Atherosclerotic renal artery stenosis and reconstruction

Renal artery stenosis is common especially in patients with generalized atherosclerosis. It is frequently associated with difficult-to-treat hypertension and with renal failure. There is an ongoing debate about the appropriate screening and treatment of atherosclerotic renal artery stenosis. Advances in imaging and interventional devices offer new opportunities, however, clinicians still have to decide individually in every patient to treat or not to treat stenosis with revascularization. This review evaluates the current literature in order to help the physician to find the right decision in this challenging clinical issue.     

Atherosclerotic renal artery stenosis: current status and future directions

PURPOSE OF REVIEW: Atherosclerotic renal artery stenosis is a common, progressive problem that increases in prevalence with age. It can have important clinical consequences such as hypertension, pulmonary edema, and renal failure. In addition, it is associated with increased cardiovascular mortality. The purpose of this review is to describe the current status of knowledge and future directions for this evolving field. RECENT FINDINGS: In patients who are suspected of having the disease, duplex Doppler ultrasound and magnetic resonance angiography remain the most promising noninvasive screening tests. Percutaneous revascularization continues to advance, and technical success is possible in the vast majority of patients. Revascularization for hypertension is of modest clinical benefit. Limited information is available on the effect of revascularization on preservation of renal function or cardiovascular events and mortality. SUMMARY: Further studies are still needed focusing on the identification of which patients will derive benefit from percutaneous revascularization and whether intervention provides an advantage over medical therapy, particularly with respect to preservation of renal function and reduction in cardiovascular morbidity and mortality.     

Comparison between gadolinium and iodine contrast for percutaneous intervention in atherosclerotic renal artery stenosis: clinical outcomes

Background. Percutaneous angiography with iodinated contrastin patients with chronic kidney disease carries a risk of contrastnephropathy, which is independently associated with renal diseaseprogression and increased mortality. Gadolinium contrast isa potential alternative to iodinated contrast for percutaneoustransluminal renal angioplasty (PTRA), and appears to be safeand well tolerated. The aim of this study was to assess theresults of gadolinium use to facilitate PTRA in patients withchronic kidney disease. Methods. Clinical outcomes were compared between patients withserum creatinine (Cr) 176 µmol/L (2 mg/dL), who had eithergadolinium (n = 57; gadoteridol or gadodiamide), iodinated (n= 68; iohexol or iodixanol) or a combination of gadolinium andiodinated-contrast-enhanced (n = 38) PTRA. Results. Despite similar degrees of pre-procedural renal insufficiency,the incidence of immediate contrast nephropathy [defined asan increase in serum Cr of 44 µmol/L (0.5 mg/dL) within7 days without other identifiable causes] was lowest in thegadolinium group (3/57, 5.3%) compared to those receiving acombination of modest iodinated contrast in addition to gadolinium(4/38, 10.5%) or solely iodinated contrast (14/68, 20.6%). Thiswas associated with a reduction in the 30-day progression toneed for renal replacement therapy (RRT) (P < 0.005). Yet,over a mean follow-up of 40 ± 22 months, renal functionoutcomes or all-cause mortality were not different between thecontrast groups. The type of contrast used had no effect ontechnical success and both short- and long-term blood pressureoutcomes were comparable between the groups. Two patients developedpathology-proven nephrogenic fibrosing dermopathy, a seriousskin condition that has been seen in patients with kidney diseasefollowing administration of gadolinium. Conclusions. Gadolinium contrast appears to be an effectiveagent for interventional renal angiograms. Compared to iodinatedcontrast, gadolinium contrast is associated with a significantlylower incidence of contrast nephropathy and early progressionto end-stage renal disease (ESRD) in patients with pre-existingchronic kidney disease. The risk of fibrosing dermopathy howeverand remains to be established.     

Atherosclerotic renal artery stenosis as a cause for hypertension in an adolescent patient

Background

Atherosclerosis causing renal artery stenosis (RAS) is one of the most common secondary causes of hypertension in adults, but is rare in children.

Case-diagnosis/treatment

RAS associated with coronary artery stenosis was diagnosed in a teenage patient who presented with intermittent chest pain and elevated blood pressures for 6 years. The diagnosis of RAS was suspected after physical examination revealed an abdominal bruit. Renal ultrasound with Doppler revealed normal appearing kidneys with high velocity in the aorta and renal arteries. Computed tomography angiography (CTA) of the chest and abdomen demonstrated generalized calcified atherosclerotic narrowing of the arteries including the renal, celiac, superior mesenteric and coronary arteries in the setting of hyperlipidemia. The lipid panel revealed hypercholesterolemia with elevated serum plant sterol concentrations, suggesting the diagnosis of sitosterolemia. Cardiac catheterization demonstrated left anterior descending artery and left circumflex artery stenosis, which required bypass of the left anterior descending artery and stenting of the left circumflex artery. Aggressive lipid control was recommended and he was treated medically with a beta-blocker, low-dose angiotensin-converting enzyme inhibitor, aspirin, statin, and clopidogrel.

Conclusion

Although very rare, generalized atherosclerosis caused by genetic disorders should be considered an underlying cause for severe hypertension in children with hyperlipidemia.     

Endovascular revascularization of renal artery stenosis: technical and clinical results

PURPOSE: The natural history of renal artery stenosis is progression with subsequent deterioration of kidney function and development of renovascular hypertension. Percutaneous transluminal renal angioplasty is effective in the treatment of nonostial lesions but less effective for ostial stenoses. Because of the poor technical success experienced with percutaneous transluminal renal angioplasty, stenting of ostial stenoses is becoming the standard of endovascular care. In this retrospective study we analyzed the technical and clinical outcomes after renal artery stenting in 73 consecutive patients. PATIENTS AND METHODS: From July 1992 to January 1999, 88 Palmaz stents were deployed in 85 renal artery stenoses in 73 patients, with a mean age of 67.9 +/- 9.4 years. Twelve patients (16%) underwent bilateral stent placement. Atheromatous lesions were the most prevalent (99%: 82% ostial, 16% nonostial). Most stents were implanted for suboptimal balloon dilation (52%) or dissection (24%). Mean percent stenosis was 86% +/- 12%. Renal insufficiency (creatinine level > or = 1.5 mg/dL) was present in 50 (68%) patients, and uncontrolled hypertension (systolic > or = 160 mm Hg or diastolic > or = 90 mm Hg with more than two medications) was present in 57 (78%). RESULTS: Primary technical success was achieved in 89%. At the initial procedure, three additional stents were placed for residual stenoses, and urokinase was used to treat one intraprocedural stent thrombosis, resulting in an assisted primary technical success rate of 94%. Major complications occurred in 9.1% of stents placed: access artery thrombosis (n = 4), renal artery extravasation (n = 1), renal artery thrombosis (n = 1), and hematoma requiring operation (n = 2). Long-term clinical data were available on 69 (95%) patients at 20 +/- 17 months. Overall, a significant decrease in systolic and diastolic pressures (P <.001) and reduction of medication (P <.01) were noted without a change in renal function (P = NS). Angiography was performed on 22 patients at 11.3 +/- 10.3 months for persistent or worsening renal function or hypertension or for other reasons; 10 patients had significant restenoses in 14 renal arteries. CONCLUSION: Our retrospective analysis demonstrates that endovascular stenting of renal artery stenosis in patients with poorly controlled hypertension or deteriorating renal function is a safe and effective alternative treatment to surgical management.     

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.     

Atherosclerotic renal artery disease diagnosis update

Atherosclerotic renal artery disease represents a cause of which little is known but not a cause to be neglected for hypertension and renal insufficiency. Even though its occurrence remains badly defined, atherosclerotic renal artery disease is constantly on the rise due to the aging population, the never prevailing hypertension and diabetes mellitus. This review aims to give a clinical profile of patients presenting with atherosclerotic renal artery disease and to discuss, in the light of study results, which diagnostic evaluation should be used considering the sequence and the benefit and risk of each in order to initiate a personalized treatment. Patients affected by atherosclerotic renal artery disease are likely to have more complications and more extensive target-organ damage than patients without renal artery stenosis. The evolution of the atherosclerotic renal artery disease is in general slow and progressive. Nevertheless, certain clinical cases manifest themselves with the onset of acute renal failure bought upon by the administration of blockers of the rennin-angiotensin-aldosterone system, or by some other causes responsible for a sudden drop in renal plasma flow (e.g., thrombosis of the renal artery). The relationship between atherosclerotic renal artery disease and atherosclerosis is complex, and mediators implicated in the pathophysiology of renovascular disease may also contribute to the progression of cardiovascular damage. An early assumption of the atherosclerotic renal artery stenosis is warranted to determine the adapted treatment (i.e., medical treatment, revascularisation...) just as the assumption and the correction of the more general cardiovascular risk factors.     

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.     

Pheochromocytoma and renal artery stenosis

Cases with concurrent pheochromocytoma and renal artery stenosis, two "surgically curable" hypertensive disorders, are rare. The stenosis is generally secondary to direct compression or stretching of the renal artery by the tumor. Five such cases are reported. Sometimes the tumor and the renal artery stenosis occur independently giving rise to some pathogenetic queries. Diagnosis and therapy are briefly discussed.     

Transplant renal artery stenosis

Transplant renal artery stenosis (TRAS) is a recognized, potentially curable cause of posttransplant arterial hypertension, allograft dysfunction, and graft loss. It usually occurs 3 mo to 2 yr after transplantation, but early or later presentations are not uncommon. The prevalence ranges widely from 1 to 23% in different series, reflecting the heterogeneous criteria used to establish the diagnosis, the different manner of preservation of the graft, and surgical expertise. Reported cases are progressively increasing in parallel with the use of non-invasive investigation procedures, such as Doppler ultrasonography and magnetic resonance (MR) angiography, that arouse the suspicion of the disease even in less symptomatic cases. However, definitive diagnosis of hemodynamically significant stenosis rests on the use of invasive angiographic techniques. Percutaneous transluminal angioplasty (PTA) is the treatment of choice and restores kidney perfusion in 60 to 90% of cases. The risk of re-stenosis, the major drawback of the procedure, is prevented by the use of expandable endoprostheses. Surgery is indicated for stenoses that cannot be treated by PTA or that recur after it. Doppler ultrasonography is the procedure of choice to evaluate graft perfusion before and after revascularization.     

Transplant renal artery stenosis

A group of 31 patients with transplant renal artery stenoses was identified among 2002 patients undergoing renal transplantation at the University of Minnesota; 29 of the stenoses were at the anastomosis. A total of 43 procedures were performed to correct the stenosis. Angioplasty was performed 25 times, with 3 patients cured and 2 patients improved; 20 procedures resulted in a poor result (3) or a failure (17). The failures were usually due to recurrent stenosis (7 patients) or to arterial injury that resulted in graft loss (4 patients) or successful emergency surgery to save the transplant (3 cases). Surgical repair of the stenosis was performed 18 times. No grafts were lost and 13 patients were cured or improved. These data suggest that angioplasty for anastomotic stenosis yields poor results and that a surgical repair is probably warranted. All 7 patients who had a poor results or failed a technically successful intervention did not have a rise in creatinine secondary to captopril or had a systolic pressure gradient of less than 60 mmHg across the anastomosis. These data also suggest that patients without physiological evidence of renal artery stenosis may not have improvement in their hypertension following repair.     

Prevalence and prediction of renal artery stenosis in patients with coronary and supraaortic artery atherosclerotic disease.

BACKGROUND: Renal atherosclerosis is associated with increased cardiovascular mortality. This study aimed to determine the prevalence and predictors of renal artery stenosis (RAS) in patients with coronary artery disease (CAD) and supraaortic arteries (SA) stenosis. METHODS: Renal angiography was performed in 1193 (807 men) consecutive patients referred for coronary or SA angiography. Group I included 296 (136 men, 60.1 +/- 9.5 years) patients with no significant (< 50%) lesion in coronary arteries or SA; group II included 706 (526 men, 62.2 +/- 9.7 years) patients with stenosis > or = 50% within single arterial territory (coronary arteries or SA) and group III included 191 (145 men, 64.9 +/- 8.5 years) patients with stenosis > or = 50% in both territories. RESULTS: Some RAS was found in 55 (18.6%) patients in group I, 250 (35.4%) patients in group II and 115 (60.2%) patients in group III (P < 0.001). The proportion of patients with RAS > or = 50% in groups I, II and III was 3.3, 6.2 and 18.3%, respectively (P < 0.001). RAS prevalence increased with the number of stenosed coronary arteries (38.4% in 1-vessel, 42.1% in 2-vessel, 48.5% in 3-vessel CAD, P < 0.001). Independent predictors of RAS > or = 50% identified by logistic regression analysis were SA stenosis [relative risk (RR) = 3.28, P < 0.001], 2-3-vessel-CAD (RR = 2.04, P = 0.002), creatinine level > or = 1.07 mg/dl (RR = 2.95, P < 0.001), hypertension (RR = 2.97, P = 0.012) and body mass index < 25 kg/m(2) (RR = 1.42, P = 0.169). A calculated score for RAS > or = 50% prediction (based on the regression model) was reliable (coefficient of determination, R = 0.978) and showed a sensitivity of 77.5% and a specificity of 63.9%. CONCLUSIONS: RAS prevalence and severity increases with the number of arterial territories involved and CAD severity. The following independent predictors of RAS > or = 50% were identified: SA involvement, 2-3-vessel-CAD, serum creatinine level and hypertension.     

Laparoscopic partial nephrectomy with segmental renal artery clamping: technique and clinical outcomes

Background

Warm ischemic injury is one of the most important factors affecting renal function in partial nephrectomy (PN). The technique of segmental renal artery clamping emerges as an alternative to conventional renal artery clamping for renal hilar control.

Objective

To evaluate the feasibility and efficiency of laparoscopic PN (LPN) with segmental renal artery clamping in comparison with the conventional technique.

Design, setting, and participants

A total of 75 patients underwent LPN from June 2007 to November 2009. All patients had T1a or T1b tumor in one kidney and a normal contralateral kidney. Thirty-seven patients underwent surgeries with main renal artery clamping, and 38 underwent surgeries with segmental artery clamping.

Intervention

All procedures were performed by the same laparoscopic surgeon.

Measurements

Blood loss, operation time, warm ischemia (WI) time, and complications affected renal function before and after operation were recorded.

Results and limitations

All LPNs were completed without conversion to open surgery or nephrectomy. The novel technique slightly increased WI time (p < 0.001) and intraoperative blood loss (p = 0.006), while it provided better postoperative affected renal function (p < 0.001) compared with the conventional technique. The total complication rate was 12%. Among the 38 cases where segmental renal artery clamping was performed, 7 had to convert to the conventional method. Tumor size and location influenced the number of clamped segmental arteries. Long-term postoperative renal function is still awaited.

Conclusions

LPN with segmental artery clamping is safe and feasible in clinical practice. It minimizes the intraoperative WI injury and improves early postoperative affected renal function compared with main renal artery clamping.     

Renal artery stenosis and chronic ischemic nephropathy: epidemiology and diagnosis

Atherosclerotic renal artery stenosis (RAS) is the most common primary disease of the renal arteries and results in renovascular hypertension and ischemic nephropathy. Ischemic nephropathy from atherosclerotic RAS is increasingly recognized as a cause of chronic kidney disease (CKD) and in severe cases can lead to end-stage renal disease. The exact prevalence of atherosclerotic RAS is unknown because the disease is often asymptomatic and few are screened unless they have significant traditional cardiac risk factors or symptoms. A high prevalence of atherosclerotic RAS is seen in patients with advanced age, congestive heart failure, and extrarenal atherosclerosis. The primary reason for diagnosing ischemic nephropathy from renovascular disease is that the loss of kidney function is potentially reversible through treatment of the occlusion with surgical revascularization or percutaneous transluminal renal angioplasty. However, the benefits of revascularization have to be considered in the context of other comorbid disease and remain controversial. There are several tests available for the screening and diagnosis of atherosclerotic RAS; however, the diagnostic test of choice should be based on patient factors and institutional expertise because the best test is the one performed most often at the individual medical facility.     

嗜铬细胞瘤合并肾动脉狭窄

目的提高对嗜铬细胞瘤合并肾动脉狭窄（ＲＡＳ）的诊断与治疗水平。方法报告４例嗜铬细胞瘤合并ＲＡＳ。４例患者均行嗜铬细胞瘤切除术。结果２例切除ＲＡＳ肾及１例松解局部粘连所致ＲＡＳ患者血压均正常,而１例松解长段ＲＡＳ后保留ＲＡＳ肾者持续高血压。结论当嗜铬细胞瘤定性与定位之后在上腹部或背部闻及血管杂音,一侧肾影变小或遇到单用α受体阻滞剂降血压效果欠佳,需加用血管紧张素转化酶抑制剂者,以及嗜铬细胞瘤术后血压持续不降而又排除残留嗜铬细胞瘤者均应考虑合并ＲＡＳ可能。对因嗜铬细胞瘤直接压迫,粘连造成肾动脉成角或局部狭窄者,在去除嗜铬细胞瘤及松解粘连之后ＲＡＳ多能缓解,而对嗜铬细胞瘤致肾动脉广泛狭窄或闭塞,肾实质明显萎缩者,应切除患肾。