Endovascular Treatment of Renal Arteriovenous Malformations

Endovascular Embolization of Aneurysmal Renal Arteriovenous Malformation

Renal arteriovenous malformations (AVM) represent an uncommon vascular condition characterized by an abnormal direct communication between an intrarenal artery and vein. Though asymptomatic in many individuals, treatment is often indicated if the AVM causes flank pain, hematuria, or medically refractory hypertension, or if there is an associated renal artery aneurysm. We present a case of a large right renal AVM with associated renal artery aneurysm and large varix which was incidentally found on magnetic resonance imaging of the spine. Endovascular and open surgical options were considered, including ex-vivo renal vascular reconstruction and nephrectomy. The patient was successfully treated with endovascular embolization of the AVM with coil packing of the arterial aneurysm and inflow artery. The patient recovered uneventfully with well-maintained renal function and blood pressure control. We review and discuss the literature on the etiology and treatment options for renal AVM.

A Huge High-Flow Aneurysmal Renal Arteriovenous Malformation Treated With Endovascular Transcatheter Embolization

Renal arteriovenous anomalies are uncommon. They are characterized by an abnormal vascular connection that usually bypasses the capillary bed. Most are acquired arteriovenous fistulas (AVF) while the rest are congenital or idiopathic arteriovenous malformations (AVM). AVF are usually caused by renal interventions, trauma, or neoplastic processes. They can lead to hypertension, heart failure, hematuria, and renal insufficiency. A 69-year-old woman presented with arrhythmia, tachycardia, mild ankle edema, and increasing fatigue. Right kidney color Doppler ultrasound confirmed the presence of a huge AVM with a blood flow of 9 L/minute and a dilated, 35 mm in diameter, right renal vein. Two months later, an attempt to embolize the AVM failed as the Amplatzer™ Vascular Plug II (Abbott Laboratories, Chicago, Illinois, United States) migrated to the pulmonary circulation and was later removed. Complete embolization was achieved by implanting two Amplatzer Vascular Plug IIs, various embolization coils, histoacryl glue, and lipiodol. Control angiography revealed significant stenosis in the right subclavian artery endovascular access, which was managed with BeGraft (Bentley InnoMed GmbH, Hechingen, Germany) and Zilver (Cook Group Incorporated, Bloomington, Indiana, United States) stents. The patient was discharged on the third postoperative day, all her symptoms resolved, and she reported eventual recovery. Three months later, the patient was operated on due to a 40x58 mm pseudoaneurysm at the right femoral access site. Thus, renal AVMs should be included as a potential alternative diagnosis for various symptoms such as hematuria and hypertension resistant to medication. Endovascular embolization is a less-invasive, safer, and more effective option than open surgery but has a risk of complications. Success requires fully occluding the shunted vessel, preventing embolic material migration, and preserving normal arterial branches. It depends on selecting adequate techniques and embolic materials individually, based on etiology and precise vascular anatomy assessment.

Use of a 4 mm Amplatzer Vascular Plug II in the treatment of a renal arteriovenous fistula: a case report

Background

We report the use of a 4 mm vascular Amplatzer for the occlusion of a renal arterovenous fistula between the renal artery, at the hylum trifurcation point, and an aneurismatic vein draining into the main renal vein, where there was no possibility to use any other device from the venous side, because of the diameter and the high flow, neither from the arterious side without sacrificing lobar branches. The device was implanted at the exact point of communication, like a patent foramen ovale occluder, with the distal disc into the artery lumen and the other two proximal discs into the venous side.

Case presentation

A 34-years-old Caucasian woman suffered several episodes of paroxysmal supraventricular tachycardia associated with dyspnoea, after the onset of post-pregnancy hypertension. She underwent CTA, spectral Doppler sonography and angiography which showed a renal arteriovenous fistula (RAVF) between the renal artery, at the hylum trifurcation point, and an extremely ectatic vein draining into the main renal vein of the right kidney.

With both arterial and venous access, the RAVF was selectively embolized using a 4 × 6 mm Amplatzer Vascular Plug II, released into the communication between artery and vein ensuring the patency of vessels involved.

The RAVF was almost completely excluded and the hemodynamic effects associated were also corrected.

Conclusions

The use of this device, though in an alternative way, allowed the exclusion of the high flow A-V fistula without sacrificing any parent renal vessel and preserving the renal function.

Management of renal arteriovenous malformations: A pictorial review

Background

Arteriovenous malformations (AVMs) are communications between an artery and a vein outside the capillary level. This pathologic communication may be either a fistula, a simple communication between a single artery and a dilated vein, or a more complex communication, a nidus of tortuous channels between one or more arteries/arterioles and one or more draining veins. The latter type of lesion is most frequently seen in the extremities; in the kidney they tend to appear more rarely. The most common clinical presentation of renal arteriovenous malformations (RAVMs) is haematuria. Percutaneous treatment with selective endovascular techniques offers a minimally invasive, nephron-sparing option in comparison to the more invasive surgical approaches. The purpose of this pictorial review is to highlight the general lines of management and to show the range of imaging findings of the percutaneous treatment of RAVMs.

Methods

The imaging characteristics of a selection of cases of percutaneously managed congenital RAVMs are presented and the most common lines of approach are discussed.

Conclusion

The imaging spectrum of diagnosis and percutaneous treatment of RAVMs is presented in order to aid interpretation and endovascular management.

Teaching points

• Renal arteriovenous malformations are very rare lesions.

• Clinical expression is usually haematuria.

• Diagnosis is made with CT or MRI but the gold standard is digital subtraction angiography.

• Catheter-directed treatment with the use of coils or liquid embolics is minimally invasive, safe and effective.

The role of transarterial embolization in the management of hematuria secondary to congenital renal arteriovenous malformations

OBJECTIVE

To evaluate the efficacy and safety of transarterial embolization (TAE) in the management of hematuria secondary to congenital renal arteriovenous malformations (AVM).

PATIENTS AND METHODS

Between May 2007 and February 2012, 6 patients with congenital AVM treated with TAE were analyzed retrospectively, followed by a brief review of TAE in the treatment of congenital AVM. Clinical records with respect to general conditions, location, embolic materials, complications and overall outcome were collected from the original hospital charts and outpatient medical records.

RESULTS

Three patients with AVM were confirmed by contrast-enhanced CT scans, and the other 3 patients were detected by renal angiography. TAE was performed with steel coils in 2 patients and n-butyl-2-cyanoacrylate (NBCA) in 4 patients. After a mean follow-up of 22 months, no serious adverse effects were observed in all patients. There were no complaints of hematuria at the end of the follow-up period.

CONCLUSION

For unexplained massive hematuria, congenital renal AVM needs to be considered as a differential diagnosis. Selective renal angiography and embolization should be recommended as the first choice to treat massive hematuria secondary to congenital renal AVM.

Transcatheter renal artery embolization: clinical applications and techniques

Renal artery embolization is a minimally invasive procedure that is increasingly being used for treatment of a wide range of conditions. The main indications for renal artery embolization include (1) prenephrectomy and preradiofrequency ablation infarction of renal tumors, (2) management of renal angiomyolipomas, (3) palliations of unresectable renal malignancy, (4) renal hemorrhage (life-threatening or chronic debilitating hematuria), (5) arteriovenous fistulas, (6) vascular malformations, (7) renal artery aneurysms and pseudoaneurysms, and other less common indications, such as severe hydronephrosis and hypertension. A variety of embolic materials are available, such as metal coils, sclerosants (glue, Onyx, absolute ethanol, lipiodol), and particulate embolic agents (polyvinyl alcohol particles and embospheres). Selection of the appropriate agent depends on the clinical application, technical and clinical endpoints, as well as the pathology lesion(s) targeted. Renal artery embolization can be performed alone or in combination with remodeling techniques, stent-grafting, and balloon- or stent-assisted coiling in more complicated cases. The procedure is generally regarded as safe and effective for diverse applications and is considered as an evolving area in the field of endoluminal therapy.

Superselective embolization of renal hemorrhage occurring after percutaneous coronary intervention

A 69-year-old female was hospitalized for acute coronary syndrome and received full antiplatelet and anticoagulant therapy. The patient underwent angioplasty and stent implantation on right coronary and left circumflex arteries with good angiographic result. After the procedure, the patient developed hemorrhagic shock due to massive left renal hemorrhage. An emergent digital subtraction angiography showed bleeding from a left segmental renal artery. The hemorrhage was successfully managed with transcatheter superselective embolization. The patient was discharged after 22 days in good general condition with normal renal function. One-year follow-up was uneventful.