Ebstein’s anomaly & Truncus Arteriosus

Ebstein’s Anomaly &

Truncus Arteriosus Dr Tarun Bhatnagar

Consultant AnaesthesiologistNarayana Hrudayalaya, Ahmedabad

dr.tarunbhatnagar@yahoo.co.in

Ebstein’s Anomaly

First described by Dr William Ebstein in 1866

Rare disease, accounts for 0.5% of cases of CHDs

Ch by maldevelopment of of tricuspid valve

Aetiology ?? maternal Lithium ingestion

Associated with Cyanotic congenital heart diseases

Atrial septal defect (ASD)

Cases of severe right heart failure

Isolated severe tricuspid regurgitation

L-transposition of the great vessels

WPW /Preexcitation Syndrome

Ebstein’s Anomaly Wide spectrum of anatomic

malformation

Wide spectrum of clinical presentation

Fetus- HydropsNeonate- Severe cyanosis with circulatory collapseChild- Mild cyanosisAdult- Minimal or no symptoms

Maldevelopment of Tricuspid Valve Embryologically, TV is normally formed by

delamination or exfoliation of inner layer of RV myocardium up towards the tricuspid annulus

If this process is arrested or incomplete, the attachments of the leaflets are apically displaced

Anatomy

Characteristic features The septal & posterior leaflets are displaced

downwards or apically into the RV and are dysplastic

Anterior leaflet is, large, redundant (sail-like), undisplaced & attached to the ventricular free wall rather than to the papillary muscles

Atrialized RV (ARV)- proximal inlet portion of the RV that is above the displaced leaflets but below the annulus

Functional RV (FRV)- remaining part of RV that lies below the displaced TV & is much smaller than usual

Anatomy

Anatomy

Anatomy

The predominant clinical finding is tricuspid insufficiency or regurgitation that leads to Severe cyanosis due to

Dilated RA with R→L shunting thru an interatrial communication (ASD or PFO)

Inadequate function of Distal RV - In severe cases the RV can’t develop adequate force to open the pulmonary valve (Functional Pulmonary Atresia)

Compromised LV filling by the dilated RV

Other causes of cyanosis due to ↓ Antegrade PBF

Anatomic pulmonary stenosis or atresia

Subpulmonary Obstruction due to abnormal TV tissue

Elevated PVR of neonatal period

Pathophysiology

Neonates Cyanosis is the most common presentation in infancy Cyanosis alone can improve by normal postnatal ↓ in PVR

or by conservative management Neonates with severe TR- present with Cyanosis ,CHF ,

Metabolic acidosis or Supraventricular tachyarrythmias High Mortality rate in the neonatal group (20%)

Older children DOE, fatigueability consistent with CHF Supraventricular Tachyarrythmias Neurological complications- CVA , Brain abscess Infective Endocarditis LV Dysfunction secondary to RV dilatation

Clinical course

Physical Examination CXR ECG Echo Cardiac Cath

Preop Evaluation

Cyanosis Active precordium Regurgitant holosystolic murmur Widely split S2 Gallop rhythm

Physical Examination

CXR Massive

Cardiomegaly due to enlarged right atrium

Decreased pulmonary vasculature

Small aortic root and main pulmonary artery shadow

Twelve-lead ECG

RAD +Abnormal largeP waves consistent with right atrial enlargement – “Himalayan P waves”

PR interval ◦ Commonly prolonged ◦ May be normal or short in patients with WPW syndrome

QRS complex ◦ RBBB

Rhythm◦ Paroxysmal SVT, atrial flutter, atrial fibrillation,

ventricular tachycardia

Echocardiogram Two-dimensional

◦ Displaced Septal & Posterior leaflet & the redundant

anterior leaflet are easily seen

◦ Apical displacement of the septal leaflet of greater than 8

mm/m2 - Most specific sign.

◦ Eccentric leaflet coaptation.

◦ Dilated right atrium.

◦ Delayed closure of tricuspid valve leaflet.

◦ Various left heart structural abnormalities

Color flow Doppler studies

◦ Varying degrees of tricuspid regurgitation

◦ R-L atrial shunting

◦ Status of pulmonary blood flow

No longer required to make/confirm the diagnosis

The most diagnostic characteristic- Typical atrial pressure & ventricular intracardiac ECG in the atrialized portion of the RV

Elevated RAP R-L atrial shunting with systemic

desaturation Elevated RVEDP

Cardiac Cath

Hypoxia & Acidosis cause pulmonary vasoconstriction !!

while

Hyperoxia & Alkosis causes pulmonary vasodilatation !!

Preop Mx of Critically ill neonates & infants

Measures to reduce PVR-Mechanical Ventilation -High FiO2/ Hyperventillation /PEEP-Sedation +Paralysis –avoids reflex ↑ in PVR secondary to noxious stimuli-Alkalosis-pulmonary vasodilator /pH7.50-7.60/ sodabicarb or THAM-Inhaled NO-starting dose 5-40ppm

PGE1 infusion- to keep the ductus arteriosus patent & maintain the pulmonary blood flow

Correction of Metabolic Acidosis –improves myocardial function

Inotropes- Avoid Adrenaline as far as possible as it ↑es PVR

Avoid Overzealous Volume Infusions-can cause further annular dilatation –worsen the TR

Preop Mx of Critically ill neonates & infants

Indications Severe cyanosis(spO2< 80%) CHF Intractable Arrythmias due to accessory AV

pathway Cardiomegaly (CTR ratio>0.65 on CXR) Paradoxical embolism

Surgery

Surgical Options

Critically ill neonates

Aortopulmonary Shunt

Palliative Sx ECMO Ortho topic Cardiac

Transplantation

Non critical older children

ASD closure

Tricuspid Valvuloplasty /Replacement

Fontan Operation

In neonates with severe Ebstein anomaly, the functional RV is hypoplastic, and the patient is usually best treated by closing the TVand creating a tricuspid atresia physiology (Starnes procedure)

This strategy commits the neonates for future single ventricle palliations like BDG or Fontan

Plication of Rt atrial tissue +

Atrial Septectomy +

Patch closure of tricuspid annulus (surgically creating tricuspid atresia)

+ Insertion of Aortopulmonary shunt

Palliative Sx

Indication: Mild- Moderate Tricuspid insufficiency where chordae & papillary muscles are intact

Median sternotomy/CPB

Surgery-Patch closure of ASD/PFO +-Plication of Atrialized RV +-Plastic repair of TV+-Posterior tricuspid annuloplasty+-Rt atrial redundant tissue excision+-Correction of any associated anomalies(PS / division of accessory conduction pathways)

Tricuspid Valvuloplasty

Tricuspid valve replacement Indication

Complete failure of formation of TV with no chordae or papillary muscles

Disadvantage-Higher incidence of complications-High chances of Redo TVR (pts growth)

Major Concerns↓CO, R→L shunting with cyanosis, Atrial tachyarrythmias

Anaesthetic GoalsMinimizing PVR, Optimizing RV preload, Maintain RV contractility to optimize PBF

Continue PGE1 infusion untill the completion of Aortopulmonary shunt

InductionPrimary Narcotic based technique+ Pancuronium

Atrial tachyarrythmias RxExternal Cardioversion-0.5J/kg in hemodynamically unstable ptsAdenosine 0.1mg/kg for PSVT

MonitoringInvasive Arterial & CVP Atrial & Ventricular pacing wires

Anaesthetic Considerations

Low CO Pulmonary insufficiency Residual TR Dysrhythmias-PSVT, VT,VF, Heart

Block

Postop Problems

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364415_NITHAN_20111007_140427_0011.AVI

Truncus Arteriosus

Uncommon lesion, 1.4% CHDs Ch by single arterial trunk arising from

both ventricles due to the failure of truncus arteriosus to divide into the Aorta & PA

Commonly assoc with a VSD & Coronary anomalies

Most infants present with CHF during the first 2 weeks; 85% of untreated children die by 1 year of age.

Truncus Arteriosus

Truncus Arteriosus

Truncal valve

VSD

Embryology

Classification & Anatomy

Collet & Edwards Classification-Type I

Collet & Edwards Classification-Type II

Collet & Edwards Classification-Type III

Collet & Edwards Classification-Type IV

Truncus-Longer than normal aorta-Overrides the ventricular septum more towards RV-The Coronaries & one or two PAs arise from it-Branch PA stenosis when present protect pul vasculature from pulmonary overcirculation & pulmonary vascular disease

Truncal Valve-Dysmorphic, stenotic, regurgitant-Tricuspid(60-70%), quadrcuspid(25%), bicuspid(5%)

Coronary artery Anomalies(50%)Clinically imp variations are-High origin of LCA: makes it vulnerable to surgical injury when explanting the PAs)- Large infundibulae or anterior descending artery crossing the RVOT making it vulnerable at the time of RVOT conduit placement

VSD- large, lies immediately beneath the truncal valve

Anatomy

Aortic Coarctation Type B interrupted Aortic Arch Persistent LSVC ASDs Digeorge Syndrome

Associated Anomalies

Pathophysiology

Pulmonary Over circulation

Coronary Ischemia

After the 1st/2nd wk of life PVR falls →Qp/Qs >1

↓ Pulmonary Overcirculation

↓ Volume Overload (LV) + Pressure

Overload (RV)

↓ CHF ↑ Truncal Valve Insufficiency

Pulmonary Circulation Runoff during diastole

↓ Low systemic diastolic

pressure ↓ Low coronary perfusion

pressure ↓ Coronary Ischemia &

Impaired myocardial function

Pulmonary Overcirculation

Progressive Pulmonary Vascular Disease

Lethal Increase in PVR as early as 3rd mth of age

Pathophysiology

Physical Examination S/s of CHF : tachycardia, tachypnea,

irritability, poor feeding, recurrent pulmonary infections

Jerky collapsing arterial pulse Systolic thrill over LSB Loud Ejection Click & holosystolic murmur Early diastolic murmur – if truncal valve

insufficiency present

Preop Evaluation

CXRCardiomegaly, ↑ Pulmonary vascular markings

ECGBVH

Echo- diagnostic-Single great artery with a semilunar valve that overrides the ventricular septum & is continuity with the mitral valve-Enlarged LA-Origins of PAs -Conotruncal VSD -Competence of truncal valve- Caliber of aortic arch

Cardiac Cath- Indicated in older infants with significant PVD-Type IV truncus to delineate MAPCAs & PA anatomy- SaO2<84% indicates significant PVD the child may not tolerate the operative correction

Sx is recommended within the first 2 mths of life as PVD develops by 3-6 mths of age

Infants with CHF are mx by fluid restriction, diuretics , digitalis & afterload reduction

Infants with persistent severe CHF- Complete repair immediately

Surgery is not recommended-Fixed PVD with PVR > 8 Woodunits/m2

Surgery is recommended -Reactive PVD responding to O2 & hyperventillation

Timing of Surgery

Airway abnormalities-Small mouth, micrognathia: Difficult Intubation

CHF-occur due to torrential PBF that can be exacerbated by hyperoxia & hypocapnia-FiO2 of 0.21 + Ventilatory adjustment to maintain SaO2 of 85-95% & pCO2 of 40mmHg is desirable

-Afterload reduction (Milrinone) may improve Systemic CO & reduce PBF

Myocardial Ischemia- can occur before & after induction of anaesthesia

-↑ myocardial wall tension on LV due to volume overload ↑ diastolic runoff to pulmonary circulation

- Mx by Temporary PA banding followed by Complete repair once BP & ECG settles

Anaesthetic Considerations

CPB-Deep Hypothermia-Cardioplegic arrest The PAs are removed from the truncus- site is

oversewn with a running suture VSD is closed allowing the LV to eject thru the

truncal valve to the aorta A valved conduit (cryopreserved valved

pulmonary or aortic homograft) is placed from the RV into the distal main PA

Moderate truncal insufficiency –Valve repair+ commissural annuloplasty

Severe truncal insufficiency- Valve replacement

Surgical Technique- Repair of Truncus

Operative technique for type I truncus arteriosus.

Operative technique for types II and III truncus arteriosus

Pulmonary Hypertensive Crisis-Commonly occur in 3-6 mths old infants after truncus repair-Ch by hypotension, bradycardia & cyanosis-Triggered by hypoxia , hypercapnia, acidosis, pain airway stimulation ,LVF- Rule out Large residual VSD before medical mx- Mx by Mechanical ventilation/NMB/Sedation- Refactory cases-ECMO

Low Cardiac OutputCauses: RV failure (m/c) due to Rt ventriculotomy & wide swings in PVR Others -Truncal valve insufficiency, inadequate myocardial protection , Coronary artery compression- Mx by optimizing preload, Adjusting ventilation to reduce airway pressures, Inotropes/Inodilator

Major Late Complication – Obstruction or Stenosis of Conduit

Postop Problems

Early Truncus repair (within 6 wks) at University of California Sanfrancisco (UCFS) have achieved 86% survival in their series of 244 pts since1975

All children were followed carefully to watch for the development of complications

Outcome

Thanks