Topic 15: Transposition of the Great arteries Flashcards

1
Q

Transposition of the Great Arteries is what?

A

Discordant ventricular-arterial relationship
Transposition of the great arteries (TGA) or
vessels (TGV) is a malformation in which the
two great arteries carrying blood away from the heart are transposed or reversed.
LV–>PA
RV–> Aorta

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2
Q

Classification of congenital heart disease – how to get to TGA?

A

Cyanotic–>Mixed Blood Flow –>TGA/TAPVR/Truncus Arteriosus/HLHS

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3
Q

TGA – when is it compatible with life?

A

This defect is incompatible with life unless some communication exists between the two separate circulatory systems.

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4
Q

TGA frequently occurs with what?

A

Frequently, patients with TGA have ASD’s or VSD’s

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5
Q

TGA kids acid base status ?

A

acidodic usually

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6
Q

Classification of congenital heart disease

if patient is Cyanotic and has decreased Pulmonary BF what do they have?

A

TOF or Tricuspid atresia

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7
Q

If kid is bicaval and less than 6 kgs what venous cannulas do you use?

A

12/12 Fr

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8
Q

Classification of congenital heart disease

if pt is acyanotic and has increased Pulmonary BF what may they have?

A

ASD, VSD, PDA or AVSD (AV canal)

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9
Q

TRANSPOSITION OF THE GREAT ARTERIES (TGA) (WITH BOTH AN VSD AND A ASD)
involve what?

A

higher aortic pressure
prob aortic to pulm ductal flow

  1. Aorta emerges from RV
  2. PA emerges from LV
  3. Hole or defect in atrial septum
  4. Hole or defect in ventricular septum
  5. PDA
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10
Q

TGA - Parallel circulation exists - what are their orders from Body and from lungs?

A

Body—->RA—->RV—->AO—->Body

Lungs—>LA—->LV—->PA—->Lungs

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11
Q

TGA hematologic symptoms? (6)

A
Poor mixing
Hypoxia & Acidemia
Hyperventilation
Increased pulmonary flow
CHF
Myocardial depression
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12
Q

the most common cyanotic congenital heart lesion presenting in the neonate?

A

TGA
5 % of cases of CHD
More common in males, with a ratio of about 3:1

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13
Q

TGA epidemiology – maternal increased risk factors?

A

Maternal factors associated with an increased risk include rubella or other viral illness during
pregnancy, alcoholism, maternal age over 40 and diabetes

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14
Q

TGA embryology? what is the defect caused by?

A

Bulbus cordis defect
After outflow tract septation development
begins then:
Improper spiraling of the aorticopulmonary septum
Leads to congenital disruption in pulmonary
and systemic circulations (sounds a bit like the TOF defect development)

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15
Q

how to tell the difference between a picture of D and L TGA?

A

look at the sizes of the ventricles?

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16
Q

anterior and to the right is which TGA defectt?

A

D-TGA

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17
Q

anterior and to the left is which TGA?

A

L-TGA

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18
Q

Outflow tract septation? TA and CC becomes what?

A

Partitioning of the outflow tract
Truncus Arteriosus –Aorta
Conus Cordis–Pulmonary Artery
Created by a septum that forms in the outflow tract from these swellings

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19
Q

Outflow tract septation is what day?

A

29th day

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20
Q

As is with TAPVR, without intervention infants

with TGA what will happen?

A

die within their first year of life

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21
Q

In 60% of the patients, the aorta is anterior and to the right of the pulmonary artery called what?

A

(dextro-transposition of the great arteries [d-TGA]).

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22
Q

levo-transposition of the great arteries [l-TGA].

A

The aorta may be anterior and to the left of the pulmonary artery

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23
Q

arterial switch

A

is physically switching the arteries

FIRST OPTION for tga

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24
Q

atrial switch

A

is baffling the blood

Mustard
Senning

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25
Q

the ONLY distinguishing characteristic that defines TGA?

A

Discordant ventriculo-arterial connection

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26
Q

Common Presentations of TGA - 4

A
  • Transposition of the great arteries with intact ventricular septum (TGA w/IVS)
  • Transposition of the great arteries with vsd (TGA w/VSD)
  • Transposition of the great arteries with VSD and left ventricular outflow tract obstruction (TGA W/VSD, LVOT obstruction)
  • Transposition of the great arteries with vsd and pulmonary vascular obstructive disease.
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27
Q

development of surgical atrial septectomy when?

A

1950s

28
Q

balloon atrial septostomy when?

A

1960s

29
Q

Once Surgical atrial septectomy and ballon atrial septostomy were accomplished – what procedures followed?

A
Physiological procedures (atrial switch operation)
Anatomic repair (arterial switch operation)
Today, the survival rate for infants with TGA is greater than 90%.
30
Q

using kids own pericardial tissue is what kind of baffle?

A

mustard

31
Q

atrial tissue baffle

A

senning procedure

32
Q

TGA surgical considerations initial treatment? and what will this treatment help with? (3)

A

Initial treatment consists of maintaining
ductal patency with continuous IV prostaglandin E1 infusion (PGE1):
↑ pulmonary blood flow
↑ increase left atrial pressure
promote L→R shunting at the atrial level (↓cyanosis)

33
Q

Giving PGE1 to TGA pts is important with pts with what?

A

with severe LVOT obstruction

34
Q

TGA pts where a PDA will not help blood flow is when the defect has what?

A

has intact septum’s-and separate circulations

35
Q

TGA surgical repair - alternative procedure

TGA with intact septum?

A

Atrial Switch

36
Q

TGA surgical repair - alternative procedure

TGA with septal defect?

A

Rastelli

37
Q

In TGA w/IVS and LVOT obstruction. An arterial switch operation may not be feasible due to what?

A

pulmonary (left ventricular outflow tract) stenosis or atresia

38
Q

In TGA if the ventricular septal defect is nonrestrictive and not too remote from the aorta, what procedure may be possible?

A

a Rastelli intracardiac repair could be possible

39
Q

Trouble with peds and reimplanting Coronary arteries ?

A

the coronary artery can kinda and your systemic pressure will drop bc there is no blood flow to heart so its not going to pump and that is why the pressure is going to
tank

40
Q

in a half full heart how is dp/dt?

A

great contractilility

41
Q

Rastelli procedure on a TGA?

A

-conduit from the RV to the PA , delaying repair

In this case, placing an aorto-pulmonary shunt during the newborn period may be necessary to establish adequate pulmonary blood flow while waiting. (i.e. central shunt et al.)

42
Q

Rastelli Procedure 2 steps?

A
  1. VSD closed with patch what allows blood in LV to reach aorta
  2. conduit from RV to PA
43
Q

TGA corrective procedures - Atrial Switch Types?

A

Mustard

Senning

44
Q

TGA corrective procedures - Arterial Switches type?

A

Jatene

Le Compte

45
Q

Mustard Procedure Atrial Baffle is what-explain?

A

The Mustard procedure restores the circulation, but reverses the direction of the blood flow in the heart
Blood is pumped to the lungs via the LV and
disseminated throughout the body via the RV.
But the right ventricle is not the optimal shape to support the high pressure work performed in a normal heart by the left ventricle

46
Q

TGA is one of the few cases that you will give what type of CPG?

A

neonatal ostial CPG

47
Q

If give a neonate ostial CPG with too much pressure what could you cause?

A

Myocardial edema

48
Q

Atrial Baffles 4 steps? (senning or mustard)

A
  1. Blue blood redirected to LA
  2. LV pumps blood to lungs
  3. Red blood from lungs redirected to RA
  4. RV pumps blood to body
49
Q

At a coronary pressure of 8mmHg do the coronaries kink?

A

NO

50
Q

Senning Procedure - atrial tissue baffle - explain it?

A

A baffle is created within the atria that
redirects the deoxygenated caval blood to the mitral valve and the oxygenated pulmonary venous blood to the tricuspid valve.

The anatomic LV continues to act as the
pulmonary pump and the anatomic RV acts as the systemic pump

51
Q

Atrial baffles – the difference between the two types?

A

The Mustard procedure and Senning procedure are identical except that the baffle is constructed from atrial tissue in the Senning and from pericardium in the Mustard

52
Q

By the 1980s, late complications of TGA
repairs had become well recognized, which led
to the adoption of the ______, which is now standard therapy for transposition

A

neonatal arterial switch procedure

53
Q

The Mustard procedure was replaced in the late 1970s by what?

A

the Jatene procedure (arterial switch)
Native arteries are switched back to normal flow, so that the RV would be connected to the pulmonary artery and the LV would be connected to the aorta.
This surgery had not been possible prior to 1975 because of difficulty with re-implanting coronary arteries which perfuse myocardium

54
Q

TA - what determines aortic flow?

A

SVR

55
Q

TA - what determines pulmonary flow?

A

PA restriction

56
Q

TGA - the ideal operation is Arterial switch operation which represents what?

A

It represents an anatomic repair and establishes ventriculo-arterial concordance.

57
Q

When should TGA 0 Arterial switch be completed?

A

This procedure should be performed when the infant is younger than 4 weeks, (the LV may not be able to handle systemic pressure in the pulmonary system)

58
Q

which type of TA will have the most Pulm overcirculation

A

TA - III

bc there is nothing restricting flow

59
Q

Arterial Switch - 2 steps?

A
  1. PA connected to RV

2. Aorta connected to LV

60
Q

Jatene Procedure is to fix what?

A

D-TGA

61
Q

TA - I

A

single trunk that bifurcates into the pulmonary arteries

62
Q

to ligate a PDA – how do you go in the chest?

A

left thoracotomy

63
Q
TGA  - CPB considerations 
Cann - Arterial ?
Venous?
Temp?
CPG?
A
Cannulation
Arterial: Aortic
Venous : Single Atrial (bicaval if 4+ kg)
Hypothermia: DHCA/Low flow w/HCA
Cardioplegia: Antegrade, Retrograde and
Ostial (multiple dosing)
64
Q

As you tighten a PA band what happens to aortic pressures?

A

Aortic pressures goes up

65
Q
TGA - CPB considerations?
wt?
time?
post-op?
CPG ?
A

These children are larger weight (around 3 kg)
Be very careful with cardioplegia (flow/pressure)
Most often, this is a complete correction not a
palliation
Open chest-post procedure (silastic patch)
Reduce myocardial edema
Longer procedure (technically difficult)
ECMO may be in the cards w/good prognosis

66
Q

Doing a PA band - how will you know you PA pressures?

A

stick the needle in the PA after and before the band to look at the pressure drop and that will show a PA pressure

67
Q

Lack of pulmonary flow will make the patient what acid base status?

A

Acidotic
Qs Increases and Qp decreases

if there is a leak the bld gases will show you