Clinical Questions, Surgery and Anaesthetic Management

Q.1) What is Monology of Fallot ?

     Van Praagh described a single unifying developmental anomaly.Monology is “Anterior and leftward displacement of the infundibular septum”.

Q.2) What is Triology of Fallot ?

    Pulmonary stenosis, Righy ventricular hypertrophy, Atrial septal defect (ASD) forms triology of Fallot.

Q.3) What is Tetralogy of Fallot ?

   Ventricular septal defect, Pulmonary stenosis, Overriding of aorta and Right ventricular hypertrophy are the 4 components of TOF.

Q.4) What is Pentalogy of Fallot ?

   ASD alongwith the 4 components of tetrology is pentalogy.

Q.5) What is Castaneda doctrine ?

  “Operate as soon as the patient needs it.Whenever  possible, do corrective surgery,not palliative surgery. One operation is better than two (or more)” are the words by Aldo Castaneda who became the 'father' of neonatal and first-year-of-life corrective congenital heart surgery. 

Q.6) What is the incidence of TOF ?

•    5-10%

Q.7) What is the frequency in siblings ?

•    3%

Q.8) What is the survival pattern in TOF ?

•    50% at 3 years

•    25% at 10 years

•    12% at 20 years 

•    6% at 30 years

•    3% at 40 years

Q.9) What is the role of karyotyping in TOF ?

•    Deletion of chromosome 22q11 can be identified in 15% of individuals.

Q.10) What is CATCH 22 syndrome ?

•    Cardiac defect, 

•    Abnormal facies, 

•    Thymic hypoplasia,

•     Cleft palate,   

•    Hypocalcemia, 

•    22q11 deletion 

Q.11) Which syndromes are associated with TOF ?

•    Down’s syndrome 8%

•    Noonan syndrome 1%

•    DiGeorge syndrome and 22q11 spectrum

•    Ectopia cordis (pentalogy of Cantrell)

•    Maternal rubella syndrome 

•    CHARGE

•    Goldenhar syndrome 

Q.12) Is “Tetralogy” same as TOF physiology ?

•     VSD & PS  is TOF physiology and the other two components RVH and overriding of aorta are in addition to VSD and PS in tetrology. 

Q.13) Which conditions are in  TOF Physiology ?

•    TOF VSD PS

•    DORV VSD PS

•    cTGA VSD PS 

•    dTGA VSD PS

•    VSD PS

•    ASD PS

•    TA 1b/2b

Q.14) Which conditions have cyanosis with increased PBF ?

•    TAPVC

•    Truncus

•    Taussig Bing

•    TGA

•    Common atrium 

•    Eisenmengerisation

Q.15) What are the major cardiac defects associated with TOF ?

•    Right Aortic Arch 25%

•    ASD 9%

•    LSVC 8%

•    ALCAPA 5-12%

•    PDA 4%

•    Additional VSDs 2.4%

•    Complete AV septal defect 2.2%

•    Anomalies of Pulmonary Venous connection 1%

•    Dextrocardia 1%

•    Aortic valve incompetence 

Q.16) What are the differential diagnosis of TOF ?

•    TOF

•    DORV+ PS

•    TGA + VSD PS

•    SV + PS

Q.17) Why no respiratory tract infections in TOF ?

•    Pulmonary stenosis is present so no overflow of lungs

•    Volume overload is not present 

•    No left to right shunt

Q.18) What is your diagnosis at the end of history ?

• Diagnosis by history is TOF physiology as delayed onset and H/O squatting 

Q.19) What are the morphologic categories of RVOT Obstruction ?

•    Infundibular 26%

•    Infundibular + valvar 26%

•    Infundibular +valvar + annular 16%

•    Diffuse hypoplasia 27%

•    Valvar 5%

Q.20) What is the age of onset of cyanosis for various conditions ?

Cyanosis at birth - 

Pulmonary atresia 

Aortic atresia 

Tricuspid atresia 

TAPVC

TGA

TOF with Pulmonary atresia 

TruncusArteriosus

Taussig Bing Anomaly

Hypoplastic left heart syndrome 

Cyanosis at 1 week –

Ebstein’s anomaly 

Tricuspid atresia 

Hypoplastic left heart syndrome 

Cyanosis from 1 week to 1 month –

TGA

TAPVC

TruncusArteriosus

TOF with severe PS

DORV with severe PS

Common atrium 

Cyanosis after 6 months –

TOF and its variations 

Eisenmengerisation

Q.21)What are the causes for late onset of cyanosis ?

1)    TOF with mild PS

2)    TOF with good collaterals 

3)    DORV + VSD + PS

4)    ASD + PS

5)    Ebstein's anomaly

Q.22) What are the factors precipitating cyanosis ?

LRTI

Exertion

Ductus thrombosis 

Ductus infective endocarditis 

Q.23) When does cyanosis appear in TOF ?

25% are cyanotic at birth and by the age of 1 year 75% are cyanotic 

Q.24) Why does cyanosis appear late in TOF ?

1)    PDA closes

2)    Activity of child increases causing decrease in SVR

3)    Fetal hemoglobin decreases

4)    Anaemia may get corrected

5)    Progressive increase in PS may occur

6)    Progressive increase in oxygen demand

Q.25) Define Cyanotic spell.

Cyanotic spell is progressive increase in rate and depth of respiration and which culminates in paroxysmal hyperapnea,deepening of cyanosis, limpness, syncope,occasionally convulsions or death.

Q.26) What are the other terminologies used for cyanotic spell ?

Hypoxia spell

Tet spell

Paroxysmal hyperapnea

Q.27) Cyanotic spells – what are the differential diagnosis ?

TOF

DORV VSD PS

VSD PS

ASD PS

TA 1b/2b

Q.28) What are the triggering factors for cyanotic spell ?

Spontaneous 

Crying 

Feeding 

Bowel movements 

If stress occurs upon waking up in the morning 

Hot water bath

Q.29) What age does spells are most frequent ?

6 months to 2 years,more so in early morning 

Q.30) Why spells are less common in neonates or immediately after birth ?

Fetal hemoglobin has high affinity for oxygen 

PDA is present 

Once active physical activity starts

Infundibular spasm progresses as age increases

Q.31) Spells decrease after 2 years of age, why ?

The infundibulum or the RVOTO gets fixed due to fibrosis

Child learns to avoid spell- Adaptability- Child adapts by assuming right posture, level of activity etc

Collaterals grow

Improved hemoglobin

Respiratory centre matures

Q.32) What are the clinical features of spell ?

Increase in depth of respiration

Increasing cyanosis 

Hypotonia

Syncope

Seizures 

Q.33) What are the various theories proposed for mechanism of cyanotic spell ?

Theories of Cyanotic Spell are :

Guntheroth & Morgan : Vulnerable respiratory centre mechanism which is sensitive after a prolonged sleep.It reacts to sudden increase in cardiac output which may occur due to 

Decrease in SVR, Crying, RVOT spasm :All these lead to increase in Right to Left shunt Which lead to decrease in PO2, increase in PCO2 and decrease in pH

All these cause Hyperapnea Which increase in venous return and this again causes increase in R-L shunt.

Wood Theory : Increased sympathetic activity leads to infundibular spasm which increases Rt to Lf shunt. The low arterial 

PO2 leads to stimulationof carotid receptors and brainstem nuclei and this leads to increase in rate and depth of respiration which causes increase in venous return to right side and increase shunting.

Young Theory : Atrial tachycardia leading to increased R-L shunt

Kothari Theory : Stimulation of mechanoreceptors in RV which increases contractility,decreases RV size, triggers hyperventilation, peripheral vasodilatation and initiates spell.

Other theories are – Rudolf’s theory, Brooke’s theory, Hamilton theory 

Q.34) In hypovolumia why should spell occur ?

     RVOT orifice is reduced as venous return is decreased so cardiac output is reduced 

Q.35) How does a spell terminate ?

Spell terminates on squatting or Some CNS event occurs

Q.36) How to manage spell on table under anaesthesia ?

- Partially clamp the aorta as it mimics like squatting situation 

-Fold legs upto chest along with other measures/drugs

Q.37) How does squatting help ?

Increase in the SVR by kinking the femoral arteries decreasing the right to left shunt

Decreased return of a more deoxygenated blood to the heart from the lower limbs by kinking the femoral veins

Pushing relatively more oxygenated blood from the splanchnic circulation/abdominal viscera to the heart

Relaxation of sympathetic overdrive by rest

Q.38) What are the different postures assumed in TOF ? OR What are squatting equivalents ?

•    Squatting 

•    Sitting with legs drawn nearer

•    Sitting cross legged

•    Legs crossed while standing 

•    Mother holding infant with legs flexed 

•    Lying down 

Q.39)What is the most common precipitating factor for spell ?

 Anaemia -It also masks cyanosis 

Q.40)What is the treatment of spell ?

Knee chest position

Inj Morphine 0.1-0.2 mg/kg IM suppresses respiratory centre and abolishes hyperpnea and breaks the vicious circle

100% Oxygen decreases hypoxic pulmonary vasoconstriction, does not relieve spasm

Inj Sodabicarbonate 1-2 mEq/kg, repeated in 15 min, it reduces respiratory stimulating effect of acidosis

Inj Propranolol iv 0.01-0.25mg/kg slow iv 

Inj Phenylehrine 0.02mg/kg iv ,increases systemic arterial pressure

Inj Ketamine 1-2 mg/kg iv, increases SVR and sedates the child

Intubation

BT shunt

Q.41) How do you know that the patient is improving after treatment of spell ?

Murmur reappears 

Cyanosis decreases

Q.42) What are the associated anomalies in TOF ?

Rt aortic arch 25%

ASD 9%

LSVC 6%

Coronary anomalies 5-12%- left arising from RCA

Conal crossing RVOT

Aberrant origin of right subclavian 0.3%

Interrupted aortic arch 0.2%

Q.43) Describe VSD in TOF ?

•    VSD in TOF is typically described as large,non-restrictive ,malaligned,subaortic VSD 

Q.44) How is septum displaced ?

•    Cephalad or Anterocephalad

Q.45) What is DORV ?

•    >50 % overriding 

•    Aortomitral discontinuity is a must

•    AV and PV are at same level ( Normally AV is lower than PV )

Q.46) What are the complications of TOF ?

•    Brain abscess 

•    CVA

•    Decreased IQ 

•    Gout

•    Gallstones 

•    Infective endocarditis 

Q.4) Why seizures occur in TOF ?

•    Due to hypoxia polycythemia occurs which lead to thrombosis, thrombosis in cerebral vessels can cause seizures 

        Right to Left embolisation 

•    Cerebral infarcts and cerebral abscesses can lead to seizures

Q.47) What is the reason for cerebral abscess in TOF ?

•    Right to left shunt bypass the phagocytic filtering action of pulmonary capillary bed

•    Also, polycythemia leads to high viscosity of blood causing tissue hypoxia, microinfarcts in brain ,complicated by bacterial colonization and abscess formation.

Q.48) Why DIC occurs in TOF ?

Increased hematocrit leads to relative plasma deficiency. Coagulation abnormalities leading to decrease in number of platelets

Q.49)What are the causes of TOF in failure ?

TOF with anaemia

TOF with PDA

TOF with MAPCAS

TOF with Infective Endocarditis

TOF with Hypertension

TOF with PR in absent PV

Adult TOF

TOF with RV dysfunction

Closing down of VSD- restrictive VSD

TOF with AR/ TR/PR

TOF with HTN/AS 

Q.50)What are the causes of raised JVP in TOF ?

TOF with anaemia

Associated TR/AR/Hypertension

AdultTOF

Restrictive VSD

Shunted TOF/PDA

Infective Endocarditis

Q.51)What are the causes of LV apex in TOF ?

- Shunted TOF

- TOF with PDA

- TOF with HTN

- TOF with AR

- TOF with MAPCAS

Q.52)When is LV well developed in TOF ?

- AR

- Good collaterals/ PDA/ shunt

- Adult TOF

- Common AV canal

- VSD is restrictive

Q.53) What are the features of adult TOF ?

•    CHF 15%

•    HTN 

•    AR

•    LVH

•    No RVH

•    q in lateral leads in ECG

 

Q.54)What are the indications for surgery ?

•    Indications for surgery –

•    Two stage repair is prudent for institutes not

•    Primary repair should be the aim,when severe symptoms develop in first 3 months an initial shunting followed by ICR within 12 months is a reasonable alternative 

Q.55) Primary repair versus Palliation,what is preferred ?

•    Kirklin concluded that primary repair without a transannular patch is as safe as a second stage procedure shunt- ICR,when child is >6 months and BSA is 0.35 sq m

•    When a transannular patch is required, 2 stage procedure is safer if the infant is < 9>

Q.56) What are the advantages of  Primary Intracardiac Repair ?

 Development of right ventricular hypertrophy can be prevented, Also, early repair provides adequate pulmonary blood flow with homogeneous distribution to both the lungs, allows normal growth and development of the pulmonary arteries. This is advantage over the potential negative effect of systemic to pulmonary shunts on PAs. 

Q.57) What are the types of Palliative shunts ?

•    Classical BT shunt –Subclavian artery to pulmonary artery, done first in 1945, side opposite arch, subclavian artery dissected down and anastomosed to the side of PA. 

•    Modified BT –It is side to side anastomosis, Gortex conduit

•    Potts shunt – Descending aorta to LPA

•    Waterston Shunt – Ascending aorta to RPA

•    Central shunt – Gortex between aorta to RPA

•    Glenn shunt – SVC to RPA 

Q.58)What is Waterston shunt ?

Shunt between the posterior ascending aorta & anterior LPA through a right lateral thoracotomy.

Problems of Waterston shunt :Size of shunt- if small then cyanosis, if large then CCF

Distortion of RPA & preferential flow to one lung

Q.59)What is Waterston Cooley shunt and Potts shunt ?

Anastomosis is done between aorta & RPA, anterior to SVC

Potts shunt:

Between descending aorta & posterior LPA

Problems: 

•    Increased flow- leading to CCF

•    Decreased flow- leads to cyanosis

•    LPA aneurysm

•    Difficulty in takedown

Q.60)What is the operating room PRV/PLV ratio ?

A fine needle is passed through RV through septum into LV to record pressures.

Ratio should be <0>

Q.61) Palliative procedures are indicated when ?

      Prv/Plv>1

•    Blackstone – diameter of RPA,LPA + PA annulus 

•    Jakarta – PA area index

•    Naito – LV EV < 30ml>

Q.62) What are the incremental risk factors for death after surgery ?

•    Demographic- smaller BSA, older age

•    Clinical- Previous Potts, previous RVOTO repair, high hematocrit

•    Morphological- Multiple VSD, Dextro

•    Surgical – Annular patch,post repair Prv/lv

Q.63) When should Intracardiac repair be done after BTS ?

           ICR is done when pulmonary arteries are developed 

  4-12 weeks is the optimum time to take down BTS and do ICR 

Q.64) Why total correction is done even though BTS is functioning well ?

PVOD may develop so BTS is not left for longer duration 

Q.65) Why is ICR performed earlier now a days ?

       Advantages of doing ICR earlier are – 

•    RVH does not set in

•    Avoids one more procedure 

•    No development of MAPCAs

•    No cyanosis related problems like polycythemia

Q.66) What gets affected in infective endocarditis in TOF ?

RVOT Obstruction 

Pulmonary valve

Tricuspid valve

Q.67) What are the causes of thromboembolism in TOF ?

Infective endocarditis 

Paradoxical embolus from DVT

Dehydration 

Q.68)What are the characteristics of Adult TOF ?

Growth retardation

Fatigue/ dysnea on exertion

No cyanotic spell

Polycythemia due to chronic hypoxia

Stroke 

Cyanosis,clubbing,single S2,parasternal heave,systolic thrill,ESM in 2nd/3rd intercostal space may be present 

Q.69)Should Radio femoral delay be mentioned in TOF examination ?

Ideally should not be mentioned because it never occurs in TOF- because with right & left sided obstruction patient will not survive.It was mentioned due to routine format of case presentation.

Q.70)What are the causes of Radio-radial delay in TOF ?

- Classical BT shunt

- Modified BT shunt with kinking / thrombosis of subclavian secondary to shunt.

Q.71)What is the D/D of TOF ?

VSD, PS:

- Generally late (5-6 years) presentation,

- Mild cyanosis,

- LRTI in early childhood

- LV apex

PS, VSD:

- Harsh PS murmur with late peaking

DORV, VSD, PS:

- On echo

cTGA, VSD, PS:

- Heart block

- qR in V1

TA IIb:

- No RV inflow 

- No R in V1, V2

Q.72)Why Quiet precordium in TOF ?

  Because of large non restrictive VSD & RV ejects into LV

through VSD & not in the PA.

Q.73)In which conditions Active precordium is seen in TOF ?(same DD for Cradiomegaly in TOF).

- CCF in TOF – Anaemia /IE / AR.

- Dilated Aorta – Post Shunt / PDA.

- LV dilatation – Gross AR / HTN.

- Restrictive VSD.

Q.74)What are the causes of thrill in TOF ?

- Mild PS – 2nd LICS.

- Interscapular area – Collterals

   Restrictve VSD.

- PDA.

- BT shunt.

Q.75)What are the causes of dullness in the 2nd left intercostal space in TOF ?

 Dilated PA: Due to

- Post stenotic dilatation

- Post shunt

- Absent pulmonary valve syndrome

Q.76)Whatinformation about TOF can you get from murmur ?

Harshness/ duration of murmur ? severity of RVOT obstruction.

Site of the murmur – 

4th ICS best heard & radiating up – Infundibular PS.

2nd ICS best heard & radiating up - Valvar PS.

Q.77) What are the relationships between murmurs and increasing severity of RVOTO ?

•    Mild PS – VSD is holosystolic,P2 delayed but readily heard

•    Moderate PS – VSD murmur declines in later systole,P2 delayed softer

•    Severe PS – VSD murmur is replaced by a long PS murmur 

•    Severe PS exceeds SVR – RV blood is diverted, murmur shortens and softens

•    Very severe PS – Ejection click, A2 prominent, murmur very short 

•    Pulmonary atresia – No murmur or only ejection click and collateral murmur may be present 

 As the severity of TOF increases, the murmur becomes shorter and softer

 Shorter because infundibulum becomes more narrow in late systole 

 Softer because right to left shunt increases with increasing stenosis 

Q.78) Why is S2 single ?

As P2 is soft or absent as less or no blood flow through PA

Q.79)Which points are in favour of diagnosis as TOF?

- Late onset of cyanosis.

- Severe cyanosis but never in failure

- JVP not raised.

- Quiet precordium.

- No cardiomegaly.

- Normal apex.

- Single S2.

- ESM pulmonary area.

Q.80)Which points dictate severity to TOF ?

Severity ? degree of RVOT obstruction – The only confounding factor is the presence of collateral circulation. 

Early age of presentation.

Spells & squatting.

- Effort intolerance

- Deep cyanosis.

- Grade 4 clubbing.

- Murmur already decreased.

- Collateral murmur.

- Single S2 in TOF

- Increased blood flow through Aorta.

- Dilated aorta.

Q.81)Which conditions have continuous murmur in cyanotics ?

- Truncus arteriosus

- TOF with PA

- Shunted TOF

- TOF with collaterals

- TOF with PDA

Q.82)What  additional auscultatory signs can be present in TOF ?

Murmurs –

- Diastolic murmur of AR.

- Collateral murmur – Interscapular & Lateral scapular.

- Subcostal murmur of TR – RV failure.

- Shunt murmur – best heard in same side – suprascapular/Deep axilla/ Infra clavicular.

- Continuous murmur - PDA.

- Continuous murmur – axilla – Branch PA stenosis.

Clicks –

- Aortic due to blood flow through aorta.

- Pulmonary due to Valvar PS.

Q.83)What is differential diagnosis of TOF ?

- TOF

- DORV VSD PS

- Single Ventricle PS

- TGA VSD PS

- VSD PS

- ASD PS

- PS VSD

Q.84) Chest Xray is typically described as what ?

      Couer en Sabot 

Incidence – 25 – 30 % / >.

Main causes for boot shaped heart.

Absence of LV shadow.

Pulmonary baying.

Predominantly RV shadow is seen

Q.85) What will you expect in CXR ?

- CTR < 50> - Pulmonary Bay

- Boot shaped heart

- Pulmonary blood flow –Reduced in TOF,

                        In Shunted TOF normal/reduced/increased.

- Rib notching in shunted TOF

- Contour - LV type Shunted TOF/TOF with MAPCAS,

            RV type – Cour en Sabot/Wooden shoe

Q.86)What are the causes of rib notching ?

- TOF with MAPCAS

- Shunted TOF

- Classical BT Shunt

- Coarctation of Aorta

- Interrupted aortic arch

Q.87)Discuss Rt. aortic arch in TOF.

Incidence – 25%.

Important to know in deciding Shunt / Cannulation.

Right aortic arch seen in

- TOF with PA

- Truncus

- TOF

- TA

- Single ventricle

- AP window

Q.88)When dilated PA shadow is seen in TOF ?

- Collaterals.

- Post shunt.

- Low infundibular obstruction with 3rd chamber.

- Absent pulmonary valve.

Q.89)What are the reasons for Narrow pedicle on X-ray ?

- Truncus

- Aortic dilatation- AR/ PDA

- Aortic override- PS, PA

 

Q.90)What are the causes of Prominent aortic knuckle in TOF ?

- TOF with AR

- TOF with Hypertension

 Prominent right heart border in TOF

- TOF with TR

- TOF with ASD

Q.91) What  ECG findings are present in TOF ?

  RAD

  Axis 90-180

  RAE- Adult TOF P waves are peaked but not increased in amplitude.The duration of P wave is normal or short as LA is underfilled and small.

  LVH –Adult TOF, Shunted TOF/TOF with MAPCAS

  Clockwise loop – q in II, III, aVF

  Dominant “R” in V1, Dominant “S” in V6

  T inversion – Severe RVH

  RVH – Monophasic R in V1

  Transition zone is in V2

  Early transition in V2- Window effect of VSD / LV forces through VSD 

  Depolarisation is clockwise with rS complex in lead 1 and prominent R in lead 2 and lead 3

  QRS duration is normal 

  T waves in right precordial leads are normal or inverted with equal frequency.Deeply inverted right precordial T waves that characterize severe PS with intact septum are uncommon because the RV pressure does not exceed the systemic level 

Q.92)ECG in adult TOF

- Due to high RVEDP- RV dilatation leading to tall p in II & V1.

 

Q.93)What are D/D of Fallot physiology on ECG ?

- TOF: -QRS axis between 90- 150 degrees

- DORV, TGA: - If > 150 degrees

- Tricuspid atresia: -30 to -60 degrees with LVH

- AV canal, Single ventricle:- Left axis deviation with RVH

- Single ventricle:- Right axis deviation without RVH 

Q.94) What are the indications of Cath and Angiography in TOF ?

•    Peripheral PA stenosis 

•    VSD- if multiple vsds not diagnosed on echocardiography 

•    Coronary anomalies 

•    MAPCAs- plan for unifocalization can be done 

•    Prior BTS functioning 

Q.95) What do you see in angiography of this patient ?

•    Anatomy, Additional VSD 5%

•    Coronary Anatomy, Coronary crossing RVOT 5%

•    PA Anatomy, Peripheral pulmonary stenosis 28%

•    Hemodynamic measurements

•    Collateral circulation

•    Therapeutic interventions

Q.96) What are the coronary anomalies ?

•    Conal branch of RCA crossing RVOT

•    Entire LAD arising from RCA crossing the RVOT 

Q.97)What transthoracic echo views are important in TOF and What information do you want from echo ?

Parasternal long axis –VSD, Aortic overriding.

Parasternal short axis – RVOTO, Descending aorta, PA size

Apical 5 chamber view – VSD

Apical 4 chamber view – Aortic overriding

Subcostal coronal view – descending aorta at diaphragm

Suprasternal view – PA size

Information to be sought from echo - 

- VSD - Site, size, number

- RV –Infundibular stenosis

- PA – MPA, RPA, LPA

- Coronaries

- LV/RV function

- Associated anomalies

 Q.98)Echo findings of use to surgeons in TOF.

- Size, position & restriction of VSD.

- Type of RVOT obstruction – Infundibular / valvar / supra valvar.

- Infundibular obstruction,

 Low OS infundibular – RVOT patch not req.

 Diffuse tubular narrow – RVOT patch.

 Short atretic Infundibulum – Approach through PA.

- Pulmonary annulus size.

- MPA size.

- Branch PAs – Confluence / stenosis / size.

- Associated anomalies – ASD / VSD / PDA / LSVC / Rt. aortic arch.

- Coronary arteries crossing RVOT.

- LV size – Normal systolic volume – 30 ml / m2.

- LV volume < 60> - MV size - < 2SD>

Q.99)Discuss TEE assessment in BT shunt.

TEE for BT shunt

UE Aortic Arch view is best for visualising shunt.

Mosaic pattern and increased velocity >3m/s indicate blockage of shunt

Transthoracic Echo to be done postoperatively- 

BT shunts are best viewed from the suprasternal notch or high parasternal window. 

A right-sided shunt may be seen in the suprasternal short-axis view.

As the RPA passes below the aortic arch, the insertion of the conduit can be recorded. 

A left-sided shunt may be more difficult to record. 

From the suprasternal notch, the scan plane is tilted far to the left to include the LPA.

When the shunt cannot be observed directly, Doppler and color flow imaging are helpful for identification.

The patency of shunt and kinking or stenosis (usually at distal insertion site) can also be determined with Doppler imaging.

Velocity within 1-1.5m/s is normal flow in shunt,higher velocities indicate obstruction.

Q.100)Discuss TEE assessment in TOF 

Intraoperative TEE evaluation -

is done to confirm the diagnosis,define the RVOT obstruction, estimate the size and direction of the ventricular shunt, and exclude associated pathology.

The perimembranous VSD is seen as a large subaortic defect between the right and noncoronary cusps in the midesophageal (ME) aortic valve short- and long-axis views.

Additional communications at the atrial and ventricular levels should be seen for.

Aortic override is best appreciated in the ME aortic valve long-axis view.

Evaluation of the RVOT and PAs requires a combination of scanning planes that define the subvalvular, valvular, and supravalvular regions.

ME AV long-axis view demonstrates:VSD and an overriding aorta. 

Spectral and CFD: to interrogate the direction and velocity of the ventricular shunt and determination of severity of RVOT obstruction.

The TEE examination should also include an assessment of aortic valve competence. 

Examination after repair:

TEE evaluation after bypass includes an evaluation for possible tricuspid, pulmonary, and aortic regurgitation and an estimation of RV and LV size, thickness, and function.

VSD:Look for intact patch,no residual shunt,no LVOT obstruction

RVOT: for residual RVOT obstruction look in ME RV inflow-outflow view and transgastric views.

Q.101)Discuss VSD position in TOF.

Best in Apical 5 chamber view- show VSD below Aorta.

Other in short axis view – VSD positions,

 Between 12 & 1 o’ clock position – Sub pulmonic VSD- part of margin by pulmonary

annulus.

Between 11 & 12 o’ clock position – Sub aortic VSD – Part of margin by aortic annulus.

 Between 9 & 11 o’ clock position – Perimembranous VSD – part of margin formed by fibrous trigone.

 Inlet VSD – part of margin formed by tricuspid annulus.

Q.102)What is the incidence of multiple VSD in TOF ?

2% - mainly inlet type 

Q.103)What is the criteria of  LV size for TOF contraindicating intracardiac repair ?

LVEDV < 30> LVED (D) < 60> MV area < -2 Z

LV size in TOF- range

Large if diameter > RV

Small if diameter < 3> Diminutive if diameter < ½ RV

(all diameters taken transversely at the end diastole)

Q.104)What are the indications for cath in TOF ?

 Branch PA stenosis.

Coronary crossing RVOT.

PA confluence.

 MAPCAS

 Points to note on cardiac cath.

- Distal RVOT.

- Peripheral PAs.

- Coronary anatomy.

- Collaterals.

Q.105)Discuss use of coronary angio in TOF.

- Prominent conal artery crossing RVOT

- LAD from RCA

- Entire LCA from rt. Side

- Double LAD from LCA & RCA

Q.106)What does Left Heart study in TOF  reveal ?

- Coronary anomalies

 -MAPCAS

- PDA

- AR

- LV gram – VSD.

Q.107)What is the catheter course in TOF ?

Right heart study- RFV->IVC->RA->RV->PA

Left heart study – RFA-> Aorta->LV

Q.108)If the catheter course RV->Aorta possibilities are

- TGA

- AP window

- Pulmonary atresia

- TOF

Q.109)How to assess PA size or How to decide for Transannular patch ?

Various indices like McGoon & Nakata are used to assess Pas.

Q.110)What is Mc Goon Ratio ?

•    It is Angiographic ratio.

•    Calculated as: Diameter of RPA & LPA at pre branching level ( RPA is measured at the right border of spine & LPA before its 1st lobar artery) Divided by Diameter of descending aorta at the diaphragm level in systole

•    >2 – ideal, >1.5 – Acceptable, <0> Drawback-Descending aorta at the diaphragm level tends to be more narrow in TOF than normal individual making Mc Goon ratio falsely more favourable.

Q.111)Fallacies of Mc Goon ratio-

•    Post stenotic dilatation

•    Peripheral pulmonary artery coarctation

•    PS PAH Situation

•    TOF with APV syndrome

Mc Goon used his little finger & index finger to size the PA annulus

Little finger if BSA is <1> 1.4

A little finger = 13mm

Index finger = 17mm

Q.112)What is Nakata Index ?

Index described by Echocardiography

CSA of RPA & LPA Divided by BSA

Normal value 330+/- 30 mm2/m2

<150> >100 mm2/m2 –ICR in TOF

Q.113)What are the Fallacies of Mc Goon/Nakata?

It does not take into account: Distal PA stenosis and PA dilatation

Q.114)What is Kirklin’s index ?

Kirklin, Blackstone & colleagues have described.

Post op PRV: LV - < 0>

Q.115)What is Z value ?

 Z value is an expression of the outflow tract circumference normalized to the body surface area or 

Number of standard deviations that the patient’s pulmonary valve annulus is away from the mean normal value.

Established by Rowlatt, Rinoldi & Lev.

Q.116)When is TAP done ?

TAP is placed after measuring RVOT diameter with Hegar dilators and comparison to standard tables is done to obtain Z value.TAP is considered when the Z value of the pulmonary valve annulus is -3 or less from the Z value

Q.117)Which drugs are contraindicated in TOF ?

Digoxin- Causes infundibular spasm

Lasix – Causes hemoconcentration

Vasodilators – precipitates spell

Q.118)How does Propranolol reduce spell ?

It decreases heart rate

Relieves spasm by decreasing the adrenergic drive

Increases SVR antagonizing the vasodilatation by Beta adrenergic stimulation

It stabilizes vascular reactivity of systemic arteries thereby preventing the decrease in SVR

Q.119)What is the dosage of propranolol ?

 Inj Propranolol iv 0.01-0.25mg/kg slow iv

 

Q.120)What is Optimum propranolol therapy ?

Till HR falls by 25% of the basal HR

No bronchospasm

Q.121)What is the limitation of propranolol treatment during spell ?

Heart rate: Bradycardia

Systolic BP: if SBP falls by more than 20 mm Hg of baseline, then propranolol administration has to be stopped

Q.122)What is Non surgical treatment in TOF ?

- Blood letting

- Balloon pulmonary valvotomy

- PDA kept patent by stenting & PGE2

- Embolisation of MAPCAS

- Balloon atrial septostomy

Q.123)What are the Indications for a BT Shunt ?

- CCHD not fit for ICR, with severe symptoms

- TOF with pulmonary atresia

- TOF with

•     Unresolved spell

•    Age < 6> •     Hypoplastic PA

•     Underdeveloped LV (< 60> •     MV annulus < -2 ‘Z’

- Institutional criteria for performing an ICR

Q.124)Which palliative procedures for cyanotics are done from midline ?

- BT shunt

- Waterston Cooley shunt

- Gazzaniga shunt

- Glenn shunt

- Davidson’s shunt (direct anastomosis of MPA to aorta)

- Brock’s procedure (infundibulectomy only through a purstring in RVOT)

- Mc Goons procedure (patch widening of the MPA, RPA & LPA)

Q.125)Which shunts are done from left lateral thoracotomy ?

- BT shunt- classical & modified

- Potts shunt

- Benson Roe procedure (anastomosis of LAA to vertical vein for palliation of TAPVC) 

Q.126)Which palliative procedures are done from right thoracotomy ?

- Right BTS

- Blalock Hanlon atrial septectomy

- Waterston shunt

Q.127) Site of BT Shunt murmur

Classical BT shunt-

Supraclavicular & interscapular region radiating to neck

Modified BT shunt-

Infraclavicular not radiating to the neck

Q.128) What is modified Right BT shunt through Midline?

Innominate artery to RPA shunt through midline.

Q.129)What is Central shunt ?

- Very small PAs.

- Two techniques-

Direct (Gazzaniga shunt) Transect MPA & anastomose distal end to ascending aorta-Roger Mee tech.

Indirect Gortex tube graft from ascending aorta to MPA (Davidson’s shunt)

Q.130)TOF –PA with PDA, How will you manage?

Do modified BT shunt on the side of PDA & ligate PDA.

Q.131)What  investigations  are required prior to an emergency BT shunt in a child with unresolved spell ?

- Hct (SOS blood letting to obtain Hct of around 65%)

- Platelet function & count

- Echo examination for

 PA size,

 PA confluence

 Side of arch

Q.132)Why modified BT Shunt on the same side as arch ?

Longer length available of SCA before it branches

Lesser chances of damage to recurrent laryngeal nerve.

Q.133)What is the disadvantage of a BT Shunt through a thoracotomy ?

Due to a thoracotomy there is increased collateral formation & may interfere during and post intracardiac repair if Fontan performed

Which  size of Gortex to be used?

Protocol by age

•     If < 6> •     6mnths to 2 years- 5mm

•     2 to 6 years- 6mm

•     > 6 years- 8mm

Protocol by weight

< 7> 7 to 12 Kg- 5mm

12- 20 Kg- 6mm

> 20 kg- 8mm

(However the decision for the size is ultimately based on the size of the SCA)

Q.134) Why “as proximal LPA” as possible for BT Shunt ?

- More equal distribution of blood flow &

- Easy to loop from midline (for later closure during an ICR)

Q.135)What are causes of bradycardia on clamping the LPA ?

- RPA absent/ ostial stenosis/ hypoplastic/ non confluent

- Isolated left lung ventilation

- Vagus nerve included in the clamp.

Q.136) Measures to be taken if bradycardia occurs ?

- Check bilateral ventilation

- Allow reexpansion of lung

- Check if vagus nerve is clamped

- Try side clamping the artery

Q.137)What are signs of good functioning of shunt ?

- Graft Sweating

- Thrill over PA

- Hemodynamics

- Improvement in O2 saturation%

- Fall in DBP

Q.138)What are the causes of absent thrill after BT shunt ?

- Check BP- low BP

- High Hct

- Small SCA (ligate distal SCA)

- Neointimal proliferation.

 Shunt thrombosis.

- Infective endocarditis.

- Patient outgrows the shunt.

Q.139)What changes occur after BT shunt ?

- Symptomatic improvement

- PA size grows 

- LV develops

- Hct decreases & coagulation profile normalizes

- Collaterals close

Q.140)What are the causes of patient being symptomatic after BT Shunt ?

- Patient has outgrown shunt

- Shunt blocked due to

Thrombosis

Neointimal hyperplasia

Infective endocarditis

PA distortion

- Intracardiac cause- AR/ PR

Q.141)What are the problems during BT shunt ?

- Bradycardia.

- V-P mismatch.

- Absent PA on that side.

- Vagal stimulation.

- Spell under anaesthesia.

- Horner’s syndrome.

- Bleeding.

Q.142)What are the complications BT shunt ?

Immediate

- Shunt blockage

- Over size/Under size- CCF/ Inadequate perfusion

- Bleeding

- Seroma

- Weeping shunt

- Kinking of shunt

- Necrosis of arm – Classical BT shunt

- Diastolic hypotension

- Metabolic acidosis

- Haemorrhagic pulmonary edema

Late

- Pulmonary plethora/Inadequate perfusion

- CCF

- Distortion of PA

- Acquired pulmonary stenosis/pulmonary atresia

- Disparity in arm- Classical BT shunt

- Chylothorx

- Horner’s syndrome

Q.143)What are the reasons for postoperative hypoxia or fall in saturation after BT shunt ?

Large shunt - pulmonary flooding

small shunt - thrombosis

Pulmonary vasospasm increasing R-L shunt

Q.144)What is the advantage of modified vs classical BT shunt ?

- Decrease chances of distortion of PA & SCA

- Less dissection

- Blood supply to arm is maintained

Q.145)Discuss CCF in modified BT Shunt Vs classical BT Shunt.

Same incidence; as the flow limiting factor is the subclavian artery.

Q.146)What is the E/o previous BT Shunt on X-ray?

Of thoracotomy

- Rib crowding

- Synostosis/ callous formation

- Subperiosteal resection

Of dissection

- Elevation of dome of diaphragm

Of shunt

- Normalization of pulmonary vasculature

- MPA prominent

- LV developed

Q.147)Discuss dose of Heparin & Aspirin after shunt.

Heparin 10 units/kg/hr on table till 24 hours

Aspirin 5mg/kg daily after 24 hours

Q.148) Discuss Collateral supply to hand after classical BT shunt.

- Superior intercostal artery

- Transverse cervical artery

- Transverse scapular artery

- Subscapular artery

- Suprascapular artery

- Circumflex humeral artery

Q.149)What are the reasons for Blocked BT shunts ?

a) Technical reasons –

- Narrow anastomosis.

- Bite through posterior wall.

- Graft kinking.

b) Neointimal proliferation at the anastomotic site.

c) Shunt thrombosis.

d) Infective endocarditis of the shunt.

e) Patient outgrows the shunt physiological blockage.

Q.150)Discuss Indications for ICR in TOF .

- Mc Goon ratio >0.7

- Nakata Index >100

- Z value > -3

- LV Volume 60% or more than normal (30 ml/m2)

- Absent peripheral pulmonary coarctation

- No major conal branch crossing RVOT

Q.151)What are the contraindications for ICR TOF ?

- Unfavourable PA anatomy 

- Multiple VSDs 

- Coronary artery crossing RVOT 

- Hypoplastic LV (LVEDV < 30> - Institutional criteria for performing ICR at a particular age & weight

Q.152) Define obligatory & non obligatory collaterals.

Obligatory collaterals – is one when the collateral is the sole supply to a portion of the

lung whereby it cannot be ligated as then the lung become ischemic.

Non obligatory collaterals – is one when the collateral supplies the lung by joining with

the pulmonary artery so that even on ligation the blood supply to lung is not necessarily

jeopardised.

Q.153)What is Unifocalisation?

The procedure of connecting all obligatory collaterals to the main or branch pulmonary arteries so that the pulmonary arteries form the main blood supply to the lungs is called unifocalisation of the vasculature.

Q.154)How are MAPCAS classified ? 

2 classification system.

Robinovitch’s classification – based on origin

 Direct origin –

Type I – Bronchial artery

Type II – From Aorta

 Indirect origin – Type –III – branches of aorta.

Mc Goon‘s classification – based on termination

Type  I – Intra pericardial end – side entry into MPA.

Type II – Extrapericardial end – side entry into Branch PA.

Type III – Sole supply to lobe of lung.

Q.155)What are the sources of collateral blood supply in the TOF ?

- Descending aorta.

- Bronchial arteries.

- Arch of aorta.

- PDA.

Mediastinal collaterals

Bronchopulmonary collaterals

- Intercostal vessels

Internal mammary collaterals: these bleed post BT shunt

Q.156)What is the role of angio in MAPCAS ?

- Number

- Site.

- Type.

- Flow through MAPCAS.

- Embolisation of MAPCAS.

Q.157)Why are MAPCAS important ?

Intraoperative Considerations –

Flooding of field

Rewarming of heart

Distension of heart

Decrease return to pump (CPB)

Postoperative Consideration –

Pulmonary oedema

Q.158)Where to look for MAPCAS ?

On Rt side – Between Aorta & SVC.

On Lt. Side – Posterior pericardium left of MPA & LAA.

Q.159)How will you manage TOF with MAPCAS?

If  MAPCAS are not supplying major portion of the lung & that side of the lung is supplied by PA - On the day of surgery embolize the MAPCAS & do ICR or ligate them on CPB

Q.160)What are the  CPB implications in TOF patient ?

1) Maintain optimum Hb – Blood letting to be done safely.

2) Maintain HCT 45 – Avoids capillary leak syndrome. As lower Hct shall lead to capillary leak syndrome

3) Blood letting :On table after induction from IV line.

                          From venous cannulae.

                          On bypass from reservoir.

4) Dilution preferentially with colloids – Albumin or FFP

5) Maintain low perfusion pressure as all blood goes to collaterals.

 6)Massive bronchopulmonary return due to collaterals can be harmful because of it fills the field and interferes with rewarming.

7) Distension of the heart - should be prevented.

Q.161)What is the cause of low pressure on CPB in TOF ?

Hemodilution

Collaterals

Reason for excessive LA return :

 PDA, collaterals

Q.162)Discuss - TOF corrected clamp released but heart is not beating ….

Rule out & correct

- Hypothermia

- Hyperkalemia

- Acidosis

 Look for LV distension – Put LV vent if needed

- Put vent in RSPV 

Pacing

Q.163)Discuss -TOF corrected, Heart is beating, But not able to come off CPB…..

Check the following :

- Hypothermia

- Hyperkalemia

- Acidosis

- Urine output

- Residual shunt (RA-PA step up / TEE)

- Residual RVOTO (RV-PA pressure / MPA-RPA pressure / MPA –LPA pressure / TEE)

- Pulmonary regurgitation (TEE)

Homograft conduit

Prosthetic conduit

Prosthetic valve

Still not able to come off CPB

- Rest the heart for some time on CPB & after maximize inotropic support try again to come off CPB

 

Q.164)Incidence of complete heart block post ICR TOF.

Less than 1%

Q.165)Incidence of RBBB +/- LAHB post ICR TOF.

20- 25%.

Q.166)What is the problem with TOF with multiple VSDs ?

If multiple VSDs are closed with a big VSD patch all over interventricular septum, it cannot move and IVS dysfunction occurs and cardiac failure can ensue.

Q.167)What are the late complications of ICR TOF ?

- RVOT restenosis

- PR/TR leading to RV failure

- Arrhythmias

- Aneurysm of RVOT patch

- Calcification of RVOT patch (Dacron, PTFE)

Q.168)Why are Adult TOF at higher risk for surgery ?

- RVH may lead to RV failure

- Endocardial fibroelastosis

Q.169) Discuss Post ICR TOF arrhythmias.

Ventricular arrhythmias in 40- 50% of patients in postoperative period.

Predictors of arrhythmias are:

- Age of surgery

- Moderate/severe PR

- Prolonged QRS interval (> 180 msec)

- RBBB is common after TOF surgery but complete heart block is rare.

Q.170)What are the postoperative issues in TOF ?

Residual PR

RV dilatation and dysfunction

Residual RVOTO

Branch PA stenosis or hypoplasia

Sustained VT

Sudden cardiac death

AV block/ Atrial flutter/ Atrial fibrillation

Aortic regurgitation

Syndromal association

Q.171)Why postoperative LV dysfunction occurs in TOF ?

Excess CPB time

Improper myocardial protection

Damage to coronaries

Secondary to RV dysfunction

Q.172)What are the causes of RV dysfunction in TOF ?

Incision over RV

Improper myocardial protection

Damage to coronaries

PR/TR

Excess CPB time

Large adynamic patch

Residual VSD

Q.173) What are the chronic complications following surgery ?

•    Pulmonary regurgitation

•    RVOT aneurysm 

•    Residual VSD

•    Residual PS

•    Mild AR

•    Arrhythmias

Q.174)When is Rerepair in TOF considered ?

Pulmonary valve replacement

AVR if AR

Bentall’s procedure if ascending aorta dilated

VSD

ASD

Maze for atrial arrhythmias

Pacemaker/ICD

TV repair/Replacement

Aneurysm of RVOT

Q.175) How will you do anaesthetic management of Palliative Shunt procedure and Intracardiac Repair ?

          Goals of Anaesthesia- 

          According to Cardiac Grid –

•    Heart Rate – Avoid tachycardia as patient can go in cyanotic spell

•    Contractility – Maintain 

•    SVR –Increased

•    PVR – Decreased

•    Preload – Increased

•    After load – Increased so that PBF occurs

•    SpO2 of > 80%

•    PO2 > 50%

Patient weight taken here is 5kg

NPO orders according to guidelines of 2,4,6,8 hours 

Premedication- IM Inj Ketamine 5mg/kg with Glycopyrrolate 0.01mg/kg with Inj Midazolam 0.05mg/kg 

This is given in the premedication room outside OT under monitoring 

Monitors placed –ECG, SpO2 probe connected

Oxygen started

IV line secured if it is not placed earlier 

Induction- Intravenous induction is better as with volatile induction SVR will be decreased if high volatile gases are used. Also, patient undergoes slowly in volatile induction 

IV induction is faster and preferred in all congenital heart diseases but in left to right shunts volatile induction is faster than right to left volatile induction 

Induction- Inj Ketamine 2 mg/kg iv 

                Inj Fentanyl 2 micrograms/kg iv slows HR and blunts catacholamine surge

               InjVecuronium 0.1 mg/kg

Ventilate patient with 100% oxygen (little hyperventilation)

Intubate with appropriate sized ETT, confirm bilateral equal air entry 

Secure central venous access and arterial access

Maintenance of Anaesthesia- 

Oxygen with air

Volatile anaesthetic agent

InjVecuronium 0.05mg/kg iv every half hourly 

Inj Fentanyl 1microgm/kg iv 1 hourly 

CVP preferably through right IJV and Femoral artery

Temperature monitoring 

Foley’s catheter for urine output monitoring 

Heparinisation with Inj Heparin 

Before going on CPB check ACT >

Give anaesthetic drugs on CPB – Inj Fentanyl 2 micrograms/kg iv,InjVecuronium 0.05mg/kg iv 

Temperature 30 degree Celsius usually maintained 

Pump flow 1.8 to 2.4 L/min/m sq

PO2 , Hematocrit watch for

MAP 30-50 mmHg

UO 1 ml/kg/hr

Weaning from CPB

Temperature normal

ABG normal

Electrolytes normal 

Deairing done

MAP >60 mmHg

Inotropes – Inj Dopamine, Inj Adrenaline, Inj Milrinone

Rhythm- sinus

Rate 

Assess – for Prv/lv > 0.75 again revise transannular patch (in ICR)

After coming off CPB, Inj Protamine given 1:1 or 1.5:1 ratio with heparin 

After completion of surgery( BT shunt) and shifting patient to ICU the ventilatory settings after palliative procedure are done as to maintain the 

PaCO2 : 25-35mm/Hg, 

pH > 7.5 to decrease PVR

No PEEP

I:E – long expiratory time 1:2 or 1:3 to promote PBF

Mean airway pressure- normal

High airway pressure will increase PVR

Before extubation an Echo assessment of BT shunt has to be done.

176)What is VATER syndrome ?

Vertebral defects, Anal atresia, Tracheoesophageal fistula with esophageal atresia, Renal and radial anomalies.

177)What is CHARGE syndrome ?

Coloboma, Heart disease,Atresia choanae, Retarded growth and development and/or CNS anomalies, Genital hypoplasia, and Ear anomalies and/or deafness.