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Pediatrics > Atrio-Ventricular Canal (AVC) Endocardial Cushion Defects (ECD) Atrio-Ventricular Septal Defects (AVSD) > Flashcards

Atrio-Ventricular Canal (AVC) Endocardial Cushion Defects (ECD) Atrio-Ventricular Septal Defects (AVSD) Flashcards

1
Q

Definition:AVSD/ECD/AVC Defects

A

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.
Incomplete fusion of the endocardial cushions
which form primum atrial septum, A-V valves, and inlet ventricular septum

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2
Q

Incidence of congenital heart disease is approximately

A

8 per 1000 live births.

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3
Q

AVSD is the

A

5th most common occurring CHD.

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4
Q

AVSD is commonly associated with

A

Down’s syndrome and cardiac malformations such as Tetralogy of Fallot (TOF), Double outlet right ventricle (DORV), and sub- aortic stenosis (SAS)

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5
Q

down syndrome is also present

A

in 60% of patients with heterotaxy* syndrome.

• *Certain organs forming on the opposite side of the body

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6
Q

children with a complete AV canal fail to

A

thrive in the first few months of life.

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7
Q

Patients may survive the first few years of life if the

A

PVR is high.

• High PVR decreases left to right shunting , increases LVEF

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8
Q

If AV canal is repaired between

A

4-6 months of life, survival is >80%.

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9
Q

An endocardial cushion defect consists of defects in

A

lower atrial and upper ventricular septa, and deficiencies in the mitral/tricuspid valves.
Also called AVC, or AVSD

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10
Q

Atrioventricular septal defects can be classified into one of three categories called

A

Complete • Partial • Transitional

CAVSD) (PAVSD) (TAVSD

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11
Q

AVSD Classification

Balanced

A
  • 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.
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12
Q

AVSD Classification unbalanced

A
  • One of the ventricles may be hypoplastic

* Size will be different

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13
Q

AV septal defects occur at the embryonic age and occurs because

A

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.

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14
Q

• After fusing with the endocardial cushion, if there is a small residual opening at the ECC it is called

A

ostium primum ASD (AVSD).

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15
Q

Embryology of AVSD

What is the end result?

A

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

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16
Q

If the leaflet opens preferentially toward a ventricle, (limiting flow to the other ventricle),

A

hypoplasia occurs and creates an unbalanced AVSD

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17
Q

Complete AVSD

A
  • 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”. all chambers can mix
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18
Q

Partial AVSD

A

• A partial atrioventricular septal defect is one in which the part of the ventricular septum formed by the endocardial cushions has filled in: (no VSD)

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19
Q

Partial AVSD fills in by

A

issue from the AV valves or directly from the endocardial cushion tissue causing
• tricuspid and mitral valves dividing into two distinct valves. valvular geometry may be affected

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20
Q

Partial AVSD

• The defect is, therefore,

A

primarily in the atrial septum and mitral valve.

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21
Q

Partial AVSD. This type of atrial septal defect is referred to as an

A

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)

22
Q

Partial AVSD Considerations

A

Conduction system disruption (A-V node displaced inferiorly between coronary sinus and ventricular crest)
• Coronary sinus ostium often displaced
• Associated anomalies: PDA, persistent LSVC

23
Q

Transitional AVSD. looks similar to the complete form of atrioventricular septal defect, but the

A

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.

24
Q

Transitional AVSD

• As a result, a transitional atrioventricular septal defect behaves more like a

A

partial atrioventricular septal defect, even thought it looks more like a complete atrioventricular septal defect.

25
Q

Surgical Repair of AVSD

• Palliation for excessive pulmonary flow:

A
  • PA Band: • Increases PVR

* Decreases Pulmonary Flow • Decreases Pulmonary Over-circulation

26
Q

Surgical Repair of AVSD

Palliation for insufficient pulmonary flow:

A

In patients with inadequate pulmonary flow/hypoxemia, aBlalock-Taussig- Thomas shunt or central shunt will be used.

27
Q

Surgical Repair of AVSD

• Palliation (overview)

A

PA Band B-T Shunt Central Shunt

28
Q

• Two Types of Complete Repair

A

• Bi-ventricular Repair • Univentricular Repair

29
Q

The treatment of choice for an AVSD is

A

complete surgical repair.

30
Q

Bi-ventricular Repair

• The VSD is often closed with

A

a synthetic patch (Dacron).

31
Q

Bi-ventricular Repair. the ASD is often closed with

A

a pericardial patch

32
Q

Bi-ventricular Repair Valve repait technique

A

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.

33
Q

Surgical Goals of Univentricular Repair

A

• 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.

34
Q

Univentricular Repairs AVSD

• Stage One

A

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.

35
Q

Univentricular Repairs AVSD

• Stage two

A

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.

36
Q

Hemi-Fontan Procedure

Bi-directional CavopulmonaryAnastomosis

A

• Anastamosis PA/Right atrial appendage • SVC is patched

37
Q

Univentricular Repairs AVSD

• Stage 3

A

• 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).

38
Q

Fontan

Intracardiac

A

Atrial Baffle Lateral Tunnel

39
Q

FONTAN fenestration acts as

A

POP OFF VALVE

40
Q

Why is atrioventricular canal a concern?

A
  • 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.
41
Q

Pathophysiology of atrioventricular canal on lungs

A
  • 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
42
Q

CPB Circuit Considerations of AVSD

• Palliation stage

A

Shunts: Usually done early with small size to

prevent damage caused by flow and pressure

43
Q

May/may not utilize CPB (standby)

A

PA Band:off CPB BT shunt: OFF CPB Central Shunt : both on and off CPB

44
Q

CPB Circuit Considerations of AVSD
• Surgical Repair: Bi-ventricular
• Cannulation:

A

Arterial: Aortic cannulation
• Venous: Bicaval cannulation
• LV Vent:Flexible vent when the heart is open

45
Q

CPB Circuit Considerations of AVSD

• Surgical Repair: Bi-ventricular CROSS CLAMP and cpb time

A

Aotic Cross-Clamp w/ multiple antegrade CP dosing

• CPB time is moderate in length

46
Q

Surgical Repair: Univentricular • Bi-Directional Glenn Shunt:

A
  • Single Atrial Cannula • (Circulatory arrest – short or off-pump)
  • Aortic Arterial
47
Q

Surgical Repair: Univentricular • Bi-Directional Glenn Shunt. fontan

A

• Single Atrial Cannula (DHCA) • Aortic arterial

48
Q

Defect of the endocardial cushions • 3 Types:

A

• Complete Partial Transitional. Will be: • Unbalanced Balanced. corrected by Complete Repair Staged Procedures

49
Q

Surgical Summary of Repairs

• Complete:

A

• ASD patch • VSD patch • Valve repair

50
Q

Surgical Summary of Repairs staged procedures

A
  1. Palliative Shunt
    - BTS
    - Central 2. Bi-Directional Glenn 3. Fontan Procedure

Pediatrics (14 decks)

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