Topic 10: AVC ESD AVSD Flashcards
Definition: AVSD/ECD/AVC Defects
Incomplete fusion of the endocardial
cushions which form primum atrial septum, A-V valves, and inlet ventricular septum
A deficiency or absence of septal tissue immediately above and/or below the normal plane of A-V valves. The valves are abnormal in shape and/or function
Incidence of congenital heart disease is approximately?
8 per 1000 live births.
AVSD - how common?
5th most common occuring CHD
AVSD is commonly associated with what syndromes?
Down’s syndrome and cardiac malformations such as Tetralogy of Fallot (TOF), Double outlet right ventricle (DORV), and sub-aortic stenosis (SAS)
•It is also present in 60% of patients with heterotaxy* syndrome.
AVSD is associated with what organs malformation?
Certain organs forming on the opposite side of the body
Morbidity/mortality of AVSD?
High what can prolong life?
repaired btwn 4-6month % survival?
- Children with a complete AV canal fail to thrive in the first few months of life.
- Patients may survive the first few years of life if the PVR is high
- High PVR decreases left to right shunting, increases LVEF
- If AV canal is repaired between 4-6 months of life, survival is >80%
Morbidity/mortality of AVSD?
High what can prolong life?
repaired btwn 4-6month % survival?
- Children with a complete AV canal fail to thrive in the first few months of life.
- Patients may survive the first few years of life if the PVR is high
- High PVR decreases left to right shunting, increases LVEF
- If AV canal is repaired between 4-6 months of life, survival is >80%
An endocardial cushion defect consists of ?
aka?
defects in lower atrial and upper ventricular septa, and deficiencies in the mitral/tricuspid valves.
Also called AVC, or AVSD
Atrioventricular septal defects can be classified into what categories?
into one of three categories called complete, partial (or incomplete), or transitional.
•Complete (CAVSD)
•Partial (PAVSD)
•Transitional (TAVSD)
- A. Balanced
- B. Unbalanced
Balanced AVSD?
Ventricles are equal in size
•Size is relatively normal
•Both left and right AV valves may equally share the common AV valve orifice. This arrangement is termed a balanced defect
Unbalanced AVSD?
One of the ventricles may be hypoplastic
•Size will be different
What day is Outflow Tract Septation in Embrology
DAY 29
AV septal defects occur at the embryonic age of what?
of 34-36 days when fusion of the endocardial
cushions fails.
•This occurs when the endocardial cushion
fibroblasts fail to migrate normally to form
the septum of the AVC.
After fusing with the endocardial cushion, if there is a small residual opening at the ECC it is called what?
ostium primum ASD (AVSD)
AVSD embryology end result, deficiency where?
Deficiency of the primum atrial septum, the ventricular septum, the septal leaflet of the tricuspid valve, and the anterior leaflet of the mitral valve occurs
•AV valves becomes offset
•Anterior leaflet of the AV valve extends across septum
AVSD embryology end result — •If the leaflet opens preferentially toward a ventricle, what occurs?
•If the leaflet opens preferentially toward a ventricle, (limiting flow to the other ventricle), hypoplasia occurs and creates an unbalanced AVSD
Complete AVSD - where is defect? AV valve?
All chambers can mix
Defect is one in which there are defects in all structures formed by the endocardial cushions.
•Therefore, there are defects (holes) in the atrial and ventricular septal, and the AV valve remains undivided or “common”.
A partial atrioventricular septal defect
one in which the part of the ventricular septum formed by the endocardial cushions has filled in:(no VSD)
•Fills in by tissue from the AV valves or directly from the endocardial cushion tissue causing
•tricuspid and mitral valves dividing into two distinct valves
Note: Valvular geometry may be affected
A partial atrioventricular septal defect how is it formed?
How and which valves affected?
one in which the part of the ventricular septum formed by the endocardial cushions has filled in:(no VSD)
•Fills in by tissue from the AV valves or directly from the endocardial cushion tissue causing
•tricuspid and mitral valves dividing into two distinct valves
Note: Valvular geometry may be affected
Partial AVSD is primarily in what valves?
atrial septum and mitral valve
causes the valve to leak (mitral regurgitation-MR)
Partial AVSD AKA
This type of atrial septal defect is referred to as an ostium primum atrial septal defect, and is usually associated with a cleft in the mitral valve that causes the valve to leak (mitral regurgitation-MR)
Partial AVSD
Ostium Primum ASD w/MV cleft
Partial mixing
Partial AVSD Considerations (3)
Conduction system disruption (A-V node displaced inferiorly between coronary sinus and ventricular crest)
•Coronary sinus ostium often displaced
•Associated anomalies: PDA, persistent LSVC
Delineated vs.
Non-delineated flow
Partial AVSD - delineated
Complete AVSD - non-delineated
Delineated vs.
Non-delineated flow
Partial AVSD - delineated
Complete AVSD - non-delineated
Transitional AVSD
looks similar to the complete form of atrioventricular septal defect, but the leaflets of the common AV valve are stuck to the ventricular septum, thereby effectively dividing the valve into two valves and closing most of the hole between the ventricles
a transitional atrioventricular septal defect behaves more like a what?
partial atrioventricular septal defect, even thought it looks more like a complete atrioventricular septal defect
Surgical Correction of AVSD is all about what?
It’s all about pulmonary blood flow
Palliative Surgical Correction of AVSD for excessive pulmonary flow: how? (increase what? decrease what?)
- PA Band:
- Increases PVR
- Decreases Pulmonary Flow
- Decreases Pulmonary Over-circulation
Palliation surgery for AVSD for insufficient pulmonary flow: how: for who?
In patients with inadequate pulmonary flow/hypoxemia, a Blalock-Taussig-Thomas
shunt or central shunt will be used
Surgical Repair of AVSD Palliation repair types?
PA Band
B-T Shunt
Central Shunt
The treatment of choice for an AVSD is what?
complete surgical repair
Surgical Correction of AVSD •Two Types of Complete Repair?
- Bi-ventricular Repair
* Univentricular Repair
Surgical Correction of AVSD •Two Types of Complete Repair?
- Bi-ventricular Repair
* Univentricular Repair
Bi-ventricular Repair
The VSD is often closed with?
The ASD is often closed with?
Valve repair technique?
- synthetic patch (Dacron).
- pericardial patch
•Attempt to repair the abnormal valve.
This is accomplished by suturing/cutting the cleft (the cut in the valve leaflets) to recreate a two-leaflet mitral valve.
•The tricuspid valve may also be repaired.
Surgical Goals of Univentricular Repair?
culminates in what?
•The eventual goal of surgical repair is to separate pulmonary and venous outflow, and is usually done with staged procedures,
culminating in the Fontan Procedure
Univentricular Repairs AVSD - stage 1
Blalock-Taussig (BT) shunt: usually performed within the first few days after birth, and establishes a systemic-to-pulmonary artery shunt between the brachiocephalic artery or the right subclavian artery, to the right pulmonary artery via (usually) a tubed homograft or synthetic graft.
Univentricular Repairs AVSD - stage 2
Bi-Directional Glenn Procedure or Hemi-Fontan
:usually performed at 4-6 months after birth as a bridge to Fontan completion. The BT shunt and pulmonary artery band is usually removed. The
superior vena cava is then attached to right
pulmonary artery, creating a systemic venous
-to-pulmonary connection
Hemi-Fontan Procedure
(Bi-directional Cavopulmonary Anastomosis)
•Anastamosis where?
- Anastamosis PA/Right atrial appendage
* SVC is patched
Hemi-Fontan Procedure
(Bi-directional Cavopulmonary Anastomosis)
•Anastamosis where?
- Anastamosis PA/Right atrial appendage
* SVC is patched
Univentricular Repairs AVSD - stage 3
Fontan Completion:
Usually performed at 2-3 years of age; the inferior vena cava is connected to the right pulmonary artery via a tunnel like patch within the right atrium (Lateral Tunnel Fontan), or by creating a conduit for IVC flow outside the right atrium (Extracardiac Fontan)
Fontan Intracardiac two aspects?
Univentricular Repairs AVSD
Atrial Baffle
Lateral Tunnel
connect IVC and SVC inside RA kinda so no blood flows into the RA thus non goes into the heart it just goes straight into the pulmonary arteries
Fontan Fenestration present
Fontan Extracardiac procedure?
Univentricular Repairs AVSD
shunt from IVC to pulmonary arteries outside of RA
and SVC is connected directly to pulmonary arteries and so none goes into RA thus heart
Fontan Fenestration present
Fontan Fenestrations act as what?
fenestration acts as a pop-off valve
Why is atrioventricular canal a concern? (3)
•If not treated, this heart defect can cause lung
disease.
•larger volume of blood than normal must be
handled by the right side of the heart.
•causes higher volume than normal and higher
pressure than normal in the blood vessels in the lungs
Why is atrioventricular canal a concern? (3)
•If not treated, this heart defect can cause lung
disease.
•larger volume of blood than normal must be
handled by the right side of the heart.
•causes higher volume than normal and higher
pressure than normal in the blood vessels in the lungs
What if Atrioventricular canal goes untreated?
- The lungs are able to cope with this extra volume of blood at high pressure for a while.
- lungs become damaged by this extra volume of blood at high pressure.
- The blood vessels in the lungs get thicker.
- With time, these changes in the lungs become irreversible
CPB Circuit Considerations of AVSD
•Palliation stage - shunts
Shunts: Usually done early with small size to
prevent damage caused by flow and pressure
CPB Considerations of AVSD use or not?
PA Band?
BT shunt?
Central shunt?
May/may not utilize CPB (standby)
PA Band: off CPB
BT shunt: off CPB
Central Shunt: both on and off CPB
CPB Circuit Considerations of AVSD •Surgical Repair: Bi-ventricular •Cannulation: •Arterial: •Venous: •LV Vent: •Aotic Cross-Clamp with what? •CPB time
- Arterial: Aortic cannulation
- Venous: Bicaval cannulation
- LV Vent: Flexible vent when the heart is open
- Aotic Cross-Clamp w/ multiple antegrade CP dosing
- CPB time is moderate in length
CPB Circuit Considerations of AVSD •Surgical Repair: Univentricular •Bi-Directional Glenn Shunt: cannulation? temp? •Aortic Arterial •Fontan: cannulation?
- Bi-Directional Glenn Shunt:
- Single Atrial Cannula
- (Circulatory arrest–short or off-pump)
- Aortic Arterial
- Fontan:
- Single Atrial Cannula (DHCA)
- Aortic arterial
Complete AVSD Procedure:
- ASD patch
- VSD patch
- Valve repair
