transposition of great_arteries

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TRANSPOSITION OF GREAT ARTERIES

Dr amarja sachin nagre MD,DM,FCA


D-TGA first described by MATHEW BAILLIE

1797.Farre coined the word TRANSPOSITION in

1814 (Trans : Across, ponere : to place)Van Praagh & co-workers introduced terms Concordant & Discordant 1971.Clinical description-Fanconi in 1932 & Taussig in 1938

HISTORY


DEFINITIONDefined as Congenital Cardiac Anomaly in which Aorta arises from the morphologic R.V. and pulmonary trunk from morphologic L.V. (Atrio-ventricular concordance with Ventriculo-arterial disconcordance)


• D Transposition - Classic complete TGA in which Aorta is located anteriorly and to the right of PA.

• L Transposition – When aorta is located to the left of the PA.


EMBRYOLOGY Theory of CONAL INVERSION is most accepted Normally sub-aortic portion of conus is absorbed & sub-

pulmonic persists moves anteriorly to connect RV to PA. In TGA> sub-aortic persists which brings aorta anterior

to be connected to RV,at the same time sub-pulmonic is absorbed –pulmonary valve remains posterior in continuity to mitral valve.


INCIDENCE

5-8% of CONGENITAL HEART DISEASES.1 in 2300 - 1 in 5100 LIVE BIRTHSMale Preponderance ratio of 4:1Association of Extracardiac anomalies <10%Increased prevalence in Diabetic mother & Prenatal sex hormone therapy.

More common in later pregnancies


PATHOPHYSIOLOGY


Simple TGA- when TGA pts have intact ventricular septum & no other significant associated lesions

Complex TGA- TGA with other associated lesions like large VSD, large PDA, LVOTO,hypoplasia of RV,pulmonary or tricuspid Artesia.


CO-EXISTING ANOMALIESPFO/PDA - 50%.VSD-40% - small, large & multiple.VSD+LVOTO -5-10%.LVOTO-5%.Functional TV & MV anomalies 4%.Bronchopulmonary collaterals 30%.CoA, Arch interruption & hypoplasia 5%.


TGA – PHYSIOLOGICAL –CLINICAL CLASSIFICATION

I. TGA – (IVS or Small VSD)II. TGA – (VSD Large) III. TGA (VSD & LVOTO), with Restricted PBFIV. TGA (VSD & PVOD), with Restricted PBF


INTERCIRCULATORY MIXING

ANATOMY PBF IC MIXING

TGV + IVS INCREASE LESS

TGV + IVS + ASD/ PDA INCREASE MORE

TGV + VSD INCREASE MORE

TGV + VSD + LVOTO DECREASE LESS

TGV + PVOD DECREASE LESS


LVOTO• DYNAMIC – not at birth -develops after few wks -degree varies spontaneously• Decrease PVR – decrease LV sys pres - but RV pres high to

cause syst movement of septum into LV

• Systolic anterior motion of AML – venturi effect


LVOTOFIXED-

Fibrous ridge / membrane

Valvular Stenosis --Annular Hyperplasia Accessory mitral leaflet tissue Leftward/posterior deviation of infundibular septum


CORONARY PATTERN Important in planning arterial switch

The morphologic RCA-concordant-morph RV morphologic LCA-concordant-morph LV

Left and post aortic sinus-face RVOT right- does not Dual sinus origin-90%-lf sinus –LMCA-LAD/LCX post sinus--RCA Single sinus origin-both coronaries arise from

one facing sinus


CLINICAL FEATURES HISTORY M:F:::4:1

More common in multiple pregnancies

Neonates- normal to large birth weights


MODES OF CLINICAL PRESENTATION

Predominantly Cyanosis (poor inter circulatory mixing) -TGA with IVS & no significant ASD.

CCF (good inter-circulatory mixing)- TGA with large VSD.

Asymptomatic (balanced mixing)- TGA with VSD or adequate sized ASD.


TGA/IVS – Cyanosis 1st day of life TGA/nonrestrictive VSD or large PDA – Mild Cyanosis

CHF in 3 – 6 weeks. TGA/VSD/PVOD – Progressive Cyanosis. Infants may have necrotizing enterocolitis-

reduced mesenteric circulation. Cerebral infarct & brain abscess can occur.


SIGNS S1- Normal S2-loud & single A2- palpable at the left base. Pulmonary arterial impulse is absent.


Contd… TGA with LVOTO—Ejection systolic murmur

VSD murmur is absent at birth, appears after pulmonary vascular resistance falls. Later murmur disappears when pulmonary vascular resistance is high.

Murmur of fixed LVOTO present at birth, best heard at mid-left sternal border- sub pulmonary obstruction- radiate upward & to right.

Large PDA-systolic murmur (flow from aorta to PA occurs in systole)


DIFFERENTIAL DIAGNOSIS• Pulm atresia with IVS • TOF with absent pulm valve• TOF with pulm atresia• TAPVC• Tricuspid atresia• Truncus arteriosus


RADIOLOGICAL FEATURES

Oval / egg shaped cardiac silhouette with narrow superior mediastinum {egg on string appearance} Mild cardiomegaly

Increased pulmonary vascular markings.


ELECTROCARDIOGRAM

RAD, RVH-TGA with IVS or restrictive VSD

Biventricular hypertrophy- Large VSD with low pulmonary vascular résistance with volume overload of LV.

LAD –TGA with AV canal type VSD


ECHOCARDIOGRAPHY• To demonstrate atrio-ventriculo , ventriculo- arterial relation

Parasternal short axis- cup/ saucer appearance TGA- double barrel gun

• Diagnose VSD, LVOTO

• Coronary anatomy –see for anterior ,posterior double looping - origin from single /2 ostia• If 2 ostia and ant loop-LAD : RCA 2 ostia and post loop- LCX : RCA 1 ostium and 1 loop – all 3 : RCA • If coronaries - intramural


Cardiac Catheterization Coronary Artery Anomaly. VSD,PAP, Pulm vascular resistance & aortic arch

abnormality.

Therapeutic (Balloon atrial septostomy)

C T Angiography preferred.


Management of TGA

MEDICALSURGICAL


Palliative Rashkind balloon atrial septostomy. Blalock-Hanlon operation. Prostaglandin E1 -0.05-0.1mcg/kg/min


ATRIAL balloon septostomyWilliam Rashkind & William Miller 1966

Indications• D-TGA• TAPVC with restrictive ASD• Tricuspid atresia with restrictive ASD• Pulmonary atresia with intact IVS• Mitral atresia• Pulmonary HTN.


Technique

• Balloon is placed in LA – bobbing movement of balloon over mitral valve

• Inflate till movement is lost


Technique• Pull backward• Interatrial septum gets displaced towards

IVC• Primum septum ruptures• Immediately move the catheter cranially

with deflation


success• Inflated at lower volume -balloon should

easily pass• HR & BP improve• Decrease in cyanosis• Loss gradient across atria• ASD at least 5-6 mm


complications• Atrial arrythmias• Perforation of IVC ,pulmonary veins ,atria• Air embolism• Cardiac arrest• Procedure failure. 12%• Mortality 10-30%


Other methods• Echoguided BAS• Blade BAS• Parks blade • Amplatzer fenestrated device for ASD


SURGICAL MANAGEMENTATRIAL LEVEL• SENNING OPERATION• MUSTARD OPERATION

VENTRICULAR LEVEL• RASTELLI OPERATION

GREAT ARTERY LEVEL • ARTERIAL SWITCH OPERATION


Sennings operationIt uses atrial septal flap and

the RA free wall to redirect the pulmonary and systemic venous returns at the atrial level.

First performed in 1958 by Senning.


Mustard operationRedirecting pulmonary and

systemic venous return at the atrial level by using either a pericardial or a prosthetic baffle.

First done in 1964.


Complications of atrial switch

• SVC obstruction < 5%.• IVC obstruction 1%• Pulm Venous obstruction < 5%.• Residual intra atrial baffle-shunt <

20%.• Leaks 1-2%• Arrythmias >50%, SVT.,sick sinus

syndrome• RV depression.• Sudden death.• PVOD• TV regurgitation


RV FAILURE• 2-15%• Echo 40% RV dysfunction• Causes –• Morphology of RV [RT ventriculotomy]• Infundibulum - akinetic• Myocardial ischaemia & hypokinetic segments• Septum bulging to RV


Surgery at the ventricular levelRastelli Procedure

Done in patients of TGA with VSD-PS or LVOTO.

First performed in 1969. An intraventricular tunnel is created

between VSD and aortic valve, and a conduit is placed between RV and PA (homograft/heterograft).


RASTELLI OPERATION


Complications of Rastelli

• Mortality 20-30% • two year survival 92%• Conduit obstruction.• Needs a re-operation as child grows.• Intervention-relieve RVOTO/LVOTO• Myocardial dysfunction


Great Artery level

ARTERIAL SWITCH OPERATION• First done by Jatene in 1975.

• The coronary arteries are transplanted to the PA, and the proximal great arteries are connected to the distal end of the other great artery.


challenge

• Functional adequacy of LV • Dynamic LVOTO• Delayed decrease of PA pressure


• One stage procedure (in first few weeks of life)

• Two stage procedure -pulmonary artery banding + ASO


Arterial Switch

Lecompte procedure


Arterial Switch


ARTERIAL SWITCH MORTALITY

• Simple TGA 5% to 15%• Complex 10 % to 20%• Survival rates (Kirklin & Barrat Boyes)

85% 5yrs & 81% 9 yrs


Complications of arterial switch• Kinking & obstruction of coronary arteries- myocardial ishaemia • Haemorrhage at suture lines• May require graft• Asymtomatic ischaemia• Perfusion defects are common• Low C.O. state


Supravalvular pulmonary stenosis

(5-30%) Inadequate growth of PAStenosis at suture lineTension on anastomosis siteMalaligned RVOT to MPA


Supravalvular aortic stenosis • Seen in < 5%• Coarctation of neoaorta• Tubular hypoplasia / kinking of transverse

arch• Enlargement of neoaorta to see in follow

up• Neoaortic regurgitation 50 % but always

mild.


CPB in Switch• CPB at 18-25 deg C

• High degree of myocardial & cerebral ischaemia

• Necrotizing enterocolitis• Renal failure.


Damus-Kaye-Stensel operation• In patients with TGA – VSD – RVOTO –

Damus-Kaye-Stensel operation.• MPA is transected near its bifurcation and

proximal MPA is anastomosed to ascending aorta end to side & LV to aorta continuity is established.

• RV-PA valved conduit.• VSD is closed to direct the flow from LV to

native pulmonary ( neoaortic valve)


Contd…• Suitable for pts abnormal coronary

anatomy• Aortic regurgitation is common• Suitable for taussig bing type


REV- Reparation a L’etage Ventriculaire Procedure

• Alternative to ASO – TGA/VSD RASTELLI- TGA/VSD/LVOTO

• Adv- Coronary reimplantation valved conduit not required

• Procedure - VSD patch for LV to aorta continuity. PA transected, distal segment reanastomosed to RV –RV to PA continuity.


PLAN THE PROCEDURE• TGA/IVS – ASO -age< 4 wks – L V regresses

• TGA/VSD- ASO + VSD closure -if coronaries unfavourable- Rastelli-age-better conduit placement -if CCF – PA banding to restrict PBF• TGA/VSD/LVOTO-ASO not as LVOTO -Rastelli done


CONTD…

TGA/VSD/PVOD- Surg may not be appropriate if PVR is high


Anaesthetic Goals• Maintain HR, Contractility,Preload C.O.• Maintain Ductal patency.• Avoid increase in PVR• Avoid decrease in SVR.• Avoid hypoxaemia, hypercarbia,acidosis.


Pre-anaesthetic Considerations In Pts with decreased PBF & poor mixing,

PVR decreased by • 1) Nitric oxide inhalation• 2) Prostacyclin nebulization• 3) IV Sildenafil• 4) Ventilatory interventions. -Fio2 - increase -Pco2 – 25-35 mmHg -pH – 7.5 -7.56


Pre-anaesthetic Considerations

• Pts with Hct > 65 % --- Maintain hydration.

• Chronic cyanotic pts. --- Coagulopathies.


Pre-anaesthetic Preparations• PGE1 Infusion• Ballon atrial Septostomy.• Mechanical Ventilation• Medications – Inotropes- Digoxin Diuretics- Furosemide Antibiotics • ECMO


PGE1 (Alprostadil)• Direct vasodilator - PG receptor• Selectively dilates Ductus arteriosus• Metabolised – lung enzymes so less

systemic vasodilatation• Disadv– syst vasodilatation-hypotension

apnea seizures fever expensive platelet dysfunction


• INDICATION- cyanotic CHD-dec PBF severe P’ HTN• Dosage-- 0.05 to 0.1 to max 0.4 µg/kg/m

• PGI -2 - (EPOPROSTENOL) - long term pulm HTN


NITRIC- OXIDE• Vasoactive gas– L’ arginine in endothelial cells• M/A- diffuses to vascular smooth muscles increases c GMP decreases Ca++• PVR– decreased• SVR – no change• OFFSET - ½ life – 6 sec binds to heme –methHb


• ADV- Selective pulm vasodilator No systemic actions Improves V/Q • DISADV- NO2 –P’ edema methHbnemia ciliary depletion corrosive to metal


• USES- P’ HTN ARDS• Therapeutic conc- 0.05-80 ppm• Onset- 1-2 min• Available-prediluted in Nitrogen• Not allowed to contact air,O2


Anaesthetic Management• Monitoring - Blood Gas ,Electrolytes ECG, pulse-oximeter ETCO2,CVP IBP,Temperature,TEE • Induction - Opoids – Hemodynamic stability No myocardial depression Blunt reactive P HTN


• Dosage – Fentanyl – 5-25 -100mcg/kg Sufentanil-0.5-2.5-10mcg/kg• Isoflurane/Sevoflurane• Benzodiazepine – Midazolam• Pancuronium -0.1mg/kg [Vagolytic]• Ketamine +Glycopyrrolate• Avoid injecting air alongwith


PostOperative Concern• ASO BleedingMyocardial ischemia.Low C. O. state

• Rastelli procedureRV dysfunction


THANK YOU

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