Efficacy and safety of Palmaz stent insertion in the treatment of renal artery stenosis in kidney transplantation

Abstract The aim of this study was to verify the safety and long‐term efficacy of Palmaz stent insertion in the treatment of transplant renal artery stenosis (TRAS) in kidney transplantation. Nine of our transplanted patients were submitted to Palmaz stent insertion because of recurrence of renal artery stenosis after previous percutaneous transluminal angioplasty or because of severe ostial stenosis. The post‐stenting results were excellent in all patients, with a follow‐up period ranging from 1 to 3 years. The mean blood pressure (one‐third systolic pressure plus two‐thirds diastolic pressure) fell from 118.11 ± 7.44 to 103.21 ± 9.25 mm Hg; P < 0.001. Renal artery peak blood flow velocity as determined by Doppler sonography fell from 352 ± 73.24 cm/s to 169.8 ± 23.35 cm/s; P < 0.001. The serum creatinine 1‐year after stenting was 1.3 ± 0.3 mg/dl with a slight reduction with respect to the prestenting values (1.5 ± 0.3 mg/dl; NS). As no complication occurred, we conclude that insertion of the Palmaz stent is a safe and effective way to treat recurrence of artery stenosis or ostial stenosis in renal transplanted patients.     

Renal artery stenosis in children: therapeutic percutaneous balloon and stent angioplasty

Background

Renal artery stenosis (RAS) accounts for 10 % of cases of systemic hypertension in children. Initial management involves anti-hypertensive therapy. Percutaneous interventions are documented for the treatment of RAS in the adult population. In children, case reports suggest benefit.

Methods

This is a retrospective analysis of consecutive patients referred for catheterization for RAS between 2002 and 2010 at a single institution. Recorded variables included: age, weight, systemic blood pressure, minimal luminal diameter, interventional devices, antihypertensive medications, contrast volume, and complications.

Results

Twelve patients (median age 8.2, IQR 6–12.4 years); median weight 42.8 kg, IQR: 25–47.4 kg) were referred for renal artery catheterization and underwent percutaneous intervention. Overall, minimal luminal diameter (MLD) increased by 1.2?±?0.9 mm for all patients (p?<?0.05) and by 1.3?±?0.9 mm for post-renal transplant patients (p?<?0.05). Only stent angioplasty patients demonstrated significant improved blood pressure (p?<?0.05). One patient had stent thrombosis requiring re-intervention with repeat balloon angioplasty.

Conclusions

This retrospective analysis suggests that percutaneous intervention might play a role in the management of RAS, with an improvement in MLD in children with RAS. Transcatheter intervention is technically feasible with low morbidity. A prospective, longitudinal study is warranted to compare standard medical therapy with percutaneous interventions.     

肾动脉狭窄的介入治疗分析

目的 分析介入治疗肾动脉狭窄（RAS）的疗效。方法自2003年3月至2008年3月共收治45例RAS患者,53支肾动脉中单纯行腔内球囊扩张术（PTA）治疗11支,行球囊扩张及内置支架术（PTA／Stent）治疗者42支,随访9～48个月,检测患者的血压与血肌酐水平,并作肾动脉彩超。结果手术成功率为100％。手术后高血压治愈者9例,改善28例,肾功能改善12例。肌纤维发育不良及多发性大动脉炎的血压改善有效率均为100％,高于动脉粥样硬化的有效率65．1％（P〈0．05）。行彩色多普勒超声检查肾动脉18支,发现再狭窄者7支。结论PTA和PTMStent治疗肾动脉狭窄具有微创、安全、有效的优点。     

肾动脉狭窄的腔内治疗经验

目的探讨腔内治疗肾动脉狭窄的临床疗效及影响因素。方法2003年2月至2005年6月共收治19例肾动脉狭窄患者,分析其中行腔内治疗12例的临床资料。其中动脉硬化9例,多发性大动脉炎1例,纤维肌性发育不良2例。结果本组12例,均有严重高血压,1例肾功能异常。支架置入10例,技术成功率91．7％(11／12)。随访12例,随访时间3—15个月,随访平均6．5个月,患者血压从(172±26／98±15)降至(156±22／88±14)mmHg。高血压治愈2例,改善6例,未愈4例,高血压控制率为66．7％。术后肾功能无明显变化。无并发症和死亡病例。再狭窄1例,再狭窄率为8．3％。结论严格掌握手术适应证,腔内治疗肾动脉狭窄是安全、有效的。     

Resolution of Renal Failure 1 Month After Onset through Angioplasty of Renal Artery Stenosis

Abstract

The stent placement in patients with atherosclerotic renal artery stenosis and impaired renal function (STAR) and revascularization versus medical therapy for renal-artery stenosis (ASTRAL) trials concluded that renal artery angioplasty was not superior to medical management in delaying progression to renal failure or controlling blood pressure in a selected population. There were several criticisms of the STAR trial’s methodology, and an important criticism of ASTRAL was that the patient was excluded if their clinician was uncertain of the value in correcting the stenosis. Anuric renal failure by renal artery stenosis is a rare occurrence and falls outside this criteria.     

Severe renovascular hypertension in an infant with congenital solitary pelvic kidney

Renal artery stenosis (RAS) is one of the most common causes of severe arterial hypertension in infants. Its management is very difficult, especially when present in a single kidney. We report a case of severe hypertension caused by RAS of congenital single pelvic kidney in a 4-month-old boy. The patient presented with cardiorespiratory insufficiency that was first treated as acute fulminate myocarditis. Medical treatment of arterial hypertension was disappointing, as it had to be balanced between congestive cardiac failure and acute renal failure. Percutaneous transluminal angioplasty (PTA) done by coronary balloon dilatation catheters through the left axillary access was successful. Following dilatation of the renal artery, blood pressure decreased and its good control was possible by only one drug. With improved medical blood pressure control and normal growth development, the reassessment of clinical therapy options adjusted to a larger vessel size would be possible. Renovascular hypertension due to RAS in infants with a solitary kidney is difficult to control by medical treatment alone. PTA should be considered as a viable option in infants with refractory hypertension due to renal artery stenosis in a solitary kidney, since it has the potential of improving hypertension while preserving renal function.     

Resolution of renal failure 1 month after onset through angioplasty of renal artery stenosis

The stent placement in patients with atherosclerotic renal artery stenosis and impaired renal function (STAR) and revascularization versus medical therapy for renal-artery stenosis (ASTRAL) trials concluded that renal artery angioplasty was not superior to medical management in delaying progression to renal failure or controlling blood pressure in a selected population. (1,2) There were several criticisms of the STAR trial's methodology, and an important criticism of ASTRAL was that the patient was excluded if their clinician was uncertain of the value in correcting the stenosis. Anuric renal failure by renal artery stenosis is a rare occurrence and falls outside this criteria.     

Current endovascular management of atherosclerotic renal artery stenosis

The recent advances in stent technology and renal endovascular management have provided a technically reproducible method of percutaneously treating atherosclerotic renal artery stenosis (RAS).In many centers, this has resulted in endovascular management being the primary therapy for atherosclerotic RAS. Although still controversial, it appears that endovascular management of RAS by primay stent deployment provides better blood pressure control than that afforded by best medical management. The impact on renal function is less than that found for hypertension, but there is evidence to suggest that the use of protection devices and primary stenting may enhance renal function outcomes. Whether the ultimate benefit of enhanced survival follows remains an important question and should be the subject of future prospective studies.     

Two cases of atherosclerotic renal artery stenosis treated by percutaneous transluminal renal angioplasty and intravascular stent placement, leading to improvement of hypertension and renal function

We describe here two cases of renal artery stenosis(RAS) caused by atherosclerosis. Both patients were treated by percutaneous transluminal renal angioplasty(PTRA) and stent placement, leading to the improvement of renal function as well as hypertension. The two patients were a 75-year-old male(case 1) and a 56-year-old male(case 2), who both showed mild proteinuria, renal dysfunction, and refractory hypertension. Case 1 showed a unilateral ostial stenosis in the left main renal artery. On the other hand, case 2 showed an ostial stenosis in the left renal artery and a widespread narrowing in the right renal artery. After evaluation of the lesions by renal Doppler sonography, renogram, magnetic resonance signal intensity, and magnetic resonance angiography(MRA), each stenosis was treated by balloon angioplasty and intravascular stent placement without any major complications. Thereafter, in addition to hypertension, renal function also ameliorated significantly, and has remained stable for more than 12 months. Non-invasive screening tests and appropriate therapy for renovascular lesion should be considered in the case of elderly patients with refractory hypertension and progressive renal dysfunction, since ischemic nephropathy is increasing as a common cause of end stage renal disease and is showing favorable outcomes of revascularization.     

Transluminal vascular stent implantation for a patient with renovascular hypertension due to renal artery stenosis

In recent years, transluminal vascular stents have been implanted in patients with renal artery stenosis. At present, controversy remains as to whether the long-term outcome of stent implantation is better than that of percutaneous transluminal renal angioplasty (PTRA). However, until now, no clinical experience of a stent placement for renal artery stenosis has been reported in our country. We implanted a Palmaz stent in a patient with renovascular hypertenstion due to renal artery restenosis who had already undergone PTRA. The renal function and blood pressure of the patient improved remarkably.     

同种异体肾移植术后移植肾动脉狭窄 介入治疗的临床疗效分析

目的探讨同种异体肾移植术后移植肾动脉狭窄（TRAS）介入治疗的临床疗效。方法介入治疗同种异体肾移植术后TRAS患者22例,其中单纯球囊扩张治疗10例（球囊组）,内支架治疗12例（支架组）。对所有患者术前及术后2年内血压、肾功能以及生活质量进行评估,并与同期接受单纯药物治疗的6例TRAS患者（药物组）进行比较。结果球囊组技术成功率90.00%,支架组技术成功率100%。术后在血压及肾功能改善方面,球囊组和支架组均取得显著疗效,两组近期疗效未见明显差异,药物组疗效不满意。术后随访6个月～2年,支架组再狭窄率16.67%,除1例不明原因治疗无效外,其余11例均能比较健康的生活和工作。球囊组手术失败1例,再狭窄率达40.00%。结论内支架植入术可作为TRAS特别是I型及Ⅱ型狭窄的首选治疗方法。     

Nonsurgical treatment of renovascular hypertension by percutaneous transluminal angioplasty

A case of renovascular hypertension treated with percutaneous transluminal angioplasty is reported. Our patient was a 22-year-old housewife with 90 per cent stenosis of the right renal artery due to fibromuscular dysplasia. The renal artery was dilatated by percutaneous transluminal angioplasty with a Grützig balloon catheter to 25 per cent stenosis. Five hours after the procedure, blood pressure decreased from 180/114 mmHg to 130/95 mmHg; one day after, plasma renin activity fell from 4.7 ng/ml/hr to 1.7 ng/ml/hr. The patient was rehospitalized six months after percutaneous transluminal angioplasty to examine restenosis of the dilatated renal artery. Although her blood pressure remained normotensive and plasma renin activity was normal, replasty was performed since selective renal arteriography revealed 50 per cent stenosis.     

Pulmonary artery stenosis secondary to fibrosing mediastinitis: management with cutting balloon angioplasty and endovascular stenting

Cutting balloon angioplasty is a common treatment modality in the pediatric population for pulmonary artery stenosis. We present an adult with histoplasmosis induced fibrosing mediastinitis resulting in pulmonary artery stenosis that was successfully treated with cutting balloon angioplasty and subsequent stent deployment. Percutaneous endovascular stent placement has be shown to effectively alleviate pulmonary artery stenosis, however in-stent restenosis does limit durability. Pharmacologic therapy is indicated with either mediastinal adenitis or mediastinal granuloma with anti-fungal agents such as amphotericin B and itraconazole. Surgical intervention for histoplasmosis induced fibrosing mediastinitis is rarely indicated and may result in fatal complications that stem from mediastinal fibrosis due to resultant destruction of surgical planes. To our knowledge, this is the first reported case of utilizing cutting balloon angioplasty and stent insertion for the treatment of histoplasmosis induced fibrosing mediastinitis complicated by pulmonary artery stenosis.     

Combined Percutaneous Transrenal and Transfemoral Endovascular Recanalization and Angioplastic Reconstruction of a Disrupted Transplant Renal Artery Stent: A Novel Salvage Technique

Renal artery stenosis is the most common vascular complication following renal transplantation. Percutaneous endovascular transluminal angioplasty with stenting is the treatment of choice for clinically significant renal artery stenosis. The authors present a case describing a novel combined transrenal parenchyma and transfemoral approach to repairing a disrupted transplant renal artery stent. The patient's allograft renal artery stenosis was initially managed via the standard percutaneous approach, but during follow‐up the stent became disrupted and crushed, causing partial occlusion of the renal artery. This was manifested by persistently elevated serum creatinine values, lower extremity edema, and four‐medication hypertension. After a failed traditional percutaneous transfemoral attempt, the authors were able to successfully access the renal arterial system via a combined transrenal and transfemoral approach, using an upper‐pole artery through the renal parenchyma. This transrenal approach used a 3 Fr system, allowing the authors to get a wire across the stent, which they were previously unable to do. With wire access, they performed a balloon angioplastic reconstruction to restore the stent's patency, resulting in a reduction in serum creatinine, lower extremity edema, and blood pressure. This technique avoided a potentially difficult reoperative repair without immediate complication and provides a method for vascular access to the renal arterial system in select patients.     

“The Challenge Facing Renal Artery Revascularization: What Have we Not Proven and Why we Must?”

Endovascular renal artery stent therapy for atherosclerotic renal artery stenosis (RAS) is associated with excellent acute technical success, low complication rates and acceptable long-term patency. However, the clinical benefits to patients of renal artery stenting remain uncertain.

To facilitate debate regarding the treatment of RAS, we need to understand the epidemiology, basic physiology and clinical consequences of renal artery stenosis. We must attempt to determine which patients are likely to benefit from renal artery stenting, assess the nuances of the percutaneous procedure and review the current literature pertaining to renal artery stenting.     

Prospective studies of diagnosis and intervention: the Dutch experience

This prospective multicenter study included 1,205 patients, who were referred for difficult-to-treat hypertension or analysis of possible secondary hypertension. After a standardized selection protocol based on sharply defined drug-resistant hypertension or renal function impairment during angiotensin-converting enzyme inhibition, patients underwent renal scintigraphy and a captopril-renin challenge test. A set of clinical characteristics was also recorded. Sensitivity and specificity of renal scintigraphy for diagnosing renal artery stenosis were 0.72 and 0.90 and of the captopril-renin test 0.77 to 0.91 and 0.69 to 0.75 depending on the criterion used. The clinical characteristics were used to construct a clinical prediction rule for renal artery stenosis, which had a sensitivity of 0.68 and a specificity of 0.87 at a cut-off level of 30% predicted probability. However, with the prediction rule a sensitivity of 0.90 could be reached by performing arteriography only in patients with a predicted probability of stenosis of > or =10%, resulting in a considerable reduction of the number of arteriograms to be made. A diagnostic strategy is advocated starting with drug-resistant hypertension and continuing to renal arteriography only in patients with increased probability of stenosis. Patients with atherosclerotic renal artery stenosis were then randomized to balloon angioplasty (n = 56) versus antihypertensive medication (n = 50). Three months after randomization 22 patients from the medication group underwent balloon angioplasty in second instance. In an intention-to-treat analysis, no difference in blood pressure was found between the groups after 3 months, nor after 12 months of follow-up, although there was a small medication-sparing effect of balloon angioplasty. The lack of a beneficial effect of balloon angioplasty compared with medication could not be attributed to the high stenosis recurrence rate after angioplasty, nor to the fact that the inclusion criterion was set at a stenosis level of > or =50% so that patients with relatively mild stenosis were also included. Renal function after angioplasty was slightly better in the angioplasty group than in the medication group, and improvement of the renal scintigram occurred more often after angioplasty. Apart from the treatment of patients with specific characteristics, the presented therapeutic approach starts with extending the antihypertensive drug therapy to control blood pressure. Only if blood pressure cannot be controlled or if renal function deteriorates, balloon angioplasty (with stent placement) is indicated.     

Metal stent placement for two patients with post-transplantation renal artery stenosis,using intravascular ultrasound imaging

Post-transplantation renal artery stenosis is recognized at relatively early periods after renal transplantation. We report herein our experience of utilizing transluminal expanded metal stents (Palmaz stent and Wall stent) for post-transplantation renal artery stenosis, and monitoring with intravascular ultrasound (IVUS) imaging. The recipients were a 51-year-old woman (case 1) and a 57-year-old man (case 2), and the grafts were procured from cadaveric donors. Renal function had deteriorated suddenly at 5 months after renal transplantation in case 1 and at 86 months in case 2. The cause of the graft dysfunction was renal arterial stenosis. Color doppler ultrasound imaging and angiography diagnosed post-transplantation renal artery stenosis. The renal artery stenosis was serious, being greater than 90% in both patients. Percutaneous transluminal angioplasty (PTA) was performed, but its effectiveness was not sufficient; therefore, an indwelling endoluminal metallic Palmaz stent and an indwelling Wall stent were placed at the sites of stenosis while monitoring was done with IVUS. No complications were recognized at all. The length and degree of stenosis location became clear by using IVUS, and suitable stents could be selected for the renal artery stenosis. The clinical effect was excellent; the renal function improved to the pre-hospitalization value. We conclude that the Palmaz stent and the Wall stent were useful as a noninvasive strategy for treating post-transplantation renal artery stenosis. This procedure could be performed safely and surely using IVUS.     

"The challenge facing renal artery revascularization: what have we not proven and why we must"?

Endovascular renal artery stent therapy for atherosclerotic renal artery stenosis (RAS) is associated with excellent acute technical success, low complication rates and acceptable long-term patency. However, the clinical benefits to patients of renal artery stenting remain uncertain. To facilitate debate regarding the treatment of RAS, we need to understand the epidemiology, basic physiology and clinical consequences of renal artery stenosis. We must attempt to determine which patients are likely to benefit from renal artery stenting, assess the nuances of the percutaneous procedure and review the current literature pertaining to renal artery stenting.     

Atherosclerotic renal artery disease management update

In the case of atherosclerotic renal artery disease, the best conclusive results lie principally not in the degree of the stenosis but rather in the degree the renal parenchymal disease beyond the stenosis itself. These determining factors involve the controlling of the patients blood pressure, the improvement in the renal function and the beneficial results to the cardiovascular system. Besides the indispensable medical treatment, a revascularisation by angioplasty may be indicated. This procedure with or without vascular stent often allows satisfactory angiographic results. A treatment by surgical revascularisation is only recommended in the case of extensive atherosclerotic lesions of the aorta, complex lesions of the latter or an abdominal aortic aneurism. Although the frequency of restenosis of angioplasty with stent remains extremely low, the risk of cholesterol emboli due to the diffuse atherosclerotic lesions of the abdominal aorta, must be considered at the time of each aortic catheterization. The therapeutic approach of atherosclerotic renal artery disease must be dictated by the whole cardiovascular risk factors and by the threat of target organs. The control of the blood pressure and the maintenance of the renal function must be integrated in the decisional algorithm as well as the possible risks in carrying out an eventual revascularisation procedure. Finally, the renal angioplasty should in numerous situations be integrated in the overall assumption of responsibility of the atherosclerotic vascular diseases, and should be part of the medical treatment. Several questions still do exist; at what moment an atherosclerotic renal artery stenosis should and e considered critical, and which procedure should be considered for which patient? The purpose of this review is to propose a decisional tool for individualized treatments in the light of results from randomized and controlled studies.     

Renovascular disease: effect of ACE gene deletion polymorphism and endovascular revascularization

BACKGROUND: Renal artery stenosis (RAS) is associated with high cardiovascular mortality and significant clinical complications, including resistant hypertension and ischemic nephropathy. Despite availability of endovascular revascularization techniques, determining which patients should undergo revascularization and the timing of the procedure still are controversial. Several studies have reported a higher frequency of the DD genotype of the insertion/deletion (I/D) polymorphism of the angiotensin converting enzyme (ACE) gene in patients with RAS, and one study found higher mortality in patients with the DD genotype.Material and methods We retrospectively studied 100 patients with documented atherosclerotic RAS and evaluated long-term (median follow-up, 28 months) mortality, blood pressure control, and renal function in relation to the ACE genotype and two therapeutic strategies, that is, endovascular treatment with percutaneous renal transluminal angioplasty or stenting (ET group) versus conservative drug therapy (CT group). RESULTS: Comparison between therapeutic groups showed a higher cumulative probability of survival (86.7% vs 67.1%), better blood pressure control (57.4% vs 29%), and slower decline in renal function (17.9% vs 48.4%) in the ET group. The DD genotype was strongly represented in our study patients (DD, 50%; II, 15.5%; I/D, 34.5%), but bore no relation to mortality, blood pressure control, decline in renal function, or rate of recurrent stenosis. CONCLUSIONS: Conservative medical treatment of RAS, compared with endovascular treatment, is associated with higher mortality, poorer blood pressure control, and impaired renal function over the long term. Early endovascular treatment enables amelioration of this unfavorable evolution. The DD genotype does not predict clinical outcome of RAS.