. The fact that Dr. Lim’s patient was cured by renal artery reconstruction must indicate that the problem was renovascular in origin. Dr. Halasz’s comment on the deterioration of renal function in a transplanted kidney due to renal artery stenosis is important. We had one such patient in our series. I always consider that renal artery stenosis has two deleterious effects on the patient. The first of course is hypertension, but the second, of equal importance, is gradual deterioration of renal function and ultimate renal infarction. The latter possibility, which is often forgotten in our preoccupation with hypertension, should also be considered in renovascular surgery.
The American Journal of Surgery
