Figura 1. Computed tomography angiography of the abdominal aorta and renal arteries, showing right r...

Figura 2. Selective angiography of the right renal artery showing an image compatible with chronic ...

Figura 3. Percutaneous transluminal angioplasty of the right renal artery occlusion. A) Selective c...

Introduction

Renal artery stenosis (RAS) is the most frequent cause of renovascular hypertension, accounting for 5% to 28% of all secondary hypertension cases1. Atherosclerosis has been shown to be the main cause of occlusive renovascular disease, adding up to 90% of all RAS cases2. Evidence suggests that the presence of RAS, regardless of its etiology, may lead to negative consequences in terms of adverse clinical events and exacerbation of concomitant comorbidities. In this sense, decreased blood flow distal to the stenosis increases renin release in the affected kidney, which activates the renin–angiotensin–aldosterone system and the sympathetic nervous system, leading to secondary arterial hypertension (HTN) and increased cardiovascular risk3. Furthermore, RAS can progressively reduce renal blood flow, resulting in functional loss and organ atrophy.

RAS revascularization involves performing percutaneous transluminal angioplasty (PTA). In this context, clinical management guidelines discourage systematic RAS revascularization and suggest elective endovascular treatment in specific situations, such as stenosis secondary to fibromuscular dysplasia (FMD), sudden pulmonary edema, hypertensive crises with target organ damage, congestive heart failure, and cases of renal artery disease with acute renal failure accompanied by oliguria or anuria4. However, there is limited evidence regarding the percutaneous therapeutic approach to renal artery occlusion, defined as complete obstruction without antegrade flow, and to chronic renal occlusion, which is associated with hypertension or renal insufficiency for more than 3 months5.

The following is the clinical case of a young female patient with resistant hypertension secondary to right renal artery occlusion, who was hospitalized due to oligoanuria associated with hypertensive encephalopathy.

Clinical case

The patient was a 35-year-old female patient with resistant hypertension under pharmacological treatment with four drugs at maximally tolerated doses (valsartan 320 mg, hydrochlorothiazide 25 mg, carvedilol 25 mg, lacidipine 20 mg). Active smoking and cocaine use were her cardiovascular risk factors, with no known atherosclerotic disease. A prior transthoracic color Doppler echocardiogram showed concentric left ventricular hypertrophy without wall motion abnormalities and preserved left ventricular ejection fraction.

She was admitted to the emergency room of a multidisciplinary medical center in Buenos Aires City for clinical symptoms compatible with hypertensive encephalopathy, associated with acute pulmonary edema. Vital signs on admission were blood pressure 230/110 mmHg, heart rate 119 beats per minute, tachypnea, and bibasilar crepitant rales on auscultation, requiring supplemental oxygen via noninvasive ventilation and intravenous diuretics with only partial clinical response. A computed tomography (CT) scan of the brain showed no parenchymal lesions, vascular abnormalities, or arteriovenous malformations. Due to suspected secondary hypertension, renal ultrasound and color Doppler of the renal arteries were requested, revealing right renal hypotrophy and right renal artery occlusion. Despite the mentioned renal hypotrophy, there was no renal insufficiency, with a creatinine value of 0.9 mg/dL. Subsequently, a CT angiography was performed to characterize the occlusion and define the therapeutic approach (Figure 1). The case was interpreted as a hypertensive crisis secondary to right renal artery occlusion, and a choice was made for percutaneous revascularization via PTA.

Procedure

The procedure was performed under general anesthesia, via left femoral arterial vascular access optimized under ultrasound guidance, positioning a 7-Fr introducer. Subsequently, a 7-Fr left internal mammary guide catheter was advanced over a 0.035” guidewire, performing selective catheterization of the right renal artery. Selective injection of low-osmolar iodinated contrast helped identify an occlusion in the proximal third, probably secondary to FMD given the patient’s age and comorbidities, with visualization of distal beds via recanalization through collateral circulation from the superior polar artery (Figure 2).

The therapeutic approach to the occlusion considered algorithms of strategies available for coronary vascular disease6, thus opting for the antegrade wire escalation technique (AWE). Initially, a 0.014” hydrophilic wire (PT²™ Moderate Support, Boston Scientific) was advanced, but it was unsuccessful in crossing the proximal cap of the occlusion. Subsequently, a higher-bore wire (Hornet™ 14 Guidewire, Boston Scientific) was used, optimized with the assistance of a metallic coil microcatheter (2.1F MAMBA™ Flex 135, Boston Scientific). This achieved successful lesion recanalization (Figure 3).

Pre-dilation was performed with semi-compliant balloons of progressively increasing diameters (1.5 × 20 mm, 2.0 × 20 mm, and 2.5 × 33 mm), restoring antegrade flow. Two sirolimus-eluting stents with biodegradable polymer and cobalt-chromium structure with abluminal grooves (Firehawk®, Shanghai MicroPort Medical Group, 3.0 × 18 mm and 3.5 × 18 mm) were implanted, with optimal angiographic results. The use of coronary stents, instead of devices specifically developed for the renal vascular territory, was due to availability on the day of the procedure. Final angiography confirmed the restoration of antegrade flow and the presence of parenchymal blush in the kidney (Figure 3).

Upon procedure completion, the guidewire catheter and introducer were removed, and hemostasis of the vascular access site was achieved using an endovascular closure device with a bioabsorbable anchor and collagen sponge (Angio-Seal™ 8F Vascular Closure Device, Terumo Interventional Systems).

Clinical evolution

The patient progressed favorably, with normalization of blood pressure. Forty-eight hours after the initial procedure, antihypertensive medication was reduced, maintaining only valsartan 160 mg. There were no changes in renal function, with creatinine at 0.8 mg/dL. There were no new neurological episodes, and the patient achieved complete recovery without the need for additional pharmacological treatment. She was discharged 72 hours after the therapeutic procedure.

Discussion

As demonstrated in the present clinical case, renal artery occlusion can be identified as a clinical entity with low prevalence but substantial clinical significance, which allows for feasible and safe percutaneous treatment.

To date, the medical literature offers limited evidence regarding percutaneous revascularization in cases of chronic total renal artery occlusion5, 7. This limitation can be attributed to restricted therapeutic indications, inherent technical challenges posed by the procedure, and uncertainty regarding its clinical benefits. In this context, several randomized studies have not demonstrated a clinical benefit of renal PTA compared to optimal medical therapy8-10, so it should be considered only in selected cases.

Identifying which patients might benefit most from this invasive treatment is one of the main challenges. While there is currently no conclusive evidence precisely defining the ideal subgroup for percutaneous revascularization, certain variables such as young age, refractory hypertension, and visualization of the distal bed beyond the occlusion through collateral circulation may be associated with greater clinical benefit, as they suggest the presence of viable renal parenchyma that can be potentially recovered after the intervention. Furthermore, due to the low prevalence of renal artery occlusion, there are no well-established therapeutic algorithms for its management. In this context, applying revascularization strategies used in chronic total occlusions of other vascular territories has proven useful. However, more evidence is needed to determine the most appropriate revascularization technique in this patient group and to identify precise markers that predict procedural success.

Conclusions

Revascularization via percutaneous transluminal angioplasty of chronic total occlusions of the right renal artery is a feasible and safe strategy that should be considered in selected cases. The application of invasive treatment algorithms, based on experiences involving other vascular territories, can lead to optimal angiographic results.

1. Almeida MQ, Silva GV, Drager LF. What Is the Most Common Cause of Secondary Hypertension?: An Interdisciplinary Discussion. Curr Hypertens Rep. 2020;22(12).

2. Parikh SA, Shishehbor MH, Gray BH, et al. SCAI expert consensus statement for renal artery stenting appropriate use. Catheter Cardiovasc Interv. 2014;84(7):1163-71.

3. Covic A, Gusbeth-Tatomir P. The role of the renin-angiotensin-aldosterone system in renal artery stenosis, renovascular hypertension, and ischemic nephropathy: diagnostic implications. Prog Cardiovasc Dis. 2009;52(3):204-8.

4. Aboyans V, Ricco JB, Bartelink MLEL, et al. 2017 ESC Guidelines on the Diagnosis and Treatment of Peripheral Arterial Diseases, in collaboration with the European Society for Vascular Surgery (ESVS): Document covering atherosclerotic disease of extracranial carotid and vertebral, mesenteric, renal, upper and lower extremity arteriesEndorsed by: the European Stroke Organization (ESO)The Task Force for the Diagnosis and Treatment of Peripheral Arterial Diseases of the European Society of Cardiology (ESC) and of the European Society for Vasc. Eur Heart J. 2018;39(9):763-816.

5. Yang M, Lin L, Niu G, et al. Successful endovascular treatment of chronic renal artery occlusion: a preliminary retrospective case series including 15 patients. Int Urol. 2019;51(2):285-91.

6. Wu EB, Brilakis ES, Mashayekhi K, et al. Global Chronic Total Occlusion Crossing Algorithm: JACC State-of-the-Art Review. J Am Coll Cardiol. 2021;78(8):840-53.

7. Li P, Niu G, Yan Z, et al. Case Report: Endovascular Treatment of Chronic Atherosclerotic Renal Artery Total Occlusions with Failed Medical Therapy. Front Surg. 2022;9.

8. Cooper CJ, Murphy TP, Cutlip DE, et al. Stenting and medical therapy for atherosclerotic renal-artery stenosis. N Engl J Med. 2014;370(1):13-22.

9. Wheatley K, Ives N, Gray R, et al. Revascularization versus medical therapy for renal-artery stenosis. N Engl J Med. 2009;361(20):1953-62.

10. Mann SJ, Sos TA. Stent placement in patients with atherosclerotic renal artery stenosis and impaired renal function. Ann Intern Med. 2010;152(3):197.

Para descargar el PDF del artículo
Therapeutic approach to chronic total renal artery occlusion: a rare, treatable, and technically challenging condition

Haga click aquí