Due
to major advances in both diagnosis and treatment of congenital
heart disease in children, many are living into adulthood. There
are almost one million such patients this year.
Congenital
heart disease can be divided into two types:
1.
The acyanotic ones in which the oxygen level in the blood is
high enough to keep the patients' color pink;
2.
The cyanotic ones in which the oxygen level in the blood is
low enough for the lips and skin to show varying degrees of
bluish discoloration.
1.
Acyanotic congenital heart consist of the following:
a)
atrial septal defect
( figures 112a,
112b
)
b) ventricular septal
defect ( figure 112c
)
c) patent
ductus arteriosus ( figure 22
)
d) aortic stenosis ( figures
24a,
24b,
46a,
46b,
46c,
47
)
e) pulmonary stenosis
( figure 25a,
25b
)
f) parachute
mitral valve ( figures 44g-1
and 44g-2
)
g)
coronary artery fistula
h) anomalies of the great veins
Brickner,M.E.
and others,Congenital Heart Disease inAdults,N.Engl.J.Med.,Vol.342.N.4,Jan.27,2000
Coronary Artery
FistuLa
A coronary artery fistula is an abnormal
communication between an epicardial coronary artery and a cardiac
chamber, major vessel (vena cava, pulmonary veins, pulmonary
artery), or other vascular structure (mediastinal vessels, coronary
sinus) (see: cavf-1a, cavf-1b, cavf-2, cavf-3, cavf-4a, cavf-4b
and cavf 5). In other words, some of the oxygenated blood from
the lungs, which has come into the left ventricle and is pumped
out into the ascending aorta to feed the coronary arteries and
the rest of the body, is being siphoned off by the fistula into
the right ventricle, atrium or other vascular structure.
This infrequent abnormality can affect persons
of any age and is the most important hemodynamically significant
coronary artery anomaly. Many are small and found incidentally
during coronary arteriography, whereas others are identified
as the cause of a continuous murmur, myocardial ischemia and
angina, acute myocardial infarction, sudden death, coronary
steal, congestive heart failure, endocarditis, stroke, arrhythmias,
coronary aneurysm formation (rupture, emboli), or superior vena
cava syndrome. Some of the symptoms or complications are related
to the amount of blood loss into the shunt and how much stress
is placed on the left ventricle to compensate.
Of over 33,000 patients undergoing coronary
arteriography, coronary artery fistula occurred in 0.1 percent,
whether due to congenital or acquired causes (Table see below
). Fistulas from the right coronary artery are more common than
from the left, and over 90 percent of the fistulas drain into
the venous circulation. Most fistulas are single communications,
but multiple fistulas have been identified.
The natural history of coronary artery fistulas
is variable, with long periods of stability in some and sudden
onset or gradual progression of symptoms in others. Spontaneous
closure is uncommon.
Surgical repair of the fistula is recommended
for symptomatic patients and for those asymptomatic patients
at risk for future complications (coronary steals, aneurysms,
large shunts). Transcatheter embolization of fistulas has been
reported. Direct connection between a major epicardial coronary
artery and a cardiac chamber or major vessel (vena cava,coronary
sinus, pulmonary artery) is the most hemodynamically significant
coronary artery anomaly(see figures above) Myocardial ischemia
has been documented in some patients with coronary artery fistulas,
who have no evidence of atherosclerosis.
Figure
cavf-2 : Diagram
showing coronary artery fistula connecting pulmonary trunk
and left anterior descending (LAD) artery. It originalty was
misdiagnosed as an anomalous coronary artery. LADD, diagonal
branch of LAD; IC, left circumflex; LM, Left main; R, right.
Figure
cavf-5 : A 25-year-old asymptomatic
marathon runner was found during a routine examination to
have a continuous murmur that was more pronounced during systole
and loudest at the aortic root on the right side of the sternum.
Coronary angiography revealed a fistula connecting the left
main coronary artery with the right atrium. Since we could
not rule out the possibility that this abnormality could result
in sudden death during overexertion, the patient was advised
to reduce his level of physical activity. In about 55 percent
of cases of coronary arteriovenous fistula, the right coronary
artery or its branches are the site of the fistula; the left
coronary artery is involved in about 35 percent of cases,
and both coronary arteries are involved in about 5 percent
of cases. The connection between the left main coronary artery
(LCA) and the right atrium (RA) is unusual. Drainage occurs
into the right ventricle in 41 percent of cases, the right
atrium in 26 percent, the pulmonary artery in 17 percent,
the left ventricle in 3 percent, and the superior vena cava
in 1 percent; in the other 12 percent of cases, there are
multiple connections between the fistula and different chambers
of the heart. About half the patients with large fistulas
are asymptomatic, whereas in the other half, congestive heart
failure, infective endocarditis, or myocardial ischemia develops
or the fistula ruptures. Pulmonary hypertension may occur
when the fistula drains into the pulmonary artery. Survival
into adulthood is the rule in these patients, but life expectancy
is reduced.
HELMUT BRUSSEE, M.D.and ROBERT GASSER,
M.D., PH.D NewEJM, Vol.346, No.12,
P904, 3/21/02
TABLE 39-3 Causes and Associations of Coronary Artery FistuLa
I. Congenital
1. Embryonic
2. Multiple; systemic hemangioma
II. Acquired
1. Closed-chest ablation of accessory pathway
2. Percutaneous coronary balloon angioplasty8789
3. Hypertrophic cardiomyopathy
4. Right/left ventricular septal myectomy'°'
5. Penetrating and nonpenetrating trauma
6. Acute myocardial infarction
7. Dilated cardiomyopathy
8. Mitral valve surgery
9. "Sign" of mural thrombus
10. Tumor
11. Permanent pacemaker placement
12. Cardiac transplant
13. Endomyocardial biopsy
14. Coronary artery bypass grafting
Pathophysiology:
The pathophysiologic mechanism of CAF is myocardial
stealing or reduction in myocardial blood flow distal to the
site of the CAF connection. The mechanism is related to the
diastolic pressure gradient and runoff from the coronary vasculature
to a low-pressure receiving cavity. If the fistula is large,
the intracoronary diastolic perfusion pressure diminishes progressively.
The coronary vessel attempts to compensate
by progressive enlargement of the ostia and feeding artery.
Eventually, myocardium beyond the site of the fistula's origin
is at risk for ischemia, which is most frequently evident in
association with increased myocardial oxygen demand during exercise
or activity. With time, the coronary artery leading to the fistulous
tract dilates progressively, which, in turn, may progress to
frank aneurysm formation, intimal ulceration, medial degeneration,
intimal rupture, atherosclerotic deposition, calcification,
side-branch obstruction, mural thrombosis, and, rarely, rupture.
Anatomy
Normally, 2 coronary arteries arise from the
root of the aorta and taper progressively as they branch to
supply the cardiac parenchyma. A fistula exists if a substantive
communication arises that bypasses the myocardial capillary
phase and communicates with a low-pressure cardiac cavity (atria
or ventricle) or a branch of the systemic or pulmonary systems.
Normal thin-walled vessels exist at the arteriolar
level that may drain into the cardiac cavity (arteriosinusoidal
vessels) and venous communications (thebesian veins) to the
right atrium. These small vessels do not steal significant nutrient
flow and do not constitute fistulous connections. Fistulae usually
are large (>250 mm) and dilated or ectatic, and they tend
to enlarge over time. Often, the limits of what constitutes
a fistula and what constitutes a normal vessel are debated.
Most fistulae arise from the right coronary
artery (60%) and terminate in the right side of the heart (90%).
The most frequent sites of termination, in descending order,
are the right ventricle, right atrium, coronary sinus, and pulmonary
vasculature. Coronary fistula communications often appear in
the context of other congenital cardiac anomalies, most frequently
in critical pulmonary stenosis or atresia with an intact interventricular
septum, but also in pulmonary artery branch stenosis, coarctation
of the aorta, and aortic atresia. Although most often congenital,
a coronary fistula rarely may arise as a consequence of surgical
resection of obstructing right ventricular muscle bundles (as
in tetralogy of Fallot), endomyocardial biopsy, or penetrating
or blunt trauma.
Embryology
CAF may appear as a persistence of sinusoidal
connections between the lumens of the primitive tubular heart
that supply myocardial blood flow in the early embryologic period.
These channels most often persist when associated with outflow
obstruction (eg, pulmonary atresia), yet they also may persist
in the absence of obstruction.
Associated syndromes include pulmonary atresia
or stenosis with an intact ventricular septum. In this setting,
epicardial coronary blood may flow to and fro during the cardiac
cycle. In systole, right ventricular flow decompresses via coronary-sinusoidal
connections to the aorta in a reverse direction, while in diastole,
the aorta perfuses the coronary artery in a normal antegrade
fashion. This contrasts with coronary arteriovenous fistulae
in the absence of outflow obstruction, in which coronary steal
is the primary pathophysiologic problem. In pulmonary atresia
and coronary-sinusoidal connections, myocardial ischemia, necrosis,
fibrosis, and systemic desaturation may occur. Areas of coronary
stenosis and/or interruption of the coronary system may complicate
this abnormality. No associated noncardiac conditions exist.
Frequency:
In the US: CAF accounts for 0.2-0.4% of congenital
cardiac anomalies. Approximately 50% of pediatric coronary vasculature
anomalies are CAFs.
Mortality/Morbidity:
Fistula-related complications are present
in 11% of patients younger than 20 years and in 35% of patients
older than 20 years. Larger fistulae progressively enlarge over
time, and complications, such as congestive heart failure (CHF),
myocardial infarction, arrhythmias, infectious endocarditis,
aneurysm formation, rupture, and death, are more likely to arise
in older patients. Spontaneous closure rarely has been reported.
Surgery-related complications: The mortality
rate related to surgical repair of coronary arteriovenous fistulae
typically ranges from 0-4%. Variations that may increase surgical
risk include the presence of giant aneurysms and a right coronary
artery-to-left ventricle fistula. Complications of surgery include
myocardial ischemia and/or infarction (reported in 3% of patients)
and CAF recurrence (4% of patients).
Race: No
race predilection exists.
Sex: No
sex predilection exists.
Age: CAF
may present in patients at any age, but CAF usually is suspected
early in childhood when a murmur is detected in an asymptomatic
child. Older children with murmurs may present with symptoms
of coronary insufficiency.
Imaging Studies:
Echocardiogram: Two-dimensional echocardiograms
may reveal left atrial and left ventricular enlargement as a
consequence of significant shunt flow or decreased regional
or global dysfunction as a consequence of myocardial ischemia.
The feeding coronary artery often appears enlarged, ectatic,
and tortuous. High-volume flow may be detected by color-flow
imaging at the origin or along the length of the vessel. Carefully
seek the site of drainage; often, it is evident as a disturbed
flow signal, most frequently within the right ventricle.
Cardiac catheterization remains the modality
of choice for defining coronary artery patterns of structure
and flow. Most frequently, intracardiac pressures are normal
and shunt flow is modest.
Aortography (see cavf-1a,
cavf-1b) or selective coronary arteriography (see cavf-3,
cavf-4a, cavf-4b ) supplies the information required to
manage the condition. In addition, therapeutic embolization
using occlusive coils or devices may be performed via catheterization.
Spontaneous closure is rare but may occur
in small fistulae. Small fistulous connections in the asymptomatic
patient may be monitored. Most lesions enlarge progressively
and warrant surgical repair, either by transcatheter or surgical
techniques. Provide endocarditis prophylaxis in all patients.
Cardiac catheterization (transcatheter embolization)
may be performed as intervention. Initial diagnostic catheterization
should both define hemodynamic significance of the lesion and
provide detailed angiographic assessment of the anatomy of the
abnormality. Surgical options can be delineated by careful identification
of the number of fistulous connections, nature of feeding vessel(s),
and sites of drainage.
Transcatheter embolization is described as
follows:
Indications: In view of the natural progression
in larger fistulae to dilate over time, with progressively increasing
risk of thrombosis, endocarditis, or rupture, the general advice
is to close all but the small fistulous connections. In borderline
situations, provide close echocardiographic or angiographic
follow-up imaging to identify enlargement of feeding vessel
in asymptomatic patients. Patients with large fistulae, multiple
openings, or significantly aneurysmal dilatation may not be
optimal candidates for transcatheter closure.
Technique: Transcatheter embolization techniques
using coils, bags, or other devices can be performed on an outpatient
basis at the time of diagnostic studies or later, and they obviate
the need for cardiac surgical intervention. The transcatheter
approach frequently is a fairly complicated intervention and
requires an experienced operator and interventional specialist
with expertise in both coronary arteriography and embolization
techniques. Embolization often requires complicated catheter
manipulation, as well as selection of various catheters and
wires.
Surgical Care: Cardiac surgical intervention
is described as follows:
Indications: Indications for surgical
intervention are the same as in embolization (see above). Some
fistulae are unsuitable for the transcatheter approach and preferably
are addressed surgically. These CAFs may include fistulae with
multiple connections, circuitous routes, and acute angulations
that make catheter positioning difficult or impossible.
Techniques: Surgical repair usually is approached
via a median sternotomy and cardiopulmonary bypass. Identify
the feeding vessel and delineate its course and site of insertion.
Identify the site of presumed fistulous drainage prior to institution
of the cardiopulmonary bypass. A typical procedure includes
opening the chamber into which the fistula drains, identifying
the fistula, and closing the suture. If the fistula enters the
ventricle or if the feeding vessel is large, the coronary artery
is opened, and the opening to the fistula is closed with a running
suture. The arteriotomy is closed. Large aneurysms may require
excision. Rarely, when the fistula is an end artery, it may
be ligated with or without bypass.
Patients treated surgically and with transcatheter techniques
should receive maintenance doses of antiplatelet agents and,
perhaps, an anticoagulant regime for the first 6 months postoperatively,
until the operative surface has undergone endothelialization.
Patients remain at risk for development of
endocarditis until the flow is stopped and should receive antibiotic
prophylaxis for any dental, gastrointestinal tract, and urologic
procedures.
Complications:
Complications of surgery include myocardial
ischemia and/or infarction (reported in 3% of patients) and
recurrence of the fistula (4% of patients).
Major complications associated with transcatheter
embolization relate to manipulation of stabilizing catheters
and wires in the coronary vasculature and may include coronary
artery spasm, ventricular dysrhythmias, and perforation. Inappropriate
positioning or proximal extension of occlusive coils or devices
may result in obstruction of side branches and muscle loss.
Intimal dissection of the coronary artery or thrombosis also
may occur. However, morbidity and mortality rates generally
are considered to be low.
Prognosis:
Further Outpatient Care:
Provide follow-up care after hospital
discharge to check for evidence of ischemia or recurrence of
fistulae. Individuals who have undergone coronary surgical interventions
and, particularly, patients who have sustained cardiac muscle
loss should have ongoing cardiac follow-up monitoring that may
include stress studies and repeat angiography as needed.
Patients treated surgically and with transcatheter
techniques should receive maintenance doses of antiplatelet
agents and, perhaps, an anticoagulant regime for the first 6
months postoperatively, until the operative surface has undergone
endothelialization.
Patients remain at risk for development of
endocarditis until the flow is stopped and should receive antibiotic
prophylaxis for any dental, gastrointestinal tract, and urologic
procedures.
Complications:
Complications of surgery include myocardial
ischemia and/or infarction (reported in 3% of patients) and
recurrence of the fistula (4% of patients).
.Major complications associated with transcatheter
embolization relate to manipulation of stabilizing catheters
and wires in the coronary vasculature and may include coronary
artery spasm, ventricular dysrhythmias, and perforation. Inappropriate
positioning or proximal extension of occlusive coils or devices
may result in obstruction of side branches and muscle loss.
Intimal dissection of the coronary artery or thrombosis also
may occur. However, morbidity and mortality rates generally
are considered to be low.
Prognosis:
Recent results of both transcatheter and
surgical approaches indicate a good prognosis. Approximately
4% of patients may require additional surgery for recurrence.
Life expectancy is considered normal. However, risk of degenerative
atherosclerotic disease may be higher if ectasia and dilatation
of the coronary artery persist or progress. In young surgical
patients, anticipate the involution of the dilated segment of
the feeding vessel; this is not the case in adults.
Abstract
Coronary artery fistula is rare, but it is
the most common congenital coronary artery anomaly with hemodynamic
significance. It usually causes no symptoms in young patients
but may be associated with symptoms and complications in older
patients. Surgery has been the traditional treatment. In this
report, a 7-year-old girl who had a coronary artery fistula
from the left circumflex coronary artery to the right atrium
was successfully treated by percutaneous transcatheter technique.
[Chin Med J (Taipei) 1997;59:194-8 Be-Tau
Hwang M.D., Department of Pediatrics, Veterans General Hospital-Taipei,
No. 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan, R.O.C.
Introduction
Coronary artery fistula is a direct communication
between a coronary artery and one of the cardiac chambers or
vessels around the heart . Although the fistula is rare, it
is the most common congenital coronary artery anomaly with hemodynamic
significance . Analyses of large coronary angiographic series
show the incidence of 0.1-0.2% . This particular anomaly usually
causes no symptom in young patients but may present with symptoms
and/or complications in older patients including congestive
heart failure, myocardial ischemia, infective endocarditis,
atrial fibrillation, pulmonary hypertension and rupture . Because
of these complications, surgical closure has been advocated
in most reported series . However, surgery usually requires
a median sternotomy and cardiopulmonary bypass. The perioperative
mortality rates range from 2 to 4 % . In this report, we describe
the successful percutaneous transcatheter embolization of a
coronary artery fistula by coils.
Case Report
A 7-year-old girl was referred to this hospital
because of a heart murmur. Otherwise she was symptom free, active
and thriving. Physical examination revealed a grade 3/6 continuous
murmur over the whole precordial area. Chest X-ray showed mild
cardiomegaly. Electrocardiogram showed left atrial and ventricular
hypertrophy. Two-dimensional echocardiograms disclosed a tortuous,
dilated, tubular vessel from the aorta and around the heart.
Color Doppler flow mappings demonstrated that the entrance of
this abnormal vessel was located at the junction of the right
atrium and ventricle. Cardiac catheterization revealed normal
right and left ventricular pressures and a significant O2 step-up
(74.4% to 88.5%) in the right atrium. The pulmonary to systemic
flow ratio (Qp/Qs) was calculated as 2.5 by Fick's principle.
Selective coronary angiograms (cavf-4a) disclosed a huge, tortuous,
dilated coronary artery fistula from the left circumflex coronary
artery with a single opening into the right atrium. A test inflation
of a balloon of a 5 Fr Berman catheter showed that it produced
complete occlusion without untoward clinical effects or electrocardiographic
abnormalities. The coronary artery fistula was then occluded
by using the Gianturco coils (Occluding Spring Coil, Cook, U.S.A.)
through a 5F Judkins catheter. Three coils sized 10 mm in diameter
and 12 cm long, 8 mm in diameter and 10 cm long, and 5 mm in
diameter and 8 cm long were introduced sequentially. Transient
myocardial ischemia with ST-T change was noted immediately after
the procedure but spontaneously recovered one minute later.
Postocclusion coronary angiograms (cavf-4b) demonstrated the
complete occlusion without residual flow. The previous murmur
vanished immediately. The follow-up Doppler echocardiography
demonstrated a tiny residual flow into the right atrium 24 hours
later. The prophylactic antibiotic, oxacillin, was given 30
minutes before the procedure and then administrated intravenously
every 6 hours. However, high fever developed two days later.
Blood culture was negative. One week after coil embolization,
a pericardial effusion was found by echocardiography. The amount
of effusion increased gradually in spite of aspirin administration,
and so pericardial tapping was done on the 14th day after coil
embolization. A total of 60 ml serosanguinous fluid was drained
out and the fluid study revealed WBC 257/cumm, RBC 45,320/cumm,
protein 4,400 mg/dl, and sugar 88 mg/dl. No bacteria was isolated
from the fluid. The amount of pericardial effusion decreased
gradually in the following days and was completely resolved
two months after pericardial tapping. Follow-up study four months
after coil embolization revealed that the patient is asymptomatic
without cardiac murmur. The echocardiographic study showed minimal
residual flow without pericardial effusion.
Discussion
Most coronary artery fistulas are believed
to arise from the incomplete obliteration of primary myocardial
sinusoids . This developmental arrest results in retained continuity
between the mature coronary artery and cardiac vein or chamber
. Although these fistulas are rare, they may gradually enlarge
and become the most common congenital coronary artery anomalies
with hemodynamic significance . Diagnostic methods include physical
examination, electrocardiography, chest X-ray, echocardiography
and angiocardiography. Liberthson et al. found that 91% of patients
with these fistulas younger than 20 years were asymptomatic
compared to 37% of patients older than 20 years. The symptoms
or complications included congestive heart failure, myocardial
ischemia, infective endocarditis, atrial fibrillation, pulmonary
hypertension and rupture . Myocardial ischemia results from
coronary steal, with the fistula acting as a low resistance
pathway . Spontaneous closure of a fistula is very uncommon.
On the basis of these data, most authors have recommended surgical
closure of these fistulas during childhood even in the absence
of symptoms . However, surgery requires a median sternotomy
and usually cardiopulmonary bypass. The perioperative mortality
rates ranged from 2 to 4 % in the literature.
Therapeutic transcatheter embolization of
abnormal thoracic vessels was first reported in 1974 . In 1983,
Reidy et al. reported the first case of transcatheter embolization
of a coronary artery fistula. Since then, several reports had
demonstrated the feasibility of transcatheter closure of coronary
artery fistulas . Coils, detachable balloons, umbrellas and
polyvinyl foam had been used for successful occlusion of these
fistulas. The choice among these devices is somewhat arbitrary.
Coils cost less than other devices and can be delivered through
a smaller catheter . It is imperative that the feeding artery
is occluded distal to all normal branches to the myocardium
. The risks associated with transcatheter embolization of coronary
artery fistulas include coronary artery disruption, pulmonary
or systemic embolization, pericardial effusion , myocardial
ischemia or infarction . In this case, transient myocardial
ischemia occurred because the catheter induced left anterior
descending coronary artery spasm during manipulation. The ischemia
recovered spontaneously one minute later. Otherwise, aseptic
pericardial effusion developed one week after coil embolization.
The mechanism of pericardial effusion following transcatheter
embolization of coronary artery fistula is unknown. It may be
associated with increased hydrostatic pressure of pericardial
vessels, pericardial inflammation or be similar to the postpericardiotomy
syndrome after open heart surgery . After pericardial tap and
anti-inflammatory agents with aspirin, the effusion disappeared
gradually. Although there was a small residual flow by echocardiography
in the reported case, the flow murmur could not be appreciated.
On the basis of our results and those previously
reported , we believe that percutaneous transcatheter embolization
is a safe and effective treatment for coronary artery fistulas.
When a coronary artery fistula with hemodynamic significance
is diagnosed, transcatheter embolization should be considered
as a replacement to surgery.
2.
Cyanotic Congenital Heart
Disease features bluish discoloration
of the skin and lips as opposed to the normal pink appearance.
The cyanosis is due to the shunting of systemic venous blood
to the arterial circulation causing arterial blood desaturation
of oxygen. The size of the shunt determines the degree of desaturation.
In adults the most common causes of cyanotic congenital heart
disease are tetralogy of Fallot and Eisenmenger's syndrome.
a) Tetralogy
of Fallot ( figure 23d
)
b) Ebstein's Anomaly
( figure 23e
)
c) Transposition
of the Great Arteries ( figure 23h
)
d ) Eisenmenger's syndrome
( figure 23j
)
Brickner,M.E.
and others,Congenital Heart Disease in Adults,N.Engl.J.Med.,Vol.342.N4,2000,pp.334-342
