Figura 1. Coronary computed tomography angiography (CCTA) with left renal stenosis and infarction in...

Figura 2. A) Estenosis renal izquierda con imagen endoluminal. B) Pasaje de guía coronaria en la lu...

Figura 3.

INTRODUCTION

It is estimated that thromboembolic aortic disease causes 5% of all peripheral arterial embolisms reported at abdominal portion level.1,2

Acute renal infarction as a complication of aortic debris is an entity rarely described in the routine clinical practice. Because of its low incidence rate, it is often misdiagnosed. It is more common among women during the 6th and 8th decades of their life.4 These patients have a past medical history of high thromboembolic risk and many of them have already experienced an embolic event in their lifetime.3,4,5

As a complication associated with this event, the significant loss of renal function can compromise the perfusion of such organ. This has triggered the development of new percutaneous revascularization techniques that are still in their infancy.5,6,7,9

CASE REPORT

We present the case of a 71-year-old woman with a past medical history of arterial hypertension and type II diabetes, heavy smoker of 20 cigarrette packs/year, and unconfirmed arrhythmias. She presents with sudden lower back pain radiating to her back of 2 hour evolution that becomes exacerbated when changing positions. She experienced 2 similar episodes of shorter duration and intensity for the previous 72 hours.

AHT confirmed at admission (160 mmHg /90 mmHg). Physical examination within normal parameters. EKG: sinus rhythm (75 bpm); lateral subepicardial ischemia. Acute coronary syndrome is ruled out. The laboratory parameters test positive for leukocytosis and slightly elevated LDH levels. The patient is admitted to the ICU with a complete course of anticoagulant and anti-ischemic therapy.

Due to persistent pain, a chest-abdomen-pelvis computed tomography (CT) scan is performed. The CT scan reveals the presence of diffuse significant atheromatous disease in both the ascending and descending aortas with mural thrombosis of irregular surface and small ulcerations in the junction between the aortic arch and the descending aorta. Abdominal aorta with significant diffuse atheromatous disease in its walls, mural thrombosis, and calcifications associated with ulcerations on the surface. Presence of significant left renal artery ostium stenosis with a significantly smaller luminal diameter of the infarct related vessel compromising the entire left kidney with good perfusion of this organ upper pole only (figure 1).

An angiographic study is performed to assess the possibility of solving the patient’s lower back pain. A 6-Fr introducer sheath was used via right femoral access and a renal arteriography was performed that revealed the presence of an endoluminal thrombus at left renal artery proximal level. Therefore, the recanalization of the vessel is attempted using a 6-Fr hockey stick guide catheter (Cordis) followed by a 0.014 in Floppy guidewire (Abbott) that is placed distal to the vessel lumen (figure 2).

Thrombus aspiration is performed using a 6-Fr Fetch2TM thrombus aspirator (Boston Scientific). Due to the persistent lack of endoluminal filling it was decided to place a SpiderFXTM distal protection filter (Medtronic) and advance a 4.5 mm x 16 mm conventional Rebel stent (Boston Scientific) that was inflated at 12 atmospheres of pressure. The distal protection filter was eventually removed and a control angiography confirmed the good final outcome with no traces of residual plaque.

The patient remained clinically stable and her lower back pain improved after the procedure. The patient was then transferred to the ICU to monitor disease progression.

A control CT scan was performed 24 hours later that confirmed the improved renal perfusion. The patient responded well to therapy and remained symptom-free; she was released from the hospital 48 hours later on dual antiplatelet therapy.

DISCUSSION

Renal infarction (RI) is due to the interruption of blood flow into the renal arteries and/or their branches. It is a rare and often misdiagnosed condition given its variable clinical presentation. The medical literature available on this entity is based on case reports and series of cases.1

It often starts with a sudden pain in the renal flank or fossa followed by fever, hematuria, nausea, and vomiting.1,2 It is associated with high laboratory parameters: leukocytosis, high GOT, alkaline phophatase, and LDH levels being the latter the most characteristic of all. As a matter of fact, it can go up by a factor of 5 within the first 48 hours. This condition should be suspected in patients with lower back pain and thromboembolic risk factors. According to the current scientific evidence available, cardioaortoembolic causes are the leading cause of renal infarction (45.4%), and within this group, atrial fibrillation represents 75.5%.3,4,5

A total of 70% of the patients who experience this event have a past medical history of high thromboembolic risk. Actually, most of them have already experienced a previous embolic event in the past,5,6 which is consistent with our case report presented here.

Diagnosis is confirmed through imaging modalities: ultrasound, CT scan or scintigraphy.9,10 Angiography is still the gold standard while a vessel revascularization strategy should be scheduled simultaneously.

It is more common on the left side,5 though it may be bilateral (15% to 30% of the cases) progressing towards acute kidney injury. In 50% of the cases, the acute kidney injury becomes a chronic condition.6,7,8 That is why new percutaneous minimally invasive therapies have been proposed to preserve renal perfusion.

Endovascular treatment: thrombectomy and/or angioplasty with stenting using different devices and/or types of protection filters to avoid short and long-term complications that may end up causing kidney injuries.8,9,10

Knowing that the mechanism of kidney injuries is distal embolization, it has been confirmed that the use of embolic protection devices (EPD) improves the outcomes of percutaneous revascularization procedures in this territory.6,7,9

Hiramoto et al. proved that stent implantation into the renal artery is associated with atherothrombolic fragments,6,7 and that every step of the procedure—guidewire passage included—is associated with the embolization of thousands of fragments.7

Currently, EPDs can be divided into 3 categories: proximal protection devices, distal occlusive devices, and distal filter protection devices like the one we used in this case report.6,7

All EPDs are effective only after being deployed, which is why they cannot protect the kidneys against the atheroembolism that may occur during the early contact with the guide catheter. They certainly cannot protect the contralateral kidney or other organs from the embolic particles released during former passes.6,7,8

The potential advantage of distal protection filters is their capacity to maintain renal perfusion during the entire procedure.

CONCLUSION

Clinical suspicion facilitates the early diagnosis and timely treatment of this entity.

Angioplasty with stenting for the management of renal infarction is a safe therapeutic strategy with low morbidity, mortality, and complication rates that preserves the renal parenchyma as much as possible.

Further studies are needed to elucidate the role played by embolic protection devices in this territory.

1. Metsemakers W J, Duchateau J, Vanhoenacker F, et al. Floating aortic thrombus: the endovascular approach. Acta Chir Belg 2013;113:47-50.

2. Cañadas V, Vilacosta I, Luaces M, et al. Trombosis en aorta torácica aparentemente normal y embolias arteriales. Revista Española de Cardiologia 2008;61:196-200.

3. Hazanov N, Somin M, Attali M, et al. Acute Renal artery embolism. Forty four cases of renal infarction in patientswith atrial fibrillation. Medicine 2004;83:292-9.

4. Korzets Z, Plotkin E, Bernheim J, Rivka Z. The clinical spectrum of acute renal infarction. Isr Med Assoc J 2002;4:781-4.

5. José U, Felix M, Carlos C. Embolia de colesterol evaluada por microscopía de luz polarizada después de la colocación de un stent en la arteria renal primaria con filtro de protección. Revista de radiología vascular e intervencionista 2008:169-194.

6. Hiramoto J, Hansen KJ, Pan XM, Edwards MS, Sawhney R, Rapp JH. Atheroemboli during renal artery angioplasty: an ex vivo study. J Vasc Surg 2005;41:1026-30.

7. Holger E, Michael H, Dietrich B, Olaf D. A New Temporary Occlusion and Aspiration System for Prevention of Distal Embolization During Percutaneous Transluminal Renal Angioplasty.

8. William R, Colyer Jr, Christopher J. Embolic Protection And Antiplatelet Use For Renal Artery Stenting. Interventional Cardiology. ICR. 2008;3(1):79-82.

9. William R, ColyerJr,Christopher J. Cooper. Protección embólica y uso de antiagregantes plaquetarios para la colocación de stents en la arteria renal.ICRJournal.Cardiología intervencionista 2008; 3 (1): 79–82.

10. Pizzarossa A, Merola V. Etiología del infarto renal. Revisión sistemática de 1.582 casos de la literatura. Revista Médica Chile 2019; 147: 891-900.

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