Renal Arteriovenous Shunts: Clinical Features, Imaging Appearance, and Transcatheter Embolization Based on Angioarchitecture

Abstract

Renal arteriovenous (AV) shunt, a rare pathologic condition, is divided into two categories, traumatic and nontraumatic, and can cause massive hematuria, retroperitoneal hemorrhage, pain, and high-output heart failure. Although transcatheter embolization is a less-invasive and effective treatment option, it has a potential risk of complications, including renal infarction and pulmonary embolism, and a potential risk of recanalization. The successful embolization of renal AV shunt requires a complete occlusion of the shunted vessel while preventing the migration of embolic materials and preserving normal renal arterial branches, which depends on the selection of adequate techniques and embolic materials for individual cases, based on the etiology and imaging angioarchitecture of the renal AV shunts. A classification of AV malformations in the extremities and body trunk could precisely correspond with the angioarchitecture of the nontraumatic renal AV shunts. The selection of techniques and choice of adequate embolic materials such as coils, vascular plugs, and liquid materials are determined on the basis of cause (eg, traumatic vs nontraumatic), the classification, and some other aspects of the angioarchitecture of renal AV shunts, including the flow and size of the fistulas, multiplicity of the feeders, and endovascular accessibility to the target lesions. Computed tomographic angiography and selective digital subtraction angiography can provide precise information about the angioarchitecture of renal AV shunts before treatment. Color Doppler ultrasonography and time-resolved three-dimensional contrast-enhanced magnetic resonance angiography represent useful tools for screening and follow-up examinations of renal AV shunts after embolization. In this article, the classifications, imaging features, and an endovascular treatment strategy based on the angioarchitecture of renal AV shunts are described.

Complex Renal Arteriovenous Malformation (AVM) Embolization using Ethylene Vinyl Alcohol (EVOH) Copolymer and a Balloon Microcatheter

“…Many liquid embolic agents have been described, such as, gelfoam, ethanol and n-butyl-cyano-acrylate (nBCA). 5,6 The disadvantages of gelfoam includes potential recanalization of the vessel. nBCA is frequently used, and can reach the nidus of the AVM.…”

“…7 There are a number of published cases using Onyx as the embolic agent for visceral vascular malformations, the treatment of acute hemorrhage, and also for embolization of renal AVMs. 5 The use of an occlusal balloon can substantially decrease the risk of reflux of the embolic agent and allow an extensive cast within the renal AVM to be safely formed. 8 Complications of balloon occlusion include injury to the vessel, such as dissection and rupture.…”

Simultaneous transarterial and transvenous coil embolization for a large aneurysmal-type renal arteriovenous fistula

“…The incidence of pulmonary embolism has not been reported so far, but case reports of pulmonary embolism and inferior vena cava thrombus exist [4] , [5] . AVF rupture during the procedure has not been reported, but it could occur in theory [1] . To occlude AVF, transarterial coil embolization is necessary; thereby coil migration and pulmonary embolism may occur.…”

“…Aneurysmal-type renal arteriovenous fistulas (AVFs) are often asymptomatic but can present with hematuria, pain, hydronephrosis, and heart failure [1] . Transcatheter embolization is associated with high success rates [2] .…”

Endovascular Treatment of 12 Cases of Renal Arteriovenous Malformations: The Experience of 1 Center and an Overview of the Literature

“…Pathologic shunting of blood from the arterial to the venous side may cause massive hematuria, pain, and heart failure. [1][2][3][4] Congenital rAVMs could be classified into 3 types according to the classification of arteriovenous (AV) malformations in the extremities and body trunk. 5 Type I AVMs include fewer than 4 separate arteries shunting to a single draining vein, type II AVMs include multiple arterioles that shunt to a single draining vein, and type III AVMs include multiple fine arteriovenous fistulas.…”