Renal Artery Bypass Research Articles

Antegrade aortorenal bypass graft: A new alternative

The search for a site of origin for renal artery bypass grafting other than the inclusion aorta has resulted in a variety of recommendations, including use of the splenic, hepatic, gastroduodenal, and superior mesenteric arteries and even retrograde bypass grafts originating from the iliac artery. The present study has described our early experience with a new procedure utilizing an antegrade aortorenal bypass graft originating in the mediastinal supraceliac aorta. Eight patients underwent operation; four for renovascular hypertension and four for renal salvage plus hypertension. There were no operative deaths. All grafts (three saphenous and five polytetrafluoroethylene) functioned well, as judged by clinical response and renal scan. One graft failed at 6 weeks. Hypertension was cured in three patients and improved in four at a mean follow-up of 27 months (range 3 to 58 months). Improved hemodynamic performance of antegrade flow, avoidance of liver and biliary complications, and applicability to the right or left kidney are the advantages of this technique. When renal artery reconstruction is required and the infrarenal aorta is to be avoided, we believe this operation is a useful alternative.

Multicenter prospective study of nonruptured abdominal aortic aneurysms. I. Population and operative management

This article describes the patient population and operative management of 666 patients with nonruptured aneurysms of the abdominal aorta. Statistical significance of variables was determined by the chi-square test and logistic regression analysis. There were no statistically significant differences (p > 0.05) in mortality rate for abdominal aortic aneurysm (AAA) on the basis of indication for surgery (asymptomatic, 3.9%; asymptomatic but with evidence of enlargement, 4.9%; and symptomatic, 7.2%) or the urgency of operation (elective operation, 4.5%; and urgent operation, 7.1%). Characteristics of the 72 participating surgeons did not influence the operative mortality rate. A family history of AAA was documented in 6.1% of cases and was more common if the patient was female (p = 0.03) and less than 65 years of age (p = 0.04). Patients without clinical evidence of coronary artery disease had a 0.8% mortality rate from cardiac disease compared with 6.2% if any stigmata of coronary disease were present. Prior aortocoronary bypass surgery did not reduce the incidence of postoperative cardiac events or operative mortality rate. Patients having “routine” angiography did not have a less complicated operative course, fewer thrombotic complications, or lower mortality rate than those not having it. Those patients with an inflammatory AAA (4.5%) did not have a significantly higher incidence of pain. Heparin administration (84.8%) did not reduce the complications of graft thrombosis, “trash”, distal thrombosis, and/or amputation. The 6.8% of patients requiring suprarenal aortic cross-clamping had a higher incidence of postoperative renal dysfunction (p = 0.02) and intraoperative blood loss (p < 0.001), but cardiac events were not more frequent. When the aortic cross-clamping time was prolonged (more than 70 minutes), the requirement for crystalloid fluid administration increased (p < 0.001) and postoperative myocardial infarction was more common (p = 0.004). After ligation of the left renal vein in 7.9%, renal damage or dialysis was more frequent (p = 0.01). Patients having an intra-abdominal graft (tube, 38.5% and biiliac, 30.7%) had fewer wound infections (p = 0.02) and graft thromboses (p < 0.001) than the patients with a femoral anastomosis. When the internal iliac artery flow was interrupted bilaterally (12%), diarrhea (p = 0.03) and ischemic colitis (p = 0.03) were more frequent complications. Reimplantation of the inferior mesenteric artery was carried out in 4.8%. After renal artery bypass in 2.1%, the mortality rate was not increased, but the incidence of transient renal dysfunction was increased (p = 0.03). In the 6.6% having concomitant nonvascular surgery with potential for bacterial contamination, there were no cases of wound infection, but graft sepsis was the cause of death in one case. Observations from this prospective multicenter study can be generalized to reflect current surgical practice and standards of AAA surgery on a national level.

腎動脈閉塞後長期間の腎不全より回復した大動脈炎症候群の一例 腎のｖｉａｂｉｌｉｔｙ術前評価についての考察

腎動脈閉塞後長期間の腎不全より回復した大動脈炎症候群の一例 腎のｖｉａｂｉｌｉｔｙ術前評価についての考察

Use of polytetrafluoroethylene grafts for renal bypass.

Fifty-six revascularizations of the renal arteries were performed in 52 patients with renovascular hypertension with the use of polytetrafluorethylene grafts between June 1979 and October 1984, with an average follow-up of 25.0 +/- 7.7 months. Ninety-two percent of the patients were considered to have good results (30% cured and 62% improved). Four patients were classified as unsuccessfully treated; one died postoperatively of myocardial infarction. All patients underwent late angiographic studies, with only one graft thrombosis being identified. No evidence of anastomotic stenosis, graft dilatation, or false aneurysm occurred during the follow-up period. From this experience, we believe polytetrafluoroethylene grafts are a valuable alternative to other graft materials for renal artery bypass and may be the preferred graft in the management of atheromatous lesions.

Use of polytetrafluoroethylene grafts for renal bypass

Fifty-six revascularizations of the renal arteries were performed in 52 patients with renovascular hypertension with the use of polytetrafluorethylene grafts between June 1979 and October 1984, with an average follow-up of 25.0 ± 7.7 months. Ninety-two percent of the patients were considered to have good results (30% cured and 62% improved). Four patients were classified as unsuccessfully treated; one died postoperatively of myocardial infarction. All patients underwent late angiographic studies, with only one graft thrombosis being identified. No evidence of anastomotic stenosis, graft dilatation, or false aneurysm occurred during the follow-up period. From this experience, we believe polytetrafluoroethylene grafts are a valuable alternative to other graft materials for renal artery bypass and may be the preferred graft in the management of atheromatous lesions.

The effect of coronary bypass on the outcome of peripheral vascular operations in 1093 patients

One of the greatest risks in peripheral vascular operations is the presence of significant coronary artery disease. To assess the proper timing and demonstrate a possible protective effect of coronary artery bypass (CAB), 1093 patients who underwent one or more peripheral vascular operations in addition to CAB from 1976 through 1984 were analyzed. During that same period, 24,441 patients underwent CAB procedures, and 8530 patients underwent major vascular operations. Carotid endarterectomy (493 patients), abdominal aneurysm resection (130 patients), renal artery bypass (12 patients), aorto-femoral bypass (77 patients), femoral-popliteal-tibial bypass (190 patients), and combined vascular procedures (191 patients) were included. The patients were divided into three groups according to severity of disease, which determined timing of the procedure. Group 1 (255 patients) underwent simultaneous CAB and peripheral vascular operation because of unstable coronary artery disease and severe vascular disease. The early mortality rate for group I was 4% (10 patients). Seven of the 10 deaths were cardiac. In group II, 279 patients had CAB and peripheral vascular operation during the same hospital admission with the same operative mortality rate (4%, 10 patients). Six deaths were from cardiac causes, three from neurologic causes, and one from hemorrhage. In group III, 559 patients underwent CAB first, then peripheral vascular operation during a separate hospital admission. There were no cardiac-related deaths and only one neurologic-related death (operative mortality rate, 0.2%). These data demonstrate the protective effect of CAB in patients who undergo elective vascular surgery. The increased risk in patients undergoing simultaneous or same admission procedures was related to the severity of the vascular and coronary artery disease and not to the combined operations. Operative complications were not increased by performing simultaneous or same admission procedures.

Surgical correction of abdominal aortic coarctation and hypertension

Coarctations of the abdominal aorta are often associated with renal artery stenosis resulting in hypertension, which is commonly the presenting symptom. Controversy exists concerning the origin of these lesions, but there is general agreement that surgical intervention is the treatment of choice. We report four patients with abdominal aortic coarctation and concomitant renal artery stenosis who required aortoaortic bypass and appropriate bypass to the renal vessels. We advise total correction in one stage and proximal renal artery bypass from native aorta or iliac artery when it is technically feasible.

Complex Renal Artery Reconstruction: Surgical Techniques

We analized the techniques and results of 28 complex renal artery recon structions. The techniques employed for reconstruction included patch angio plasty of renal artery aneurysms, right iliac to right renal artery bypass for redo revascularization, renal artery reimplantation and renal artery bypass simulta neous with the surgical treatment of associated aortic, visceral or peripheral arterial lesions. Of the 28 reconstructions, 2 (7%) failed requiring revision. There was no hospital mortality and only 1 late death. With proper patient selection, operative exposure, renal protection and ingenuity, most complex re nal lesions can be treated successfully in situ and concomitant with other associ ated arterial problems.

The occluded renal artery: Durability of revascularization

Between 1970 and 1982, 50 patients (38 male and 12 female) underwent revascularization of 51 occluded renal arteries. Ages ranged from 8 to 71 years (mean 54.6 years). Occlusion was caused by atherosclerosis in 43 patients, fibromuscular dysplasia in three, chronic dissection in two, abdominal aortic coarctation in one, and neurofibromatosis in one. Contralateral renal artery occlusive disease occurred in 22 patients. Extrarenal atherosclerosis occurred in 44 patients. Mean preoperative serum creatinine level ranged from 0.5 to 8.4 mg/dl (mean 1.9 mg/dl). No patient required preoperative dialysis. Length of the involved kidney ranged from 8.4 to 14.5 cm (mean 11.5 cm). Indication for renal revascularization was hypertension in 49 patients and preservation of renal function in one. Renal artery bypass was performed in 36 patients, renal artery endarterectomy in six, transaortic endarterectomy in five, and reimplantation of the renal artery in three. Simultaneous revascularization of the contralateral renal artery was performed in 20 patients. There were three operative deaths. At hospital dismissal, hypertension had improved in 45 of 46 patients. Follow-up periods ranged from 4 months to 12 years (mean 50.2 months). Thirty-four patients remained normotensive, five still had less hypertension, and seven became worse. These data demonstrate that revascularization of an occluded renal artery can be effective in controlling hypertension and that this effect is durable in the majority of patients.

The occluded renal artery: durability of revascularization.

Between 1970 and 1982, 50 patients (38 male and 12 female) underwent revascularization of 51 occluded renal arteries. Ages ranged from 8 to 71 years (mean 54.6 years). Occlusion was caused by atherosclerosis in 43 patients, fibromuscular dysplasia in three, chronic dissection in two, abdominal aortic coarctation in one, and neurofibromatosis in one. Contralateral renal artery occlusive disease occurred in 22 patients. Extrarenal atherosclerosis occurred in 44 patients. Mean preoperative serum creatinine level ranged from 0.5 to 8.4 mg/dl (mean 1.9 mg/dl). No patient required preoperative dialysis. Length of the involved kidney ranged from 8.4 to 14.5 cm (mean 11.5 cm). Indication for renal revascularization was hypertension in 49 patients and preservation of renal function in one. Renal artery bypass was performed in 36 patients, renal artery endarterectomy in six, transaortic endarterectomy in five, and reimplantation of the renal artery in three. Simultaneous revascularization of the contralateral renal artery was performed in 20 patients. There were three operative deaths. At hospital dismissal, hypertension had improved in 45 of 46 patients. Follow-up periods ranged from 4 months to 12 years (mean 50.2 months). Thirty-four patients remained normotensive, five still had less hypertension, and seven became worse. These data demonstrate that revascularization of an occluded renal artery can be effective in controlling hypertension and that this effect is durable in the majority of patients.

Percutaneous Transluminal Dilatation or Surgery in the Management of Renal Vascular Hypertension?

1. Twelve patients with renal artery stenosis due to fibromuscular disease (FMD) were treated with percutaneous transluminal dilation (PTD) and their results (first year) compared with those for 26 patients treated with attempted renal artery bypass. The cumulative probability of cure at 1 year was 0.67 for PTD and 0.36 for surgery (P = N.S.) in patients with FMD. The cumulative probability of being improved or cured was 0.92 for PTD and 0.88 for surgery. 2. Eighteen patients with renal artery stenosis due to atherosclerosis were treated with PTD and their results compared with those of 28 patients treated by surgery. The cumulative probability of cure at 1 year was 0.11 for PTD and 0.17 for surgery (P = N.S.). The cumulative probability for cure or improvement at 1 year was 0.30 for PTD and 0.88 for surgery (P less than 0.001). 3. We conclude that PTD may be a satisfactory alternative to surgery in fibromuscular disease, but is inferior to surgery in atherosclerotic disease causing renal artery stenosis. 4. A randomized clinical trial is needed to define the role of PTD and surgery in renal artery stenosis.

Abnormal saphenous vein composition in human hypertension.

The water, sodium, potassium, glycosaminoglycan (hexosamine), and bound sodium content of saphenous veins obtained from 90 male patients undergoing coronary artery or renal artery bypass surgery was measured. For measurement of bound sodium content, the veins were frozen and thawed twice (to disrupt cell membranes) then incubated in physiologic salt solution at 37°C for one hour. Bound sodium was calculated by subtraction of dissolved sodium from total sodium. Based on chart review, the patients were classified as normotensive (N=43, aged 56.1 years, mean), hypertensive (N=35, aged 55.6) and borderline hypertensive (N=12, aged 58.3). Seventy-seven percent of hypertensive, 17 percent of borderline hypertensive and 2 percent of normotensive patients were receiving thiazide diuretics prior to surgery. Saphenous vein water, 734 ± 3 ml/kg wet weight (mean ± SE), and hexosamine, 34.1 ± 1.2 mM/kg dry weight (N = 14), content of hypertensive patients was increased (p < 0.05) compared to values obtained in normotensives (724 ± 3 and 30.7 ± 1.0, N = 20). Venous wall hexosamine and bound sodium contents were positively correlated in the normotensive (r = 0.89, p < 0.01, N = 10) but not in the hypertensive group of patients (r = 0.35, N = 9). The water content of veins of patients with borderline hypertension was 740 ± 11 ml/kg wet weight (N=11, p < 0.06). The extensive use of diuretics might have accounted for the lack of differences in the electrolyte and bound sodium content of veins among the groups. The findings indicate that vascular wall waterlogging may occur on both the high- and low-pressure side of the circulation in human hypertension; therefore, circulating humoral factors also may participate in its pathogenesis. The increased hexosamine concentration of veins in human hypertension may be a manifestation of systemic atherosclerosis rather than of hypertension.

Late results of reconstructive surgery for renovascular disease.

In order to determine the late results of reconstructive surgery for renovascular disease, a review was made of a series of 505 consecutive patients who underwent operation over a 20-year period. There were 257 males (50.9%) with an age range of 3-80 years. Renal artery bypass grafts were used in 75.4% (471/625) and thromboendarterectomy and/or patch angioplasty in 15.0% (94/625) of reconstructions. Associated vascular procedures were performed in 38.0% (186/489) of patients. Operative mortality (30-day) was 1.8% (9/489) overall, and 4.8% (9/186) with associated procedures but there was no operative mortality in 303 consecutive isolated renal artery reconstructions. The blood pressure was normal or improved in 65% of patients at a mean follow-up interval of 49.3 months, range 1-240 months. The best response rate was obtained in younger patients with isolated renal lesions. Linear regression analysis showed age at operation to be the most important determinant of blood pressure response (p < 0.003) with the presence or absence of diffuse atherosclerosis as another but less powerful determinant of responsiveness (p < 0.07). Crude 15-year survival was 70% (340/489). The overall five- and ten-year actuarial survival probabilities were 80 and 62% respectively. The most common causes of death were myocardial infarction, stroke, and cancer. Cox regression analysis for variables influencing survival indicated that age at operation (p < 0.001), sex (p < 0.01) and the presence or absence of fibromuscular disease (p < 0.002) were the major determinants of late survival with persistent severe hypertension exerting an important but lesser influence. The results of this study indicate that about two-thirds of patients will experience long-term relief of hypertension after operation and that the best long-term survival and blood pressure relief will be obtained in patients less than 50 years of age. Because hypertension in females is better tolerated, younger, male patients appear to have the most to gain from successful renovascular reconstruction.

Progression of medial fibroplasia of the renal artery and the development of renovascular hypertension.

A 33-year-old normotensive white women was rejected as a kidney donor because arteriography disclosed medial fibroplasia of the right renal artery. 44 months later she became hypertensive and arteriography revealed progression of the lesion. When renal venous renin assay demonstrated lateralization, a saphenous vein aortico-distal right renal arterial bypass graft was done; her blood pressure has been normal for more than 2 years since. Such patients should not donate kidneys because the course of renal arterial dysplastic lesions cannot be predicted.

主題I-2-14 上腸間膜動脈・右腎動脈バイパス法による腎血管性高血圧症の外科治療

主題I-2-14 上腸間膜動脈・右腎動脈バイパス法による腎血管性高血圧症の外科治療

Aortoenteric Fistula

Gastrointestinal bleeding commonly occurs secondary to peptic ulceration, erosive gastritis, and rupture of esophagogastric varices. Bleeding caused by an aortoenteric fistula may be confusing, and must be differentiated, because immediate operation is mandatory.¹Aortoenteric fistulization, first reported by Salmon²in 1843, frequently results from rupture of an abdominal aortic aneurysm into the bowel. The incidence of this complication is higher today, consequent to frequent vascular surgical and aortic reconstructive procedures, and has been reported in up to 5% of cases.³In 1963, Humphries et al³reported 70 cases of aortoenteric fistula after aortic surgery, including 26 cases of their own, noting that preventive measures had reduced, but not abolished, this complication. Although aortoenteric fistula following abdominal aortic aneurysm or aortoiliac reconstructive surgery has been reported by many investigators,^4-7a vascular enteric fistula after a renal artery bypass graft has been reported only once.^8.9Our

Renovascular Surgery: Current Concepts

When feasible, the preferred procedure in renovascular hypertension is the aortorenal saphenous vein bypass procedure. The innovations of revascularization of the totally occluded renal artery and hepatic renal artery bypass are discussed.

Aortoduodenal Fistula: Complication Of Renal Artery Bypass Graft

A case of an aortoduodenal fistula manifested by intermittent gastrointestinal bleeding over a 2-month period is presented as a complication of renal artery bypass graft surgery. The clinical features of aortointestinal fistula complicating aortic reconstructive surgery are reviewed. It is likely that any arterial graft surgery in proximity to the gastrointestinal tract may be complicated by gastrointestinal bleeding from fistula formation.

Renal function changes following surgery for vascular hypertension.

INCREASED systemic blood pressure due to occlusive renal arterial disease is a potentially reversible form of diastolic hypertension. The offending anatomic lesion usually consists of narrowing or occlusion of the renal artery or its primary branches by atheromatous plaques, but it may be of other origin, either congenital or acquired. 1 The surgical goal in such cases is to preserve functional kidney tissue, whenever possible, with arterial revascularization by endarterectomy, angioplasty, or bypass graft. 2-7 Nephrectomy is performed only when these latter procedures are not technically feasible or when the involved kidney is nonfunctional. Although renovascular surgery or nephrectomy may result in blood pressure reduction, little information is available regarding renal functional changes in such cases following surgery. In the patients reported herein, long-term observations indicated that significant sustained blood pressure reduction was accomplished in 12 of 15 subjects treated by renal artery bypass or nephrectomy. It is the

Treatment of hypertension associated with renal arterial occlusive disease

Renal artery stenosis is a common cause of diastolic hypertension. Recent development of arterial reconstructive technics provides the opportunity to cure most patients with renovascular hypertension and to salvage the involved kidney or kidneys. Resectional therapy provides a second type of treatment when definitive arterial reconstruction is impossible. Patch graft angioplasty and renal artery bypass are the two most satisfactory technical means of renal revascularization. Selection of patients with renal artery stenosis for revascularization is primarily a matter of exclusion. Specific contraindications include cerebrovascular insufficiency and coronary artery disease. Eighty per cent of 140 patients having renal revascularization procedures were cured of hypertension.