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Central nervous system: 52% Hepatic vascular tumors: 39% Pulmonary arteriovenous fistulas: 9% Boston Children's Series 1973-1987 (Fyler, n = 31) - Coronary: 45%
- Cerebral: 16%
- Systemic: 16%
- Pulmonary: 13%
- Hepatic: 10%
Pathophysiology
Direct arterial-to-venous shunt; If large, results in high output cardiac failure, or other manifestations depending on location
Etiology
The causes of the congenital fistulas are unknown.
Associated Conditions
- Hereditary hemorrhagic telangiectasias
- Capillary-cavernous hemangiomas
- Klippel-Trenaunay-Weber syndrome
Diagnosis
Signs and Symptoms
Intracranial Arteriovenous Fistulas
- These are commonly aneurysms of the vein of Galen but may be found in any vessel in the central nervous system.
- Clinical manifestations depend on the age of presentation.
- Birth to 1 month of age
- Heart failure is the most common presenting sign and may be associated with a cranial bruit and rarely with hydrocephalus.
- Severe symptoms may present in the first few hours after birth.
- Because the shunt is mandatory and not dependent on pulmonary vascular resistance, right and left heart failure occur early.
- Right ventricular failure is secondary to both volume loading from the arteriovenous malformation and pressure loading from the high pulmonary vascular resistance of the newborn period.
- The early onset of heart failure seen in this lesion is in sharp contrast to intracardiac left-to-right shunts such as a ventricular septal defect, in which manifestations of heart failure are not seen until the pulmonary vascular resistance decreases associated with an increase in left-to-right shunting.
- Rarely an AVM can be the cause of fetal hydrops.
- 1-12 months of age, or later
- Hydrocephalus is the most common presenting sign at this age. Heart failure (33%) and seizures (33%) also can occur.
- Coronary Artery Fistulas
- Can occur between the coronary arteries and the atria, ventricles, and pulmonary artery; the right ventricle is most common, followed by the right atrium, pulmonary artery, and left ventricle.
- Small fistulas
- Usually asymptomatic but can present with a heart murmur, endocarditis, or ischemia later in life secondary to coronary steal
- Large fistulas
- Can rarely present with congestive heart failure in the newborn period
- Pulmonary Arteriovenous Fistulas
- Congenital
- Hereditary hemorrhagic telangiectasia
- Acquired
- Severe liver disease and cirrhosis
- Following cardiopulmonary anastomosis (Glenn shunts)
- Clinical manifestations include dyspnea, cyanosis, clubbing, polycythemia, hemoptysis, and signs of embolic phenomenon including transient ischemic attacks, strokes, and cerebral abscesses.
- The heart examination is usually normal.
Hemangiomas
- Hemangiomas are not true AVMs, but rather are vascular tumors of proliferating endothelial cells with capillary channels. These tumors are common in the first year of life and then usually undergo spontaneous involution. Occasionally they require treatment because of their unusual size or location.
- Small hemangiomas often are visible in the skin, usually follow a benign course, and resolve spontaneously.
- Large capillary cavernous hemangioma can present with serious or life-threatening complications secondary to:
- Congestive heart failure due to increased volume
- Respiratory compromise due to tracheal compression
- Loss of vision due to invasion of the orbit
- Kassbach-Merritt syndrome (rapidly enlarging hemangioma, thrombocytopenia, acute or chronic consumption coagulopathy)
- Hepatic hemangiomas most commonly are hemangioendotheliomas or cavernous hemangiomas. These may present in infancy, causing congestive heart failure or hepatomegaly and are often associated with hemangiomas of the skin.
History
Depends on location
Physical Exam
Intracranial Arteriovenous Fistulas
- Tachypnea, tachycardia, and congestive heart failure
- Pulses are usually bounding, especially in the upper extremities.
- In patients with an intracranial aneurysm, bounding pulses in the arms and neck with decreased pulses in the lower extremities simulating a coarctation of the aorta have been reported.
- A bruit is typically heard over the fistula; therefore, auscultation of the head should be part of the physical examination in all newborns.
Imaging
- Intracranial arteriovenous fistulas
- Chest radiographs
- Demonstrate cardiomegaly and increased pulmonary markings
- Echocardiography
- Demonstrates normal intracardiac anatomy in most children
- The degree of cardiac enlargement is proportional to the size of the fistula.
- The presence of a large cerebral AVM can be suspected on echocardiography because of the increased size of the aorta, pulmonary artery, and superior vena cava.
- The great vessels leading to the AVM are enlarged.
- Doppler flow studies demonstrate abnormal retrograde diastolic flow patterns in the descending aorta.
- Cranial ultrasonography will demonstrate the abnormal vessels in the majority of patients.
- Cardiac catheterization is not the usual method to establish the diagnosis of a cerebral AVM.
- Coronary artery fistulas
- Echocardiography
- Can localize the size and location
- More precise localization by angiography is usually necessary to determine the extent of the lesion.
- Pulmonary arteriovenous fistulas
- Echocardiography utilizing peripheral venous contrast techniques may be useful by identifying abnormal appearance of pulmonary arteries and veins.
- Catheterization demonstrates pulmonary venous desaturation in the affected segment.
- Angiography demonstrates the rapid filling of the pulmonary vein in the affected segment.
Differential Diagnosis
- Large cerebral, hepatic, or peripheral AVMs can present shortly after birth with signs and symptoms of congestive heart failure. Tachycardia, tachypnea, hepatomegaly, and severe respiratory distress mimic heart failure due to other causes such as cardiomyopathy, and congenital heart lesions with large left-to-right shunts.
- Pulses are bounding, especially in the upper extremities, similar to findings in a patent ductus arteriosus, and often there is a differential in blood pressures between the arms and the legs, simulating a coarctation of the aorta.
Treatment
General Measures
- Intracranial arteriovenous fistulas
- Treatment consists of medical control of congestive heart failure and occlusion of the arteriovenous fistulas with embolization. Surgical techniques may be utilized depending on the size and location of the lesion.
- A variety of catheterization techniques using liquid adhesives, particulate agents, balloons, and coils can be used to achieve closure of the AVM.
- Optimal management uses a team approach combining neurosurgical, interventional, and pediatric disciplines.
- The use of these catheterization procedures can sometimes obviate or delay the need for neurosurgical procedures. Despite all measures, the prognosis is often poor.
- Coronary artery fistulas
- Because the majority of these remain open, surgical treatment is usually required and may be lifesaving in those children with heart failure.
- Small to moderate fistulas are closed to prevent endocarditis and late myocardial ischemia.
- Tiny fistulas may close spontaneously.
- Pulmonary arteriovenous fistulas
- Pulmonary AVMs often can be treated successfully by coil embolization.
- Hemangiomas
- Small hemangiomas usually require no treatment and undergo spontaneous regression.
- Large hemangiomas have been treated with steroids, cyclophosphamide, laser therapy, and interferon with variable rates of success.
- Surgical excision is difficult because of the lack of clear lines of demarcation between normal and abnormal tissue. Fortunately, these lesions often regress with age.
Surgery
May be useful in selected patients depending on location and size (see individual lesions)
Followup
Prognosis
Variable (see individual lesions)
Complications
Variable (see individual lesions)
Patient Monitoring
- Patient follow-up depends on the size of the fistulas and the response to treatment.
- Children in heart failure require hospitalization to initiate management of heart failure and undergo closure of the fistulas.
- These children uniformly do poorly without treatment, and the success of treatment is dependent on the degree of closure of the AVM.
- Complete closure of the lesion is sometimes not possible, and partial closure can significantly decrease the degree of heart failure and allow the infant to grow and develop.
- Repeat attempts at closure can be undertaken when the child is older. In general, the overall prognosis for large AVMs in the central nervous system is guarded, although new catheter closure techniques are promising.
- The prognosis for hepatic hemangiomas most often is favorable, depending on the type of hemangioma. The prognosis for cardiac AVMs is usually excellent with optimal management.
References
1
Burrows PE, Dubois J, Kassarjian A. Pediatric hepatic vascular anomalies. Pediatr Radiol. 2001;31:533-545.
2
Fyler DC. Aortopulmonary fistulas. In: Fyler DCNadas' Pediatric Cardiology. Baltimore: Hanely & Belfus, 1992;707-714.
3
Grifka RG, Preminger TJ. Vascular anomalies, In: Allen HD, Clark EB, Gutgesell HP, Driscoll DJ Moss and Adams, Heart Disease in Infants, Children, and Adolescents Including the Fetus and Young Adult, 6th ed. Baltimore: Lippincott Williams & Wilkins, 2001;689-706.
4
Holzer R, Johnson R, Ciotti G, Piozzi M, Kitchiner D. Review of an institutional experience of coronary arterial fistulas in childhood set in context of review of the literature. Cardiol Young. 2004;14:380-385.
5
Knudson RP, Alden ER. Symptomatic arteriovenous malformations in infants less than 6 months of age. Pediatrics. 1979;45:81-102.
6
McMahon WS. Arteriovenous fistulas. In: Garson A, Bricker JT, Fisher DJ, Neish SRThe Science and Practice of Pediatric Cardiology, 2nd ed.Baltimore: Lippincott Williams & Wilkins, 1998;1677-1688.
7
Musewe NN, Burrows PE, Culham JAG, Freedom RM. Arteriovenous fistulae: A consideration of extracardiac causes of congestive heart failure. In: Freedom RM, Benson LN, Smallhorn JFNeonatal Heart Disease. London: Springer Verlag, 1992;759-772.
8
Preminger TJ, Perry SB, Burrows PE. Vascular anomalies. In: Emmanouilides GC, Riemenschneider TA, Allen HD, Gutgessel HPMoss and Adams' Heart Disease in Infants, Children, and Adolescents Including the Fetus and Young Adult, 5th ed. Baltimore: Williams & Wilkins, 1995.
Codes
ICD9
- 747.81 Congenital anomalies of cerebrovascular system
- 746.85 Coronary artery anomaly, congenital
- 747.3 Congenital anomalies of pulmonary artery
SNOMED
128617001 arteriovenous fistula (morphologic abnormality)