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Surgical Correction of Renovascular Hypertension
Urologic Surgery
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Surgical Correction of Renovascular Hypertension
Andrew C. Novick, M.D. *
There are two main categories of renal artery disease, atherosclerosis and fibrous dysplasia, which account for approximately 60 per cent and 40 per cent of all such lesions, respectively. Other, less common, causes of renal artery disease include an arterial aneurysm, arteriovenous fistula, neurofibromatosis, extrinsic obstruction, the middle aortic syndrome, and renal artery thrombosis or embolism. 32 Surgical renal revascularization is well established as an effective method for treating patients with severe hypertenSion or renal insufficiency or both resulting from renal artery disease. Multiple factors must be weighed in determining whether surgical treatment is indicated for a given patient. These include the causal relation of renal vascular disease to the hypertension, the adequacy of blood-pressure control with medical therapy, the natural history of untreated renal vascular disease with particular regard for the risk of impaired renal function, the medical condition of the patient, and the known results of surgical therapy and percutaneous transluminal angioplasty in various clinical subgroups.
DIAGNOSIS OF RENAL VASCULAR HYPERTENSION
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It is important to differentiate renal vascular disease from renal vascular hypertension, because lesions of the renal artery do not always result in hypertenSion. The diagnosis of renal vascular disease depends on angiographic demonstration of a lesion in the renal artery or its branches, whereas the diagnosis of renal vascular hypertension can be confirmed only in retrospect and connotes permanent relief of hypertension after surgical treatment or transluminal angioplasty. In our experience, the most useful clinical assessments for establishing the diagnosis of renal vascular hypertension are a positive rapid-sequence intravenous urogram, a systolicdiastolic abdominal bruit,lO a short (less than 5 years) duration of *Chairman, Department of Urology, Cleveland Clinic Foundation, Cleveland, Ohio
Surgical Clinics of North America-Vol. 68, No, 5, October 1988
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hypertension 21 and the finding on angiography of a high-grade stenotic lesion involving the renal artery. Lateralization to the affected kidney (ratio of 2:1 or more) with differential renal-vein plasma renin assays strongly supports the diagnosis of renal vascular hypertension, but this test is less meaningful when it is negative. 5, 28 More recently, the peripheral plasma renin response to a single dose of oral captopril has proved to be a useful screening test for identifying patients with renal vascular hypertension, 31 Differential isotope renographic changes following captopril administration also appear to be useful in demonstrating functional renal artery stenosis. 17 By considering these assessments in the aggregate, patients with renal vascular hypertension can be identified with a high degree of accuracy.
INDICATIONS FOR SURGICAL TREATMENT Renal Vascular Hypertension In patients with renal vascular hypertension secondary to fibrous dysplasia, the decision for intervention (surgery or angioplasty) is guided by the specific type of disease as determined by angiographic findings and the associated natural history. 19, 30, 47 Medical management of hypertension is the preferred initial treatment for patients with medial fibroplasia, because loss of renal function from progressive obstruction is uncommon with this disease. Interventive treatment in the latter category is reserved for patients whose blood pressure is difficult to control with multiple drugs. Conversely, renal artery stenosis secondary to intimal or perimedial fibroplasis generally progresses and often eventuates in ischemic renal atrophy. Furthermore, these lesions tend to occur in younger patients and to cause hypertension that is extremely difficult to control. Early interventive therapy in these patients is therefore indicated both to preserve renal function and to minimize the need for long-term antihypertensive medication. In selecting patients with fibrous dysplasia for surgical renal revascularization, the efficacy of transluminal angioplasty must also be considered. The results of angioplasty for fibrous dysplasia of the main renal artery have been excellent and equal to those obtained with surgical revascularization; therefore, angioplasty is the initial treatment of choice in such cases. 6. 12,20,49 However, as many as 30 per cent of patients with fibrous dysplasia have branch renal arterial involvement, which increases the technical difficulty of, and often precludes, angioplasty. Therefore, surgical renal revascularization is the primary interventive treatment in this category. 34 In patients with atherosclerotic renal vascular hypertension, more vigorous attempts at medical management are warranted, because these patients are older and often have extrarenal vascular disease. Therefore, multiple-drug regimens that control the blood pressure are often the preferred approach. Indeed, the advent of new beta-blocking agents and converting enzyme inhibitors has enhanced the efficacy of medical antihypertensive therapy. Intervention with surgery or transluminal angioplasty is best reserved for patients whose hypertension cannot be adequately
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controlled or wherein renal function is threatened by advanced vascular disease. Recent experience has shown that angioplasty provides excellent results for the minority of patients with unilateral nonostial atherosclerotic renal artery lesions. 4, 6, 20, 49 The results of angioplasty in the more common ostial atherosclerotic lesions have been poor, however, and surgical revascularization remains the treatment of choice in this category. 34 Renal Artery Aneurysm Renal artery aneurysms may require surgical treatment when they are the cause of significant hypertension or to avert rupture. 44 The latter is of greatest concern with aneurysms that are larger than 2 cm in diameter and noncalcified, particularly when they occur in premenopausal women, because of the predisposition for aneurysmal rupture during pregnancy. Saccular aneurysms can cause hypertension through several mechanisms. 33 These include compression or displacement of the renal artery or its branches, with resulting ischemia; aneurysmal erosion into a renal vein, with formation of an arteriovenous fistula; mural thrombus formation within the aneurysm, with peripheral renal embolization; and the association of some aneurysms with stenosing fibrous renal artery disease. Saccular aneurysms may also cause hypertension, in the absence of any of the above mechanisms, through relative renal ischemia caused by the turbulent flow of blood as it passes through an aneurysmally dilated arterial segment. Preservation of Renal Function in Atherosclerotic Renal Artery Disease Knowledge of the natural history of atherosclerotic renal artery disease has made it possible to identifY those patients in whom such disease poses a significant threat to overall renal function. 47 This designation applies to patients with high-grade (greater than 75 per cent) arterial stenosis affecting the entire renal mass, namely where such stenosis is present bilaterally or involves a solitary kidney. In such patients, the risk of complete renal arterial occlusion is significant, and if this occurs, the clinical outcome is a critical decrease in functioning renal mass with resulting renal failure. It is in such patients that intervention to restore normal renal blood flow is indicated for the purpose of preserving renal function. 35 Clinical experience has shown that these are generally older patients with diffuse atherosclerosis and ostial renal artery lesions. This description encompasses a group in which the results of trans luminal angioplasty have been poor and where surgical revascularization provides optimum therapy. 4, 34, 35, 56 It has been well demonstrated that surgical revascularization can be safe and successful even in older patients with diffuse extrarenal vascular disease. In considering potential candidates for revascularization to preserve renal function, a determination must be made of the potential for salvable renal function. Total occlusion of the renal artery does not necessarily imply irreversible ischemic parenchymal damage, and it is well accepted that with gradual arterial occlusion, the viability of the kidney can be maintained through the development of collateral arterial supply. Helpful clinical clues suggesting renal salvability in such cases include:
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1. A kidney size greater than 9 cm. 2. Function of the involved kidney on intravenous urography or isotope renography. 3. Angiographic demonstration of retrograde filling of the distal renal arterial tree from collateral vessels on the side of total renal arterial occlusion. 4. A renal biopsy demonstrating well-preserved tubules and glomeruli with minimal arteriolar sclerosis.
When criteria indicative of renal salvability are present, successful revascularization can reverse renal failure. 27. 46 It is also important to emphasize that revascularization to preserve renal function is generally not worthwhile in patients with severe azotemia (serum creatinine greater than 4.0 mg per dl), because advanced underlying renal parenchymal disease inevitably is present and prevents improvement in renal function with restored perfusion. The single exception to this occurs in patients with chronic bilateral total occlusion where, fortuitously, the viability of one or both kidneys has been maintained through an abundant collateral supply. The degree of preoperative renal functional impairment in such patients often is severe, and the improvement following revascularization may be dramatic. 54 Unfortunately, this clinical presentation is rare, and a less favorable outcome of bilateral arterial occlusion on renal viability is far more common.
PREPARATION FOR SURGICAL TREATMENT When surgical revascularization is indicated for renal artery disease, it is important to define the general medical condition of the patient accurately because this will determine the risk of undertaking a major vascular operation. Most patients with renal arterial fibrous dysplasia are young and otherwise healthy, and the operative risk is minimal in this group. In patients with atherosclerotic renal vascular disease, the preoperative evaluation should include a thorough search for coronary artery disease, because this has been the leading cause of operative death following surgical revascularization. 36 In addition to a careful history, a physical examination, and an electrocardiogram, all operative candidates in this category undergo a thallium cardiac stress test in our program. If any of the latter assessments suggests the presence of coronary artery disease, our policy is to perform coronary cine angiography and left-sided ventriculography. Myocardial revascularization is recommended for patients with significant correctable coronary artery disease prior to renal revascularization. Cerebrovascular accident has also been a significant cause of death after renal revascularization in patients with atherosclerosis, albeit a less common complication than myocardial infarction. The approach to patients whose history or examination suggests extracranial cerebrovascular disease is analogous to that employed for patients with suspected coronary artery disease. In such patients, carotid arteriography is obtained preoperatively, and if significant occlusive disease is found, endarterectomy is recommended before renal revascularization. 36
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In patients with generalized atherosclerosis and renal artery disease, cardiac function is often compromised to various degrees. In these patients, hypertension increases the workload on the left ventricle, which decreases cardiac reserve and renders the heart less efficient. In addition to an impaired myocardium, these patients also often have a decreased intravascular volume because of prior treatment with diuretic agents. These patients can benefit from a careful hemodynamic assessment in an intensive care unit for 12 to 24 hours prior to surgical revascularization. In the intensive care unit, Swan-Ganz arterial and urethral catheters are placed for measurement of blood pressure, pulmonary capillary wedge pressure, pulmonary artery pressure, cardiac output, total peripheral resistance, and urinary output. While these parameters are being monitored, intravenous vasodilators can be administered to control the blood pressure and decrease cardiac afterload while the intravascular space is carefully expanded with isotonic fluid. Afterload reduction and fluid repletion in this manner optimize perioperative cardiac function by increasing cardiac output and decreasing cardiac work. This approach can enhance the safety of surgical renal revascularization in patients with generalized atherosclerosis. 16
OPERATIVE TECHNIQUES
Nephrectomy
Advances in surgical renal vascular reconstruction have limited the role of total or partial nephrectomy in the management of patients with renal artery disease. These operations are occasionally indicated in patients with renal infarction, severe arteriolar nephrosclerosis, severe renal atrophy, and noncorrectable renal vascular lesions. Nephrectomy may also be indicated in the elderly poor-surgical-risk patient with a normal contralateral kidney or following a failed revascularization procedure. Aortorenal Bypass
Although a variety of surgical revascularization techniques are available for treating patients with renal artery disease, aortorenal bypass with a free graft of autogenous saphenous vein or hypogastric artery is the preferred method in most cases. 11. 37. 51 Although an arterial autograft is theoretically advantageous, use of the hypogastric artery as a bypass graft is limited by its short length and frequent involvement with atherosclerosis. Therefore, autogenous saphenous vein is most often employed, and excellent clinical results continue to be achieved with this type of bypass graft (Fig. 1). It is important to note that the gonadal vein should never be used as a renal artery bypass graft. This vein is extremely friable and may either rupture postoperatively or undergo severe dilatation. Currently, aortorenal bypass with a synthetic material is indicated only when an autogenous vascular graft is not available, and polytetrafluoroethylene has become the synthetic graft of choice in such cases. 23 Aortorenal bypass is performed through a transperitoneal subcostal incision, the medial end of which is curved across the midline. After
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A Figure 1. A, The technique of aortorenal bypass. The bypass graft is anastomosed endto-side to the aorta and end-to-end to the distal renal artery. (From Novick AC: Aortorenal bypass. In Stewart's Operative Urology. Edition 2. Novick AC, Streem SB, Pontes E (eds): Baltimore, Williams & Wilkins Co, 1988; with permission.) B, Aortogram 7 years following bilateral aortorenal saphenous vein bypass shows patent grafts to both kidneys. (From Novick AC: Complications of renovascular surgery. In Ehrlich RM, Smith RB (eds): Complications in Urologic Surgery. Philadelphia, W B Saunders Co, 1988; with permission.)
reflection of the colon medially to expose the kidney and renal vessels, the Buckwalter self-retaining ring retractor is inserted; this provides excellent exposure and allows the operation to be comfortably performed by a surgeon and one assistant. The aorta is exposed from the level of the left renal vein to the inferior mesenteric artery, ligating overlying lymphatic vessels and lumbar segmental branches as necessary to gain exposure. An end-to-side anastomosis of the bypass graft to the aorta is done first to minimize the time of renal ischemia. On the right side, it is important to bring the graft off the anterolateral aspect of the aortic wall to avoid kinking of the proximal anastomosis as the graft passes in front of the vena cava. In most cases, the lateral aortic wall is only partially occluded during this anastomosis, thereby preserving distal aortic flow and obviating systemic heparinization. The main renal artery is then mobilized, and end-to-end anastomosis of the graft to the distal disease-free renal artery is performed. The graft and distal renal artery are spatulated to create a wider anastomosis, which minimizes the possibility for subsequent stenosis. An end-to-end anastomosis of the graft to the renal artery is preferred to an end-to-side technique, because this provides better flow rates, is easier to perform, and allows removal of the diseased renal arterial segment for pathologic study. Both the proximal and distal anastomoses of the bypass graft are performed with interrupted 6-0 arterial sutures. Surgical revascularization is more complicated when the disease extends into the branches of the renal artery or when vascular reconstruction is required for a kidney supplied by multiple renal arteries. When diseasefree distal arterial branches occur outside of the renal hilus, an aortorenal bypass operation can usually be done in situ. 42 In patients with disease
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Figure 2. Sequential vascular anastomoses involved in performing aortorenal bypass with a double-armed branched saphenous vein graft. (From Novick AC, Streem SB, Pontes EJ (eds): Stewart's Operative Urology. Edition 2. Baltimore, Williams & Wilkins Co, 1988; with permission.)
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confined to a single major renal artery branch, aortorenal bypass may be done exclusively to the disease-free distal branch, leaving the main renal artery and its remaining branches intact. In patients wtih disease involving two or more renal artery branches, we have found that aortorenal bypass with a branched vascular graft offers the most useful and versatile technique for in situ vascular reconstruction. 52 Although the hypogastric artery may be removed intact with its branches, this type of graft is invariably too short to reach from the aorta to the renal artery branches. In these cases, a branched saphenous vein graft is fashioned by attaching one or more side arms of vein to the main graft. These end-to-side anastomoses are done with interrupted 7-0 arterial sutures and lead to creation of a multibranched graft that can be used to replace several diseased renal artery branches. Following insertion of the proximal graft into the aorta, direct end-to-end anastomosis of each graft branch to a renal artery branch is done. During performance of each individual branch anastomosis, the remainder of the kidney continues to be perfused, and overall renal ischemia is thus limited to the time required for completion of a single end-to-end anastomosis (approximately 15 to 20 minutes), which is an important advantage (Fig. 2).
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Techniques in the Surgically Difficult Aorta
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In some patients with renal artery disease, involvement of the abdominal aorta with severe atherosclerosis, aneurysmal disease, or dense fibrosis
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Figure 3. A. Location and course of the celiac, splenic, and left renal arteries. B, Completed left splenorenal bypass with end-to-end anastomosis of the splenic artery to the left renal artery. C, Digital subtraction angiogram in a patient who underwent splenorenal bypass demonstrates a patent anastomosis (arrow). (A and B from Novick AC, Khauli RB, Vidt MD: Diminished operative risk and improved results following revascularization for atherosclerotic renovascular disease. Urol Clin North Am 11:435, 1984; with permission.)
from a prior operation may render an aortorenal bypass technically difficult and potentially hazardous to perform. Simultaneous aortic replacement and renal revascularization have been associated with high operative mortality rates 13 , 18. 48, 53 and should be considered only in patients with a significant aortic aneurysm or symptomatic aortoiliac occlusive disease. Alternate surgical approaches that allow renal vascularization to be safely and effectively accomplished while avoiding operation on a badly diseased aorta are preferable in such cases. 38 Splenorenal bypass is the preferred vascular reconstructive technique for patients with a troublesome aorta who require left renal revascularization. 1• 24 A requisite for utilization of this approach is the demonstration on preoperative aortography, with both anteroposterior and lateral views, of widely patent celiac and splenic arteries. The splenic artery must also be carefully examined intraoperatively for intramural atheromatous disease, which may preclude its use for renal revascularization. The technique of splenorenal bypass is described in detail elsewhere. 39 The advantages of this operation are that it involves performance of only a single vascular anastomosis and that it is done well away from the aorta. Transposition of the splenic artery by retroduodenal passage for right renal revascularization has been unsatisfactory and is not recommended. The results of splenorenal bypass for left renal arterial occlusive disease have been excellent and support its use when aortorenal bypass is contraindicated (Fig. 3). At our center, hepatorenal bypass has become the preferrred approach for patients with a troublesome aorta who require right renal revasculari-
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Figure 4. A, Normal course of the main hepatic artery and its various branches. B, The most common method of performing hepatorenal bypass with an interposition saphenous vein graft anastomosed end-toside to the common hepatic artery and endto-end to the right renal artery. C, Digital subtraction angiogram in a patient who underwent this type of hepatorenal bypass. Arrows indicate the interposition saphenous vein graft. (A and B from Novick AG. Khauli RB, Vidt MD: Diminished operative risk and improved results following revascularization for atherosclerotic renovascular disease. U rol Glin North Am 11:435, 1984; with permission.)
zation. 3 The hepatic circulation is ideally suited for a visceral right renal arterial bypass operation. The liver receives 28 per cent of the cardiac output in resting adults and is unique in having a dual circulation from the portal vein and hepatic artery, which contribute 80 per cent and 20 per cent of hepatic blood flow, respectively. Hepatic oxygenation is equally derived from these two circulations. It has been well demonstrated that hepatic artery flow can be safely interrupted. When this occurs, hepatic function and morphology are maintained by increased extraction of oxygen from portal venous blood and by the rapid development of an extensive collateral arterial flow to the liver. In patients considered for a hepatorenal bypass operation, preoperative aortography with lateral views must demonstrate patent celiac and hepatic arteries. In our experience, the hepatic artery is rarely involved with atherosclerosis, certainly less often than the splenic artery. Hepatorenal bypass should also be undertaken only when preoperative biochemical screening reveals normal liver function. The most common method of performing hepatorenal bypass is with an interposition saphenous vein graft anastomosed end-to-side to the common hepatic artery just beyond the gastroduodenal origin and then end-to-end to the right renal artery (Fig. 4). This technique preserves distal hepatic arterial flow and thereby reduces the risk of ischemic liver damage. Other technical variations for employing the hepatic arterial circulation to achieve right renal revascularization are described in detail elsewhere. 29
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A Figure 5. A, Iliorenal bypass with a long saphenous vein graft. B, Angiogram in a patient who underwent a successful right iliorenal bypass operation. (A from Novick AC, Khauli RB, Vidt MD: Diminished operative risk and improved results following revascularization for atherosclerotic renovascular disease. Urol Clin North Am 11:435, 1984; with permission.)
Iliorenal bypass is another useful technique for revascularization in patients with severe aortic atherosclerosis, provided there is satisfactory flow through the diseased aorta and absence of significant iliac disease 40 (Fig. 5). Our approach is to consider this operation only when a splenorenal or hepatorenal bypass cannot be done because of disease involving the celiac, splenic, or hepatic arteries. This philosophy is based on the fact that aortic atherosclerosis may continue to worsen in these patients, and if it does, this process is more likely to involve the infrarenal aorta. Such a development might then compromise flow to a revascularized kidney whose blood supply is derived exclusively from one of the iliac arteries. The suprarenal aorta from which the celiac artery originates is more often spared progressive atherosclerosis, hence our preference for splenorenal or hepatorenal bypass. In patients with good flow through a severely atherosclerotic aorta and a relatively healthy common iliac artery, renal autotransplantation has also been employed as a method of renal revascularization (Fig. 6). In general, we prefer an iliorenal bypass in such cases for several reasons. Compared with renal autotransplantation, an iliorenal bypass involves a shorter period of renal ischemia, and, because mobilization of the kidney is not required, the collateral renal arterial supply is preserved. An iliorenal bypass also requires less operative time, which is an important consideration in patients with generalized atherosclerosis. In unusual cases, aortography reveals an enlarged superior mesenteric
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Figure 6. A. Technique of renal autotransplantation in patients with severe aortic atherosclerosis. B, Arteriogram in a patient with severe aortic atherosclerosis who underwent autotransplantation of the left kidney demonstrates a patent anastomosis of the left renal artery to the left common iliac artery. (From Novick AC, Khauli RB, Vidt MD: Diminished operative risk and improved results follOwing revascularization for atherosclerotic renovascular disease. Urol Clin North Am 11:435, 1984; with permission.)
artery that may be employed for visceral arterial bypass to either kidney. 25 We have employed the superior mesenterorenal bypass technique in patients with a troublesome aorta in whom a bypass to the kidney from the celiac or iliac arteries was not possible (Fig. 7). An enlarged and widely patent superior mesenteric artery is most often observed in patients with total occlusion of the infrarenal aorta. In such cases, the mesenteric artery has a wider caliber than normal because it is supplying collateral vessels to areas ordinarily vascularized from the infrarenal aorta, namely, the large bowel, pelvis, and lower extremities. Use of such an enlarged artery for performance of a mesenterorenal bypass has been well tolerated, with no compromise of intestinal blood flow. We have been reluctant to use this approach in patients with a normal-size superior mesenteric artery and cannot comment on its efficacy in this setting. Extracorporeal Microvascular Branch Renal-Artery Reconstruction Extracorporeal microvascular repair and autotransplantation are indicated in patients with extensive branch renal-artery disease where intrarenal vascular extension or small vessel size preclude a satisfactory in situ repair. 7, 9, 41. 42, 45 Prior to the advent of extracorporeal surgery, such patients would have been considered either inoperable or candidates for nephrectomy, The advantages of employing an extracorporeal surgical approach include optimum exposure and illumination, a bloodless surgical field, greater protection of the kidney from ischemia, and easier employment of microvascular techniques and optical magnification. Removing and flushing
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A Figure 7. A. Superior mesenterorenal bypass with an interposition saphenous vein graft anastomosed end-to-side to the superior mesenteric artery and end-to-end to the renal artery. (A from Novick AC, Khauli RB, Vidt MD: Diminished operative risk and improved results following revascularization for atherosclerotic renovascular disease. Urol Clin North Am 11:435, 1984; with permission.) B, Aortogram demonstrates bilateral renal artery stenosis, more severe on the left side, and total occlusion of the infrarenal aorta. Note the enlarged superior mesenteric artery (arrow). C, Digital subtraction angiogram in this patient following left renal revascularization with a superior mesenterorenal bypass shows a widely patent graft (arrow). (B and C from Khauli R, Novick AC, Coseriu GV, et al: Superior mesenterorenal bypass for renal revascularization with infrarenal aortic occlusion. J Urol 133:188, 1985; with permission.)
the kidney also causes it to contract, thereby enabling more peripheral dissection in the renal sinus for mobilization of distal arterial branches. Finally, the completed branch anastomoses can be tested for patency and integrity prior to autotransplantation. Imrl1ediately following its removal, the kidney is flushed intra-arterially with chilled Collins' intracellular electrolyte solution and then submerged in a basin of ice slush saline to maintain hypothermia. The extracorporeal operation is completed under ice slush surface hypothermia and, if there has been minimal warm renal ischemia, the kidney can safely be preserved in this manner for many more hours than are needed to perform even the most complex renal repair. In performing extracorporeal revascularization, we have found it cumbersome to work on the abdominal wall with the ureter attached. It is
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Figure 8. A, Selective right renal arteriogram demonstrates fibrous dysplasia of the main renal artery that also involves an upper segmental branch. There is also an aneurysm involving this branch distal to the area of stenosis. 8, Operative photograph showing the completed extracorporeal revascularization with a branched graft of the hypogastric artery. The hypogastric arterial branches are anastomosed end-to-end to the distal disease-free renal artery branches (short arrows). The resected diseased portion of the renal artery, including the aneurysm, is also shown (long arrow). C, Operative photograph following autotransplantation into the right iliac fossa with end-to-side anastomosis of the renal artery to the common iliac artery and endto-side anastomosis of the renal vein to the external iliac vein (long arrows). The branch renal artery anastomoses are also shown (short arrows). D, Postoperative digital subtraction angiogram shows that the repaired main renal artery and branches are fully patent.
preferable to divide the ureter and place the kidney on a separate workbench. This provides better exposure for the extracorporeal operation and allows a second surgical team to prepare the iliac fossa simultaneously. The optimum method for extracorporeal branch renal arterial repair involves the use of a branched autogenous vascular graft. 41 This technique permits separate end-to-end microvascular anastomosis of each graft branch
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to a distal renal artery branch. A hypogastric arterial autograft is the preferred material for vascular reconstruction, because this vessel may be obtained intact with several of its branches (Fig. 8). Occasionally, branched grafts containing segments of the saphenous vein or inferior epigastric artery are used. When extracorporeal revascularization has been completed, autotransplantation of the repaired kidney into the iliac fossa is performed, with anastomosis of the renal vessels to the iliac vessels and restoration of urinary continuity by ureteroneocystostomy.
POSTOPERATIVE CARE Patients undergoing surgical renal revascularization may experience wide fluctuations in blood pressure in the early postoperative period, with either hypotensive or hypertensive episodes, which may predispose to graft thrombosis or bleeding from vascular anastomotic sites, respectively. Therefore, these patients are placed in the intensive care unit for monitoring of the central venous pressure, urine output, pulse rate, and serum levels of hemoglobin and creatinine. During this period, the diastolic blood pressure is maintained between 90 and 100 mm Hg to ensure satisfactory renal perfusion. If hypertensive episodes occur, they are managed with intravenous infusion of sodium nitroprusside. Within the first 24 hours postoperatively, a technetium renal scan is obtained to verify perfusion of the revascularized kidney. If clear evidence of perfUSion is not present, then arteriography should be done immediately to examine the repaired renal artery. If the patient's condition is stable, the nasogastric tube, central venous line, arterial line, and urethral catheter are removed 48 hours postoperatively, and intensive care monitoring is discontinued. Prior to discharge from the hospital, if there is no contraindication to the administration of contrast material, an intravenous digital subtraction angiogram is obtained. This study is an excellent noninvasive method for evaluating the arterial supply of the revascularized kidney. 55 Subsequent follow-up is performed by periodic evaluation of the blood pressure; serum creatinine level, or glomerular filtration rate, or both; and technetium renal scanning.
SURGICAL COMPLICATIONS In patients who undergo renal revascularization, general complications associated with any type of major intra-abdominal surgery can develop postoperatively. These include wound hematoma or infection, pleural effusion, atelectasis, pneumonia, thrombophlebitis, pulmonary embolism, paralytic ileus, mechanical bowel obstruction, cerebrovascular accident, or myocardial infarction. Occurrence of the latter two complications can be minimized by preoperative screening for coronary and cerebrovascular disease, as outlined earlier in this article. Complications that relate specifically to the performance of renal vascular surgery are listed below.
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Hypertension Hypertension following renal revascularization may be secondary to stenosis or thrombosis of the repaired renal artery but more commonly is a transient phenomenon caused by any of a variety of factors such as hypervolemia, intraoperative renal ischemia, incisional pain, or vasoconstriction from total body hypothermia. An elevated blood pressure attributable to any or all of the latter causes can persist for several days, and, in fact, this occurs in approximately 50 per cent of patients who are ultimately cured of hypertension by renal revascularization. Acute Renal Failure Because all renal revascularization operations require temporary occlusion of the renal artery, acute renal failure induced by ischemia is a potential problem. Fortunately, clinically significant postischemic acute renal failure is an uncommon occurrence that is invariably reversible with proper treatment. This complication is generally manifested by a rise in the serum creatinine level with or without oliguria. If the repaired renal artery is patent, an isotope renal scan will demonstrate continued perfusion of the revascularized kidney with evidence of diminished function. The cornerstone of treatment for acute renal failure in such cases is proper fluid management to ensure normal extracellular volume and sodium content. Administration of diuretic and vasoactive drugs may also be helpful, particularly during the period immediately after ischemic renal injury. Hemorrhage Acute hemorrhage following surgical revascularization of the kidney is an infrequent complication. When it occurs, it is generally the result of technical factors such as inadequate hemostasis of the operative field, an unsecured branch of a saphenous vein bypass graft, or vascular anastomotic bleeding secondary to improper suture placement or tension at the site of anastomosis. Other factors that may predispose to postoperative hemorrhage include hypertension, unrecognized coagulopathy, or incomplete reversal of systemic heparinization. Renal Artery Thrombosis or Stenosis Postoperative thrombosis or stenosis of the repaired renal artery occurs in less than 5 per cent of patients undergoing revascularization. 34 The causes include postoperative hypotension, a hypercoaguable state, hypovolemia, severe intrarenal arteriolar nephrosclerosis, incomplete excision of primary vascular disease, faulty suture technique, injury to the bypass graft during procurement, trauma from vascular clamps, wide disparity in vessel size, dissection of a distal intimal flap created at surgery, recurrent primary renal disease, and torsion, angulation, or kinking of the anastomosed vessels. Arterial thrombosis generally occurs within the first few days of surgery; the treatment is emergency surgical re-exploration with thrombectomy, graft revision, or both if the kidney is viable. Stenosis of a surgically repaired renal artery can occur weeks, months, or even years after revascularization. When interve,ntion is indicated, the therapeutic options are a secondary operation or trans luminal angioplasty. Because
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secondary surgical revascularization is difficult in such cases, it is reasonable to attempt angioplasty initially if this is technically feasible. Renal Artery Aneurysm Postoperative graft dilatation has been observed on long-term angiographic study of patients who have undergone an aortorenal saphenous vein bypass operation. In two studies, the incidences of this complication were 25 and 52 per cent, with frank aneurysm formation occurring in 5 and 8 per cent of patients. 8.50 The clinical significance of these abnormal~appearing vein grafts remains uncertain, as many of these patients remain normotensive with excellent clinical function. If graft dilatation is either progressive or associated with recurrent hypertension, secondary surgical revascularization may be indicated. Aortic Complications During an aortorenal bypass operation, clamping and unclamping of the abdominal aorta is performed. When the aorta is involved with atherosclerosis, this maneuver can dislodge plaque, resulting in aortic thrombosis, dissection, or distal embolization. These problems can be minimized by selecting a healthy portion of the abdominal aorta for use in such operations. Intraoperative systemic heparinization is a helpful adjunctive measure. Ultimately, the most effective prevention is to avoid operation on the extensively diseased aorta by using those alternate bypass techniques described earlier in this article. RESULTS OF SURGICAL TREATMENT The results of surgical treatment for renal vascular hypertension have always been excellent in patients with fibrous dysplasia;ll, 26. 37, 51 however, traditionally, less satisfactory results have been observed in patients with atherosclerosis. 14. 15 During the past decade, refinements in establishing a preoperative diagnosis of renin-mediated hypertension and an enhanced technical efficacy of vascular reconstruction have improved surgical results in the latter category. There are now several reports of an 85 to 90 per cent cure or improvement rate following renal revascularization for atherosclerotic renal vascular hypertension. 2, i3, 36 We recently reviewed the Cleveland Clinic experience with surgical revascularization for renal artery disease from January 1975 to December 1984. 34 During this lO-year period, a total of 380 revascularization operations were performed in 361 patients with renal artery disease; 19 patients underwent simultaneous or staged bilateral revascularization. The cause of the arterial disease was atherosclerosis in 241 patients, fibrous dysplasia in 104 patients, and an arterial aneurysm in 16 patients. The indication for revascularization in all patients with fibrous dysplasia or an aneurysm was to treat severe renal vascular hypertension. The indications in patients with atherosclerotic disease were treatment of renal vascular hypertension in 80 patients, preservation of renal function in 61 patients, and both control of hypertension and preservation of renal function in 100 patients.
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In this series, the operative mortality rate was 2.1 per cent in patients with atherosclerotic disease and 0 in patients with fibrous dysplasia or an aneurysm. Postoperative thrombosis or stenosis of the repaired renal artery followed 17 of 380 operations (4.5 per cent). Hypertension was cured or improved postoperatively in 91. 7 per cent of patients with atherosclerotic disease and in 93 per cent of patients with fibrous dysplasia or an aneurysm. Postoperative renal function was improved or stable in 88.8 per cent of patients with atherosclerosis who underwent revascularization to preserve renal function.
SUMMARY The role of surgical revascularization in the management of patients with renal artery disease has changed in recent years. This has occurred owing to the advent of transluminal angioplasty as an effective method of treatment for certain patients, improved results of surgical revascularization in older patients with atherosclerosis, an enhanced appreciation of advanced atherosclerotic renal artery disease as a correctable cause of renal failure, and the development of more effective surgical techniques for patients with severe aortic atherosclerosis and branch renal artery disease. Surgical revascularization is at present the treatment of choice for patients with branch renal artery disease, ostial atherosclerotic renal artery disease, a renal artery aneurysm, and patients in whom renal angioplasty has been unsuccessful. Excellent clinical results continue to be achieved with surgical revascularization in properly selected patients.
REFERENCES 1. Brewster DC, Darling RC: Splenorenal arterial anastomosis for renovascular hypertension. Ann Surg 189:353, 1979 . 2. Buda JA, Baer L, Parra-Carilo JZ, et al: Predictability of surgical response in renovascular hypertension. Arch Surg 111:1243, 1976 3. Chibaro EA, Libertino JA, Novick AC: Use of the hepatic circulation for renal revascularization. Ann Surg 199:406, 1984 4. Cicuto KP, McLean GK, Oleaga J, et al: Renal artery stenosis: anatomic classification for percutaneous angioplasty. AJR 137:599, 1981 5. Couch NP, Sullivan J, Crane C: The predictive accuracy of renal vein renin activity in the surgery of renovascular hypertension. Surgery 79:70, 1976 6. Council on Scientific Affairs: Percutaneous transluminal angioplasty. JAMA 251:764, 1984 7. Dean RH, Meacham PW, Weaver FA: Ex vivo renal artery reconstructions: indications and techniques. J Vasc Surgery 4:546, 1986 8. Dean RH, Wilson JP, Burko H, et al: Saphenous vein aortorenal bypass grafts: serial arteriographic study. Ann Surg 180:469, 1974 9. Dubernard JM, Martin X, Gelet A, et al: Renal autotransplantation versus bypass techniques for renovascular hypertension. Surgery 97:529, 1985 10. Eipper DF, Gifford RW, Stewart BH, et al: Abdominal bruits in renovascular hypertension. Am J Cardiol 13:48, 1976 11. Ernst CB, Stanley JC, Marshall FF, et al: Autogenous saphenous vein aortorenal autografts: a ten-year experience. Arch Surg 150:855, 1972. 12. Flechner SM: Percutaneous transluminal dilatation: a realistic appraisal in patients with stenosing lesions of the renal artery. Urol Clin North Am 11:515, 1984
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13. Foster JH, Dean RH, Pinkerton JA, et al: Ten years experience with the surgical management of renovascular hypertension. Ann Surg 177:755, 1973 14. Foster JH, Maxwell MH, Franklin SS, et al: Renovascular occlusive disease: results of operative treatment. JAM A 231:1043, 1975 15. Franklin SS, Young JD, Maxwell WH, et al: Operative morbidity and mortality in renovascular disease. JAMA 231:1148, 1975 16. Fry RE, Fry WJ: Renovascular hypertension in the patient with severe atherosclerosis . . Arch Surg 117:938, 1982 17. Geyskes GG, Oei HY, Puylaert C, et al: Renovascular hypertension identified by captoprilinduced changes in the renogram. Hypertension 9:451, 1987. 18. Gomes M, Bernatz PE: Aortoiliac occlusive disease: extension cephalad to origin of renal arterial disease with considerations and results. Arch Surg 101:161, 1970 19. Harrison HG, McCormack LJ: Pathologic classification of renal artery disease in renovascular hypertension. Mayo Clin Proc 46:161, 1971 20. Hayes J, Risius B, Novick AC, et al: Experience with percutaneous transluminal angioplasty for renal artery stenosis at the Cleveland Clinic. J U rol 139:488, 1988 21. Hughes JS, Dove HG, Gifford RW, et al: Duration of blood pressure elevation in accurately predicting surgical cure of renovascular hypertension. Am Heart J 101:408, 1981 22. Jordan JL, Novick AC, Cunningham RL: The role of renal autotransplantation in pediatric and young adult patients with renal artery disease. J Vasc Surgery 2:385, 1985 23. Khauli RB, Novick AC, Coseriu GV: Renal revascularization with polytetrafluoroethylene grafts. Cleve Clin Q 51:365, 1984 24. Khauli R, Novick AC, Ziegelbaum W: Splenorenal bypass in the treatment of renal artery stenosis: experience with 69 cases. J Vasc Surg 2:547, 1985 25. Khauli RB, Novick AC, Coseriu GV, et al: Superior mesenterorenal bypass for renal revascularization with infrarenal aortic occlusion. J U rol 133: 188, 1985 26. Lankford NS, Donahue JP, Grim CE, et al: Results of surgical treatment of renovascular hypertension. J Urol 122:439, 1979 27. Libertino JA, Zinman L, Breslin DJ, et al: Renal artery revascularization: restoration of renal function. JAMA 244:1340, 1980 28. Mark LS, Maxwell MH, Varady PD, et al: Renovascular hypertension: does the renal vein renin ratio predict operative results? J Urol 115:365, 1976 29. McElroy J, Novick AC: Renal revascularization by end-to-end anastomosis of the hepatic and renal arteries. J UroI134:1089, 1985 30. Meaney TF, Dtistan HP, McCormack LJ: Natural history of renal arterial disease. Radiology 91:881, 1968 31. Muller FB, Seeley JE, Case DB, et al: The captopril test for identifying renovascular disease in hypertensive patients. Am J Med 80:633, 1986 32. Novick AC, Stewart BH: Surgical treatment of renovascular hypertension. Curr Probl Surg 16(8), 1979 33. Novick AC: Renal artery aneurysm and arteriovenous malformation. In Novick AC, Straffon RA (eds): Vascular Problems in Urologic Surgery. Philadelphia, WB Saunders Co, 1982 34. Novick AC, Ziegelbaum M, Vidt DG, et al: Trends in surgical revascularization for renal artery disease: ten years' experience. JAMA 257:498, 1987 35. Novick AC, Pohl MA, Schreiber MJ, et al: Renal revascularization for preservation of kidney function in patients with atherosclerotic renovascular disease. J Urol 129:907, 1983 36. Novick AC, Straffon RA, Stewart BH, et al: Diminished operative morbidity and mortality following revascularization for atherosclerotic renovascular disease. JAM A 246:749, 1981 37. Novick AC, Straffon RA, Stewart BH: Autogenous arterial grafts in the treatment of renal artery stenosis. J Urol 118:919, 1977 38. Novick AC, Stewart BH, Straffon RA, et al: Renal revascularization in patients with atherosclerosis or a previous operation on the abdominal aorta. Surg Gynecol Obstet 144:211, 1977 39. Novick AC, Banowsky LH, Stewart BH, et al: Splenorenal bypass in the treatment of stenosis of the renal artery. Surg Gynecol Obstet 144:891, 1977 40. Novick AC, Banowsky LH: I1iorenal saphenous vein bypass graft: alternative for renal revascularization in a patient with surgically difficult aorta. J U rol 122:243, 1979
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41. Novick AC: Management of intrarenal branch arterial lesions with extracorporeal microvascular reconstruction and autotransplantation. J U rol 126: 150, 1981 42. Novick AC: Surgical management of branch renal artery disease: value of in situ and extracorporeal technique. Nephron 44(Suppl):40, 1986 43. Novick AC: Complications of renal vascular surgery and percutaneous transluminal angioplasty. In Marshall FF (ed): Urologic Complications. Chicago, Year Book Medical Publishers, 1986 44. Poutasse EF: Renal artery aneurysms. J Urol113:433, 1975 45. Salvatierra 0, Olcott C, Stoney RJ: Ex vivo renal artery reconstruction using perfusion preservation. J Urol 119:16, 1978 46. Schefft P, Novick AC, Stewart BH, et al: Renal revascularization in patients with total occlusion of the renal artery. J UroI124:184, 1980 47. Schreiber MJ, Pohl MA, Novick AC: The natural history of atherosclerotic and fibrous renal artery disease. Urol Clin North Am 11:383, 1984 48. Shahian DM, Najafi H, Javid H, et al: Simultaneous aortic and renal artery reconstruction. Arch Surg 115:1491, 1980 49. Sos TA, Pickering PC, Sniderman KW, et al: Percutaneous transluminal renal angiography in renovascular hypertension due to atheroma or fibrous dysplasia. N Engl J Med 309:274, 1983 50. Stanley JC, Ernst CB, Fry WJ: Fate of 100 aortorenal vein grafts: characteristics of late graft expansion, aneurysmal dilatation, and stenosis. Surgery 74:931, 1973 51. Stoney RJ, Deluccia N, Ehrenfeld WK, et al: Aortorenal arterial autografts: long-term assessment. Arch Surg 116:1416, 1981 52. Streem SB, Novick AC: Aortorenal bypass with a branched saphenous vein graft for in situ repair of multiple segmental renal arteries. Surg Cynecol Obstet 155:855, 1982 53. Tarazi RY, Hertzer NR, Beven EC, et al: Simultaneous aortic reconstruction and renal revascularization: risk factors and late results in 89 patients. Surgery 5:709, 1987 54. Wasser WC, Krakoff LR, Haimov M, et al: Restoration of renal function after bilateral renal artery occlusion. Arch Intern Med 141:1647, 1981 55. Zabbo A, Novick AC: Digital subtraction angiography for noninvasive imaging of the renal artery. Urol Clin North Am 11:409, 1987 56. Ziegelbaum M, Novick AC, Hayes J, et al: Management of renal arterial disease in the elderly patient. Surg Cynecol Obstet 165:130, 1987 Department of Urology Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland, Ohio 44106
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Surgical Correction of Renovascular Hypertension
Andrew C. Novick, M.D. *
There are two main categories of renal artery disease, atherosclerosis and fibrous dysplasia, which account for approximately 60 per cent and 40 per cent of all such lesions, respectively. Other, less common, causes of renal artery disease include an arterial aneurysm, arteriovenous fistula, neurofibromatosis, extrinsic obstruction, the middle aortic syndrome, and renal artery thrombosis or embolism. 32 Surgical renal revascularization is well established as an effective method for treating patients with severe hypertenSion or renal insufficiency or both resulting from renal artery disease. Multiple factors must be weighed in determining whether surgical treatment is indicated for a given patient. These include the causal relation of renal vascular disease to the hypertension, the adequacy of blood-pressure control with medical therapy, the natural history of untreated renal vascular disease with particular regard for the risk of impaired renal function, the medical condition of the patient, and the known results of surgical therapy and percutaneous transluminal angioplasty in various clinical subgroups.
DIAGNOSIS OF RENAL VASCULAR HYPERTENSION
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It is important to differentiate renal vascular disease from renal vascular hypertension, because lesions of the renal artery do not always result in hypertenSion. The diagnosis of renal vascular disease depends on angiographic demonstration of a lesion in the renal artery or its branches, whereas the diagnosis of renal vascular hypertension can be confirmed only in retrospect and connotes permanent relief of hypertension after surgical treatment or transluminal angioplasty. In our experience, the most useful clinical assessments for establishing the diagnosis of renal vascular hypertension are a positive rapid-sequence intravenous urogram, a systolicdiastolic abdominal bruit,lO a short (less than 5 years) duration of *Chairman, Department of Urology, Cleveland Clinic Foundation, Cleveland, Ohio
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hypertension 21 and the finding on angiography of a high-grade stenotic lesion involving the renal artery. Lateralization to the affected kidney (ratio of 2:1 or more) with differential renal-vein plasma renin assays strongly supports the diagnosis of renal vascular hypertension, but this test is less meaningful when it is negative. 5, 28 More recently, the peripheral plasma renin response to a single dose of oral captopril has proved to be a useful screening test for identifying patients with renal vascular hypertension, 31 Differential isotope renographic changes following captopril administration also appear to be useful in demonstrating functional renal artery stenosis. 17 By considering these assessments in the aggregate, patients with renal vascular hypertension can be identified with a high degree of accuracy.
INDICATIONS FOR SURGICAL TREATMENT Renal Vascular Hypertension In patients with renal vascular hypertension secondary to fibrous dysplasia, the decision for intervention (surgery or angioplasty) is guided by the specific type of disease as determined by angiographic findings and the associated natural history. 19, 30, 47 Medical management of hypertension is the preferred initial treatment for patients with medial fibroplasia, because loss of renal function from progressive obstruction is uncommon with this disease. Interventive treatment in the latter category is reserved for patients whose blood pressure is difficult to control with multiple drugs. Conversely, renal artery stenosis secondary to intimal or perimedial fibroplasis generally progresses and often eventuates in ischemic renal atrophy. Furthermore, these lesions tend to occur in younger patients and to cause hypertension that is extremely difficult to control. Early interventive therapy in these patients is therefore indicated both to preserve renal function and to minimize the need for long-term antihypertensive medication. In selecting patients with fibrous dysplasia for surgical renal revascularization, the efficacy of transluminal angioplasty must also be considered. The results of angioplasty for fibrous dysplasia of the main renal artery have been excellent and equal to those obtained with surgical revascularization; therefore, angioplasty is the initial treatment of choice in such cases. 6. 12,20,49 However, as many as 30 per cent of patients with fibrous dysplasia have branch renal arterial involvement, which increases the technical difficulty of, and often precludes, angioplasty. Therefore, surgical renal revascularization is the primary interventive treatment in this category. 34 In patients with atherosclerotic renal vascular hypertension, more vigorous attempts at medical management are warranted, because these patients are older and often have extrarenal vascular disease. Therefore, multiple-drug regimens that control the blood pressure are often the preferred approach. Indeed, the advent of new beta-blocking agents and converting enzyme inhibitors has enhanced the efficacy of medical antihypertensive therapy. Intervention with surgery or transluminal angioplasty is best reserved for patients whose hypertension cannot be adequately
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controlled or wherein renal function is threatened by advanced vascular disease. Recent experience has shown that angioplasty provides excellent results for the minority of patients with unilateral nonostial atherosclerotic renal artery lesions. 4, 6, 20, 49 The results of angioplasty in the more common ostial atherosclerotic lesions have been poor, however, and surgical revascularization remains the treatment of choice in this category. 34 Renal Artery Aneurysm Renal artery aneurysms may require surgical treatment when they are the cause of significant hypertension or to avert rupture. 44 The latter is of greatest concern with aneurysms that are larger than 2 cm in diameter and noncalcified, particularly when they occur in premenopausal women, because of the predisposition for aneurysmal rupture during pregnancy. Saccular aneurysms can cause hypertension through several mechanisms. 33 These include compression or displacement of the renal artery or its branches, with resulting ischemia; aneurysmal erosion into a renal vein, with formation of an arteriovenous fistula; mural thrombus formation within the aneurysm, with peripheral renal embolization; and the association of some aneurysms with stenosing fibrous renal artery disease. Saccular aneurysms may also cause hypertension, in the absence of any of the above mechanisms, through relative renal ischemia caused by the turbulent flow of blood as it passes through an aneurysmally dilated arterial segment. Preservation of Renal Function in Atherosclerotic Renal Artery Disease Knowledge of the natural history of atherosclerotic renal artery disease has made it possible to identifY those patients in whom such disease poses a significant threat to overall renal function. 47 This designation applies to patients with high-grade (greater than 75 per cent) arterial stenosis affecting the entire renal mass, namely where such stenosis is present bilaterally or involves a solitary kidney. In such patients, the risk of complete renal arterial occlusion is significant, and if this occurs, the clinical outcome is a critical decrease in functioning renal mass with resulting renal failure. It is in such patients that intervention to restore normal renal blood flow is indicated for the purpose of preserving renal function. 35 Clinical experience has shown that these are generally older patients with diffuse atherosclerosis and ostial renal artery lesions. This description encompasses a group in which the results of trans luminal angioplasty have been poor and where surgical revascularization provides optimum therapy. 4, 34, 35, 56 It has been well demonstrated that surgical revascularization can be safe and successful even in older patients with diffuse extrarenal vascular disease. In considering potential candidates for revascularization to preserve renal function, a determination must be made of the potential for salvable renal function. Total occlusion of the renal artery does not necessarily imply irreversible ischemic parenchymal damage, and it is well accepted that with gradual arterial occlusion, the viability of the kidney can be maintained through the development of collateral arterial supply. Helpful clinical clues suggesting renal salvability in such cases include:
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1. A kidney size greater than 9 cm. 2. Function of the involved kidney on intravenous urography or isotope renography. 3. Angiographic demonstration of retrograde filling of the distal renal arterial tree from collateral vessels on the side of total renal arterial occlusion. 4. A renal biopsy demonstrating well-preserved tubules and glomeruli with minimal arteriolar sclerosis.
When criteria indicative of renal salvability are present, successful revascularization can reverse renal failure. 27. 46 It is also important to emphasize that revascularization to preserve renal function is generally not worthwhile in patients with severe azotemia (serum creatinine greater than 4.0 mg per dl), because advanced underlying renal parenchymal disease inevitably is present and prevents improvement in renal function with restored perfusion. The single exception to this occurs in patients with chronic bilateral total occlusion where, fortuitously, the viability of one or both kidneys has been maintained through an abundant collateral supply. The degree of preoperative renal functional impairment in such patients often is severe, and the improvement following revascularization may be dramatic. 54 Unfortunately, this clinical presentation is rare, and a less favorable outcome of bilateral arterial occlusion on renal viability is far more common.
PREPARATION FOR SURGICAL TREATMENT When surgical revascularization is indicated for renal artery disease, it is important to define the general medical condition of the patient accurately because this will determine the risk of undertaking a major vascular operation. Most patients with renal arterial fibrous dysplasia are young and otherwise healthy, and the operative risk is minimal in this group. In patients with atherosclerotic renal vascular disease, the preoperative evaluation should include a thorough search for coronary artery disease, because this has been the leading cause of operative death following surgical revascularization. 36 In addition to a careful history, a physical examination, and an electrocardiogram, all operative candidates in this category undergo a thallium cardiac stress test in our program. If any of the latter assessments suggests the presence of coronary artery disease, our policy is to perform coronary cine angiography and left-sided ventriculography. Myocardial revascularization is recommended for patients with significant correctable coronary artery disease prior to renal revascularization. Cerebrovascular accident has also been a significant cause of death after renal revascularization in patients with atherosclerosis, albeit a less common complication than myocardial infarction. The approach to patients whose history or examination suggests extracranial cerebrovascular disease is analogous to that employed for patients with suspected coronary artery disease. In such patients, carotid arteriography is obtained preoperatively, and if significant occlusive disease is found, endarterectomy is recommended before renal revascularization. 36
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In patients with generalized atherosclerosis and renal artery disease, cardiac function is often compromised to various degrees. In these patients, hypertension increases the workload on the left ventricle, which decreases cardiac reserve and renders the heart less efficient. In addition to an impaired myocardium, these patients also often have a decreased intravascular volume because of prior treatment with diuretic agents. These patients can benefit from a careful hemodynamic assessment in an intensive care unit for 12 to 24 hours prior to surgical revascularization. In the intensive care unit, Swan-Ganz arterial and urethral catheters are placed for measurement of blood pressure, pulmonary capillary wedge pressure, pulmonary artery pressure, cardiac output, total peripheral resistance, and urinary output. While these parameters are being monitored, intravenous vasodilators can be administered to control the blood pressure and decrease cardiac afterload while the intravascular space is carefully expanded with isotonic fluid. Afterload reduction and fluid repletion in this manner optimize perioperative cardiac function by increasing cardiac output and decreasing cardiac work. This approach can enhance the safety of surgical renal revascularization in patients with generalized atherosclerosis. 16
OPERATIVE TECHNIQUES
Nephrectomy
Advances in surgical renal vascular reconstruction have limited the role of total or partial nephrectomy in the management of patients with renal artery disease. These operations are occasionally indicated in patients with renal infarction, severe arteriolar nephrosclerosis, severe renal atrophy, and noncorrectable renal vascular lesions. Nephrectomy may also be indicated in the elderly poor-surgical-risk patient with a normal contralateral kidney or following a failed revascularization procedure. Aortorenal Bypass
Although a variety of surgical revascularization techniques are available for treating patients with renal artery disease, aortorenal bypass with a free graft of autogenous saphenous vein or hypogastric artery is the preferred method in most cases. 11. 37. 51 Although an arterial autograft is theoretically advantageous, use of the hypogastric artery as a bypass graft is limited by its short length and frequent involvement with atherosclerosis. Therefore, autogenous saphenous vein is most often employed, and excellent clinical results continue to be achieved with this type of bypass graft (Fig. 1). It is important to note that the gonadal vein should never be used as a renal artery bypass graft. This vein is extremely friable and may either rupture postoperatively or undergo severe dilatation. Currently, aortorenal bypass with a synthetic material is indicated only when an autogenous vascular graft is not available, and polytetrafluoroethylene has become the synthetic graft of choice in such cases. 23 Aortorenal bypass is performed through a transperitoneal subcostal incision, the medial end of which is curved across the midline. After
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A Figure 1. A, The technique of aortorenal bypass. The bypass graft is anastomosed endto-side to the aorta and end-to-end to the distal renal artery. (From Novick AC: Aortorenal bypass. In Stewart's Operative Urology. Edition 2. Novick AC, Streem SB, Pontes E (eds): Baltimore, Williams & Wilkins Co, 1988; with permission.) B, Aortogram 7 years following bilateral aortorenal saphenous vein bypass shows patent grafts to both kidneys. (From Novick AC: Complications of renovascular surgery. In Ehrlich RM, Smith RB (eds): Complications in Urologic Surgery. Philadelphia, W B Saunders Co, 1988; with permission.)
reflection of the colon medially to expose the kidney and renal vessels, the Buckwalter self-retaining ring retractor is inserted; this provides excellent exposure and allows the operation to be comfortably performed by a surgeon and one assistant. The aorta is exposed from the level of the left renal vein to the inferior mesenteric artery, ligating overlying lymphatic vessels and lumbar segmental branches as necessary to gain exposure. An end-to-side anastomosis of the bypass graft to the aorta is done first to minimize the time of renal ischemia. On the right side, it is important to bring the graft off the anterolateral aspect of the aortic wall to avoid kinking of the proximal anastomosis as the graft passes in front of the vena cava. In most cases, the lateral aortic wall is only partially occluded during this anastomosis, thereby preserving distal aortic flow and obviating systemic heparinization. The main renal artery is then mobilized, and end-to-end anastomosis of the graft to the distal disease-free renal artery is performed. The graft and distal renal artery are spatulated to create a wider anastomosis, which minimizes the possibility for subsequent stenosis. An end-to-end anastomosis of the graft to the renal artery is preferred to an end-to-side technique, because this provides better flow rates, is easier to perform, and allows removal of the diseased renal arterial segment for pathologic study. Both the proximal and distal anastomoses of the bypass graft are performed with interrupted 6-0 arterial sutures. Surgical revascularization is more complicated when the disease extends into the branches of the renal artery or when vascular reconstruction is required for a kidney supplied by multiple renal arteries. When diseasefree distal arterial branches occur outside of the renal hilus, an aortorenal bypass operation can usually be done in situ. 42 In patients with disease
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Figure 2. Sequential vascular anastomoses involved in performing aortorenal bypass with a double-armed branched saphenous vein graft. (From Novick AC, Streem SB, Pontes EJ (eds): Stewart's Operative Urology. Edition 2. Baltimore, Williams & Wilkins Co, 1988; with permission.)
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confined to a single major renal artery branch, aortorenal bypass may be done exclusively to the disease-free distal branch, leaving the main renal artery and its remaining branches intact. In patients wtih disease involving two or more renal artery branches, we have found that aortorenal bypass with a branched vascular graft offers the most useful and versatile technique for in situ vascular reconstruction. 52 Although the hypogastric artery may be removed intact with its branches, this type of graft is invariably too short to reach from the aorta to the renal artery branches. In these cases, a branched saphenous vein graft is fashioned by attaching one or more side arms of vein to the main graft. These end-to-side anastomoses are done with interrupted 7-0 arterial sutures and lead to creation of a multibranched graft that can be used to replace several diseased renal artery branches. Following insertion of the proximal graft into the aorta, direct end-to-end anastomosis of each graft branch to a renal artery branch is done. During performance of each individual branch anastomosis, the remainder of the kidney continues to be perfused, and overall renal ischemia is thus limited to the time required for completion of a single end-to-end anastomosis (approximately 15 to 20 minutes), which is an important advantage (Fig. 2).
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In some patients with renal artery disease, involvement of the abdominal aorta with severe atherosclerosis, aneurysmal disease, or dense fibrosis
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Figure 3. A. Location and course of the celiac, splenic, and left renal arteries. B, Completed left splenorenal bypass with end-to-end anastomosis of the splenic artery to the left renal artery. C, Digital subtraction angiogram in a patient who underwent splenorenal bypass demonstrates a patent anastomosis (arrow). (A and B from Novick AC, Khauli RB, Vidt MD: Diminished operative risk and improved results following revascularization for atherosclerotic renovascular disease. Urol Clin North Am 11:435, 1984; with permission.)
from a prior operation may render an aortorenal bypass technically difficult and potentially hazardous to perform. Simultaneous aortic replacement and renal revascularization have been associated with high operative mortality rates 13 , 18. 48, 53 and should be considered only in patients with a significant aortic aneurysm or symptomatic aortoiliac occlusive disease. Alternate surgical approaches that allow renal vascularization to be safely and effectively accomplished while avoiding operation on a badly diseased aorta are preferable in such cases. 38 Splenorenal bypass is the preferred vascular reconstructive technique for patients with a troublesome aorta who require left renal revascularization. 1• 24 A requisite for utilization of this approach is the demonstration on preoperative aortography, with both anteroposterior and lateral views, of widely patent celiac and splenic arteries. The splenic artery must also be carefully examined intraoperatively for intramural atheromatous disease, which may preclude its use for renal revascularization. The technique of splenorenal bypass is described in detail elsewhere. 39 The advantages of this operation are that it involves performance of only a single vascular anastomosis and that it is done well away from the aorta. Transposition of the splenic artery by retroduodenal passage for right renal revascularization has been unsatisfactory and is not recommended. The results of splenorenal bypass for left renal arterial occlusive disease have been excellent and support its use when aortorenal bypass is contraindicated (Fig. 3). At our center, hepatorenal bypass has become the preferrred approach for patients with a troublesome aorta who require right renal revasculari-
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Figure 4. A, Normal course of the main hepatic artery and its various branches. B, The most common method of performing hepatorenal bypass with an interposition saphenous vein graft anastomosed end-toside to the common hepatic artery and endto-end to the right renal artery. C, Digital subtraction angiogram in a patient who underwent this type of hepatorenal bypass. Arrows indicate the interposition saphenous vein graft. (A and B from Novick AG. Khauli RB, Vidt MD: Diminished operative risk and improved results following revascularization for atherosclerotic renovascular disease. U rol Glin North Am 11:435, 1984; with permission.)
zation. 3 The hepatic circulation is ideally suited for a visceral right renal arterial bypass operation. The liver receives 28 per cent of the cardiac output in resting adults and is unique in having a dual circulation from the portal vein and hepatic artery, which contribute 80 per cent and 20 per cent of hepatic blood flow, respectively. Hepatic oxygenation is equally derived from these two circulations. It has been well demonstrated that hepatic artery flow can be safely interrupted. When this occurs, hepatic function and morphology are maintained by increased extraction of oxygen from portal venous blood and by the rapid development of an extensive collateral arterial flow to the liver. In patients considered for a hepatorenal bypass operation, preoperative aortography with lateral views must demonstrate patent celiac and hepatic arteries. In our experience, the hepatic artery is rarely involved with atherosclerosis, certainly less often than the splenic artery. Hepatorenal bypass should also be undertaken only when preoperative biochemical screening reveals normal liver function. The most common method of performing hepatorenal bypass is with an interposition saphenous vein graft anastomosed end-to-side to the common hepatic artery just beyond the gastroduodenal origin and then end-to-end to the right renal artery (Fig. 4). This technique preserves distal hepatic arterial flow and thereby reduces the risk of ischemic liver damage. Other technical variations for employing the hepatic arterial circulation to achieve right renal revascularization are described in detail elsewhere. 29
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A Figure 5. A, Iliorenal bypass with a long saphenous vein graft. B, Angiogram in a patient who underwent a successful right iliorenal bypass operation. (A from Novick AC, Khauli RB, Vidt MD: Diminished operative risk and improved results following revascularization for atherosclerotic renovascular disease. Urol Clin North Am 11:435, 1984; with permission.)
Iliorenal bypass is another useful technique for revascularization in patients with severe aortic atherosclerosis, provided there is satisfactory flow through the diseased aorta and absence of significant iliac disease 40 (Fig. 5). Our approach is to consider this operation only when a splenorenal or hepatorenal bypass cannot be done because of disease involving the celiac, splenic, or hepatic arteries. This philosophy is based on the fact that aortic atherosclerosis may continue to worsen in these patients, and if it does, this process is more likely to involve the infrarenal aorta. Such a development might then compromise flow to a revascularized kidney whose blood supply is derived exclusively from one of the iliac arteries. The suprarenal aorta from which the celiac artery originates is more often spared progressive atherosclerosis, hence our preference for splenorenal or hepatorenal bypass. In patients with good flow through a severely atherosclerotic aorta and a relatively healthy common iliac artery, renal autotransplantation has also been employed as a method of renal revascularization (Fig. 6). In general, we prefer an iliorenal bypass in such cases for several reasons. Compared with renal autotransplantation, an iliorenal bypass involves a shorter period of renal ischemia, and, because mobilization of the kidney is not required, the collateral renal arterial supply is preserved. An iliorenal bypass also requires less operative time, which is an important consideration in patients with generalized atherosclerosis. In unusual cases, aortography reveals an enlarged superior mesenteric
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Figure 6. A. Technique of renal autotransplantation in patients with severe aortic atherosclerosis. B, Arteriogram in a patient with severe aortic atherosclerosis who underwent autotransplantation of the left kidney demonstrates a patent anastomosis of the left renal artery to the left common iliac artery. (From Novick AC, Khauli RB, Vidt MD: Diminished operative risk and improved results follOwing revascularization for atherosclerotic renovascular disease. Urol Clin North Am 11:435, 1984; with permission.)
artery that may be employed for visceral arterial bypass to either kidney. 25 We have employed the superior mesenterorenal bypass technique in patients with a troublesome aorta in whom a bypass to the kidney from the celiac or iliac arteries was not possible (Fig. 7). An enlarged and widely patent superior mesenteric artery is most often observed in patients with total occlusion of the infrarenal aorta. In such cases, the mesenteric artery has a wider caliber than normal because it is supplying collateral vessels to areas ordinarily vascularized from the infrarenal aorta, namely, the large bowel, pelvis, and lower extremities. Use of such an enlarged artery for performance of a mesenterorenal bypass has been well tolerated, with no compromise of intestinal blood flow. We have been reluctant to use this approach in patients with a normal-size superior mesenteric artery and cannot comment on its efficacy in this setting. Extracorporeal Microvascular Branch Renal-Artery Reconstruction Extracorporeal microvascular repair and autotransplantation are indicated in patients with extensive branch renal-artery disease where intrarenal vascular extension or small vessel size preclude a satisfactory in situ repair. 7, 9, 41. 42, 45 Prior to the advent of extracorporeal surgery, such patients would have been considered either inoperable or candidates for nephrectomy, The advantages of employing an extracorporeal surgical approach include optimum exposure and illumination, a bloodless surgical field, greater protection of the kidney from ischemia, and easier employment of microvascular techniques and optical magnification. Removing and flushing
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A Figure 7. A. Superior mesenterorenal bypass with an interposition saphenous vein graft anastomosed end-to-side to the superior mesenteric artery and end-to-end to the renal artery. (A from Novick AC, Khauli RB, Vidt MD: Diminished operative risk and improved results following revascularization for atherosclerotic renovascular disease. Urol Clin North Am 11:435, 1984; with permission.) B, Aortogram demonstrates bilateral renal artery stenosis, more severe on the left side, and total occlusion of the infrarenal aorta. Note the enlarged superior mesenteric artery (arrow). C, Digital subtraction angiogram in this patient following left renal revascularization with a superior mesenterorenal bypass shows a widely patent graft (arrow). (B and C from Khauli R, Novick AC, Coseriu GV, et al: Superior mesenterorenal bypass for renal revascularization with infrarenal aortic occlusion. J Urol 133:188, 1985; with permission.)
the kidney also causes it to contract, thereby enabling more peripheral dissection in the renal sinus for mobilization of distal arterial branches. Finally, the completed branch anastomoses can be tested for patency and integrity prior to autotransplantation. Imrl1ediately following its removal, the kidney is flushed intra-arterially with chilled Collins' intracellular electrolyte solution and then submerged in a basin of ice slush saline to maintain hypothermia. The extracorporeal operation is completed under ice slush surface hypothermia and, if there has been minimal warm renal ischemia, the kidney can safely be preserved in this manner for many more hours than are needed to perform even the most complex renal repair. In performing extracorporeal revascularization, we have found it cumbersome to work on the abdominal wall with the ureter attached. It is
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Figure 8. A, Selective right renal arteriogram demonstrates fibrous dysplasia of the main renal artery that also involves an upper segmental branch. There is also an aneurysm involving this branch distal to the area of stenosis. 8, Operative photograph showing the completed extracorporeal revascularization with a branched graft of the hypogastric artery. The hypogastric arterial branches are anastomosed end-to-end to the distal disease-free renal artery branches (short arrows). The resected diseased portion of the renal artery, including the aneurysm, is also shown (long arrow). C, Operative photograph following autotransplantation into the right iliac fossa with end-to-side anastomosis of the renal artery to the common iliac artery and endto-side anastomosis of the renal vein to the external iliac vein (long arrows). The branch renal artery anastomoses are also shown (short arrows). D, Postoperative digital subtraction angiogram shows that the repaired main renal artery and branches are fully patent.
preferable to divide the ureter and place the kidney on a separate workbench. This provides better exposure for the extracorporeal operation and allows a second surgical team to prepare the iliac fossa simultaneously. The optimum method for extracorporeal branch renal arterial repair involves the use of a branched autogenous vascular graft. 41 This technique permits separate end-to-end microvascular anastomosis of each graft branch
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to a distal renal artery branch. A hypogastric arterial autograft is the preferred material for vascular reconstruction, because this vessel may be obtained intact with several of its branches (Fig. 8). Occasionally, branched grafts containing segments of the saphenous vein or inferior epigastric artery are used. When extracorporeal revascularization has been completed, autotransplantation of the repaired kidney into the iliac fossa is performed, with anastomosis of the renal vessels to the iliac vessels and restoration of urinary continuity by ureteroneocystostomy.
POSTOPERATIVE CARE Patients undergoing surgical renal revascularization may experience wide fluctuations in blood pressure in the early postoperative period, with either hypotensive or hypertensive episodes, which may predispose to graft thrombosis or bleeding from vascular anastomotic sites, respectively. Therefore, these patients are placed in the intensive care unit for monitoring of the central venous pressure, urine output, pulse rate, and serum levels of hemoglobin and creatinine. During this period, the diastolic blood pressure is maintained between 90 and 100 mm Hg to ensure satisfactory renal perfusion. If hypertensive episodes occur, they are managed with intravenous infusion of sodium nitroprusside. Within the first 24 hours postoperatively, a technetium renal scan is obtained to verify perfusion of the revascularized kidney. If clear evidence of perfUSion is not present, then arteriography should be done immediately to examine the repaired renal artery. If the patient's condition is stable, the nasogastric tube, central venous line, arterial line, and urethral catheter are removed 48 hours postoperatively, and intensive care monitoring is discontinued. Prior to discharge from the hospital, if there is no contraindication to the administration of contrast material, an intravenous digital subtraction angiogram is obtained. This study is an excellent noninvasive method for evaluating the arterial supply of the revascularized kidney. 55 Subsequent follow-up is performed by periodic evaluation of the blood pressure; serum creatinine level, or glomerular filtration rate, or both; and technetium renal scanning.
SURGICAL COMPLICATIONS In patients who undergo renal revascularization, general complications associated with any type of major intra-abdominal surgery can develop postoperatively. These include wound hematoma or infection, pleural effusion, atelectasis, pneumonia, thrombophlebitis, pulmonary embolism, paralytic ileus, mechanical bowel obstruction, cerebrovascular accident, or myocardial infarction. Occurrence of the latter two complications can be minimized by preoperative screening for coronary and cerebrovascular disease, as outlined earlier in this article. Complications that relate specifically to the performance of renal vascular surgery are listed below.
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Hypertension Hypertension following renal revascularization may be secondary to stenosis or thrombosis of the repaired renal artery but more commonly is a transient phenomenon caused by any of a variety of factors such as hypervolemia, intraoperative renal ischemia, incisional pain, or vasoconstriction from total body hypothermia. An elevated blood pressure attributable to any or all of the latter causes can persist for several days, and, in fact, this occurs in approximately 50 per cent of patients who are ultimately cured of hypertension by renal revascularization. Acute Renal Failure Because all renal revascularization operations require temporary occlusion of the renal artery, acute renal failure induced by ischemia is a potential problem. Fortunately, clinically significant postischemic acute renal failure is an uncommon occurrence that is invariably reversible with proper treatment. This complication is generally manifested by a rise in the serum creatinine level with or without oliguria. If the repaired renal artery is patent, an isotope renal scan will demonstrate continued perfusion of the revascularized kidney with evidence of diminished function. The cornerstone of treatment for acute renal failure in such cases is proper fluid management to ensure normal extracellular volume and sodium content. Administration of diuretic and vasoactive drugs may also be helpful, particularly during the period immediately after ischemic renal injury. Hemorrhage Acute hemorrhage following surgical revascularization of the kidney is an infrequent complication. When it occurs, it is generally the result of technical factors such as inadequate hemostasis of the operative field, an unsecured branch of a saphenous vein bypass graft, or vascular anastomotic bleeding secondary to improper suture placement or tension at the site of anastomosis. Other factors that may predispose to postoperative hemorrhage include hypertension, unrecognized coagulopathy, or incomplete reversal of systemic heparinization. Renal Artery Thrombosis or Stenosis Postoperative thrombosis or stenosis of the repaired renal artery occurs in less than 5 per cent of patients undergoing revascularization. 34 The causes include postoperative hypotension, a hypercoaguable state, hypovolemia, severe intrarenal arteriolar nephrosclerosis, incomplete excision of primary vascular disease, faulty suture technique, injury to the bypass graft during procurement, trauma from vascular clamps, wide disparity in vessel size, dissection of a distal intimal flap created at surgery, recurrent primary renal disease, and torsion, angulation, or kinking of the anastomosed vessels. Arterial thrombosis generally occurs within the first few days of surgery; the treatment is emergency surgical re-exploration with thrombectomy, graft revision, or both if the kidney is viable. Stenosis of a surgically repaired renal artery can occur weeks, months, or even years after revascularization. When interve,ntion is indicated, the therapeutic options are a secondary operation or trans luminal angioplasty. Because
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secondary surgical revascularization is difficult in such cases, it is reasonable to attempt angioplasty initially if this is technically feasible. Renal Artery Aneurysm Postoperative graft dilatation has been observed on long-term angiographic study of patients who have undergone an aortorenal saphenous vein bypass operation. In two studies, the incidences of this complication were 25 and 52 per cent, with frank aneurysm formation occurring in 5 and 8 per cent of patients. 8.50 The clinical significance of these abnormal~appearing vein grafts remains uncertain, as many of these patients remain normotensive with excellent clinical function. If graft dilatation is either progressive or associated with recurrent hypertension, secondary surgical revascularization may be indicated. Aortic Complications During an aortorenal bypass operation, clamping and unclamping of the abdominal aorta is performed. When the aorta is involved with atherosclerosis, this maneuver can dislodge plaque, resulting in aortic thrombosis, dissection, or distal embolization. These problems can be minimized by selecting a healthy portion of the abdominal aorta for use in such operations. Intraoperative systemic heparinization is a helpful adjunctive measure. Ultimately, the most effective prevention is to avoid operation on the extensively diseased aorta by using those alternate bypass techniques described earlier in this article. RESULTS OF SURGICAL TREATMENT The results of surgical treatment for renal vascular hypertension have always been excellent in patients with fibrous dysplasia;ll, 26. 37, 51 however, traditionally, less satisfactory results have been observed in patients with atherosclerosis. 14. 15 During the past decade, refinements in establishing a preoperative diagnosis of renin-mediated hypertension and an enhanced technical efficacy of vascular reconstruction have improved surgical results in the latter category. There are now several reports of an 85 to 90 per cent cure or improvement rate following renal revascularization for atherosclerotic renal vascular hypertension. 2, i3, 36 We recently reviewed the Cleveland Clinic experience with surgical revascularization for renal artery disease from January 1975 to December 1984. 34 During this lO-year period, a total of 380 revascularization operations were performed in 361 patients with renal artery disease; 19 patients underwent simultaneous or staged bilateral revascularization. The cause of the arterial disease was atherosclerosis in 241 patients, fibrous dysplasia in 104 patients, and an arterial aneurysm in 16 patients. The indication for revascularization in all patients with fibrous dysplasia or an aneurysm was to treat severe renal vascular hypertension. The indications in patients with atherosclerotic disease were treatment of renal vascular hypertension in 80 patients, preservation of renal function in 61 patients, and both control of hypertension and preservation of renal function in 100 patients.
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In this series, the operative mortality rate was 2.1 per cent in patients with atherosclerotic disease and 0 in patients with fibrous dysplasia or an aneurysm. Postoperative thrombosis or stenosis of the repaired renal artery followed 17 of 380 operations (4.5 per cent). Hypertension was cured or improved postoperatively in 91. 7 per cent of patients with atherosclerotic disease and in 93 per cent of patients with fibrous dysplasia or an aneurysm. Postoperative renal function was improved or stable in 88.8 per cent of patients with atherosclerosis who underwent revascularization to preserve renal function.
SUMMARY The role of surgical revascularization in the management of patients with renal artery disease has changed in recent years. This has occurred owing to the advent of transluminal angioplasty as an effective method of treatment for certain patients, improved results of surgical revascularization in older patients with atherosclerosis, an enhanced appreciation of advanced atherosclerotic renal artery disease as a correctable cause of renal failure, and the development of more effective surgical techniques for patients with severe aortic atherosclerosis and branch renal artery disease. Surgical revascularization is at present the treatment of choice for patients with branch renal artery disease, ostial atherosclerotic renal artery disease, a renal artery aneurysm, and patients in whom renal angioplasty has been unsuccessful. Excellent clinical results continue to be achieved with surgical revascularization in properly selected patients.
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13. Foster JH, Dean RH, Pinkerton JA, et al: Ten years experience with the surgical management of renovascular hypertension. Ann Surg 177:755, 1973 14. Foster JH, Maxwell MH, Franklin SS, et al: Renovascular occlusive disease: results of operative treatment. JAM A 231:1043, 1975 15. Franklin SS, Young JD, Maxwell WH, et al: Operative morbidity and mortality in renovascular disease. JAMA 231:1148, 1975 16. Fry RE, Fry WJ: Renovascular hypertension in the patient with severe atherosclerosis . . Arch Surg 117:938, 1982 17. Geyskes GG, Oei HY, Puylaert C, et al: Renovascular hypertension identified by captoprilinduced changes in the renogram. Hypertension 9:451, 1987. 18. Gomes M, Bernatz PE: Aortoiliac occlusive disease: extension cephalad to origin of renal arterial disease with considerations and results. Arch Surg 101:161, 1970 19. Harrison HG, McCormack LJ: Pathologic classification of renal artery disease in renovascular hypertension. Mayo Clin Proc 46:161, 1971 20. Hayes J, Risius B, Novick AC, et al: Experience with percutaneous transluminal angioplasty for renal artery stenosis at the Cleveland Clinic. J U rol 139:488, 1988 21. Hughes JS, Dove HG, Gifford RW, et al: Duration of blood pressure elevation in accurately predicting surgical cure of renovascular hypertension. Am Heart J 101:408, 1981 22. Jordan JL, Novick AC, Cunningham RL: The role of renal autotransplantation in pediatric and young adult patients with renal artery disease. J Vasc Surgery 2:385, 1985 23. Khauli RB, Novick AC, Coseriu GV: Renal revascularization with polytetrafluoroethylene grafts. Cleve Clin Q 51:365, 1984 24. Khauli R, Novick AC, Ziegelbaum W: Splenorenal bypass in the treatment of renal artery stenosis: experience with 69 cases. J Vasc Surg 2:547, 1985 25. Khauli RB, Novick AC, Coseriu GV, et al: Superior mesenterorenal bypass for renal revascularization with infrarenal aortic occlusion. J U rol 133: 188, 1985 26. Lankford NS, Donahue JP, Grim CE, et al: Results of surgical treatment of renovascular hypertension. J Urol 122:439, 1979 27. Libertino JA, Zinman L, Breslin DJ, et al: Renal artery revascularization: restoration of renal function. JAMA 244:1340, 1980 28. Mark LS, Maxwell MH, Varady PD, et al: Renovascular hypertension: does the renal vein renin ratio predict operative results? J Urol 115:365, 1976 29. McElroy J, Novick AC: Renal revascularization by end-to-end anastomosis of the hepatic and renal arteries. J UroI134:1089, 1985 30. Meaney TF, Dtistan HP, McCormack LJ: Natural history of renal arterial disease. Radiology 91:881, 1968 31. Muller FB, Seeley JE, Case DB, et al: The captopril test for identifying renovascular disease in hypertensive patients. Am J Med 80:633, 1986 32. Novick AC, Stewart BH: Surgical treatment of renovascular hypertension. Curr Probl Surg 16(8), 1979 33. Novick AC: Renal artery aneurysm and arteriovenous malformation. In Novick AC, Straffon RA (eds): Vascular Problems in Urologic Surgery. Philadelphia, WB Saunders Co, 1982 34. Novick AC, Ziegelbaum M, Vidt DG, et al: Trends in surgical revascularization for renal artery disease: ten years' experience. JAMA 257:498, 1987 35. Novick AC, Pohl MA, Schreiber MJ, et al: Renal revascularization for preservation of kidney function in patients with atherosclerotic renovascular disease. J Urol 129:907, 1983 36. Novick AC, Straffon RA, Stewart BH, et al: Diminished operative morbidity and mortality following revascularization for atherosclerotic renovascular disease. JAM A 246:749, 1981 37. Novick AC, Straffon RA, Stewart BH: Autogenous arterial grafts in the treatment of renal artery stenosis. J Urol 118:919, 1977 38. Novick AC, Stewart BH, Straffon RA, et al: Renal revascularization in patients with atherosclerosis or a previous operation on the abdominal aorta. Surg Gynecol Obstet 144:211, 1977 39. Novick AC, Banowsky LH, Stewart BH, et al: Splenorenal bypass in the treatment of stenosis of the renal artery. Surg Gynecol Obstet 144:891, 1977 40. Novick AC, Banowsky LH: I1iorenal saphenous vein bypass graft: alternative for renal revascularization in a patient with surgically difficult aorta. J U rol 122:243, 1979
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41. Novick AC: Management of intrarenal branch arterial lesions with extracorporeal microvascular reconstruction and autotransplantation. J U rol 126: 150, 1981 42. Novick AC: Surgical management of branch renal artery disease: value of in situ and extracorporeal technique. Nephron 44(Suppl):40, 1986 43. Novick AC: Complications of renal vascular surgery and percutaneous transluminal angioplasty. In Marshall FF (ed): Urologic Complications. Chicago, Year Book Medical Publishers, 1986 44. Poutasse EF: Renal artery aneurysms. J Urol113:433, 1975 45. Salvatierra 0, Olcott C, Stoney RJ: Ex vivo renal artery reconstruction using perfusion preservation. J Urol 119:16, 1978 46. Schefft P, Novick AC, Stewart BH, et al: Renal revascularization in patients with total occlusion of the renal artery. J UroI124:184, 1980 47. Schreiber MJ, Pohl MA, Novick AC: The natural history of atherosclerotic and fibrous renal artery disease. Urol Clin North Am 11:383, 1984 48. Shahian DM, Najafi H, Javid H, et al: Simultaneous aortic and renal artery reconstruction. Arch Surg 115:1491, 1980 49. Sos TA, Pickering PC, Sniderman KW, et al: Percutaneous transluminal renal angiography in renovascular hypertension due to atheroma or fibrous dysplasia. N Engl J Med 309:274, 1983 50. Stanley JC, Ernst CB, Fry WJ: Fate of 100 aortorenal vein grafts: characteristics of late graft expansion, aneurysmal dilatation, and stenosis. Surgery 74:931, 1973 51. Stoney RJ, Deluccia N, Ehrenfeld WK, et al: Aortorenal arterial autografts: long-term assessment. Arch Surg 116:1416, 1981 52. Streem SB, Novick AC: Aortorenal bypass with a branched saphenous vein graft for in situ repair of multiple segmental renal arteries. Surg Cynecol Obstet 155:855, 1982 53. Tarazi RY, Hertzer NR, Beven EC, et al: Simultaneous aortic reconstruction and renal revascularization: risk factors and late results in 89 patients. Surgery 5:709, 1987 54. Wasser WC, Krakoff LR, Haimov M, et al: Restoration of renal function after bilateral renal artery occlusion. Arch Intern Med 141:1647, 1981 55. Zabbo A, Novick AC: Digital subtraction angiography for noninvasive imaging of the renal artery. Urol Clin North Am 11:409, 1987 56. Ziegelbaum M, Novick AC, Hayes J, et al: Management of renal arterial disease in the elderly patient. Surg Cynecol Obstet 165:130, 1987 Department of Urology Cleveland Clinic Foundation 9500 Euclid Avenue Cleveland, Ohio 44106
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