Download Congenital Heart Disease with Left to Right Shunt

CONGENITAL HEART
DISEASE WITH LEFT TO
RIGHT SHUNT
Michael Pieters
Dept. of Diagnostic Radiology
Bloemfontein
OVERVIEW
 Classification of congenital heart lesions
 Factors that influence lesion presentation
 Imaging chain sequence
 Left to right Shunt lesions
 Anatomy
 Physiology
 Imaging
CLASSIFICATION OF CONGENITAL CARDIAC
LESIONS
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Shunt lesions
Right heart lesions
Left heart lesions
Abnormal origin of the great arteries
FACTORS THAT INFLUENCE LESION
PRESENTATION
 Age of child
 Severity of the lesion
 Example – VSD
 R to L shunt at birth
 L to R shunt with CCF as age increases
 The anatomy of the lesion remains constant
 Radiographic features and clinical findings change with time
 Classic radiographic features of certain lesions – rarely seen
IMAGING CHAIN SEQUENCE
 The imaging sequence varies with
 Age
 Clinical presentation
 Type of lesion
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Echocardiography
Chest Radiography
CT
MRI
Angiography
CONGENITAL CARDIAC LEFT TO RIGHT
SHUNT LESIONS
 ASD
 VSD
 PDA
 Ductus Arteriosus Aneurysm
 Aortico-Pulmonary Window
CARDIOMEGALY
 Cardiomegaly on CXR
 Asses pulmonary vascularity - ? Increased
 Read history - ? Acyanotic patient
 Ddx:
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ASD
AVSD
VSD
PDA
Aortico-pulmonary window
ASD
 10% of all CHD
 Incidence - twice as common in females
 Secundum defects – likely genetic cause
 Holt Oram
 Familial ASD
ASD ANATOMY
 3 Primary types
 Relationship to the fossa ovalis
 Secundum defects (80%)
 Region of fossa ovalis
 Ostium Primum defects (10%)
 Caudal to the fossa ovalis
 Sinus Venosus defects (10%)
 Posterior to the fossa ovalis
ASD – SINUS VENOSUS DEFECTS
 Not true ASD’s
 Defect in the septum which separates the
 sinus venosus portion of the RA from the
 right pulmonary veins and systemic veins
 Most often found in the wall between the
 Posterior inferior border of SVC and
 RA
 Commonly assosciated with anomalous connection of
 Right upper, middle or lower pulmonary veins draining to the
 RA or SVC
ASD – SINUS VENOSUS DEFECTS
 Much less commonly - defect is found in the wall between the
 Inferior RA at its junction with the
 IVC
 Assosciated with anomalous connection of
 Right middle or lower pulmonary veins
 draining to the RA or SVC
ASD – CORONARY SINUS SEPTAL
DEFECTS
 Rare spectrum of lesions
 Partial or complete absence of wall between
 Coronary sinus and LA
 Associated with a left SVC draining to the coronary sinus
 Blood shunts from the LA to the RA via “unroofed” coronary
sinus
ASD – PATENT FORAMEN OVALE
 Foramen Ovale
 Located between septum secundum and primum
 Normally patent prenatally
 Allows O2 rich blood from ductus venosus -> reach LA
 Sealed after birth
 Increased LA pressure vs RA
 Probe patency
 25% of adults
 Functionally closed
 Right to left shunt possible - Valsalva
ASD – COMMON ATRIUM
 Atrial septum completely absent
 Common in visceral heterotaxy syndromes
ASD - PHYSIOLOGY
 Left to right shunt volume determined by
 ASD size
 Left heart compliance
 Pulmonary vascular resistance
 Large defects show increased size of
 RA
 RV
 Pulmonary artery
 Right to left shunt will occur when
 Pulmonary vascular resistance > Systemic vascular resistance
ASD – CLINICAL PRESENTATON
 Detected 1-2 yr of age
 May present earlier @ 6 -8 weeks with murmur
 Older children with large ASD
 Fatigue and dyspnoea
 Split second heart sound – no variation with respiration
 Diastolic flow murmur
 Adults – flow related pulmonary arterial hypertension
ASD IMAGING - ECHOCARDIOGRAPHY
 Modality of choice for Dx
 Localising
 Size
 Shunt direction and severity (Colour Doppler)
 Right ventricular qualitative function
 Septal bowing (Rt to Lt)
 Points to volume overload
ASD IMAGING - ECHOCARDIOGRAPHY
 Right ventricular pressure
 Assessed by evaluating the degree of:
 Tricuspid regurgitation
 Septal systolic position (systolic septal flattening – increased RV
pressure)
 PFO
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Dx – flap valve or
Saline injection to right heart + Valsalva
Rt to Lt shunt on Valsalva
TEE
ASD IMAGING – CHEST RADIOGRAPHY
 Neonate
 Normal cardiac size
 Normal pulmonary flow
 Later infancy and childhood
 Mild cardiomegaly
 Triangular cardiac silhouette
 Left atrium normal
 distinguishes uncomplicated ASD from other L ->R lesions)
 Main pulmonary artery enlarged
 Eisenmenger syndrome findings
 Seen in pulmonary hypertension
 Large central pulmonary arteries
 Peripheral pulmonary artery tapering
ASD IMAGING – CHEST RADIOGRAPHY
 Mild to moderate
cardiomegaly
 Increased
pulmonary
vascularity
 No left atrial
dilatation
ASD – IMAGING
 Angiography
 Asses haemodynamic consequences of ASD or
 Used if transcatheter closure is planned
 MRI
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Adjunct to echo
>90% sensitive and specific for ASD localization and detection
Useful in pt with poor acoustic windows
Can lead to ASD being misdiagnosed
 atrial septum is thin on BW images – rather use MRI cine
 GE and steady state free precession cine – shows turbulent jet over
ASD
 Cine phase contrast sequences
 Show direction and amount of shunting
ASD – MRI DYNAMIC PERFUSION STUDY
 PFO can be demonstated by injecting Gadolinium into the
right heart + Valsalva
 ASD haemodynamic evaluation
 Demonstrates Eisenmenger syndrome physiology
 Contrast seen crossing the atrial septum from the RA to the LA
AVSD
 2-5% of all CHD
 40% of Down’s syndrome patients have CHD
 40% of Down’s pt with CHD have AVSD
 Associated with visceral heterotaxia / asplenia and
polysplenia syndromes
 Ellis van Creveld syndrome
AVSD
 Lesions associated with AVSD
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PDA (10%)
Tetralogy of Fallot (6%)
Transposition of the great arteries
Double outlet RV
Aortic coarctation
AVSD - ANATOMY
 Abnormal development of the endocardial cushions
 Mild form - partial AVSD:
 Crescent shaped defect in the inferior portion of the atrial septum
adjacent to the AV – valves
 Cleft mitral valve
 Separate mitral and tricuspid valve orifices
AVSD - ANATOMY
 Complete form:
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Single AV-valve
Ostium primum ASD just superior to the plane of the AV – valve
Large VSD beneath the plane of the AV - valve
Cleft in the anterior leaflet of the mitral valve
Cleft in septal leaflet of tricuspid valve
The common AV-valve has 5 leaflets
Shortened left ventricle inlet
Left ventricle papillary muscle defects
 abnormally close to each other or
 only one papillary muscle
 Unbalanced AVSD
 Relative hypoplasia of one of the ventricles
AVSD - PHYSIOLOGY
 Complete AVSD
 Left to right shunt - related to size of defect and pulmonary vascular
resistance
 Shunting may be interatrial or interventricular
 Cleft Mitral Valve leads to mitral regurgitation and CCF
 Pulmonary hypertension develops (more common in Down’s
pts)
AVSD PRESENTATION
 Infants with complete AVSD
 Tachypnoea, tachycardia
 CCF sx when pulmonary resistance starts to fall
 Signs and symptoms vary according to the degree of shunting
 Partial AVSD
 Infants usually asymptomatic
 Can present earlier if severe mitral incompetence
AVSD - IMAGING
 Echocardiography
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Accurately demonstrates AVSD components
Ostium primum defect
Inlet portion of the ventricle
Abnormal valve leaflet morphology
Papillary muscle architechture
Shunt level and flow direction
Ventricular function and size
 Evaluate for outflow tract obstruction
 Pulmonary and systemic venous anatomy (must be documented
because of frequency of associated heterotaxy abnormalities)
AVSD - IMAGING
 Chest Radiography
Moderate to marked cardiomegaly
RV and RA enlargement (more in complete AVSD)
Increased pulmonary vascularity
Left atrial enlargement – if associated mitral incompetence
Lung infiltrates (increased pulmonary blood flow associated with
recurrent LRTI)
 Lung hyperinflation – seen with large left to right shunts
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 due to increased blood volume with increased overall lung volume as well
as increased airway resistance from enlarged arteries and veins
AVSD - IMAGING
 Chest Radiography
 Cardiomegaly
 Pulmonary plethora
AVSD - IMAGING
 Cross sectional imaging
 Not needed in initial Dx
 Used to confirm Dx and
 evaluate the size and morphology of the atria, leaflets, ventricles and
great vessels
 Evaluate ventricular function
 Cine phase contrast MRI
 Assessment of shunt fraction (Qp/Qs)
 Valvular function
AVSD - IMAGING
 Angiocardiography
 Rarely necessary for Dx
 Used if Dx is unclear or haemodynamic information is needed
 Long axis ventriculogram
 Goose neck deformity of left ventricular outflow tract
 Anterior superiorly positioned aortic valve
 Elongated and narrowed LV outflow tract
VSD
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20% of all CHD
2/1000 Live briths
VSD + complex CHD account for > 50% of CHD
Most common lesion in trisomy 13,18 and 21
Incidence slightly higher in females
Incidence varies on age of evaluation
 Most small VSDs close spontaneously
VSD
 Isolated or
 as part of complex CHD
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Tetralogy of Fallot
Truncus arteriosus
ASD
Coarctation of the aorta
Tricuspid atresia
Transposition of the great arteries
Double outlet RV
VSD - ANATOMY
 4 Components of the ventricular septum
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Inlet septum
Muscular septum
Outlet septum
Membranous septum
 VSD involves one or more component
VSD - ANATOMY
 Inlet septum
 Contains AV valves and their attachments
 Formed from endocardial cushions
 AVSD defect location
 Muscular septum
 Trabeculated portion of RV (viewed from RV)
 From tricuspid valve leaflets to RV apex and crista supraventricularis
 Location of single or multiple muscular defects
 Outlet septum
 Extends from the crista supraventricularis to pulmonary valve (viewed
from RV)
 Membranous septum
 Inferior to the right and non-coronary cusps of the aortic valve
 80% of VSDs involve this area
VSD - PHYSIOLOGY
 Physiologic ef fect determined by
 VSD size
 Rt and Lt heart compiance
 Pulmonary vascular resistance
 Small defects
 High flow resistance
 Large defects
 Low flow resistance
 High blood flow in the pulmonary vasculature
 Leads to pulmonary vascular obstructive disease
VSD - SYMPTOMS
 Symptoms dictated by
 VSD size
 Degree of Left to Right shunt
 Typical signs in > 1 month of age
 PSM as pulmonary resistance falls
 No murmur in large VSD
 Loud split 2 nd heart sound
 Significant shunt
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Failure to thrive
Dyspnoea
CCF
Irreversable pulmonary vascular obstructive disease
Shunt reversal
VSD - IMAGING
 Echocardiography
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Method of choice
Used to asses the location, number and size of VSDs
Shunt assessment
Colour Doppler is useful to identify muscular VSDs
RV + Pulmonary artery pressures measured
Rt + Lt heart volumes are measured
Tricuspid and Aortic valves
 Assessed for possible tethering of the valve tissue into the defect borders
 TEE used if poor acoustic windows
VSD - IMAGING
 Chest Radiography
 Findings depend on VSD size
 Small VSD – may have normal CXR
 Moderate to large VSD
 Cardiomegaly with LA, LV, RV enlargement
 Enlarged pulmonary arteries
 Increased pulmonary blood flow
 CCF frequent in infants + large defects
 Older children – pulmonary hypertension likely
 Large central pulmonary arteries
 Pruned peripheral pulmonary arterial branches
VSD – CROSS SECTIONAL IMAGING
 Echocardiography usually suf ficient
 Muscular VSDs sometimes detected on routine CT Chest
 MRI
 90% accuracy in VSD detection
 Larger defects seen with
 Spin Echo or
 Double inversion recovery techniques
 Smaller defects seen with
 GE or
 Steady state free precession images
VSD – CROSS SECTIONAL IMAGING
 MRI
 Shunt evaluation
 Cine phase contrast measurements in aorta and pulmonary artery
 Rt + Lt Ventricular stroke volume comparison
 Quantative assessment
 Rt and Lt ventricular function
 Rt and Lt ventricular volumes
 Ejection fractions
 Evaluation for extracardiac vascular anomalies
VSD - IMAGING
 Angiocardiography
 Used to
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Assess pulmonary vascular resistance
Quantify intracardiac shunting
Evaluate for ventricular septal defect anatomy
Evaluate the coronary arteries
Evaluate for associated valvular and vascular anomalies
 Angiocardiography used if echocardiographic evaluation was
insuf ficient or if transcatheter VSD closure is planned
PDA
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5-10% of CHD
1/1600 live births
Twice as common in females
20-30% of prems have PDA
 Often associated with
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VSD
Aortic coarctation
Aortic stenosis
Mitral regurgitation
PDA - ANATOMY
 Persistence of embryologic 6 th aortic arch
 6 th Aortic arch connects Lt pulmonary artery with descending
aorta
 PDA may be on the right with a Rt arch
PDA - ANATOMY
 Ductus Arteriosus / Aorta angle
 Acute angle seen in isolated PDA with pulmonary atresia
 Ductal dependant pulmonary flow
 Obtuse angle seen in Non-ductal dependant pulmonary flow
PDA –PROSTAGLANDINS AND O2
 PG keep the duct patent during foetal life
 At birth blood [O2] rises and [PG] lowers
 Functional ductal constriction
 Complete closure @ 2 months
 Ligamentum arteriosum remains (may calcify)
 In Premature infants closure is delayed due to
 Less sensitive ductal tissue to [O2]
 Respiratory distress – hypoxia -> increased [PG]
 In full term infants
 Rubella
 Asphyxia
 Genetic and environmental causes
PDA - PHYSIOLOGY
 Amount of Lt to Rt shunt dictated by
 Ductal length and diameter
 Degree of pulmonary hypertension
 Untreated PDA leads to Pulmonary vascular obstructive
disease
 Prem with no significant lung disease
 Systolic high frequency murmur
 CCF (large shunt)
 Prem with significant lung disease
 PDA prevalence > 80%
 Almost inaudable murmer
 Dx with echocardiography
PDA - PHYSIOLOGY
 Term infant with small PDA
 Usually asymptomatic
 Murmur present
 Infant with moderate to large PDA
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Continuous machinary like murmur
FTT
Poor feeding
CCF
Irritability
PDA IMAGING
 Echocardiography
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Standard imaging technique
PDA size and diameter
L->R Shunt fraction
Degree of pulmonary hypertension
Can identify complicating factors – ductal aneurysm or calcification
 Chest Radiography
 Premature infants
 Pulmonary oedema
 Cardiomegaly
 +- Associated lung disease
PDA IMAGING
 Chest Radiography
 Term infants
 CXR may be normal
 Term infants with significant shunting
 Cardiomegaly
 Increased pulmonary blood flow
 Consider PDA in a prem infant with
 Increasing granularity of lung fields
 Increasing heart size on serial imaging
PDA - IMAGING
 Chest Radiography
 Prominent ascending aorta and arch
 Helps differentiate ASD and VSD from PDA
 ASD and VSD have a normal aortic arch
 Ductus bump
 Prominence of the descending aorta
PDA - IMAGING
 Cross sectional Imaging
 Reserved for complicated cases to define anatomy
 CT / MRI – ductal size and length
 Cine phase contrast sequences
 Can quantify the amount of flow through the PDA
PDA - IMAGING
 Angiocardiography
 Reserved for cases where significant pulmonary hypertension is
suspected
 Assess
 Pulmonary vascular resistance
 Ductal morphology if transcath
closure planned
ANEURYSM OF THE DUCTUS ARTERIOSUS
(DAA)
 1 .5 – 8.8% of full term infants
 Usually Dx pre-natally or after birth in asymptomatic patients
 Possible association with connective tissue disorders
 Ehlers-Danlos syndrome
DAA - ANATOMY
 Saccular or fusiform dilation of the PDA
 Etiology unknown
 ? Intrinsic weakness of wall of the duct
 ? Delayed closure of aortic side of duct with exposure to systemic
pressures
DAA - IMAGING
 Chest Radiography
 Ductal bump in area of main pulmonary artery and aortic arch
 Echocardiography
 Most oft modality used for Dx
 MRI/CT or Angiography
 Rarely used to confirm the Dx
AORTICO-PULMONARY WINDOW
 Rare – 0.2% CHD
 30-50% associated with other abnormalities
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VSD
ASD
PDA
Tetralogy of Fallot
Interrupted aortic arch
Aortic coarctation
Subaortic stenosis
Anomalous coronary arteries – pulmonary trunk origin
AORTICO-PULMONARY WINDOW ANATOMY
 Incomplete division of the primitive common arterial trunk
 Two distinct semilunar valves
 Large oval communication between ascending aorta and
pulmonary trunk above the aortic valve
AORTICO-PULMONARY WINDOW –MORI
CLASSIFICATION
 Mori type I
 Involves the proximal medial wall of the ascending aorta
 Mori type II
 Involves the distal posterior wall of the ascending aorta
 Mori type III
 Involves the medial and posterior walls of the ascending aorta
AORTICO-PULMONARY WINDOW PHYSIOLOGY
 Large high pressure Lt to Rt shunt
 Presents in 1 st weeks of life
 CCF commonly seen
 Systolic ejection murmur may be heard
 Diastolic murmur – associated pulmonary insuf ficiency
 Bounding pulses frequently encountered
AORTICO-PULMONARY WINDOW IMAGING
 Echocardiography
 Method of choice
 For evaluation of defect anatomy
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Relationship to the aortic and pulmonary valves
To define coronary anatomy
Pulmonary pressure and ventricular function
Other defects
 Chest Radiography
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Mimics PDA on CXR
Cardiomegaly
LA + LV enlargement
Increased pulmonary blood flow
Prominent ascending aorta and pulmonary artery
AORTICO-PULMONARY WINDOW IMAGING
 Cross sectional imaging
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MRI and CT can depict APW anatomy
Used as adjunct to echo
Shunt volume quantification
Ventricular function evaluation
 Angiocardiography
 Confirm Dx if echo questioned
 Used if pulmonary pressures are needed to be determined
 Critical to differentiate from truncus arteriosus (APW has two distinct
semilunar valves)
SUMMARY
 Echocardiography
 Mainstay
 MRI / CT
 Complicated cases
 Also yields good physiological information
 CXR
 Useful for screening
 Angiography
 Complicated lesions
 Usually used where catheter angio intervention is planned
RESOURCES
 Caf fey’s Pediatric Diagnostic Imaging 11 th ed – Slovis
 Classic Imaging Signs of Congenital Cardiovascular
Abnormalities – Ferguson et al - September
2007RadioGraphics, 27, 1323-1334.
 http://www.yale.edu/imaging
Thank you