Renal artery stenosis (RAS) can result in renovascular hypertension and nephrosclerosis, and accounts for approximately 1 to 3% of all causes of hypertension. The current treatment of choice for atherosclerotic renal artery disease in selected patients is balloon angioplasty and stenting. Recent technical improvements of interventional endovascular tools have led to a more widespread use of percutaneous renal artery revascularization. Despite a paucity of data from randomized trials comparing an interventional approach with medical therapy for renal artery stenosis, there is evidence indicating positive effects on blood pressure and renal function after renal artery intervention.1
There are few reports in the medical literature of angioplasty and/or stenting for multiple renal arteries. Sharma et al2 reported stenting 3 lesions in 1 patient, and Mehan and Meier reported stenting 2 lesions in 1 patient.3
We describe here a patient with 5 renal arteries, 4 of which had severe ostial stenosis and were all successfully treated with stent implantation in one session.
Case Description. A 62-year-old male was referred for coronary angiography because of chest pain. This patient had a long history of arterial hypertension and had been treated with beta-blockers, diuretics and angiotensin receptor-blockers. Despite this triple therapy, his blood pressure was not controlled properly and remained in the range of 150/100 mmHg. Because of combined aortic valve stenosis and insufficiency, this patient had undergone mechanical aortic valve prosthesis 14 years earlier. He had no history of diabetes. His serum creatine was 1.5 mg/dl and creatine clearance was 75 ml/min. No significant coronary artery lesions were observed. His renal angiogram showed 90% stenosis of the left superior renal artery, 90% stenosis of the left inferior renal artery, 25% stenosis of the right superior renal artery, 90% stenosis of the middle right renal artery and 90% stenosis of the inferior right renal artery. Percutaneous transluminal angioplasty and stenting of the 4 significant lesions was performed in a single session and a bolus of 12,500 IU heparin was administered. The left superior renal artery was engaged with a 7 Fr JL 4 guiding catheter and the lesion was crossed with a 0.014 inch guidewire. A 4 mm x 18 mm sirolimus-eluting stent was directly deployed at 18 atm without residual stenosis (Figures 1A and B). Next, the left inferior polar artery was engaged using the same guiding catheter, and the lesion was crossed with the same guidewire.
A 4 mm x 18 mm sirolimus-eluting stent was deployed at 18 atm without residual stenosis (Figures 2A and B). Using the same guiding catheter and guidewire, stenting of the right medial renal artery was also performed with implantation of a 3.5 mm x 18 mm sirolimus-eluting stent in the right medial renal artery. Because of significant elastic recoil in the ostium, a second, thick-strut bare-metal stent was deployed with a good final angiographic result (Figures 3A and B). Finally, with the same guiding catheter and guidewire, a 4 mm x 24 mm sirolimus-eluting stent was deployed in the right inferior renal artery, with a good angiographic result (Figures 4A and B). The mild stenosis of the right superior renal artery was left untreated (Figure 5). The patient recovered uneventfully and was discharged on the day after the procedure on 100 mg of acetyl salicylic acid lifelong and 75 mg of clopidogrel for 3 months. At 3-month follow up, the patient’s blood pressure control was adequate at around 120/80 mmHg on the same antihypertensive regimen.
Discussion. Accessory renal arteries have been known since the early days of human autopsy. These are aberrant arterial branches originating directly from the aorta, usually supplying a small portion of the kidney. During embryogenesis, the kidneys ascend from their original sacral location to their final location in the upper retroperitoneum. As the kidneys ascend during the sixth through ninth weeks of gestation, they maintain their arterial supply by becoming progressively revascularized by a series of arterial sprouts from the aorta. These transient aortic branches regress in a sequential fashion, and each kidney is finally left with a single main renal artery when ascent has been completed. Failure of one of the transient arteries to regress may result in an accessory renal artery.4 A thorough understanding of the variations in renal vascular anatomy has grown in importance in recent years, together with the increased frequency of renal transplantation, vascular reconstruction for congenital andacquired lesions and endovascular interventions. Khamanarongh and colleagues made a detailed description of the dissection of 267 cadavers and found a single hilar renal artery (at either side) in 82% of cases, double renal arteries in 17% of cases and triple renal arteries occurred in 1%.5 These numbers correspond well to those of other investigators, with Dhar et al6 reporting a prevalence of 20% of accessory renal arteries (15% unilateral and 5% bilateral anomalies) in a series of 40 patients and Gupta and Tello7 reporting a prevalence of 24% among 185 patients. For many years, it has been hypothesized that accessory renal arteries are related to the risk of renovascular hypertension. However, two recent studies refute this theory. Gupta and Tello7 studied 185 hypertensive patients using magnetic resonance angiography. They found that the odds of finding a renal artery stenosis in an individual with an accessory artery as compared with an individual with a single renal artery were not significantly different. In another report, studying 158 hypertensive patients with multidetector-row CT (MDCT), Coulier came to the same conclusion.8
Approximately 1–3% of the population with hypertension has a renovascular etiology. The concomitant presence of atherosclerosis significantly increases the prevalence of renovascular hypertension (9.5%) and renal insufficiency.9 The prevalence of these lesions appears to be increasing due to the aging western population and improved survival from other vascular diseases, including stroke and myocardial infarction. The last decade has been marked by significant improvements in the techniques for renal revascularization. However, there is still controversy and debate about the optimal treatment of patients with renal artery stenosis as these new therapies and techniques continue to introduce costs and risks that limit their universal application. At the base of this debate lies the ambiguity of both the benefits obtained and the risks posed by manipulation of the diseased aorta and renal arteries.10 Possible complications of endovascular stenting include significant bleeding and vascular injury, segmental infarction,systemic atheroemboli, aortic dissection, stent migration and thrombosis.11
Sufficient prospective, controlled data are not yet available to provide clear guidelines. Remarkably, only 3 randomized trials with a total of 210 patients have compared PTRA (percutaneous transluminal renal angioplasty) versus medical management. Taken individually, these studies showed modest, if any, advantage of vascular intervention over medical treatment in blood pressure control or renal function. However, a meta analysis of these trials reported that compared with medical therapy, PTRA was more effective in reducing blood pressure.12
More recently, Zeller et al1 published the long-term results from a prospective registry of 456 hemodynamically significant de novo renal artery stenoses in 340 consecutive hypertensive patients, treated with stent-supported angioplasty. During a mean follow up of 34 ± 20 months, serum creatine decreased significantly from 1.45 ± 0.87 to 1.39 ± 0.73 mg/dl (p = 0.048). In 34% of the patients, serum creatine decreased > 10%, 39% were unchanged, and 27% had an increase > 10%. The glomerular filtration rate increased from 59 ± 26 to 62 ± 26 ml/min/1.73 m2 (p = 0.6). Systolic, diastolic and mean blood pressure measurements significantly improved immediately after the intervention (132/72/93 versus 144/79/102 mmHg at baseline, p < 0.0001) and remained improved during follow up (p < 0.0001). Blood pressure control was improved in 46%, unchanged in 43% and deteriorated in 11%. In conclusion, stent-supported angioplasty of renal artery stenoses preserved renal function and improved blood pressure control. Baseline serum creatine, bilateral intervention, percent diameter stenosis and 3-vessel coronary disease were independent predictors of improved renal function during follow up; the number of antihypertensive drugs taken before the intervention predicted improved blood pressure control.1
In conclusion, we presented here a patient in whom 4 of 5 renal arteries were severely stenosed and who was successfully treated with stent implantations.
Acknowledgement. Tom Adriaenssens is supported by a fellowship in interventional cardiology from the European Society of Cardiology.
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