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Embolization in Neonates and InfantsDavid J.E. Lord, MBBS, FRANZCR, andS. Murthy Chennapragada, MBBS, DMRD, DipNB, FRANZCR

Several conditions presenting in the neonatal and infant period benefit from embolization,including hemangioma, vascular shunts, and tumors. The physiological delicacy and smallsize of newborns create distinct challenges. This paper discusses embolization of thesepatients and illustrates the techniques involved.Tech Vasc Interventional Rad 14:32-41 Crown Copyright © 2011 Published by Elsevier Inc.All rights reserved.

KEYWORDS embolization, hemangioma, infant, neonate, angiography, hemangioendothelioma

ethdamcipo

Embolization of sick neonates and infants is a critical andhighly specialized skill required in pediatric interven-

ional radiology. The indications include high-output cardiacailure from vascular tumors, such as noninvoluting congen-tal hemangioma, or congenital arteriovenous shunts in theiver or brain; embolization of tumors, such as kaposiformemangioendothelioma (KHE) with Kasabach Merritt phe-omenon (KMP); and bleeding. Representative conditionsre discussed in detail below.

This publication outlines the general techniques of embo-ization in babies and infants, but is not a substitute for thor-ugh training in this area. Sick babies, especially prematurer growth-retarded neonates, constitute a special and chal-enging patient group. Embolization of a sick neonate shouldot be undertaken by inexperienced practitioners alone, be-ause the patient is exposed to unnecessary risk with poten-ially lifelong consequences. In developed countries, profes-ional retrieval mechanisms bring sick neonates to surgicaleonatal intensive care units, for example, babies requiringardiac surgery. Similar retrieval mechanisms should bevailable, when required, for babies needing embolization. Ifransfer is not possible, less experienced practitioners shouldroceed only after thorough familiarization with the relevant

iterature, facility with small-vessel angiography and inter-ention, and collaboration and consultation from appropri-tely trained individuals.

Pediatric Interventional Radiology, Division of Medical Imaging, Children’sHospital at Westmead, Sydney Medical School, The University of Syd-ney, Westmead NSW, Sydney, Australia.

Address reprint requests to David J.E. Lord, MBBS, FRANZCR, Division ofMedical Imaging, Children’s Hospital at Westmead, Hainsworth Streetand Hawkesbury Road, Sydney Medical School, The University of Syd-ney, Locked Bag 4001, Westmead NSW, 2145 Sydney, Australia. E-mail:

davidL5@chw.edu.au

32 1089-2516/11/$-see front matter Crown Copyright © 2011 Published by Edoi:10.1053/j.tvir.2010.07.003

Conditions That MightRequire Embolizationin Neonates and InfantsHemangiomaHemangioma in an infant is a proliferative cellular neoplasm.There are two types: the “hemangioma of infancy” and the“congenital hemangioma,” which differ from each other inhistology and in clinical behavior. Formerly these were allknown as capillary (a.k.a. strawberry) hemangioma. How-ever, the more precise modified Mullikan–Glowaki nomen-clature, accepted by the International Society for the Study ofVascular Anomalies, is preferred, especially now that distinctbiological markers have been identified for each lesion.1 Forxample, hemangioma of infancy stains positive for the pro-ein glucose transporter 1 (GLUT1), whereas congenitalemangioma does not. The term hemangioma in pediatrics isistinct from the so-called “cavernous hemangioma” ofdults. (The latter lesion is more correctly termed a venousalformation, as that is its histology, and will not be dis-

ussed further.) Both lesions may appear similar. However,n a neonate, a large solitary hemangioma causing high-out-ut cardiac failure is more likely to be a congenital hemangi-ma than a hemangioma of infancy.2

Hemangioma of InfancyHemangioma is a tumor of vascular endothelial cells. Mosthemangiomata require no active treatment other than obser-vation. In rare cases, however, these lesions cause problemsbecause of rapid expansion in a critical location, such as nearthe orbit or airway; bleeding; or high-output cardiac failurefrom arteriovenous shunting.

Hemangioma of infancy (GLUT1-positive hemangioma) is

the most common vascular tumor in humans, affecting about

lsevier Inc. All rights reserved.

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Embolization in Neonates and Infants 33

10% of Caucasian infants but is found in all ethnic groups.The lesions pursue a well-defined clinical course with rapidexpansion (proliferation), usually occurring about 6 weeksafter birth followed by shrinking (involution). By school age,most hemangiomas of infancy have disappeared or fully in-voluted. The proliferative phase is characterized by increasedarterial flow with arteriovenous shunting.

Embolization of hemangioma of infancy has variable indi-cations but is generally not first-line therapy. It is used forlesions that are expansile, causing compromise of an organ;are causing high-output cardiac failure; do not respond tomedical therapy (propanolol or corticosteroids); and are ei-ther surgically inaccessible or located where excision wouldbe grossly deforming. Hemangioma of infancy may be mul-tifocal in an organ or patient.

Babies with vascular tumors in the liver are often describedas having hepatic hemangioendothelioma; this term is usedcommonly in the literature. Recent observations, however,have shown that these lesions are almost never true heman-gioendotheliomas. The large solitary lesions are usually con-genital hemangiomas, and the multifocal lesions are heman-gioma of infancy (GLUT1-positive).2

Diffuse liver hemangiomas may cause hepatic failure andexpand the liver, causing abdominal compartment syndromewith respiratory and renal failure, and are sometimes fatal.Embolization as an alternative to liver transplant has beendescribed to successfully treat abdominal compartment syn-drome.3 Hypervascular arteriovenous shunting does noteem to be a feature of this presentation as often as otherypes of liver hemangioma.4

All patients with multifocal hemangiomas, especially in theliver, should be screened for postnatal development of hypo-thyroidism. Hemangioma of infancy expresses the enzymetri-iodothyronine deiodinase, which can cause T3 hormonedeficiency and cretinism if not corrected.5 Syndromic associ-ations of hemangioma of infancy, such as PHACES6 orPELVIS,7 warrant referral to a pediatric vascular anomaliesenter.

ongenital Hemangiomahese are solitary lesions, usually large (eg, 5 cm in diame-

er), that present fully formed at birth. In the skin, they areimilar in appearance to hemangioma of infancy but may beatter, with surrounding pale halo (probably vascular steal).here may be central ulceration, usually a sign of the rapid

nvoluting variant (rapid involuting congenital hemangioma)s opposed to the noninvoluting congenital hemangioma.he degree of vascular steal may be extreme with markedigh-output cardiac failure leading to secondary respiratory,enal, and hepatic failure. Babies may be thrombocytopenicnd coagulopathic. In contrast to the setting of KHE withMP (see below), coagulopathy related to congenital heman-iomas may show fibrinogen degradation products, high D-imer, and low fibrinogen.8

Kaposiform HemangioendotheliomaAlthough rare, KHE is the other most common vascular tu-mor. Along with the lesion called tufted angioma, KHE is

associated with thrombocytopenia due to platelet trapping

within the interstices of the mass.9 This is known as KasabachMerritt phenomenon (KMP). KHE in the skin is usually apurplish-colored mass, firm, and indurated to palpation, incontrast to hemangioma, which is bright red and softer. KHEwith KMP warrants treatment, usually chemotherapy, suchas vincristine; however, there may be a role for embolization.KHE is not GLUT1-positive.

Nonvascular TumorsMassive hemorrhage from tumors, such as neuroblastomaand Wilms tumor, after either trauma or chemotherapy-in-duced necrosis may require embolization. The presentationmay be extreme, with abdominal tamponade and shock. Em-bolization has also been reported for palliative care. In 2009,Krauel and colleagues reported an eclectic series of sevenpediatric tumors that had been embolized. The striking find-ing was one child treated for palliative indications in whomthe tumor disappeared.10 Chemoembolization of a neonatal

euroblastoma has also been reported.11

Gastrointestinal BleedingPrimary angiographic management of gastrointestinal bleed-ing in babies and infants is rare. The common conditions aresurgical, such as Meckel’s diverticulum and intussusception,or medical, such as portal hypertension. However, gastroin-testinal bleeding may be a presentation of an arteriovenousmalformation, a syndromic venous malformation (such asblue rubber bleb syndrome), or the Dieulafoy lesion, a con-genital dysplastic arteriole perforating into the lumen of thestomach or duodenum. Embolization of a persistent vitel-lointestinal artery (to a Meckel’s diverticulum) should be fol-lowed by surgical exploration.12

Arteriovenous and Portal Venous ShuntsThe liver and the brain are the most common locations forarteriovenous shunts. The vein of Galen aneurysmal malfor-mation is a high-flow fistula, of varying complexity, from thechoroidal arteries into a dilated median vein of the prosen-cephalon. A pial arteriovenous fistula may be a huge intra-cranial shunt. For both of these lesions, embolization is thetreatment of choice. There is considerable literature about themanagement of these lesions,18 and this paper will not dis-cuss this further. Vascular fistulae in the liver may be arterio-venous, arterioportal, or portovenous—usually a persistentductus venosus—or a combination of all of these.13,19 Patent

uctus venosus is associated with neonatal hemochromato-is, and the ductus may be a valuable natural outlet for portalypertension in this setting –, ie, a naturally formed intrahe-atic portosystemic shunt.14 Therefore, before closing a pat-

ent ductus venosus, it is worth measuring the pressure withinthe shunt to assess for portal hypertension.

Pulmonary SequestrationTransumbilical artery embolization has been used as primarymanagement of these lesions, although it is unclear whether

this is the optimal treatment.15

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34 D.J.E. Lord and S.M. Chennapragada

TechniqueClinical Presentationand Preprocedure AssessmentArteriovenous ShuntsAn echocardiogram by an experienced pediatric cardiologistis required before any embolization in a baby or infant. Theechocardiogram will help quantify the degree of cardiac fail-ure, useful for both radiologist and anesthesiologist. If theshunt is due to hemangioma but there is no heart failure,embolization is not usually required.3 When embolization is

eing considered, it is critical that the echocardiographerssess for the existence of a right-to-left shunt; in babies withigh-output failure due to arteriovenous shunting, the righteart pressure might be suprasystemic. In this circumstance,

f neonatal anatomical systemic and pulmonary communica-ions, such as the foramen ovale or ductus arteriosus, remainpen (not uncommon), the suprasystemic right heart pres-ures may result in a right-to-left shunt. In this setting, if theadiologist chooses to embolize with a material that mightross into the venous side of an arteriovenous shunt, thenaradoxical embolization of that material will pass into theystemic arterial circulation with possible catastrophic re-ults. Death postembolization from coronary and cerebralrterial emboli has been reported from this type of unsus-ected right-to-left shunting in babies.16

Blood tests required include full blood count, electrolytes,liver function tests, and coagulation profile, including fibrin-ogen, fibrinogen degradation products, and D-dimer. Bloodgases should be performed. Elevated right heart pressure maycause liver venous congestion, which, accompanied by poorsystemic hepatic arterial flow from reduced cardiac perfu-sion, impairs hepatic function causing the profound coagu-lopathy (elevated INR, PT, and PPT) seen in these patients.Other contributing factors to coagulopathy and anemia in-clude platelet and red cell destruction due to high flow state.

The literature abounds with the term KMP, used to de-scribe patients with coagulopathy and a vascular tumor. Asdescribed above, in a strict sense, the term only belongs tothrombocytopenia from platelet trapping within the inter-stices of either a KHE or a tufted angioma. This distinctionmay seem pedantic; however, it is very important as throm-bocytopenia due to KMP does not respond to platelet trans-fusion. Indeed platelet transfusion can cause further con-sumptive anemia as the lesion traps more platelets. Althoughembolization has been reported in the management of KHE,the mainstay of therapy is chemotherapy, currently with vin-cristine. By contrast, in hemangioma, anemia and thrombo-cytopenia are often improved by embolization.17 Anemia andoagulopathy are markers of severity of the high-flow shunt.here is no benefit conferred in waiting for this to correct as

n this author’s experience, untreated, the baby will onlyeteriorate further and may become unsalvageable.By the time referral is made, extremely unwell neonates

nd infants may be intubated and ventilated, as this mayontrol cardiac failure. This may give a false sense of security.ndications to proceed with embolization include a baby who

annot tolerate extubation without developing respiratory

ailure, or in whom there is worsening anemia, liver, or renalunction despite medical therapy. This parallels the use of theicetre criteria for timing embolization in vein of Galen an-urysmal malformation.17 In the nonintubated infant, signs

may be more subtle. In the presence of a known high-flowstate, a good indicator to commence embolization is failure togain weight or clinical signs of cardiac failure, such as incom-plete feeding due to breathlessness, cough, or diaphoresis.

All focal vascular lesions should be imaged with MRI andcontrast-enhanced MR angiography. This gives valuable dataabout the size of the lesion and the nature of the surroundingstructures.

Pediatric AngiogramAll neonatal and infant angiography requires general anes-thesia with a certified pediatric (neonatal) anesthesiologist.Anesthetic considerations include asking the anesthesiologistto raise the end tidal CO2 to reduce vascular spasm, to usegents other than nitrous oxide to minimize bowel disten-ion, and to ensure the patient is motionless, particularlyuspending patient respiration during angiographic runs. Asmooth as possible an emergence from anesthesia is re-uested to reduce the risk of the arterial puncture site bleed-

ng.The patient is placed on the angiography table with special

are to avoid pressure points and ensure optimal imaging; forxample, for external carotid interventions, the neck is ex-ended slightly to separate the branches of the external ca-otid for selective cannulation. Particularly in neonates, aarming blanket is used to ensure normothermia. Neonates

ose heat quickly through their scalp, so a beanie or warmowel around the head may also be needed.

For children under 20 kg, there is a sequence of radiationose reduction features that are required. The x-ray detectorrids are removed. This causes significant dose reduction.ith the grids out, reduction of noise from scatter may war-

ant the use of an air gap, so, unlike in grid fluoroscopy, theetector is moved away from the patient. This causes geomet-ical magnification, so images need to be acquired with lessetector magnification, ie, using a larger field of view. Toeep the dose lower still, strict collimation is employed. Usehe minimum frame rate required. As this technique resultsn small images in a wide black frame, some manufacturersllow mathematical methods to either acquire the image withlarger matrix (such as 2048 � 2048) and then magnifyhile maintaining satisfactory resolution (such as 1024 �024).Prior to obtaining arterial access, the interventional radi-

logist may wish to place a central venous catheter and uri-ary catheter to aid procedural monitoring.

Informed ConsentThe main procedural risks are femoral artery injury, nontar-get embolization, and contrast-related risk. In this author’sexperience, neonates tolerate high doses of contrast (usingnonionic contrast 240 mgI/mL up to a maximum of 10 mL/

kg, although in a non-life-threatening circumstance dose is

tery

Embolization in Neonates and Infants 35

always kept lower than this, in the range of 4 mL/kg). Injuryto the access vessel may have sequelae, such as acute ischemianeeding further treatment or loss of limb, or chronic ischemiawith limb length discrepancy. Claudication in children israre; however, large size (�6 Fr) venous femoral access mayresult in total femoral and external iliac vein occlusion withlater development of (variably painful) varicosities on theanterior abdominal wall or buttock, in addition to the se-quelae mentioned above.

Vascular AccessIn the first few days of life, access may be secured through theumbilical artery. The umbilical artery in a baby over 2.5 kgshould accept a 5-Fr sheath. The access technique can betaught by a consultant neonatologist or pediatric interven-

tional cardiologist. Using sterile technique, a purse string

suture or umbilical tape is placed around the umbilicalstump. The stump is then cut back 1 cm from the skin. Thereare usually two thick-walled, rounded arteries and one ovalthin-walled vein. Curved forceps can be used to dilate theartery, allowing access. Tighten the purse string suture so asnot to leave the umbilical vein open to the air as negativeabdominal pressure can cause air embolism.

In babies under 4 kg, if femoral access is needed, the larg-est arterial sheath acceptable would be 4 Fr, or for venousaccess, 6 Fr. In this author’s view, a sheath is preferred tominimize intimal trauma from catheter movements withinvessels prone to spasm, although there is a spectrum of opin-ion about this. If a 4-Fr sheath size is considered too large,(eg, in babies under 2.5 kg), another option is fashioning asmaller sheath using the outer sheath of a 4-Fr micropunc-

re 1 (A) Celiac axis angiogram. (B) Superselec-image of gastroduodenal arcade. There is activetrast extravasation. (C) Post-NBCA embolizationhe gastroduodenal artery showing the glue castluding the bleeding point. Glue also fills and out-s the hepatic artery and branches. (D) Postem-ization angiogram of the celiac axis. (E) Fol--up abdominal Doppler ultrasound showing amal arterial trace in the recanalized hepatic ar-.

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ture access kit connected to a hemostatic valve. This is effec-

36 D.J.E. Lord and S.M. Chennapragada

Embolization in Neonates and Infants 37

tively a 4-Fr catheter with an 0.035-inch inner lumen, so hasa smaller outer diameter than a 4-Fr sheath. Large sized2.7-Fr microcatheters [such as Terumo Progreat (TerumoMedical Corporation, Somerset, NJ) or Renegade Highflow(Boston Scientific, Natick MA)] can then be used as primaryangiographic catheters; however, it is difficult to selectbranches off the aorta, especially the aortic arch, with thesecatheters. Alternatively, a 3-Fr arterial sheath (Intradyn pedi-atric arterial hemostasis introducer-B; Braun Medical, Beth-lehem, PA), can be used with a 3-Fr end hole angiographiccatheter (Cook, Bloomington, IL) with the tip steamed intoshape (P. Stanley, Childrens Hospital Los Angeles, Los Ange-les, CA, personal communication). These catheters will notadmit a second microcatheter, so when there is a need toembolize, if possible, a multilevel coaxial system is preferred(4-Fr sheath, 4-Fr catheter with 0.038-inch inner diameterand microcatheter).

This author uses ultrasound for guiding access in babiesand makes the initial puncture with a 20-gauge angiocath.The angle of approach to the vessel is very shallow, as thevessel lies just below the skin. Therefore, when making asmall nick in the skin, the skin is lifted with the other handand the blade used parallel to the groin to avoid any chance ofcutting into the neurovascular bundle just under the skin. Inbabies with a high-flow abdominal shunt, the aorta and fem-oral vessels distal to the shunt will often be hypoplastic, inwhich case left brachial access may be required. Using non-invasive preprocedure imaging to assess the size of the aorticrun off is critical in preventing risk to the femoral arteries.

Flush and contrast volumes are considered carefully.Because the arterial access sheath and any rotating hemo-static valve is connected to a pressure infusion, the rate ofinfusion needs to be closely watched. If the baby is notcoagulopathic or bleeding, intravenous heparin is givingafter obtaining arterial access (usually 50-100 U/kg) with

Figure 2 (A) Coronal plane abdominal short tau inverquadrant with some cystic areas (M). Inferior to this are aptosed below. (B) Gadolinium-enhanced MR angiogrammarked vascularity in the mass. The enlarged left hepatproximal abdominal aorta is dilated compared with the aare noted. (C) Angiogram performed before excision. Vaortogram was performed using a 4-Fr multiside-hole sdrains into a markedly enlarged left hepatic vein. (C, D)of an enlarged left hepatic vein, confirming an arterioven“Baby Judkins right coronary” catheter (Terumo) confiarteries and by branches of the splenic artery. (F) Posembolization of multiple feeding vessels with Onyx 18completely embolized and the left hepatic supply is bshunt, the partly cystic mass seen on MRI was found to bean enlarged left inferior phrenic artery given the similar aarrow). There is a vascular blush without arteriovenousartery postembolization of the left hepatic branches. Thnow visible (*). This large supplying vessel was emboliBioSphere Medical, Rockland, MA) and then coiled withzation digital subtraction abdominal aortogram confirarterial supply (arrow) was embolized with NBCA. (I) Tw

either abdominal lesion.

aim for an activated clotting time of 200-300 seconds. Theanesthesiologist and interventional radiologist should beaware that each is giving fluid. Contrast in the catheterdead space should be considered, as 1 mL of contrastflushed into a 3-kg baby is significant. When performingflushes in a neonate, it may be worth immediately re-injecting aspirated blood to the patient. Using a magneticresonance angiogram or CT angiogram to guide initialselective arterial cannulation, rather than doing an aorto-gram, may also help limit contrast doses.

As an angiographic catheter is advanced into the patient,its position should be constantly guided by fluoroscopy.Movements of the catheter and wire should be small andgentle, as it is easy to select a nontargeted vessel, particularlythe visceral branches of the abdominal aorta, and causespasm, dissection, or perforation. Spasm is a frequent prob-lem. Asking the anesthesiologist for purposeful hypercarbia(monitored by the end tidal CO2) may assist with this. Mov-ing from a guiding catheter to microcatheter may also mini-mize vessel wall reaction or injury. Intraarterial glyceryl trini-trate may minimize ongoing spasm.

Embolic MaterialsAs in adult interventional radiology, the choice of embolicagent is dictated by the goals of embolization. So to decreaseor destroy a tumor, embolic materials need to devascularizedistally at a terminal arteriolar level (eg, particles). To destroyabnormal blood vessels as in a vascular malformation, liquidembolics, such as ethanol, are used to create transmural ne-crosis, or to create a vascular cast with terminal penetration,such as Onyx or N-butyl cyanoacrylate (NBCA). Coils pro-vide proximal occlusion, decreasing blood flow but not de-stroying a lesion, unless this is the only vascular supply (eg,pulmonary sequestration).

covery MR shows a lobulated mass in the left upperr of high-velocity flow voids (arrow) with the spleen (S)s large vessels associated with the flow voids as well asconfirms an arteriovenous shunt within the liver. Thelow the celiac axis, where a number of enlarged arteries

-Fr femoral artery sheath, biplane descending thoraciccatheter. A hypervascular lesion in the left lobe of liverand late arterial phase aortograms showing early fillingunt. (E) Selective injection of the celiac axis with a 4-Frpply by numerous elongated and tortuous left hepaticlization hepatic arteriogram. Following superselective

BCA to occlude the splenic arterial supply has beencluded. (G) Following treatment of the arteriovenousied by a large vessel arising near the celiac axis, probablyo the normal caliber inferior phrenic on the right (smallReflux into the celiac trunk opacifies the dilated hepatict hepatic artery, previously unopacified due to steal, isth hydrogel spherical embolic particles (HepaSpheres;018 Tornado 6/3 coil (Cook Medical). (H) Postemboli-successful devascularization. The persistent subcostalr follow-up coronal STIR MRI showing no recurrence of

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However, infants and neonates present a challenge for thechoice of embolic materials, particularly liquid embolics,such as ethanol, in which the volume that can be used may belimited by patient weight. Consider a hydropic baby in high-output cardiac failure with a weight of 3 kg. The maximumvolume of absolute ethanol that could safely be used in oneprocedure is 1 mL/kg, ie, 3 mL (although the baby’s trueweight may be 2.4 kg, with 600 g of third space fluid). Themaximum volume of Onyx is 0.545 mL/kg of DMSO, al-though higher doses have been used (interventional radiol-ogy departments should obtain manufacturer’s recommen-dations for dosage limits). NBCA can be used in greaterquantities. Particle embolics may be limited by the contrastvolume used to deliver the particles. A further considerationwith particle embolics is the risk of crossing an arteriovenousshunt into the venous circulation, with subsequent paradox-ical embolization through the heart, as described above.

Postprocedure CarePrior to removing arterial access from the femoral artery,check the foot capillary refill and temperature. In babies,capillary refill is as sensitive as pedal pulses for assessingischemia. If the foot is cold, one option is to remove thesheath. Alternatively, an angiogram can be performedthrough the sheath. This usually demonstrates spasm fromthe level of the external iliac artery with internal iliac collat-erals reconstituting flow to the lower limb. Although vasodila-ors (such as glyceryl trinitrate) can be given intraarterially, oftenhe best management is removal of the sheath, with soft manualressure on the access point until hemostasis, during whichime the baby remains under general anesthesia. Only when theadiologist is comfortable that hemostasis has occurred shouldhe baby be allowed to emerge from anesthesia.

Following embolization, the patient should return to theeonatal or pediatric intensive care unit. The management ofhese patients is a team effort, and experienced pediatric andeonatal intensive care physicians and nurses are vital in thepre- and) postprocedure care.

The arterial access site is monitored for bleeding and lowerimb capillary refill recorded. When an infant or baby is ex-ected to have ongoing instability, or when the embolizationas an emergency, it may be prudent to leave the baby ven-

ilated another 24 hours. After a significant embolization pro-edure, a neonate may demonstrate hemodynamic instabil-ty, particularly hypertension. Generally, this is treatedggressively to reduce the risk of cerebral hemorrhage, par-icularly in premature or coagulopathic patients. If cortico-teroids are used for postembolization syndrome (such asexamethasone 0.2 mg/kg q12h), remember that this mayorsen hypertension.

Illustrative CasesCase 1: Gastrointestinal BleedingAn otherwise healthy 3-month-old boy (6.8 kg) presented tothe emergency room with episodic bright red rectal bleeding.

Over the first week, a Meckels scan, endoscopy, colonos-

copy, laparotomy, angiogram, and labeled red cell scan couldnot identify the bleeding point. At 3AM, while the baby wastill an inpatient, major hemorrhage occurred with hemate-esis. The baby required intubation and ventilation withajor resuscitation using inotropes and repeated and contin-ous bolus packed cells transfusion. Repeat angiogram waserformed. Diffuse vascular shut down necessitated ultra-ound guidance for micropuncture access of the femoral ar-ery, upsized to a 4-Fr sheath (Terumo). As frank blood waseing aspirated from a nasogastric tube, the celiac axis wasssessed first, using a 4-Fr Baby Judkins right coronary cath-ter (Terumo, Japan) (Fig. 1A).

This showed active extravasation via the gastroduodenalrtery, confirmed by selective injection via a coaxial micro-atheter (Progreat 2.7; Terumo) (Fig. 1B).

As the gastroduodenal artery is an arcade, it was felt thatcclusion of both sides of the bleeding point would be re-uired. The distal arcade was tiny, too small to catheterize.lso, the presumed diagnosis was a Dieulafoy lesion, and itas felt that this should be occluded permanently. Emboli-

ation was performed with NBCA (glue) diluted 1:1 withipiodized oil (Fig. 1C).

There was immediate cessation of bleeding. However, theepatic artery was also occluded from nontarget glue embo-

ization (Fig. 1D). No complication occurred from this, andhe baby made a complete recovery. A nuclear biliary excre-ion study (DISIDA) was normal, and the hepatic artery waseen to recanalize on ultrasound 2 months later (Fig. 1E).

Progress ultrasound at 1 year shows no evidence of hepaticuctal injury, and the hepatic artery remains patent. DISIDAcan remains normal. The recanalization of a hepatic arteryfter being glued closed highlights the occasional nonperma-ent nature of this agent.

Case 2: Liver Arteriovenous MalformationA term baby (2.74 kg) was admitted to our Children’s Hos-pital NICU at day 5 for further management of a left upperquadrant mass. He had been born by Cesarean section per-formed electively. The pregnancy had been complicated byplacement of a left pleuroamniotic shunt at 27 weeks gesta-tion for a left pleural effusion. Immediate postnatal respira-tory distress required supplemental oxygen and aspiration of30 mL straw-colored fluid from the left chest. Mechanicalventilation was required on day 6 with recurrence of theeffusion. Abdominal MRI was performed (Fig. 2A-H).

A left hepatectomy was performed 2 days later. The par-tially cystic mass in the left upper quadrant was found to bewithin the diaphragm, and subtotal excision was performed.Histopathology confirmed the presence of both an arterio-venous malformation in the liver and a sequestration in thediaphragm. There was no evidence of hemangioma. Postop-erative care was complicated by temporary hypertensionwith systolic pressures up to 115 mm Hg. The pleural effu-sion resolved, and the baby recovered. He remains well at 2years of age with no recurrence of either lesion on imaging(Fig. 2I). It is postulated that the intradiaphragmatic seques-tration involuted in response to complete embolization. This

case highlights both the complex pathologies that may occur

Embolization in Neonates and Infants 39

Figure 3 (A) Abdominal STIR MRI in coronal plane shows a large mass (M) in the left upper abdomen. The mass has increasedsignal intensity with small serpentine vascular flow voids inferiorly and dilated veins medially. (B) Summed arterial andvenous phases of digital subtraction abdominal aortogram via a 4-F multiside-hole catheter. There is a dysplastic dilated celiacaxis (arrow) with abnormal small arteries arising from the left hepatic artery. The right hepatic artery arises from the superiormesenteric artery. There is tumoral vasculature with contrast pooling in dilated veins. Steal from the tumor means lower limbrun off is not seen. (C) Selective celiac artery injection (late arterial phase) demonstrating diffuse abnormal arteriolaropacification within the tumor with dilated veins. A site of bleeding is not seen. As many vessels as possible were embolizedwith NBCA and 500-700 �m polyvinyl alcohol particles. A coil was placed in the splenic artery. (D) Unsubtracted imageshowing the NBCA casts in branches off the celiac axis. (E) Subtracted image. Celiac axis injection. The vessel has a

skeletonized appearance while the mass continues to derive supply proximally.

40 D.J.E. Lord and S.M. Chennapragada

in the neonate and complexity of the angioarchitecture en-countered.

Case 3: Unusual Hepatic MassAt 33 weeks gestation, sudden detection of polyhydramnioswith fetal distress necessitated lower segment Cesarean sec-tion of a hydropic 2.58-kg baby boy. Emergency intubationand cardiac compressions were required on delivery. Pal-pation and subsequent ultrasound found a large centralabdominal mass (8 � 5 � 7 cm). Initial management wascomplicated by jaundice, pulmonary hypertension, throm-bocytopenia (46 � 109/L) and surfactant deficiency. Thebaby was transferred to our Children’s Hospital neonatal in-tensive care for further management. Sequential clinical andimaging investigations confirmed a large hypervascular mass,exophytic from the left lobe of liver filling the upper abdo-men (Fig. 3A).

One week later, sudden deterioration was accompanied bygross abdominal distention requiring ventilation, with he-matemesis and hypovolemic shock. Resuscitation was com-menced with packed cells, plasma, and platelets. Urgent an-giogram (Fig. 3B-E) was performed.

Figure 4 (A) A(B) Chest radassociated wization was phydrogel coatuntil a maximlimitation ofbolization waon going reco

the typical flattened

The baby’s condition stabilized. Two hours later, furtherabdominal distention occurred with continuous hemorrhagefrom the nasogastric tube. Both lower limbs became pulselessfrom abdominal tamponade. Profound acidosis developed.After discussion with the parents, active resuscitation waswithdrawn and the baby died. Postmortem examination re-ported an arteriovenous malformation in the left lobe of liver,adherent to the spleen with serosal erosion and hemorrhageinto the peritoneum. The etiology of gastrointestinal hemor-rhage was not found.

This case highlights a number of issues. The size of thislesion and the size and number of the vessels involved cre-ated an extremely challenging embolization. The angioarchi-tecture was bizarre, and it was difficult to determine whichvessels were normal and which were involved in the lesion.The sudden and severe clinical deterioration leading up toembolization also reduced the chances of a lifesaving inter-vention, even with an experienced team. In circumstanceswhen the baby dies, an autopsy is very important and thelesion should be reviewed by a pathologist experienced invascular anomalies. The trauma of a child’s death can lead toa paralyzing fear that future pregnancy would have the sameoutcome. Nearly all vascular tumors and malformations are

lar mass with central ulceration was noted on her right shoulder.h showing cardiomegaly. (C) The increased size of the vesselsmass are seen well on the contrast-enhanced MRA. (D) Emboli-ed on day 4. A coaxial system was used to deliver detachablechable platinum coils (Hydrocoils) into the major feeding vesselsntrast dose had been given and the procedure stopped. (E) Thebolization is considerable persisting blood flow. (F) Further em-rmed on day 12 (F) and the patient stabilized considerably withntil discharge at 1 month. (G) There is a residual birthmark with

vascuiograpth theerformed detaum co

coil ems perfovery u

appearance of a congenital hemangioma.

Embolization in Neonates and Infants 41

sporadic and not inherited.20 Meeting with the parents at alater date allows the parents to ask and understand unan-swered questions and balance some of the grief.

Case 4A term baby with normal birth weight (3.2 kg) was trans-ferred for investigation of high-output cardiac failure. A vas-cular mass with central ulceration was noted on her rightshoulder (Fig. 4A). Chest radiograph showed cardiomegaly(Fig. 4B).

Respiratory distress after feeds worsened requiring me-chanical ventilation by day 3. The mass had clinical featuresof a rapid involuting congenital hemangioma, with centralulceration and high velocity arteriovenous shunting. The ba-by’s condition continued to decline with development of co-agulopathy and thrombocytopenia. Echocardiogram showeda persistent foramen ovale with right to left shunt. The in-creased size of the vessels associated with the mass are seenwell on the contrast enhanced MRA (Fig. 4C).

Embolization was performed on day 4 (Fig. 4D, E). Acoaxial system was used to deliver detachable hydrogel-coated platinum coils (Hydrocoils) into the major feedingvessels until a maximum contrast dose had been given andthe procedure stopped.

Why use coils? In the presence of a known right-to-leftintracardiac shunt, particles or liquid embolics might crossthe arteriovenous shunt in the tumor and so were not used.Also, the natural history of a rapid involuting congenitalhemangioma is involution, so the goal of embolization wasinterval control of cardiac failure and coagulopathy until thisoccurs. The limitation of coil embolization is considerablepersisting blood flow (Fig. 4E); however, after the emboliza-tion, the baby improved such that ionotropes could be with-drawn. High-dose corticosteroids (prednisolone 2 mg/kg)were given and the mass began shrinking daily. However,despite beta blockade, the patient remained coagulopathicand hemodynamically labile with intermittent hypertension.On day 11, the patient had three generalized seizures. BrainMRI showed small petechial hemorrhages in the right coronaradiata. Further embolization was performed on day 12 (Fig.4F), and the patient stabilized considerably with ongoingrecovery until discharge at 1 month.

Now, at 5 years, there is still a residual birthmark with thetypical flattened appearance of a congenital hemangioma(Fig. 4G), but there is no significant shunt, nor any cardiac orneurologic deficit on formal testing.

ConclusionsInfants and neonates requiring embolization present partic-ular challenges to the pediatric interventional radiologist.There are a number of potential pitfalls, not least of which iscorrect diagnosis. Successful treatment needs a team experi-

enced in angiography of babies. These infants are often small

and coagulopathic, and so this team includes not just theinterventional radiology staff but also the neonatal and pedi-atric intensive care unit who are critical in the periproceduralmanagement.

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