The durability of different reconstructive techniques for atherosclerotic renal artery disease

Revascularization for Renovascular Disease: A Scientific Statement From the American Heart Association

Renovascular disease is a major causal factor for secondary hypertension and renal ischemic disease. However, several prospective, randomized trials for atherosclerotic disease failed to demonstrate that renal revascularization is more effective than medical therapy for most patients. These results have greatly reduced the generalized diagnostic workup and use of renal revascularization. Most guidelines and review articles emphasize the limited average improvement and fail to identify those clinical populations that do benefit from revascularization. On the basis of the clinical experience of hypertension centers, specialists have continued selective revascularization, albeit without a summary statement by a major, multidisciplinary, national organization that identifies specific populations that may benefit. In this scientific statement for health care professionals and the public-at-large, we review the strengths and weaknesses of randomized trials in revascularization and highlight (1) when referral for consideration of diagnostic workup and therapy may be warranted, (2) the evidence/rationale for these selective scenarios, (3) interventional and surgical techniques for effective revascularization, and (4) areas of research with unmet need.

Renal transplantation in the setting of aortic atresia: Utilizing hepatic artery inflow with donor vessel jump graft

Both congenital and acquired recipient anatomy can present a significant challenge to renal transplantation. A patient with congenital aortic atresia and limited dialysis access options presented to our institution for consideration of transplant. Through multidisciplinary planning, a strategy to accommodate the patient's variant anatomy was devised and successfully performed. A deceased donor vessel graft was used as conduit in combination with the recipient hepatic artery for renal graft inflow.

Treatment of Complex Aortic Aneurysms Using Combination of Renal and Visceral Bypass and Fenestrated/Branched Stent Grafts

BACKGROUND

The purpose of this study was to report our experience of treatment of aortic aneurysms using combination of renal and visceral arteries bypasses and fenestrated/branched stent graft in various complex anatomical situations.

METHODS

Between November 2005 and March 2017, 10 patients underwent a hybrid strategy combining bypasses for renal and/or visceral arteries and custom-made fenestrated/branched stent grafts. Two patients had abdominal aortic aneurysm (1 juxtarenal and 1 suprarenal), and 8 patients had thoracoabdominal aortic aneurysm (1 type I, 2 type II including one dissection, 2 type III, 1 type IV, and 2 type V). In total, 37 renal and visceral arteries were targeted, of which 23 were treated using fenestrated or branched stent graft and 14 were treated by bypass (11 to renal artery and 3 to celiac trunk).

RESULTS

Technical success was 100%, and no patient died during a mean follow-up of 24.3 ± 21 months. Six patients had 7 postoperative complications after bypass surgery, and 3 patients had 3 complications after fenestrated or branched endovascular aneurysm repair (FEVAR/BEVAR) procedure. Seven reinterventions were performed in 3 patients. No occlusion of target vessels occurred. Renal function was stable during follow-up in all patients except one who developed end-stage renal failure requiring permanent dialysis. On the last follow-up computed tomography scan, aneurysm diameter decreased for 6 patients, was stable for 3 patients, and increased for one patient, in which persistent type II endoleak was observed. Aneurysm exclusion was complete in the remaining 9 patients.

CONCLUSIONS

Combination of FEVAR/BEVAR procedures with renal and/or visceral artery bypass in patients with complex aortic aneurysms is feasible with acceptable results. Morbidity associated with bypass surgery has to be carefully balanced with the risk of catheterization difficulties in the setting of adverse anatomical features of the visceral/renal arteries or the aorta.

Common hepatic artery as inflow in kidney transplantation

Kidney transplantation originating from the hepatic artery has not previously been reported. Herein, we report a third kidney transplantation with the common hepatic artery as inflow. A 62-year-old male with chronic renal failure due to polycystic kidney disease was proposed to a third kidney transplantation. CT-scan showed diffuse calcification of the aorto-iliac axis and the splenic artery. The common hepatic artery was the only artery suitable for anastomosis and as such was chosen as the inflow for retransplantation. The operation was performed through a right subcostal laparotomy. A saphenous bypass was interposed between the common hepatic artery and the graft, then the renal vein was anastomosed to the suprarenal inferior vena cava. Duration of warm ischemia was 27 min. Postoperative course was complicated with delayed graft function of 17 days and pulmonary infection. Patient was discharged at day 30. With a follow-up of 40 months, serum creatinine level and eGFR are, respectively, 191 µmol/L and 32 mL/min. Hepato-renal bypass technique can be used in kidney retransplantation when patient anatomy is not compatible with other classical options.

Diagnosis and management of atherosclerotic renal artery stenosis: improving patient selection and outcomes. Nat Rev Cardiol. 2009;6:176-190. [PMID: 19234498 DOI: 10.1038/ncpcardio1448]

Renal artery stenosis (RAS) is common among patients with atherosclerosis, and is found in 20-30% of individuals who undergo diagnostic cardiac catheterization. Renal artery duplex ultrasonography is the diagnostic procedure of choice for screening outpatients for RAS. Percutaneous renal artery stent placement is the preferred method of revascularization for hemodynamically significant RAS, and is favored over balloon angioplasty alone. Stent placement carries a class I recommendation for atherosclerotic RAS according to ACC and AHA guidelines. Discordance exists between the very high (>95%) procedural success rate and the moderate (60-70%) clinical response rate after renal stent placement, which is likely to be a result of poor selection of patients, inadequate angiographic assessment of lesion severity, and the presence of renal parencyhmal disease. Physiologic lesion assessment using translesional pressure gradients, and measurements of biomarkers (e.g. brain natriuretic peptide), or both, could enhance the selection of patients and improve clinical response rates. Long-term patency rates for renal stenting are excellent, with 5-year secondary patency rates greater than 90%. This Review will outline the clinical problem of atherosclerotic RAS and its diagnosis, and will critically assess treatment options and strategies to improve patients' outcomes.

The role of percutaneous revascularization for renal artery stenosis

Renal artery stenosis (RAS) is usually caused by atherosclerosis or fibromuscular dysplasia. RAS leads to activation of the renin-angiotensin-aldosterone system and may result in hypertension, ischemic nephropathy, left ventricular hypertrophy and congestive heart failure. Management options include medical therapy and revascularization procedures. Recent studies have shown angiotensin receptor blockers (ARB) and angiotensin converting enzyme inhibitors (ACE-I) to be highly effective in treating the hypertension associated with RAS and in reducing cardiovascular events; however, they do not correct the underlying RAS and loss of renal mass may continue. Renal artery angioplasty was first performed by Gruntzig in 1978. The routine use of stents has increased technical success rates compared with angioplasty, and surgery is now only rarely performed. Although numerous case series claimed benefit in terms of blood pressure control, no adequately powered randomized, controlled, prospective study of renal artery interventions has reported their effect on cardiovascular morbidity or mortality. The CORAL trial, an ongoing study of renal artery stent placement and optimal medical therapy (OMT) funded by the National Institutes of Health, is the first study to attempt to do so. Until the CORAL trial results are in, physicians will continue to be faced with difficult choices when determining the optimal management for RAS patients and deciding which, if any, patients should be offered revascularization.

Iliorenal Bypass: Indications and Outcomes following 41 Reconstructions

Iliorenal bypass is a nonanatomic means of renal revascularization usually performed in high-risk patients. Its efficacy was assessed in this review of 35 patients (17 males and 18 females, two children and 33 adults) ranging in age 8-84 years, who were subjected to 41 iliorenal bypasses at the University of Michigan Hospital during 1975-2003. Renal artery lesions included arteriosclerosis (n = 20), developmental narrowing (n = 10), arterial fibrodysplasia (n = 3), penetrating trauma (n = 1), and aortorenal dissection associated with Marfan disease (n = 1). All patients had hypertension attributed to their renal artery disease. Twenty patients exhibited renal insufficiency (serum creatinine >1.8 mg/dL). Primary reasons for selecting an iliorenal reconstruction over a more conventional open revascularization included advanced aortic arteriosclerosis (n = 9); prior aortoaortic, aortoiliac, or aortofemoral reconstruction (n = 7); a small aortic aneurysm not justifying aortic surgery (n = 6); prior aortorenal surgery (n = 6); congenital abdominal aortic coarctation (n = 4); a hostile retroperitoneum (n = 2); or compromised cardiac status (n = 1). Eleven patients had prior ipsilateral renal artery interventions. Iliorenal bypasses were to the right kidney (n = 20), the left kidney (n = 9), and bilateral (n = 12). Conduits were saphenous veins (n = 29), synthetic prostheses (n = 11), or direct renal artery-iliac artery reimplantation (n = 1). Initial bypass patency was 93%. Follow-up averaged 7.5 years. Three early and six late graft complications resulted in eight secondary operations. The mean preoperative and postoperative serum creatinine of all 35 patients did not vary (1.9 vs. 1.8 mg/dL), although on an individual basis renal function improved in eight, remained stable in 21, and deteriorated in six patients. The series' mean preoperative blood pressure of 180/97 mm Hg decreased postoperatively to 140/78 mm Hg (P < 0.001). Hypertension was cured in three patients, improved in 27, and became worse in four. Antihypertensive medication numbers decreased postoperatively, from a median of three to two (P < 0.0001). Surgical mortality was limited to one patient succumbing from perioperative intestinal infarction. Iliorenal bypass is an effective means of renal revascularization in patients not amenable to more conventional open or transluminal procedures.

Factors Influencing the Need for Target Vessel Revascularization After Renal Artery Stenting

PURPOSE

To provide additional insight into factors that may be associated with the need for target vessel revascularization (TVR) following de novo renal artery stenting during long-term follow-up.

METHODS

A retrospective chart and database review was conducted to analyze the progress of all patients with de novo symptomatic renal artery stenosis who underwent stent-supported angioplasty under the auspices of the Single Operator, Single Center, Renal Stent Retrospective Study (SOCRATES). The records review identified 782 patients who were enrolled in the study between 1993 and 2004; after excluding 34 (4.5%) patients (lost to follow-up or inadequate data), 748 consecutive patients (412 women; mean age 70.7+/-9.7 years, range 37-92) were suitable for longitudinal analysis. The need for TVR was based on strict clinical criteria (> or =20% rise in serum creatinine, worsening hypertension, and/or recurrent flash pulmonary edema), and all patients underwent multidisciplinary evaluation before stenting and during follow-up.

RESULTS

Follow-up spanned a mean 45.8+/-26.5 months. TVR was needed in 88 (10.03%) of 877 arteries and was best predicted by patient age < or =67 years (OR 2.91, p=0.0001), stent diameter < or =5.0 mm (OR 2.31, p=0.001), solitary functioning kidney (OR 2.01, p=0.048), history of lower extremity peripheral artery disease (OR 1.87, p=0.008), and antecedent history of stroke (OR 1.73, p=0.026).

CONCLUSION

Renal artery stenting appears to be durable, with only 10% of stented arteries requiring TVR during clinically-based long-term follow-up. Arteries with a final stent diameter < or =5.0 mm were more than twice as likely to need TVR, as were patients with a solitary kidney. The authors acknowledge that clinical recurrence is not a surrogate for ultrasound surveillance after renal artery stenting, so prospective controlled trials will be needed to determine risk factors for restenosis.

Renal angioplasty and stenting: long-term results and the potential role of protection devices

Renal angioplasty and stenting have become the first treatments to be proposed to patients presenting with renal artery stenosis. The immediate technical success rate is high, with a low complication rate and good long-term patency. In most reports, renal stenting has been proven to improve blood pressure. However, despite good immediate- and long-term results, postprocedural deterioration of renal function is a concern, and may occur after renal artery angioplasty and stenting in 20 to 40% of patients, which limits the immediate benefits of this technique. Of the causes of this deterioration in renal function, atheroembolism seems to play an important role. Contrary to earlier beliefs that atheroembolization is not an issue during percutaneous catheter interventions, there is now mounting evidence that distal atherosclerotic debris commonly embolizes from lesions in many vascular territories during percutaneous interventions. Atheroembolism seems to be the root cause of many procedural complications wherever atherosclerotic lesions are treated. Distal embolization was first demonstrated in saphenous vein grafts and now, clinical data are proving that similar embolization and distal-organ complications also occur during catheter treatment in certain native coronary lesions, carotid stenting and renal artery stenting, demonstrating the role and efficacy of protection devices to reduce the incidence of end-organ complications. The same protection devices (protection balloon and filters) utilized for coronary or carotid procedures may be used to protect the kidney from atheroembolism. In this review, the authors discuss recently published data concerning the techniques and results of renal angioplasty and stenting procedures performed under protection, and evaluate the benefits of this technique on renal function and its role in the future. Indications for this technique need to be discussed.

Intervention for renal artery stenosis: endovascular and surgical roles

The treatment options for renal artery stenosis include bypass surgery, surgical endarterectomy, or balloon angioplasty with/without stenting. Each of these procedures is delivered today with differing frequency, morbidity/mortality, and outcomes. The procedure most applicable to patients with atherosclerotic disease is percutaneous transluminal renal angioplasty with stenting. Stents prevent plaque recoil, minimizing early restenosis, and the relatively large size of the renal artery (5-7 mm) minimizes late stent restenosis rates. The clinical features that help predict a favorable response to intervention are reviewed. In short, intervention provides a durable means to control renovascular hypertension, ischemic nephropathy, and congestive heart failure due to poor renal volume control.

Evaluation of the Safety and Effectiveness of Renal Artery Stenting After Unsuccessful Balloon Angioplasty

OBJECTIVES

This study sought to define the safety and durability of renal stenting after suboptimal/failed renal artery angioplasty in patients with suspected renovascular hypertension.

BACKGROUND

Few prospective multicenter studies have detailed the safety, efficacy, and long-term clinical benefits of renal artery stent revascularization in hypertensive patients with aorto-ostial atherosclerotic renal artery lesions.

METHODS

This non-randomized study enrolled 208 patients with de novo or restenotic > or = 70% aorto-ostial renal artery stenoses, who underwent implantation of a balloon-expandable stent after unsuccessful percutaneous transluminal renal angioplasty (PTRA), which was defined as a > or = 50% residual stenosis, persistent translesional pressure gradient, or a flow-limiting dissection. The primary end point was the nine-month quantitative angiographic or duplex ultrasonography restenosis rate adjudicated by core laboratory analysis. Secondary end points included renal function, blood pressure, and cumulative incidence of major adverse events and target lesion revascularization at 24 months.

RESULTS

The stent procedure was immediately successful in 182 of 227 (80.2%) lesions treated. The nine-month restenosis rate was 17.4%. Systolic/diastolic blood pressure decreased from 168 +/- 25/82 +/- 13 mm Hg (mean +/- standard deviation) at baseline to 149 +/- 24/77 +/- 12 mm Hg at 9 months (p < 0.001 vs. baseline), and 149 +/- 25/77 +/- 12 mm Hg at 24 months (p < 0.001 vs. baseline). Mean serum creatinine concentration was unchanged from baseline values at 9 and 24 months. The 24-month cumulative rate of major adverse events was 19.7%.

CONCLUSIONS

In hypertensive patients with aorto-ostial atherosclerotic renal artery stenosis in whom PTRA is unsuccessful, Palmaz (Cordis Corp., Warren, New Jersey) balloon-expandable stents provide a safe and durable revascularization strategy, with a beneficial impact on hypertension.

A Review of the Current Treatment of Renal Artery Stenosis

PURPOSE

Atherosclerotic renal artery stenosis (ARAS) is associated with morbidity and mortality consequent to progressive ischemic renal failure and the cardiovascular consequences of hypertension. There is considerable uncertainty concerning the optimal management of patients with this condition. This review considers the aetiological factors and the physiologic consequences of ARAS and compares the results of clinical studies of medical and endovascular therapies on blood pressure control and preservation of renal function.

RESULTS

Although, in patients with fibromuscular disease the results of percutaneous transluminal angioplasty (PTA) are clearly superior to medical therapy and surgery, in asymptomatic patients with ARAS the antihypertensive benefits and preservation of renal function of endovascular, surgical and medical therapies appear similar. In selected symptomatic patients interventions may, however, be life-saving. Surgery is generally reserved for arterial occlusions with preserved renal parenchyma and function.

CONCLUSIONS

The results of larger, multicentre, randomised, controlled trials are required to clearly clarify the role of interventional therapy in asymptomatic patients.

Percutaneous and Open Renal Revascularizations Have Equivalent Long-Term Functional Outcomes

Atherosclerotic renal artery stenosis is a significant cause of poorly controlled hypertension and progressive renal dysfunction leading to ischemic nephropathy and other end-organ damage. The optimal treatment of renovascular disease contributing to hypertension and renal dysfunction is not known. This study compares the anatomic and functional outcomes of both open and endovascular therapy for chronic, symptomatic atherosclerotic renal artery disease. We performed a retrospective analysis of records from patients who underwent renal arterial interventions, endovascular or open bypass, between January 1984 and January 2004. Principal indications for intervention were hypertension (51%), chronic renal insufficiency (13%), and hypertension and elevated creatinine (36%). A total of 247 patients (109 males; mean age 69 +/- 10, range 44-89 years) underwent 314 interventions (109 open procedures; 205 angioplasties, 71% with stent placement). There was a significant difference in 30-day mortality (4% vs. <1%; p < 0.005) between the open and endoluminal groups, but not at 1, 3, or 5 years. Patients in the open group had a higher primary patency rate at 5 years (83 +/- 5% vs. 76 +/- 6%; p = 0.03), but patients in the endoluminal group had a higher assisted primary patency rate at 5 years (92 +/- 5% vs. 84 +/- 5; p = 0.03). There was no significant difference between both treatment groups in cumulative freedom from presenting symptom or in freedom from dialysis and renal-related death. Patients who presented with hypertension were more likely to have shown improvement in their blood pressure with endoluminal intervention at 1, 3, and 5 (59 +/- 6% endoluminal vs. 83 +/- 5% open; p = 0.01) years. From these results we conclude that open repair and endoluminal repair of atherosclerotic renal artery stenosis have similar immediate and long-term functional and anatomic outcomes. Patients who present with hypertension may have greater benefit with an endoluminal repair.

Divergent outcomes after percutaneous therapy for symptomatic renal artery stenosis

OBJECTIVE

Percutaneous intervention for symptomatic renal artery atherosclerosis is rapidly replacing surgery in many centers. This study evaluated the anatomic and functional outcomes of endovascular therapy for atherosclerotic renal artery stenosis on a combined vascular surgery and interventional radiology service at an academic medical center.

METHODS

This was a retrospective analysis of patients who underwent renal artery angioplasty with or without stenting between January 1990 and June 2002. Indications included hypertension (86%) and rising serum creatinine concentration (55%). One hundred forty-six patients (80 women; average age, 71 years [range, 44-89 years]) underwent 183 attempted interventions (64 to treat bilateral stenosis). Forty-five percent of patients had significant bilateral disease: 27% had greater than 50% bilateral stenosis, and the remainder had nonfunctioning, absent, or occluded vessels.

RESULTS

Of 183 planned interventions, technical success (<30% residual stenosis) was achieved in 179 vessels (98%) with placement of 137 stents (75%). Thirty-day mortality was 0.7%. The major morbidity rate was 4%, and the procedure-related complication rate was 18%. Five-year cumulative patient mortality was 25%. Primary patency, assisted primary patency, and recurrent stenosis rates were 82% +/- 9%, 100% +/- 0%, and 30% +/- 7%, respectively, at 5 years. Within 3 months of the procedure, 52% of patients who received treatment of hypertension demonstrated clinical benefit (hypertension improved or cured), which was maintained in 68% of patients at 5 years. Serum creatinine concentration was lowered or stabilized in 87% of patients within 3 months of the procedure, but this benefit, including freedom from dialysis, was maintained in only 45% of patients at 5 years.

CONCLUSIONS

Endovascular intervention for symptomatic atherosclerotic renal artery stenosis is technically successful. There were excellent patency and low recurrent stenosis rates. There is immediate clinical benefit for most patients, but divergent long-term functional outcomes. Endovascular interventions modestly enhance the care of the patient with hypertension, but poorly preserve long-term renal function in the patient with chronic renal impairment.

Preservation of renal function with surgical revascularization in patients with atherosclerotic renovascular disease

OBJECTIVE

Clinical and anatomic factors predictive of a favorable response to renal revascularization performed for renal function salvage remain poorly defined. To clarify decision making in such patients we reviewed a contemporary experience of surgical renal artery revascularization (RAR) performed primarily for preservation of renal function.

METHODS

Between June 1990 and March 2001 (ensuring 1 year minimum follow-up), 96 patients with renal insufficiency (serum creatinine [Cr] concentration >or=1.5 mg/dL) and hypertension underwent RAR for preservation of renal function. Study end points included early and late renal function response, progression to dialysis dependence, and long-term survival. Variables potentially associated with these end points were assessed with univariate analysis, Cox regression analysis, and logistic regression analysis, and survival was assessed with the Kaplan-Meier method.

RESULTS

Perioperative failure of RAR occurred in 3 patients (3%), with perioperative mortality in 4 patients (4.1%); thus 92 patients were available for long-term follow-up (mean, 39 months). Mean patient age was 70 +/- 9 years with a mean baseline Cr of 2.6 mg/dL (range, 1.5-7.8 mg/dL). Operative management consisted of aortorenal bypass in 38% of patients, extraanatomic bypass in 38% of patients, and endarterectomy in 24% of patients; 32% of patients required combined aortic revascularization and RAR, and 27% underwent bilateral RAR. At hospital discharge renal function had improved (20% decrement in Cr) in 41 (43%) patients, including 7 patients who were removed from dialysis; remained unchanged in 40 (41%) patients; and declined (20% increase in Cr) in 15 (16%) patients. At last follow-up renal function was either improved or unchanged in 72% of patients. Predictors of a favorable response to RAR at last follow-up included stable Cr at hospital discharge (odds ratio [OR], 7.1; 95% confidence interval [CI], 2.5-21.8; P =.0004) and decreased Cr at hospital discharge (OR, 16; 95% CI, 1.6-307.8; P <.0001); bilateral renal artery repair (OR, 3.1; 95% CI, 0.9-10.6; P =.07) approached clinical significance. Predictors of worsened excretory function at last follow-up included decline of renal function at hospital discharge (OR, 28.9; 95% CI, 5.0-165.4; P =.0002), intervention to treat unilateral renal artery stenosis (OR, 3.8; 95% CI, 0.8-16.6; P =.05), and level of baseline Cr (OR, 3.0; 95% CI, 1.0-4.0; P =.04). Progression to dialysis occurred in 16 (17%) patients. Dialysis-free survival at 5 years was 50%, and overall actuarial survival at 5 years was 59%. Predictors of progression to dialysis during follow-up included treatment of complete renal artery occlusion (OR, 6.2; 95% CI, 1.3-29.5; P =.02), early failure of RAR (OR, 3.1; 95% CI, 0.7-14.2; P =.04) and baseline Cr (OR, 2.9; 95% CI, 1.3-6.1; P =.006).

CONCLUSION

Long-term clinical success in the preservation of renal function, noted in 70% of patients, can be predicted by the initial response to RAR and by anatomic factors, in particular, bilateral repair. While extreme (mean Cr >or=3.2 mg/dL) renal dysfunction generally is predictive of poor long-term outcome, a subset of patients will experience favorable results, even to the extent of rescue from dialysis. These results may facilitate clinical decision making in the application of RAR for renal function salvage.

Surgical and radiological management of renovascular hypertension in a developing country

PURPOSE

We determined the long-term outcome of radiological and surgical intervention in young patients with renovascular hypertension.

MATERIALS AND METHODS

Between 1989 and 2001, 85 patients with a mean age +/- SD of 21 +/- 10.3 years, including 59 with Takayasu's arteritis (TA) and 26 with fibromuscular dysplasia (FMD), underwent radiological (percutaneous transluminal angioplasty) or surgical treatment for renovascular hypertension due to renal artery stenosis. The technical success, complications and clinical response of each treatment were compared.

RESULTS

Of the patients 29 with TA and 20 with FMD underwent a total of 56 balloon angioplasties. Technical success was achieved in 94.58 renal units with a clinical response in 41 patients (83.9%). However, the re-stenosis rate was 24.13% in TA and 10% in FMD cases. A total of 41 surgical procedures were performed in the 28 and 7 patients with TA and FMD, respectively, including aortorenal bypass with vein in 12, and with a polytetrafluoroethylene graft in 4, lienorenal bypass in 4, iliorenal bypass in 2, gastroduodenal bypass in 1, autotransplantation in 1, nephrectomy in 14 and partial nephrectomy in 2. The clinical response rate to renal revascularization procedures was 94.4%, whereas it was only 50.0% for nephrectomy/partial nephrectomy during a median followup of 42 months (range 9 to 96).

CONCLUSIONS

Percutaneous transluminal angioplasty and renal revascularization provide comparable long-term results in the management of renal artery stenosis due to TA and FMD. Although it is technically complex, surgery for TA is safe and effective. However, the rate of re-stenosis following angioplasty for TA is higher compared with FMD.

Urological manifestations of vascular disease

We have detailed several of the urological manifestations of vascular disease. With the aging of the North American population, urologists will encounter the urological complications of vascular disease with ever-increasing frequency.

Critical care and the urologic patient

Changing concepts of disease management, expanding indications for invasive therapy to elderly patients, together with technologic advances have changed the management of various urologic diseases. Although minimally invasive surgery may have reduced the need for ICU care, we are faced with new and unique treatment problems.

Recent advances in peripheral angioplasty and stenting

Utilization of percutaneous interventions for arterial and venous occlusive lesions continue to increase. With the progression of the technology supporting these therapeutic measures, the results of these interventions may be expected to improve. In general, a comparison of techniques for revascularization demonstrates similar initial technical success rates for surgery and percutaneous transluminal angioplasty. Angioplasty is often associated with lower procedural morbidity and mortality rates. Conversely, surgery frequently provides greater long-term patency. Late failure of percutaneous therapies may often be treated successfully with reintervention, however. The continued accumulation of experience with PTA and stenting will ultimately define its role in the management of occlusive disease.

Successful bilateral transaortic renal endarterectomy after failed renal artery angioplasty and stenting: a case report

Restenosis after renal angioplasty and stenting is usually treated with repeat angioplasty or surgery. Because development of substantial postangioplasty periarterial fibrosis is thought to preclude transaortic endarterectomy, renal artery bypass grafting has been the operation of choice in this setting. This report describes successful bilateral transaortic renal thromboendarterectomy undertaken for the treatment of restenosis after percutaneous angioplasty and stenting for renovascular hypertension caused by bilateral renal artery nonostial stenosis.

Multicenter Palmaz stent renal artery stenosis revascularization registry report: four-year follow-up of 1,058 successful patients

Palmaz-Schatz stent revascularization of renal artery stenosis was successfully performed on 1,058 patients who were entered into a voluntary, multicenter registry. The revascularization procedures were performed because of poorly controlled hypertension, preservation of renal function, and congestive heart failure. All 1,058 patients were eligible for > or =6-month clinical follow-up, which focused on subsequent renal function, blood pressure, number of antihypertensive medications, and survival. At 4-year follow-up, systolic and diastolic blood pressures had significantly decreased (168 +/- 27 mm Hg to 147 +/- 21 mm Hg, and 84 +/- 15 to 78 +/- 12 mm Hg; P < 0.05) and the blood pressure appeared to be more facilely controlled as indicated by the concomitant decrease in number of antihypertensive medications (2.4 +/- 1.1 to 2.0 +/- 1.0; P < 0.05). Serum creatinine had also significantly decreased (1.7 +/- 1.1 to 1.3 +/- 0.8 mg/dl; P < 0.05). The cumulative probability of survival was 74% +/- 3% at 4 years. Survival was good for patients with normal (85% +/- 3%) baseline renal function, fair (78% +/- 5%) with mildly impaired renal function, and poor (49% +/- 5%) with severely impaired renal function (baseline creatinine > or =2.0 mg/dl). The combination of impaired renal function and bilateral disease adversely effected survival (unilateral 55% +/- 6% vs. bilateral 36% +/- 11%; P < 0.05). Renal artery stent revascularization, in the presence of normal or mildly impaired renal function, had a beneficial effect on blood pressure control and on renal function (through stabilization or improvement). Survival was adversely effected by renal dysfunction despite adequate revascularization. Perhaps early diagnosis of renal artery stenosis and adequate revascularization prior to the onset of renal dysfunction could beneficially impact blood pressure control, preserve or prevent deterioration of renal function, and improve patient survival.

Long-term results of surgical revascularization for renal artery disease

This article discusses the different operative techniques used for treatment of patients with significant atherosclerotic renal artery disease. The authors then review the results and success rates of these procedures.

Primary renal artery stenting: characteristics and outcomes after 363 procedures

BACKGROUND

Stenting improves the acute results of percutaneous balloon angioplasty for atherosclerotic renal artery stenosis. Predictors of benefit and angiographic restenosis are not well understood. We describe the technical and clinical success of renal artery stenting in a large consecutive series of patients with hypertension or renal insufficiency. We identify clinical, procedural, and anatomic factors that might influence outcome, restenosis, and survival.

METHODS

Primary renal artery stenting was performed in 300 consecutive patients who underwent 363 stent procedures in 358 arteries. Angiograms were analyzed quantitatively. Clinical and angiographic follow-up data are available after a median of 16.0 months.

RESULTS

At baseline, 87% of patients had hypertension, and 37% had chronic renal insufficiency. The mean age was 70 years (interquartile range 63.1-74.6) years. The stenosis was unilateral in 49% and bilateral in 48% and involved a solitary functioning kidney in 3.6%. The stenting procedure was successful in all attempts. There were no procedural deaths or emergency renal surgical procedures. Postprocedure azotemia was seen in 45 of 363 (12%) procedures but persisted in only 6 patients (2%), all of whom had baseline renal insufficiency. Systolic and diastolic blood pressures were significantly reduced (systolic blood pressure from 164.0 +/- 28.7 to 142.4 +/- 19.1 mm Hg, P <.001). At follow-up, 70% of patients had improved blood pressure control regardless of renal function. In patients with baseline renal insufficiency, 19% had improvement in serum creatinine levels at follow-up, 54% had stabilization, and 27% had deterioration. Follow-up mortality was 10% and was predicted by baseline creatinine levels (odds ratio 1.72 for each 1 mg/dL creatinine increment, 95% confidence interval 1.13-2.49) and extent of coronary artery disease (odds ratio 1.66 for each diseased coronary artery, 95% confidence interval 1.03-2.67). Angiographic restenosis was found in 21% of 102 patients overall and was less common (12%) in arteries with a reference caliber >4.5 mm (P <.01 vs caliber <4.5 mm). Neither poststenotic dilation nor severity of angiographic stenosis predicted clinical outcome.

CONCLUSIONS

Primary renal artery stenting can be performed safely with nearly uniform technical success. The majority of patients with hypertension or renal insufficiency derive benefit. Follow-up mortality is 5-fold higher in patients with baseline renal insufficiency. Clinical and angiographic features did not predict blood pressure or renal functional outcome. Restenosis is more common in renal arteries with a reference caliber less than 4.5 mm.

Renal artery stenosis and ischemic nephropathy

Renal artery stenosis (RAS), in its most severe form, can result in diminished renal function and loss of kidney mass. The prevalence of ischemic nephropathy is greatly under-appreciated in the elderly population and is the source of substantial morbidity and mortality. Diagnostic tests for RAS in patients with renal insufficiency are problematic, and medical therapy does little to slow the natural progression of the disease. Renal artery stenting can achieve long-term vessel patency and has been shown to preserve renal function. Proper technique and careful case selection are critical to the success of such procedures. Large-scale trials are needed to clearly identify groups of patients who will benefit most from percutaneous revascularization.

Renal Artery Stenosis

Renal artery stenosis (RAS) can accelerate or generate progressive hypertension and renal dysfunction. The goals for treating patients with RAS are to reduce cardiovascular morbidity and mortality attributable to elevated arterial pressure and to preserve renal function beyond critical stenosis. Recent, randomized trials with current antihypertensive agents indicate that many patients with RAS can be managed for years without renal artery revascularization. As it does elsewhere, atherosclerotic disease can progress to more severe occlusion in the renal arteries. Rapid advances in endovascular techniques, including stenting, make restoration of renal blood flow possible in more patients than before. Therapeutic goals are achieved by 1) avoidance of tobacco, 2) reducing arterial pressure with antihypertensive drug therapy, particularly those agents capable of blocking the renin-angiotensin system, and 3) renal revascularization, using balloon angioplasty and stent placement, surgical bypass, or endarterectomy. The major clinical challenges are to identify progressive occlusive disease and to determine appropriate timing for vascular intervention.

Atherosclerotic renovascular disease: diagnosis and treatment

The technical expertise and tools required to treat renovascular obstruction have become commonplace, and many series of patients revascularized with surgery, balloon angioplasty or endovascular stenting have been reported. Nevertheless, although hypertension and renal failure are easy to diagnose, their cause often remains elusive. Evidence is developing that patients with hypertension and atherosclerotic renal artery stenosis may often have hypertension and renovascular disease but not hypertension because of renovascular disease. As a result, diagnosis and therapy are increasingly directed towards the preservation of renal function, and the future of renal revascularization will depend on how well potential therapies address this goal.

Effect of renal artery stenting on renal function and size in patients with atherosclerotic renovascular disease

BACKGROUND

Renal artery stenting is widely performed, but little is known about its effectiveness in preserving renal function and size in patients with renovascular disease and chronic renal insufficiency. We studied the effect of renal artery stenting on renal function and size in patients with obstructive renovascular disease and chronic renal insufficiency.

METHODS AND RESULTS

Stent deployment was performed in patients with chronic renal insufficiency (creatinine >1.5 mg. dL(-1)) and global renovascular obstruction (bilateral renal artery stenosis or unilateral stenosis in the presence of a solitary or single functional kidney). The effect of renal artery stenting on renal function was assessed by comparing the slopes of the regression lines derived from the reciprocal of serum creatinine versus time plotted before and after stent deployment. Renal size was assessed by serial ultrasound of pole-to-pole kidney length. Stenting was successful in all 61 vessels in 33 patients. Twenty-five patients had complete follow-up (mean 20+/-11 months). Before stent deployment, all patients exhibited a negative slope, indicating progressive renal insufficiency. After stent deployment, the slopes were positive in 18 and less negative in 7 patients. Thus, the mean slope increased from -0.0079 to 0.0043 dL. mg(-1). mo(-1) (P:<0.001). Ultrasonography on 41 kidneys revealed preservation of size, with the kidney length measuring 10.4+/-1.4 cm at baseline and 10.4+/-1.1 cm at last follow-up (P:=NS). Patient survival at 20+/-11 months was 90%.

CONCLUSIONS

In patients with chronic renal insufficiency and global obstructive atherosclerotic renovascular disease, renal artery stenting improves or stabilizes renal function and preserves kidney size.