Tetralogy of Fallot - Case Presentation

Dr Bhagirath S N

TETRALOGY OF FALLOT

CASE PRESENTATION

• Name- deepak

• Age – 4 years

• Informant- mother

• Place- Bihar

Presenting complaints

• Bluish discolouration of lips since 1 month of age

• Breathlessness on exertion since 6 months of age

• H/o present illness

• Asymptomatic in the first month of life

• Gradual, bluish discolouration of lips and skin worsens with crying and

suckling.

• H/o episodes of increasing bluish discolouration and rapid breathing on

exertion (playing, excess crying) since 2-3 months of age

• h/o episodes of loss of consciousness before which child becomes limp. 5 -6

episodes per month during exertion.

• Episodes lasted for 3-5 minutes

• Resolved with squatting posture or on calming by mother

• increased frequency of such episodes over last 1 year

• H/o breathlessness on exertion x last 1½ years NYHA II

Ordinary activity like playing with other children, climbing stairs

cause shortness of breath .Relieved on taking rest

• No H/o frequent respiratory tract infections

• No H/o feeding difficulties

• No H/o fever, headache, vomiting, convulsions, lethargy or focal

motor weakness

• No H/o headache, dizziness, blurred vision, somnolence, fatigue,

paresthesia of fingers, toes, lips

Treatment history

• No history of previous surgery

• Receiving T. propranolol (10 mg) OD x last 6 months (irregular)

Birth history

• Full term normal delivery

• Birth weight 2.3 kg

• No significant maternal illness in antenatal period

• No h/o bluish discolouration/jaundice/cyanosis in the neonatal period

• Skeletal abnormalities like

• 6 fingers in (R) hand

• 4 fingers in (L) hand, noticed since birth

• No other obvious deformity noticed since birth

Developmental history

• Developmental milestones attained within normal limits

Family history

• No history of similar complaints in the family

7 years 4 years

PHYSICAL EXAMINATION

General physical examination

• Weight – 10 kg

• Height – 95 cm

• Afebrile

• Pallor – Nil

• Cyanosis – (+), (lips, tongue, fingers)

• Icterus – Nil

• Clubbing – (+) 3°

• Oedema – Nil

• Lymphadenopathy – Nil

• Neck veins – not engorged

• Pulse – 88/min, regular, no radio-radial or radio femoral

delay

• All peripheral pulses palpable

• BP – 84/60 mmHg (left arm, supine position)

• Peripheral venous access – adequate

• Room air saturation calm child 82%

CARDIOVASCULAR SYSTEM

Inspection

• Precordium normal on inspection

• No visible apical impulse

• No visible pulsation

• No scar mark visible

• Parasternal heave

Palpation

• Apex

• Palpable at (L) 4th ICS, 1 cm lateral to the mid-clavicular line

• Thrill palpable at (L) 2nd and 3rd intercostal space along the sternal border

Auscultation

• S1, S2 audible

• Systolic murmur, grade IV, best heard at left upper sternal border harsh in

quality. Not radiating to back/axilla

Respiratory system

• No chest wall deformity on inspection

• Respiratory rate 20/min,

• regular, accessory muscles not working

• Auscultation:

• B/L air entry equal

• No added sounds

Central nervous system

• Higher functions – normal

• Cranial nerves, cerebellum, motor and sensory examination – within normal

limits

Airway assessment

• Mouth opening > 4 cm

• Neck movement adequate

• MP class I

• No facial deformity noted

Spine examination

• No abnormality detected

Provisional diagnosis

• Cyanotic congenital heart disease with no evidence of infective

endocarditis or congestive cardiac failure in sinus rhythm.

Investigations

• Hb – 16.4

• TLC – 8,900

• Na+/K+ - 139/4.4meq

• Urea – 42mg/dl

• Creatinine- 0.8mg/dl

• Bd. group B (+ve)

CXR:

• Heart size – (N)

• RV type apex

• Pulmonary vascularity ¯

ECG

• RAD

• 100/min, regular

RV apex

Pulmonaryoligaemia

Echo

• Severe infundibular + valvular PS

• Confluent good sized pulmonary arteries

• Large VSD with aortic override (perimembranous,

R L)

• No ASD, coarctation of aorta, PDA

• (N) RV/LV function

Impression

• CCHD, ¯ pulmonary blood flow, confluent good sized pulmonary

arteries.TOF

CYANOTIC CONGENITAL HEART

DISEASE

ÉTIENNE-LOUIS ARTHUR FALLOT!

• a French physician, 1888 Fallot

accurately described in detail the

four anatomical characteristics of

tetralogy of Fallot. …’la maladie

bleue

• First anatomic description…Danish

anatomist Niels Stensen, in 1672...

• Prevalence … 0.26 to 0.48 per 1,000 live births

• Genes identified : NKX2.5, [4%]; JAG1 in Alagille syndrome.; TBX5 in

Holt-Oram syndrome.

• Syndromes - DiGeorge/Velocardiofacial syndrome, Down syndrome,

Alagille syndrome, cat's-eye syndrome, recombinant chromosome (or San

Luis Valley) and Kabuki syndromes, and CHARGE and VATER/VACTERL

associations.

• Microdeletion on 22q11….seen in 15–35% of TOF patients;

• Sibling recurrence rate …2.5% to 3%

• Environmental factors

• maternal diabetes retinoic acids, maternal phenylketonuria

Developmental abnormality

Defective embryonic neural crest migration abnormal conotruncal

development.

• Incomplete rotation and faulty partitioning of the conotruncus during

septation….

• Malrotation of truncal-bulbar ridges results in misalignment of the outlet

and trabecular septum and consequent straddling of the aorta over the

malaligned VSD.

• Abnormally anterior septation of the conotruncus by the bulbotruncal

ridgessubpulmonic obstruction

• Tetrad …right ventricular outflow obstruction, aortic override, ventricular

septal defect, and right ventricular hypertrophy

PS

Most characteristic …. subpulmonic stenosis

• Obstruction along the entire course of the RVOT and pulmonary arteries

(LPA commonly) can occur.

• more severe the proximal obstruction, the greater the likelihood of distal

areas of obstruction

• Obstruction within the RV body :

• 1)hypertrophy of the septoparietal muscle bundles ;

• 2)anatomic displacement of the normal moderator band attachment

Pulm valve….bicuspid in 40%

VSD : nonrestrictive…..Few ptsVSD restrictive d/t the accessory TV

prolapsing thru the defect

Coronary Anomalies

• LAD from RCA (5%) & coursing in front of infund (Sx imp)

• Single coronary (4%)

So coronary evaluation before Sx imp -

• Echo….proximal coronary

• If needed … root angio / CAG….. MRI/CT

• Right Aortic A in 25%......Twice more common in TOF+PA

• Aortopulmonary Collateral Arteries..

• Stenosis of LPA in 40%

Associated cardiac abnormalities

• PFO or a true atrial defect in 83% of hearts with TOF… AVSD

(downs)…LSVC(11%)

• TOF with Absence of PA…almost always LPA….PS murmur radiates

to Rt chest…CXR..Lt hemithorax small,Lt lung hypovasc, Lt

hemidiaphragm elevated

Tetralogy OF Fallot

• Most common cyanotic heart disease!

• components

75%!

TOF

4 component!

Imagine this is a HEART!

TOF

1) Vetricular Septal Defect

TOF


2) Pulmonic Stenosis

TOF



3) Overriding of dextroposed aorta

TOF




4) Right Ventricular hypertrophy

TOF





Concentric R ventricular hypertrophy without cardiac enlargement

TOF





Concentric R ventricular hypertrophy without cardiac enlargement

Increase in right ventricular pressure*

RV and LV pressures becomes identical


There is little or no L to R shunt



Hence, VSD is silent



Hence, VSD is silent

Right ventricle into pulmonary artery across pulmonic stenosisproducing ejection systolic murmur

Hence, the more severe the pulmonary stenosis


The BIGGER the Left to RIGHT shunt



Less flow into the pulmonary artery




Shorter the ejection systolic murmur




Shorter the ejection systolic murmur

More cyanosis because of less flow to the lung!

Hence,

• Severity of cyanosis is directly proportional to the severity of pulmonic

stenosis

• Intensity of the systolic murmur is inversely related to the severity of

pulmonic stenosis

Congestive failure never occurs* because…

Right ventricle is effectively decompressed because of the ventricular septal

defect.

* exception

Congestive failure never occur* because…

Right ventricle is effectively decompressed because of the ventricular septal

defect.

* exception

1)Anemia2)Infective Endocarditis3)Systemic hypertension4)Unrelated myocarditis

complicating TOF5)Aortic or pulmonary valve

regurgitation

Pulmonary obstruction results in delayed P2


Pulmonary artery pressure reduce



P2 become soft or inaudible



P2 become soft or inaudible

(Second Sound) S2= A2 + P2

Since P2 is inaudible, hence S2 = A2 + P2[S2 is single sound]

Aorta is displace anteriorly too, A2 become LOUD!

• Ascending aorta in TOF is large, results aortic ejection click

• Diastolic interval is clear

• No S3

• No S4

Concentric right ventricular hypertrophy reduce the distensibility of the right ventricle during diastole

Concentric right ventricular hypertrophy reduce the distensibility of the right ventricle during diastole

“a” waves become prominent in JVP*

*but not too tall

Clinical Picture

• Symptomatic any time after birth

• Paroxysmal attacks of dyspnea

• Anoxic spells

• Predominantly after waking up

• Child cry

• Dyspnea

• cyanosis

• Loss of consciousness

• Convulsion

• Frequency varies from once a few days to many attack everyday

• Dyspnea on exertion

• Exercise intolerance

• Sitting posture – squatting

• Compensatory mechanism

• Squatting increases the peripheral vascular resistance,

• which diminishes the right-to-left shunt

• increases pulmonary blood flow.

• Cyanosis during feeding

• Poor feeding

• fussiness, tachypnea, and agitation.

• Birth weight is low.

• Growth is retarded.

• Development and puberty may be delayed.

Physical examination

• Clubbing + Cyanosis (Variable)

• Squatting position

• Scoliosis – Common

• bulging left hemithorax

• Prominent “a” waves JVP

• Normal heart size

• Mild parasternal impulse

• Systolic trill (30%)

• S1 normal

• S2 single

• only A2 heard

• P2 soft & delayed: INAUDIBLE

• Murmur

• Shunt murmur (VSD) absent

• Flow murmur: Ejection systolic,

the smaller the flow the shorter

the murmur

• Ejection aortic click

ECG

• QRS axis … same as that of a normal newborn

• RVH…Tall monophasic R in V1 with an abrupt change to an

rS pattern in V2 (Tall R extends into adj precordial leads in

TOF + APV)

• Reduced PBF+ underfilled LVrS in V2-V6

• Balanced shunt …qR in V5,V6

• L-R shuntQR in V5,V6

• LAD with counterclockwise depolarisn TOF+AVSD

ECG

• Right axis deviation (+120° to +150°)

• Right or combined ventricular hypertrophy

• Right atrial hypertrophy

• Partial or complete right bundle branch block (especially true of patients

after surgical repair)

ECG

• ECG

ECG

• ECG wiLLiammoRRow

CXR:

• Normal sized heart; [may be large in PA]

• upturned apex; attenuated & concave left heart border (infundibular and PA

hypoplasia)….boot-shaped heart, or coeur en sabot…small underfilled LV that

lies above horiz IVS, inferior to which is a concentric hypertrophied nondilated

RV

• Diminished pulmonary vascularity in proportion to the degree of cyanosis.

• Absent thymic shadow in the newborn may indicate associated chromosome

22q11.2 microdeletion (DiGeorge syndrome).

• RAA in roughly 25%...accompanied by Rt DA on Rt side

• In PA..lacy reticular pattern (d/t the anast b/w lobar/segm PAs & CAs)

• Syst arterial collaterals rarely cause rib notching as they do not run in

intercostal grooves.

• Coeur en sabot

(boot-shaped heart)

secondary to uplifting of the

cardiac apex from RVH

and the absence of a normal

main pulmonary artery

segment

• Decreased pulmonary

vascularity

• Right atrial enlargement

• Right-sided aortic arch (20-

25% of patients) with

indentation of leftward-

positioned tracheobronchial

shadow

Cardiac Catheterization

• Less often needed ;

• Diagnostic

• Therapeutic

• foremost goal …. clarification or better definition of anatomic

characteristics, such as pulmonary arterial or coronary arterial

anatomy

• coronary artery anatomy … either by aortic root angio, selective

coronary artery injection, or a combination of both.

• Definition of any aortopulmonary collaterals ….usually originate

from the descending aorta.

Course and Complication

1) Each anoxic spell is potentially fatal

2) Polycytemia

1) Cerebrovascular thrombosis

3) Anoxic infaction of CNS

1) Neurological complication

LUNG is an very good filter.

1) Bypassing it may not be a good idea!

2) TOF, venous blood from gut, peripheral system by pass the lung and

re-enter circulation

CNS complications

• Paradoxic embolus

• Cerebral thrombosis

• Cerebral abcess

• Seizures

• Hypoxic damage

• Endocarditis & vegetations

• Postoperative strokes

HYPERCYANOTIC SPELLS OR TETRALOGY SPELLS :

• best described in TOF;

• can occur with other forms of structural heart disease

• mediated, in part, by dynamic changes (acute increase)in subpulmonic

obstruction….

• . changes in contractility due to ‘endogenous catecholamines or exacerbated

by hypovolemia’

• other mechanisms - decrease in systemic vascular resistance.

• Child may assume squatting posture (instinctive) during spells …

Pathogenetic mechanisms : Vulnerable respiratory control centres ;Increase in

HR ; Increase in CO & VR ;Increase in R L shunt; Infundibular contraction

may reinforce,but does not initiate.

TYPICAL SPELL :

• The child becomes distressed and inconsolable, without apparent

reason, most often in the morning.

• Peak incidence2nd-6th m ;few after 2 yrs

• Crying is associated with progressively deeper cyanosis and hyperpnea

(not tachypnea).

• Spells are self-aggravating;

• During the spell diminished/absent murmur

• Not infrequently,the spell terminates with unconsciousness and,

rarely,convulsions. If the hypoxemia is extreme, permanent neurologic

sequelae and even death may ensue. True hypercyanotic spells are rare

in neonates, although cyanosis may increase with crying.

Hypercyanotic spells …Rx aims @ lowering impedance to pulmonary

flow and further increasing systemic vascular resistance.

Refractory Transfusion of whole blood/red cells

• Balloon angioplasty of pulm annulus

• Emergent surgical palliation or repair

Management of anoxic spell

1) Calm the baby

2) increase SVR

3) Knee chest position

4) Humified O2

5) Morphine 0.1 -0.2 mg/Kg Subcutaneous

6) Correct acidosis – Sodium Bicarb IV

6) Inj phenyelphrine

7) Propranolol

1) 0.1mg/kg/IV during spells

2) 0.5 to 1.0 mg/kg/ 4-6hourly orally

7) Vasopressors:

8) Correct anemia

MANAGEMENT

• Infants with very severe RVOT stenosis and those with TOF + PA,

• with SaO2<70%, should have surgery within a few weeks after birth.

• Infants with moderately severe stenosis and marked cyanosis (SaO2 70–

90%) should have corrective surgery by 2–4 months.

• Corrective surgery should be performed in all other infants with tetralogy

of Fallot by 6 months.

Contraindications for repair in early infancyPalliation initially

• LAD from RCA crossing infundibulum

• Severely hypoplastic PAs

• Pulmonary atresia

Palliative Procedures

Classic BT shunt[1945]…SCAPA on side opposite AA

Modified BT… esp in small infants <6 months…side to side anastom

with interposition graft of PTFE or Gore-Tex b/w SCA & PA [on the same

side of AA]

Waterston shunt : Side-side anastomosis of RPA to AA

Potts : Side - side anastomosis of LPA to DA

Waterston/Potts shunts : complications

• Excessive PBF HF [20%] & PHTN

• Difficulty taking shunt down at time of correction

• Distortion of Rt/Lt PA ; Right/Left PA aneurysm

BT shunt-advantages :

(a)low incidence of problems from excess PBF

(b)No pericardial adhesions as pericardium is not entered

(c)Easy to close @ time of complete repair..ligating its distal part just proximal to

anastom with PA

(d)Less distortion of PAs

CENTRAL SHUNT :connecting a short tubular graft of Teflon or GoreTex from the

aorta to the MPA.

advantages vs other shunts:

• the size of the communication could be controlled by selecting a tube with a diameter

appropriate for the patient;

• branch PAs are not disturbed so that reconstruction is not required at the time of

corrective surgery.

Blalock Taussig Shunt

• Subclavian artery – Pulmonary artery anastomosis

Modified Blalock Taussig Shunt

• Goretex graft

Surgical Palliation

CLASSIC BT shunt

POTTS SHUNT WATERSTON SHUNT

Interventional procedures :

In patients with severe annular hypoplasia….. palliation of significant

cyanosis by balloon valvuloplasty or RVOT stent placement can be

done… Improvement in antegrade flow is thought to simultaneously

enhance pulmonary arterial growth by augmenting PBF

Balloon angioplasty of the pulmonary valve annulus is preferable to a

shunt procedure as it is

• less traumatic,

• it avoids a thoracotomy,

• reduces the likelihood of distortion of the pulmonary arteries

Coil embolization of APCs ….Coiling of vessels that perfuse

pulmonary segments already supplied by pulmonary arterial flow

serves to reduce LV volume loading as well as to eliminate runoff into

the pulmonary arterial bed during CPB

Surgery aims @

• relieving all possible sources of RVOTO;

• If possible, pulmonary valve function is preserved by avoiding a transannular patch

• Closure of VSD (dacron patch)

• To relieve RVOTOpulmonary valvotomy, the insertion of an outflow tract patch

or a transannular patch are often required.

• Surgery during early infancy, when the pulmonary annulus is markedly stenotic,

frequently requires the insertion of a long and wide transannular patch.

• Consequently, most patients acquire PR as a result of the repair. PR may be well

tolerated by many in the early postoperative years, but in the long term chronic PR

is associated with reduced exercise capacity, RV dilatation, ventricular

arrhythmias, and sudden death.

PVR : Early PVR in selected patients results in beneficial remodelling of the right

ventricle

Optimal timing is critical for preserving RV function (not too late) and avoiding the

need for early re-operation (not too early). Amelioration of RV function following

PVR has to be weighed against the risk of subsequent re-operation for homograft

failure.

Studies…RV end-diastolic volume may become a helpful indicator for defining both

a lower limit (150 mL/m2) and an upper limit for re-intervention

(200 mL/m2).[normal 60-100]

CMR is the gold standard for evaluation of RV volumes and quantification of the

degree of PR & TR.

SURGERY in TOF contd…

VSD closure : Done thru’ RA approach whether or not a trans-annular patch is used,

as this approach allows to minimise the length of the right ventriculotomy

(length only necessary to relieve the RVOT obstruction and not for the VSD

exposure).

Efficacy of the RA approach ….

• Preserves the right ventricular function, …..

• Resultant PR after limited transannular patching is less severe than that which

occurs after transventricular repair

• Less incidence of ventricular/atrial arrhythmias is

• Easier to preserve the integrity & function of the tricuspid valve.

Concerns of right ventriculotomy (classical RV approach)

• Low cardiac output in the early postoperative period,

• a higher incidence of arrhythmias,

• Risk of late sudden death

In case of a major coronary artery crossing the RVOT…an external conduit or

homograft would be necessary;

Risk factors for early death after repair:

1) very young age

2) older age

3) severity of annular hypoplasia

4) small size of pulmonary arteries

5) need for transannular patch (debatable)

6) high peak RV to LV pressure ratio

7) previous palliative operations

8) multiple VSDs

9) co-existing cardiac anomalies

Advantages of early total correction

• Prevents cerebral hypoxia,cerebral embolism, abscess and hematological changes

• Decrease RVPprevent persistent myocardial hypertrophy and probably reduce

the risk of fibrosis of the RV

• Providing adequate PBF will optimize the opportunity for normal growth of the

main and branch PAs…also normal pulmonary circulation may be important for

lung development.

• Tendency for progressive hypertrophy of the RV infundibular region is largely

abolished by early repair.

• Early separation of MAPCAs from aorta reduces the risk of PVOD

SURGERY IN TOF + PA :

• PA anatomy not favourable? ….Palliative procedures… Central shunt vs

reconstruction of RVOT using a patch/conduit while leaving open the VSD

• If PA anatomy appears amenable to reconstruction, procedures leading to complete

repair are indicated.

Such procedures include RV outflow reconstruction for inducement of central

pulmonary artery growth using a valved conduit / aortic or pulmonary homograft

• If there is a connection between RV & PT correction can be achieved with a

patch reconstruction

PA anatomy assessment

1) McGoon ratio: (Diameter of RPA/DAo + Diameter of LPA/DAo)

• Normal 2.1

• Adequate for VSD closure 1.2

• Inadequate <0.8 for VSD closure

2) Nakata Index:(CSA of RPA + CSA of LPA)/BSA

• Normal value > 200 mm2/m2

> 150 mm2/m2 is adequate.

(Not usable preoperatively when MAPCAs are the major source of PBF & one-

stage unifocalization + full repair is planned).

3) Total Neo-Pulmonary Artery Index (TNPAI) = APC index + Nakata Index

• APC index is the sum of CSA of all usable APCs/BSA

>250 - suitable for one-stage repair including VSD closure (These pts. have low

RV/LV pressure ratio postoperatively).

Critique of all these indices: These indices consider only the size of proximal vessel

and not consider the condition of distal parts of the vessels (which may be stenosed).

Recently the value of all these has been questioned

MAPCAs : management : 2 options

1)Obliterate them by Sx ligation/coil embolisation

2)Surgical unifocalisation : if it is the sole supply to many segments …..connecting

all MAPCAs, as well as the small native pulmonary arteries, to one source of blood

flow from the RV [ie to a central PA confluence or prosthetic PA confluence]….. If

performed early,it avoids the dvpt of PVOD changes, as well as stenoses in the

MAPCAs.

If the pulmonary vascular morphology and resistance are such that adequate PBF

can be accommodated…then RVP after correction will be low enough to close the

VSD.

• To assess whether this is likely, surgeons at the University of California in San

Francisco perfuse blood from the perfusion system through the pulmonary artery at

a rate of 2.5 L/min per m. If PA mean pressure is <25 mmHg, it is considered safe

to close the VSD. If it is not closed, the patient is followed; the PVR may decrease

over time, allowing later closure. Also, if stenoses in pulmonary vessels are noted,

relief by balloon angioplasty, with stenting if necessary, may permit RVP to fall

and permit closure of the defect.

• Post surgery if the RVP/LVP is >0.75….RVF may result…avoid closure VSD /

fenestrated patch closure

Hypoplastic PAs … intervene early …. Encourage them to grow

• Reconstruction of RVOT with a patch or valveless conduit

• Placement of a central AP shunt

• If MPA,RPA & LPA are present, even though very small (diameter 3 mm), they are

capable of considerable enlargement if blood flow through them is increased.

Creating an AP window early in infancy sufficient enlargement of the pulmonary

arterial tree to later perform successful repair using the normal pulmonary arteries

and a unifocalization procedure can be avoided.

Dvpt of small pulmonary arteries(A) Before central shunt wasperformed, the Nakata index was64 and the McGoon ratio was0.82. (B) One hundred seventy-four days after operation, theNakata index rose to 89 and theMcGoon ratio to 1.1.

Post Repair for TOF in general

Current surgical survival, even for symptomatic infants <3 months of age, is

excellent.

Hospital and 1-month survival rates of 100% have been reported.

Earlier age at repair (<1 year of age) did not adversely affect the rate of

reintervention; so primary repair should be regarded as the preferred management

strategy.

Twenty-year survival for hospital survivors, irrespective of management strategy,

was 98% for patients who have TOF with PS and slightly lower for patients with

PA, reflecting the overall excellent long-term survival of these patients.

COURSE

In unrepaired TOF….increasing cyanosis due to progressive infundibular

obstruction. Beyond the neonatal period, they are also at increasing risk for

developing hypercyanotic spells.

Older children with unrepaired or palliated TOF … complications a/w chronic

cyanosis ,polycythemiastroke, brain abscess, and pigment gallstones.

Now rare …

‘infant repair is the rule’

PVOD in TOF : rare

• large surgical systemic-to-pulmonary artery shunts

• persisting large aortopulmonary collaterals

REPAIRED TOF :

Outcomes : excellent…recent reports…mortality <3%

Problems that may develop include

a)Residual VSDs

• Persistent defects at the patch margin or

• Previously unrecognized or underestimated additional defects in the muscular

septum.

• Partial patch dehiscence

b)Recurrent RVOTO :

• Muscle bundles obstruct the os infundibulum in 3%

• Nontransannular patches…annulus becomes restrictive as child grows

• Transannular patch…restriction at the distal insertion of the patch into the branch

pulmonary arteries.

• Stenosis owing to compression from an aneurysmal RVOT patch …. should be

approached surgically with revision of the patch and repair of the proximal

obstruction.

• may dvp additional sites of peripheral PS over time.

c)Progressive aortic root dilation &AR :

• Intrinsic dvptal abnormalities of aortic valve/root

• Palliative shunts or significant APCs left-to-right shunt volume contribute to

aortic dilation.

Progressive dilation of aorta correlate with longer time between palliation & repair ;

Pulmonary atresia ; right AA & male gender.

d) RV dilation;syst/diast dysfunction later RHF

• excess volume load from pulmonary regurgitation

• pressure load from outflow obstruction,

• Hypoxemic coronary perfusion,

• surgical incision, patch and scarring, and post–cardiopulmonary bypass ischemia

reperfusion injury—possibly superimposed on tetralogy associated congenital

abnormalities of the myocardium.

e) LV dysfunction … consequence of adverse ventricular interaction.

f) Rhythm disturb./SCD : Long-term mortality …. 3% to 6%.

A review of 125 adult patients with TOF suggested that a greater degree of PR, a

history of sustained VT, QRS duration >180 ms, or LV dysfunction was a predictor

of sudden death

g) Lower IQ

h) Life time increased risk for IE

i)Membranous subaortic stenosis …..may be seen years after the initial repair in a

few patients…may require surgical excision.

j)Small coronary-to-RV fistulas, thought to relate to the excision of muscle in the

right ventricular outflow tract.

Post repair TOF + PA :

• Need for reoperation/ transcatheter balloon dilation and stenting of an obstructed

conduit in RV to PA conduit surgery patients.

• Ongoing risk for recurrent peripheral PS…serial catheterizations are indicated for

ongoing pulmonary artery rehabilitation

• higher risk for progressive aortic root dilation and AR

TOF + AVCD :

• risk for atrioventricular valve incompetence …. TR right ventricular dilation,

and dysfunction.

Congenital Absence of Pulmonary Valve Syndrome

• Chever in 1847

• incompletely formed, rudimentary pulmonary valve that typically is both stenotic and

regurgitant ; aneurysmally dilated PA, and a large malaligned outlet VSD.

• PDA is always absent….has been postulated as being responsible for its pathogenesis

and PA dysplasia.

• Other clinical features fairly typical in this disorder include the common association of

airway abnormalities that may lead to severe respiratory failure .

• The conal septal abnormalities and infundibular obstruction, however, in distinction to

typical tetralogy, are less severe or absent, and much of the PS results from annular

hypoplasia.

• Typically present in the neonatal period, and are diagnosed based on the presence

of their characteristic murmur and the presence of cyanosis.

• A significant proportion of patients will present with associated respiratory distress

or frank respiratory failure, often requiring mechanical ventilation.

• harsh to-and-fro murmur of PS followed by the diastolic murmur of PR….sound of

’sawing wood’

• CXR…Massively dilated Pas ; Infundibular dilation project leftward as a hump

shaped shadow ; Pulmonary vascularity is normal

• Some neonates present with severe bronchial obstruction and require immediate

tracheal intubation and mechanical ventilation, followed by early surgical repair.

• Moderate resp obstruction … lying prone may help … by relieving the anterior

vascular compression of bronchi

• Mild or no airway obstruction may require no additional support in the neonatal

period and go on to elective repair later in infancy.

• The surgical repair….. in addition to ventricular septal defect closure and right

ventricular outflow reconstruction, involves reduction of the aneurysmal

mediastinal pulmonary arteries to relieve bronchial compression.

Outcome of TOF + APV depends largely on the severity of airway disease.

Even after Sx,some pts continue to have bronchial obstruction

• Residual airway hypoplasia and deformity

• Abnormally branching segmental pulmonary arteries compressing the

intraparenchymal bronchi

As these patients grow, however, pulmonary function tends generally to improve as

PAP fall and the maturing tracheobronchial tree develops less compressible walls

and larger caliber.

ANAESTHETIC MANAGEMENT

Congenital Cardiac Surgery

• Perioperative concerns

• Increase in PVR or decrease in SVR leading to Right to Left shunt

• Tet Spells pre induction (crying/anxiety)

• Polycythemia and bleeding , coagulation abnormalities

• Air embolus

• RV failure


• Preoperative Preparation

• Heavy premedication

• Consider IM ketamine or inhalation induction but get rapid control of

airway.

• Keep SVR up and PVR down, maintain heart rate

• Intraoperative TEE


• Weaning from CPB, ratio RV : LV pressure should be < 0.8

• May need to keep PVR low with NTG, milrinone, dobutamine

phentolamine, PGE1

• May need RV inotrope post op

• May need temporary pacing wire.

THANK YOU

Health & Medicine

Tetralogy of Fallot - Case Presentation