Endovascular treatment of renal artery aneurysm using microcoil embolization and renal blood flow preservation: case report

Abstracts

O tratamento endovascular da doença aneurismática da artéria renal tem sido, cada vez mais, aceito como uma alternativa à cirurgia convencional, especialmente em casos de aneurismas complexos intra-parenquimatosos ou que comprometam a bifurcação da artéria renal. Os autores relatam a experiência do tratamento endovascular de uma paciente com aneurisma sacular da bifurcação da artéria renal direita, associado à hipertensão renovascular de difícil controle. Foi realizada a cateterização seletiva da artéria renal, com a inserção de micromolas no saco aneurismático. O aneurisma foi completamente ocluído com preservação total do fluxo sanguíneo renal. A evolução clínica foi satisfatória com redução significativa das medicações anti-hipertensivas. A angio-tomografia de controle, após o oitavo mês do procedimento, confirmou o sucesso do tratamento.

Embolização terapêutica; artéria renal; aneurisma

CASE REPORT

Endovascular treatment of renal artery aneurysm using microcoil embolization and renal blood flow preservation: case report

Marco Aurélio Cardozo^I; Eduardo Lichtenfels^II; Nilon Erling Junior^II; Eduardo Raupp^V; Dorvaldo P. Tarasconi^III

^IProfessor of Vascular Surgery, Fundação Faculdade Federal de Ciências Médicas de Porto Aletre (FFFCMPA), Porto Alegre, RS, Brazil. Vascular and endovascular surgeon, Irmandade Santa Casa de Misericórdia de Porto Alegre (ISCMPA), Porto Alegre, RS, Brazil

^IIResidents in Vascular Surgery, FFFCMPA/ISCMPA, Porto Alegre, RS, Brazil

^IIIInterventional radiologists, ISCMPA, Porto Alegre, RS, Brazil

^{Correspondence}

ABSTRACT

Endovascular treatment of renal artery aneurysmal disease has been increasingly accepted as an alternative to conventional surgery, especially in cases of renal artery bifurcation or complex intrarenal aneurysms. The authors report a case of endovascular treatment of a saccular aneurysm of the right renal artery bifurcation associated with poorly controlled renovascular hypertension. Selective catheterization of the renal artery was performed and microcoils were inserted into the aneurysmal sac. The aneurysm was completely obliterated with total preservation of renal blood flow. Clinical evolution was satisfactory with significant reduction in anti-hypertensive drugs. Control tomographic angiography, after eight months, confirmed treatment success.

Keywords: Therapeutic embolization, renal artery, aneurysm.

Introduction

Surgical treatment of renal artery aneurysms is usually complex. The most frequently adopted conduct is aneurysmectomy associated with arterioplasty or aortorenal bypass. Aneurysmectomy can be successfully performed in more than 95% of cases of extraparenchymal aneurysms, whereas the treatment of certain types of intraparenchymal aneurysms or those compromising renal artery bifurcation may lead to partial or total nephrectomy. Percutaneous treatment has been recently more used in cases of complex aneurysms, avoiding renal ischemic complications and nephrectomies.^1,2

We report the case of a patient submitted to endovascular treatment using microcoil embolization for a saccular aneurysm of the renal artery bifurcation, with complete preservation of renal blood flow.

Case description

A 52-year-old Caucasian woman was admitted to our service with difficult-to-control hypertension, although taking four antihypertensive drugs. She was overweight (body mass index = 28.9) and reported symptom onset 20 years ago and many unsuccessful attempts to lose weight. Over the past 2 years, she had progressive worsening and lack of disease control, with several hospitalizations in emergency rooms, presenting headache and severe hypertension (arterial pressure ranging from 200/140 mmHg). Basal arterial pressure before the surgery was 180/120 mmHg (measured in the morning, 3 different days, Tycos® sphygmomanometer). The patient was taking the following drugs: atenolol 200 mg/day, enalapril 40 mg/day, hydrochlorothiazide 25 mg/day, nifedipine 40 mg/day. Renal scintigraphy using technetium associated with captopril showed renovascular hypertension in the right kidney. Angiographic tomography showed saccular aneurysm measuring 8 mm in diameter at the right renal artery bifurcation (Figure 1). She presented serum creatinine level of 0.7 mg/dL.

Decision for intervention was based on presence of renal artery saccular aneurysm associated with difficult-to-control renovascular hypertension in the ipsilateral kidney. An endovascular procedure was performed under local anesthesia. A 5F sheath was inserted in the right common femoral artery and a systemic heparinization was performed. Through a Cobra II 5F catheter (Cordis), used for selective catheterization of the right renal artery, a Transcend 0.10 microwire and an Excelsior 1048 microcatheter (Boston Scientific) were inserted inside the aneurysmal sac. Through the microcatheter, seven Guglielmi detachable coils (GDC^TM Boston Scientific) were sequentially released inside the aneurysm (Figure 2). Control arteriography showed complete aneurysm obliteration, preserving blood flow by the renal artery (Figure 3). The patient had excellent postoperative recovery and was discharged on the second day after the procedure. Use of acetylsalicylic acid and clopidogrel for 6 weeks was indicated. Arterial pressure at rest after the surgery was 140/100 mmHg. The following drugs were used to control arterial pressure in the postoperative period: atenolol 100 mg/day, hydrochlorothiazide 25 mg/day, amlodipine 10 mg/day. Control angiographic tomography, performed 8 months after the procedure, showed total aneurysm occlusion and preservation of distal renal circulation.

Discussion

Renal artery aneurysms represent an unusual disease. They are usually an incidental finding in imaging studies performed to investigate other diseases, especially hypertension. There is an association between those two diseases in 70% of cases,³ but only a few have renovascular hypertension.⁴ Many reasons have been suggested for that effect, such as embolization, extrinsic compression and adjacent artery tortuosity.⁵ Although the exact mechanism for flow changes is still under discussion, there has been improvement in the control of arterial pressure after renal artery aneurysm resection in patients showing functional studies with affected side ipsilateral to the aneurysm.⁶

A diameter of 20 mm has often been considered the parameter, in relation to size, to indicate treatment. On the other hand, there have been cases of aneurysm rupture with lower diameters.^6,7 Fusiform type and arterial wall calcifications suggest protection against rupture. However, many series of cases have not demonstrated a correlation between these characteristics and risk of rupture.^4,8-11 Aneurysm size as an exclusive parameter for indication of treatment should not be the rule; patient's age, presence of symptoms and associated severe hypertension should also be considered, as in the case reported herein. Repair of renal artery aneurysms lower than 20 mm in diameter is not recommended in adults who do not have associated symptoms and/or severe renovascular arterial hypertension.¹²

Due to the fact that renal artery aneurysms are usually located near the main renal artery bifurcation,^3,5 inadvertent renal artery occlusion in a conventional surgical procedure or covered stent implantation (stent-graft) may lead to significant infarction of the renal parenchyma.

As a result of the development of microcatheter and microwire systems, initially designed for interventional neuroradiology,¹³ renal artery saccular aneurysms can be selectively excluded without compromising blood supply to many segments of the renal parenchyma. Microcoils provide accurate release after confirmation of proper coil position through arteriography. This technique reduces the risk of coil migration, presenting better immediate result.¹⁴ Presence of a long and narrow neck is an anatomical finding that helps prevent inadvertent displacement of coils.^1,15 In spite of that, large-neck aneurysms have also been successfully treated.²

Result of this long-term treatment has not been well established yet, and despite improvement in arterial pressure control after endovascular exclusion of renal artery aneurysm, it is not known whether it will continue to expand, which could lead to symptom recurrence. Therefore, we indicate this treatment for symptomatic patients (pain and hematuria), women in the fertile period, saccular aneurysm and associated severe renovascular hypertension. Therefore, we consider endovascular therapy with embolization using microcoils as a feasible alternative for the treatment of renal artery aneurysms, as demonstrated in the case reported herein.

References

Manuscript received September 25, 2006, accepted March 22, 2007.

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Publication Dates

• Publication in this collection
  20 Sept 2007
• Date of issue
  June 2007

History

• Accepted
  22 Mar 2007
• Received
  25 Sept 2006