15. TGA- Exam 4 Flashcards
TRANSPOSITION OF THE GREAT ARTERIES (TGA/TGV)=
–Discordant ventricular-arterial relationship
–Malformation in which the two great arteries carrying blood away from the heart are transposed or reversed.
The LV–> PA
The RV–> Aorta
an acyanotic defect with increased pulmonary BF could be what defects?
ASD
VSD
PDA
AVSD
an acyanotic defect with obstruction to BF from the ventricles could be what defects?
Coarctation of the aorta
Aortic stenosis
Pulmonary stenosis
an cyanotic defect with decreased pulmonary BF could be what defects?
TOF
Tricuspid Atresia
an cyanotic defect with mixed BF could be what defects?
TGA
TAPVR
Trunctus arteriosus
HLHS
TGA is incompatible with life unless what happens?
unless some communication exists between the two separate circulatory systems. (ASD or VSD)
with a TGA, what are the 2 parallel circulation exists
- Body—-RA—-RV—-AO—-Body
2. Lungs—LA—-LV—-PA—-Lungs
with a TGA, what do the 2 circulations cause
Poor mixing Hypoxia & Acidemia Hyperventilation Increased pulmonary flow CHF Myocardial depression
when is TGA the most common cyanotic congenital heart lesion
when presenting in the neonate
TGA % occurrence of congenital heart diseases
5%
is TGA more common in males or females? whats the ratio?
More common in males, with a ratio of about 3:1
what Maternal factors associated with an increased risk of TGA
rubella or other viral illness during pregnancy, alcoholism, maternal age over 40 and diabetes.
describe the embryology of TGA
- 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
Truncus Arteriosus becomes the…
aorta
Conus Cordis becomes the…
Pulmonary Artery
-Created by a septum that forms in the outflow tract from these swellings
Outflow tract septation occurs on what day
29
As is with TAPVR, without intervention infants with TGA will die when?
within their first year of life
dextro-transposition of the great arteries [d-TGA] =
aorta is anterior and to the right of the pulmonary artery
what is d- TGA % occurrence
60%
levo-transposition of the great arteries [L-TGA] =
aorta may be anterior and to the left of the pulmonary artery
what is the ONLY distinguishing characteristic that defines TGA
Discordant ventriculo-arterial connection
TGA w/IVS=
Transposition of the great arteries with intact ventricular septum
TGA w/VSD=
Transposition of the great arteries with ventricular septal defect
TGA W/VSD, LVOT obstruction=
Transposition of the great arteries with ventricular septal defect and left ventricular outflow tract obstruction
TGA w/VSD, PVOD
Transposition of the great arteries with ventricular septal defect and pulmonary vascular obstructive disease
Congenitally corrected TGA=
Aorta and PA are normal- LV and RV are switched
-Frequently an autopsy finding
how long ago was TGA first described
over 200 years
what where the first treatments to become available
-development of surgical atrial septectomy in the 1950s
-balloon atrial septostomy in the 1960s
–These palliative therapies were followed by:
Physiological procedures (atrial switch operation) Anatomic repair (arterial switch operation)
Today, the survival rate for infants with TGA is greater than __%.
90%
what is the initial treatment of TGA
maintaining ductal patency with continuous IV prostaglandin E1 infusion (PGE1)
what is the purpose of giving PGE1
↑ pulmonary blood flow
↑ increase left atrial pressure
promote L→R shunting at the atrial level ( ↓cyanosis).
giving PGE1 is especially important for what condition
severe LVOT obstruction
when is PGE1 not useful
the PDA will not help when the defect has intact septum’s- and separate circulations
surgical repair for a TGA: first operation=
arterial switch
alternative procedure for TGA with intact septum=
Atrial switch
alternative procedure for TGA with septal defect=
Rastelli
Rev Nikaidoh
In TGA w/IVS and LVOT obstruction. An arterial switch operation may not be feasible due to what?
pulmonary (left ventricular outflow tract) stenosis or atresia
If the ventricular septal defect is nonrestrictive and not too remote from the aorta, what procedure is possible
Rastelli intracardiac repair
Rastelli procedure=
conduit from the RV to the PA , delaying repair
what procedure may be necessary to establish adequate pulmonary blood flow while waiting for the full repair
placing an aorto-pulmonary shunt during the newborn period (BT or Central)
what are the 2 types of Atrial Switches
Mustard
Senning
what are the 2 types of Arterial Switches
Jatene
Le Compte
MUSTARD PROCEDURE –ATRIAL BAFFLE=
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 RV is not the optimal shape to support the high pressure work performed in a normal heart by the LV
SENNING PROCEDURE (ATRIAL TISSUE BAFFLE)=
- -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
The Mustard procedure and Senning procedure are identical except for what?
the baffle is constructed from atrial tissue in the Senning and from pericardium in the Mustard
when did complications from the Senning and Mustard procedure become known
1980’s
after the complications from the Senning and Mustard procedures where discovers, what procedure did they start to use instead
neonatal arterial switch procedure, which is now standard therapy for transposition.
The Mustard procedure was replaced in the late 1970s by the ____________
Jatene procedure (arterial switch)
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
why was the Jatene procedure not possible prior to 1975
because of difficulty with re-implanting coronary arteries which perfuse myocardium
what is the ideal procedure for TGA repair
ASO procedure [arterial switch]
why is an ASO procedure ideal for TGA reapir
It represents an anatomic repair and establishes ventriculo-arterial concordance
when should an ASO be performed? why?
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)
LE COMPTE MANEUVER=
Ascending aorta and pulmonary trunk are transected and switched. Coronary arteries are transected and re implanted into neo-aortic root. Straddles the neo-aorta
CPB Considerations for TGA: Arterial+Venous Cannula
Arterial: Aortic
Venous: Single Atrial (bicaval if 4+ kg)
CPB Considerations for TGA: Temp
DHCA/Low flow w/HCA
CPB Considerations for TGA: Cardioplegia
Antegrade, Retrograde and Ostial (multiple dosing)
CPB case notes for TGA: what is the typical weight of these children
These children are larger weight (around 3 kg)
CPB case notes for TGA: be very careful while delivering what?
Be very careful with cardioplegia (flow/pressure)
CPB case notes for TGA: is this a complete repair or just a palliation?
Most often, this is a complete correction not a palliation
CPB case notes for TGA: what usually happens after the case? what should you try to do?
Open chest - post procedure (silastic patch)
– try to Reduce myocardial edema
CPB case notes for TGA: whats the length and difficulty of the producure
Longer procedure (technically difficult)
CPB case notes for TGA: whay might happen after the case despite a good prognosis
ECMO may be in the cards w/good prognosis
Truncus Arteriosus=
a rare type of congenital heart disease in which a single blood vessel (truncus arteriosus) comes out of the right and left ventricles, instead of the normal two (pulmonary artery and aorta).
If Truncus Arteriosus goes tntreated, what Two Problems occur
I. Too much pulmonary blood flow
II. The blood vessels to the lungs become permanently damaged. Pulmonary hypertension develops.
what is The major problem in Truncus Arteriosus
the lungs are flooded with blood and the heart muscle is overloaded
Truncus Arteriosus symptoms (8)
Bluish skin (cyanosis) Delayed growth or growth failure Fatigue Lethargy Poor feeding Rapid breathing (tachypnea) Shortness of breath (dyspnea) Widening of the finger tips (clubbing)
what is the Trunctus Arteriosus thought to result from
failed septation of the embryonic truncus arteriosus
Aortopulmonary and interventricular defects are believed to represent an abnormality of what?
conotruncal septation.
with Trunctus Arteriosus, why is a PDA is not required to support the fetal circulation.
Because the common trunk originates from both the LV and RV, and PA’s arise directly from the common trunk
what are the truncus arteriosus and bulbus cordis are divided by
aortico-pulmonary septum
The truncus arteriosus gives rise to what
the ascending aorta and the pulmonary trunk.
The bulbus cordis gives rise to what?
the smooth parts (outflow tract) of the LV and RV
Truncus Arteriosis type 1=
truncus -> one PA -> two lateral pulmonary arteries
–characterized by origin of a single pulmonary trunk from the left lateral aspect of the common trunk, with branching of the left and right pulmonary arteries from the pulmonary trunk.
Truncus Arteriosis type 2=
truncus -> two posterior/ posteriolateral pulmonary arteries
–characterized by separate but proximate origins of the left and right pulmonary arterial branches from the posterolateral aspect of the common arterial trunk
Truncus Arteriosis type 3=
truncus -> two lateral pulmonary arteries
- -Branch pulmonary arteries originate independently from the common arterial trunk or aortic arch, (most often from the left and right lateral aspects of the trunk).
- -This occasionally occurs with origin of one pulmonary artery from the underside of the aortic arch, usually from a ductus arteriosus
Since the truncal valve is above the VSD, how does the blood flow
blood is pumped from both the RV and LV to the lungs and to the body, (mixing is occurring)
, PVR is lower than SVR… what does this cause
there is usually increased blood flow to the lungs. This increased PBF can lead to CHF
with Tructus Arteriosis…Because the lung arteries are connected to the high pressure pumping chambers (LV/RV) there is pulmonary HTN. If the lungs are exposed to both high pressure and extra blood flow for an extended time (months to years), what happens
irreversible pulmonary hypertension can occur.
PA Banding (palliative repair for trunctus arteriosis)=
involves banding the pulmonary arteries coming off the truncus (reduces pulmonary blood flow)
where is the incision site for PA Banding and is this a CPB case
The left anterior thoracotomy approach through the second or third intercostal space gives excellent exposure for isolated pulmonary artery banding.
–Extracardiac procedure – no CPB
Rastelli procedure (complete repair for trunctus arteriosis)=
connects the RV-PA. This tube is usually a homograft, (made from human cadaver tissue).
–During the Rastelli procedure, the VSD is closed with a Gore-Tex patch so that the aorta arises solely from the LV
what is the ABCD steps for Surgical Repair of Truncus Arteriosus
- A Origin of truncus arteriosus PA’s are excised and the truncus defect closed with direct suture. An RV ventriculotomy is made.
- B VSD is closed with a prosthetic patch.
- C Placement of a valved conduit into the pulmonary arteries.
- D Proximal end of conduit is anastomosed to the RV.
CPB Considerations for Truncus Arteriosus: incision
Median sternotomy
CPB Considerations for Truncus Arteriosus: arterial + venous cannula
Arterial: Aortic
Venous: Single atrial cannula
CPB Considerations for Truncus Arteriosus: temp
Mild to Moderate period DHCA
CPB Considerations for Truncus Arteriosus: cardioplegia
Antegrade, possibly retrograde
CPB Considerations for Truncus Arteriosus: aortic Xc time
moderate length
Case notes for Truncus Arteriosus: what is is often required following repair of truncus arteriosus.
Delayed sternal closure
Case notes for Truncus Arteriosus: what has Marked improvement post-op vs. pre-op
blood gases
Case notes for Truncus Arteriosus: although antegreade cpg is standard, what should you be prepared for
retrograde CP (monitor CVP should be 30- 40 mmhg)
Case notes for Truncus Arteriosus: will you see this patient for a redo? why?
At some point changing of the RV-PA Conduit would be done as a redo Rastelli ( Maybe twice ? )
