congenital heart disease with left to right shunt
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
Michael PietersDept. of Diagnostic Radiology Bloemfontein
CONGENITAL HEART DISEASE WITH LEFT TO
RIGHT SHUNT
Classification of congenital heart lesions
Factors that influence lesion presentation
Imaging chain sequence
Left to right Shunt lesions Anatomy Physiology Imaging
OVERVIEW
Shunt lesionsRight heart lesionsLeft heart lesionsAbnormal origin of the great arteries
CLASSIFICATION OF CONGENITAL CARDIAC LESIONS
Age of childSeverity 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 constantRadiographic features and clinical findings change
with time
Classic radiographic features of certain lesions – rarely seen
FACTORS THAT INFLUENCE LESION PRESENTATION
The imaging sequence varies with Age Clinical presentation Type of lesion
EchocardiographyChest RadiographyCTMRIAngiography
IMAGING CHAIN SEQUENCE
ASD
VSD
PDA
Ductus Arteriosus Aneurysm
Aortico-Pulmonary Window
CONGENITAL CARDIAC LEFT TO RIGHT SHUNT LESIONS
Cardiomegaly on CXRAsses pulmonary vascularity - ? IncreasedRead history - ? Acyanotic patient
Ddx: ASD AVSD VSD PDA Aortico-pulmonary window
CARDIOMEGALY
10% of all CHD
Incidence - twice as common in females
Secundum defects – likely genetic cause Holt Oram Familial ASD
ASD
3 Primary typesRelationship 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 ANATOMY
Not true ASD’sDefect 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 – SINUS VENOSUS 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 – CORONARY SINUS SEPTAL DEFECTS
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 – PATENT FORAMEN OVALE
Atrial septum completely absent
Common in visceral heterotaxy syndromes
ASD – COMMON ATRIUM
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 - PHYSIOLOGY
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 – CLINICAL PRESENTATON
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 Dx – flap valve or Saline injection to right heart + Valsalva Rt to Lt shunt on Valsalva TEE
ASD IMAGING - ECHOCARDIOGRAPHY
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 – CHEST RADIOGRAPHY
Angiography Asses haemodynamic consequences of ASD or Used if transcatheter closure is planned
MRI 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 ASDCine phase contrast sequences
Show direction and amount of shunting
ASD – IMAGING
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
ASD – MRI DYNAMIC PERFUSION STUDY
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
PDA (10%) Tetralogy of Fallot (6%) Transposition of the great arteries Double outlet RV Aortic coarctation
AVSD
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: 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 - ANATOMY
Complete AVSD Left to right shunt - related to size of defect and pulmonary
vascular resistanceShunting may be interatrial or interventricularCleft Mitral Valve leads to mitral regurgitation and
CCFPulmonary hypertension develops (more common in
Down’s pts)
AVSD - PHYSIOLOGY
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 PRESENTATION
Echocardiography
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
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
AVSD - IMAGING
20% of all CHD2/1000 Live brithsVSD + complex CHD account for > 50% of CHDMost 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 Tetralogy of Fallot Truncus arteriosus ASD Coarctation of the aorta Tricuspid atresia Transposition of the great arteries Double outlet RV
VSD
4 Components of the ventricular septum 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 - ANATOMY
Physiologic effect 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 - PHYSIOLOGY
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 2nd heart sound
Significant shunt Failure to thrive Dyspnoea CCF Irreversable pulmonary vascular obstructive disease Shunt reversal
VSD - SYMPTOMS
Echocardiography 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 - IMAGING
Echocardiography usually sufficientMuscular 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 – CROSS SECTIONAL IMAGING
Angiocardiography
Used to 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 insufficient or if transcatheter VSD closure is planned
VSD - IMAGING
5-10% of CHD1/1600 live birthsTwice as common in females20-30% of prems have PDA
Often associated with VSD Aortic coarctation Aortic stenosis Mitral regurgitation
PDA
Persistence of embryologic 6 th aortic arch6 th Aortic arch connects Lt pulmonary artery with
descending aortaPDA 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 - ANATOMY
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 –PROSTAGLANDINS AND O2
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 Continuous machinary like murmur FTT Poor feeding CCF Irritability
PDA - PHYSIOLOGY
Echocardiography 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
PDA - IMAGING
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
ANEURYSM OF THE DUCTUS ARTERIOSUS (DAA)
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 - ANATOMY
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
DAA - IMAGING
Rare – 0.2% CHD30-50% associated with other abnormalities
VSD ASD PDA Tetralogy of Fallot Interrupted aortic arch Aortic coarctation Subaortic stenosis Anomalous coronary arteries – pulmonary trunk origin
AORTICO-PULMONARY WINDOW
Incomplete division of the primitive common arterial trunk
Two distinct semilunar valvesLarge oval communication between ascending aorta
and pulmonary trunk above the aortic valve
AORTICO-PULMONARY WINDOW -ANATOMY
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 –MORI CLASSIFICATION
Large high pressure Lt to Rt shunt
Presents in 1st weeks of life
CCF commonly seen
Systolic ejection murmur may be heard
Diastolic murmur – associated pulmonary insufficiency
Bounding pulses frequently encountered
AORTICO-PULMONARY WINDOW - PHYSIOLOGY
Echocardiography Method of choice For evaluation of defect anatomy
Relationship to the aortic and pulmonary valves To define coronary anatomy Pulmonary pressure and ventricular function Other defects
Chest Radiography 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 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)
AORTICO-PULMONARY WINDOW - IMAGING
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
SUMMARY
Caffey’s Pediatric Diagnostic Imaging 11 th ed – SlovisClassic Imaging Signs of Congenital
Cardiovascular Abnormalities – Ferguson et al - September 2007RadioGraphics, 27, 1323-1334.
http://www.yale.edu/imaging
Thank you
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