Extracorporeal renal artery reconstruction for renovascular hypertension

Extracorporeal reconstruction can be applied to the successful repair of stenoses in the distal renal artery and its hilar branches. This study evaluates the short- and long-term results of extracorporeal renal artery reconstruction in 65 patients, including 5 children, with renovascular hypertension who were treated from 1974 through 1989. The mean age of the patients was 37 years (range, 7 to 67 years). The cause of the stenoses was arteriosclerosis in 8 patients, fibrodysplasia in 54 patients, and miscellaneous in 3. Hypertension was severe before treatment with a mean blood pressure of 187/147 mm Hg that was reduced to a mean of 159/102 mm Hg after medical therapy. Ten patients had renal dysfunction. Results were evaluated both at short-term intervals (mean, 7.9 months; 64 patients) and long-term intervals (mean, 5.9 years; 60 patients), after surgery. Blood pressure responses were classified as beneficial (cured/improved) or failures. Anatomic results were evaluated by angiography in 98% of the patients at the short-term interval and in 77% of the patients at the long-term interval. Extracorporeal renal artery surgery was performed on 78 kidneys among 65 patients (unilateral, 45 patients; bilateral, 13 patients; unilateral extracorporeal and contralateral in situ, 7 patients). In most of the cases autologous arterial graft was used for reconstruction. Early in the series one patient died as a result of the operative procedure (1/65, 1.5%). A beneficial blood pressure response occurred in 53 patients (53/65; 82%) at the short-term interval and in 49 patients (49/61; 80%) at the long-term interval, with the average blood pressure at the short-term interval being 138/85 mm Hg and at the long-term interval being 139/85 mm Hg. Renal function improved in all patients with preoperative renal dysfunction. Graft stenosis or occlusion of the main renal artery was neither observed at the short-term interval nor at the long-term interval. However, residual stenoses were observed in 9 of the 163 reconstructed distal branches (5.5%). Extracorporeal renal artery reconstruction with autologous arterial grafts can be effectively applied to lesions of the distal main renal artery and its hilar branches with durable functional results.     

Pathophysiology of experimental renovascular hypertension

The genesis of renovascular hypertension follows a continuum from an acute to a chronic phase. Reduction in renal perfusion initiates renin release and angiotensin-mediated systemic vasoconstriction. Aldosterone secretion, sodium and water retention, and expansion of the extracellular volume ensue. Sustained hypertension is further maintained by interacting physiologic mechanisms including increased angiotensin II sensitivity, vasopressin, ouabain-like substance, the sympathetic nervous system, CNS mechanisms, autoregulation, and structural changes.     

Renal artery stretching and renovascular hypertension. An experimental study

Renovascular hypertension was produced in rabbits by affixing one kidney to the iliac fossa to produce traction on the renal artery. Hyperplasia of the juxtaglomerular apparatus was seen in the kidney in which the renal artery was stretched, whereas no juxtaglomerular apparatus hyperplasia was witnessed in the untouched kidney of rabbits. Whether traction on the renal artery is a sole or contributing factor to the pathogenesis of fibrous dysplasia of the arterial wall remains a moot point.     

Improved results of vascular reconstruction in pediatric and young adult patients with renovascular hypertension

From 1955 to 1988, 56 patients 21 years old or younger underwent surgical treatment for renovascular hypertension at our clinic. The cause of renal artery disease was fibrous dysplasia in 53 patients, Takayasu's arteritis in 2 or an arterial aneurysm in 1. Bilateral or branch renal artery disease, and extrarenal arterial disease were present in 16, 23 and 11 patients, respectively. The results of 28 patients treated from 1955 to 1977 (group 1) were compared to those of 28 patients treated from 1978 to 1988 (group 2). Hypertension was cured or improved postoperatively in 83% of the patients from group 1 and in 96% from group 2 (p = 0.07). However, this outcome was achieved through surgical revascularization in only 48% of the patients from group 1 compared to 96% from group 2 (p = 0.0002). A multivariate analysis revealed that the only significant variable related to clinical outcome was the era of treatment, which reflects the improved technical efficacy of revascularization during the last decade. Aortorenal bypass and renal autotransplantation have emerged as the preferred revascularization operations. It currently is possible to achieve amelioration of hypertension and preservation of renal function in most young patients with renal artery disease.     

Renal vascular disease and renovascular hypertension in children

Renal vascular disease is the second most common cause of secondary pediatric hypertension, usually occurring as intimal or atypical medial-perimedial stenoses. Developmental lesions account for 40 per cent of these stenoses. Assessments of renin activity and arteriography are useful in identifying functionally important lesions. Urography in this age group has little diagnostic utility. Renal revascularization offers a 95 per cent beneficial outcome to properly selected patients.     

Renal artery streching and renovascular hypertension experimental studies

Summary Renovascular hypertension was produced in rabbits by displacing one kidney to the iliac fossa in order to produce traction on the renal artery. Hyperplasia of the juxtaglomerular apparatus was seen in the kidney where the renal artery was streched, whereas no JGA hyperplasia was witnessed in the untouched kidney of rabbits. Whether traction on the renal artery is the sole or a contributing factor to the pathogenesis of fibrous dysplasia of the arterial wall remains a moot point.Supported by Max Kade Foundation New York.     

Clinical evaluation of renovascular hypertension and therapeutic decisions

The renal arteriogram alone, useful as an anatomic guide for the surgeon or radiologist, is inadequate to predict potential blood pressure reversal by correction of the obstructing lesion. A patient must be identified as having functionally significant renal arterial disease before intervention can be recommended. The authors discuss uncovering functionally significant renal artery stenosis, the pathophysiology of experimental Goldblatt hypertension, and criteria to identify renovascular hypertension, including peripheral plasma renin activity and differential renal-vein renin determinations.     

Diagnostic criteria for renovascular hypertension

Renovascular hypertension is a clinical situation characterized by high blood pressure in the presence of renal ischemia mainly related to atherosclerotic or fibromuscular dysplasic narrowing of the renal artery (ies). This diagnosis is often "a posteriori" validated, because the discovery of a significant renal artery stenosis is not obligatory responsible of the blood pressure elevation. This article proposes a diagnostic strategy for exploring patient with this suspected secondary cause of hypertension before proposing an invasive approach (intra-arterial angiography) possibly followed by a revascularization. However, the methods for exploring such population are mainly based on patient characteristics and local expertise and habits. These must thus be individualized. First, clinical symptoms or signs frequently associated with hypertension and renal artery stenosis must be searched. If present, a non invasive and functional exploration of the renal arteries is to be proposed (Captopril radioisotope renography, colour duplex sonography) followed by magnetic resonance angiography or spiral computer tomography angiography if the clinical suspicion index is moderate or high. If this is very high, an intra-arterial arteriography could immediately be performed if not too dangerous. On the opposite site, if the clinical index is low, it is recommended to follow clinically and to treat risk factors.     

Effect of renal revascularization by splenic artery implantation on experimental renovascular hypertension

The antihypertensive effect of implanting a branch of the splenic artery into the renal cortex of uninephric rats with renal artery stenosis is presented. Systolic blood pressure determinations were performed by Doppler auscultation over the ventral aspect of the tail distal to a sphygmomanometer cuff.     

Treatment of renovascular disease and of renovascular hypertension

ABSTRACT: Treatment of occlusive lesions of renal arteries, defined as renovascular disease (RVD), is aimed both at preventing ischemic renal disease (IRD) and rescuing renal function through revascularization procedures, such as PTRA, endovascular stenting and surgical revascularization, as well as curing or improving hypertension in the presence of renovascular hypertension (RVH), i.e. hypertension caused by these vascular lesions. Preventive treatment of IRD is still an individual decision making process based on the type of renal lesions, degree of renal stenosis and progressive loss of renal mass as well as on immediate and late technical success of revascularization procedures together with their rate of complications. Rescue of renal function and-or prediction of the outcome of renal function after successful revascularization depends not only on the possibility of clarifying whether the decrease in renal function is a functioning-reversible phenomenon linked to renal hypoperfusion but also on the potential risk that the revascularization procedure may induce irreversible kidney damage. The rationale for treating RVH through revascularization procedures derives from the possibility of establishing a pathogenetic link between the occlusive lesions and hypertension, mainly through renal vein renin measurement and captopril renography and possibly their combination. Finally, medical treatment of hypertension is needed in patients who cannot undergo or refuse revascularization and whose blood pressure is not normalized by these procedures.     

Clinical and experimental study on reconstruction after pancreatectomy--Part I. Cholangitis and its relationship to reconstruction

The purpose of the present study is to clarify pathogenesis of cholangitis after pancreatectomy. The clinical study consisted of follow-up survey and hepatobiliary scintigraphy for the patients with type-I reconstruction (e.g. Imanaga procedure) and type-II reconstruction (e.g. Child procedure) after pancreatoduodenectomy. The experimental study was performed in dogs by creating three types of biliary reconstruction, namely, cholecystoduodenostomy (C-D), cholecystojejunostomy (C-J) and Roux-Y cholecystojejunostomy (R-Y). In the follow-up survey, cholangitis occurred in 19.0% of 21 type-I patients and in 33.3% of 18 type-II patients. In the hepatobiliary scintigraphy, type-I demonstrated smooth transit of bile along the reestablishing intestine. Type-II, on the other hand, showed marked stagnation of bile in the excluded loop, which could even trigger cholangitis. The experimental study showed that the results obtained from R-Y were no better than those obtained from C-D and C-J with respect to prevention of cholangitis based on histological, biochemical and bacteriological point of view. These studies suggest that type-I reconstruction carries little risk of causing cholangitis, whereas type-II reconstruction is not effective in preventing cholangitis.     

Arterial reconstructive surgery for renovascular hypertension

Many hypertensive patients with renal artery stenosis and abnormal findings on renin angiotensin assay can be cured or markedly improved by renal artery surgery. Because the mortality is low, we think that patients whose blood pressures are resistant to medical management should be examined carefully for renal artery stenosis as the cause of their hypertension. If such a lesion is found, many of these patients can expect to enjoy a good clinical response from renal artery reconstruction. Those patients who do not have satisfactory results from the surgical correction should undergo aggressive reevaluation to detect any correctable anatomic defects.     

Autotransplantation for treating renovascular hypertension.

Autotransplantation is presented as a surgical technique for the repair of diseases of the renal artery causing hypertension. Investigation of patients with renovascular hypertension is reviewed stressing the importance of radiologic studies. The author discusses the results obtained in 31 patients who underwent renal autotransplantation. In his experience the procedure has proven to be particularly effective for repairing renal artery stenosis and in patients presenting with severe renovascular hypertension. Associated lesions of the renal artery requiring extensive reconstruction may be repaired with greater safety to both the patient and the kidney using this technique.