AVSD

Question 1

Other names for AVSD

Answer 1

• Common AV canal defect
• AVSD
• AV canal defect
• AV communis
• Endocardial cushion defect

Question 2

Associations of AVSD

Answer 2

• 75% of complete AVSD occurs with trisomy 21
• Associated with heterotaxy syndrome
• Can occur with ToF

Question 3

What role do the superior and inferior endocardial cushions have?

Answer 3

Superior and inferior endocardial cushions help from outlet portion of atrium as well as inlet portion of ventricular septum

Question 4

AVSD embryology

Answer 4

Failure of fusion of superior and inferior endocardial cushions

Question 5

Types of AVSD

Answer 5

Complete
Partial
Transitional

Question 6

What is a Partial AVSD?

Answer 6

Characterised by presence of ostium primum ASD and clefts in the anterior leaflets of the left AV valves. Typically 2 distinct AV valves with separate annuli.
Anterior and posterior bridging leaflets are fused centrally creating left and right sided orifices

Question 7

What is a transitional AVSD?

Answer 7

2 distinct AV annuli with defects in the atrial and ventricular septum. Restrictive VSD.

Question 8

What is a complete AVSD?

Answer 8

ASD and unrestrictive VSD leaving a complete, common AV annulus with an inferior and superior bridging leaflet

Question 9

What is a common AV annulus

Answer 9

Guarded by 5 leaflets: Right antero-superior leaflet, Right mural leaflet, superior and inferior bridging leaflet and the left mural leaflet.
Mural = lateral

Question 10

What classification system is used for complete AVSD?

Answer 10

Rastelli Classification
Types A, B and C
Based on morphology of anterior bridging leaflet and degree of bridging and its chordal attachment

Question 11

Mechanisms of LVOTO in complete AVSD

Answer 11

1) Elongate LVOT (‘goose neck’) due to direction of blood flow through CAVV
2) Abnormal chordal attachments to the LV side of septum
3) Discrete sub aortic stenosis
4) Septal hypertrophy
5) Anomalous anterolateral papillary muscles
6)
Aneurysm of membranous septum into LVOT
7) Arch hypoplasia and coarctation

Question 12

Partial AVSD presentation

Answer 12

RV volume overload from L-R shunt at atrial level
Left AV valve regurgitation
AF

Question 13

Transitional AVSD presentation

Answer 13

Features similar to Partial AVSD
May have left AV valve regurgitation
Minimal ventricular level shunting due to restrictive VSD

Question 14

Complete AVSD presentation

Answer 14

Unrestricted PBF dominates picture in childhood
HF and failure to thrive
Pulmonary vasculature disease by age 1

Question 15

Physical Examination Findings of AVSD

Answer 15

Unprepared partial/transitional aVSD: Wide and fixed splitting o S2; PESM; Tricuspid MDM; RV+; PSM; Complete, unprepared AVSD has Eisenmenger’s (Loud P2)

Question 16

ECG findings of AVSD

Answer 16

LAD
1st degree HB/ A Flutter/AF
LAE; LVH
RVH if PHTN or RVOTO

Question 17

Goals of Echo Exam

Answer 17

• Define primum ASD borders
• VSD and direction of shunting
• Morphology and function of the AV valve, looking for AV valve regurgitation or stenosis
• LVOTO

Question 18

Surgical Options of AVSD

Answer 18

1) Classic Single Patch technique

2) Two Patch technique

Question 19

Possible placements of suture line

Answer 19

To the right or to the left

Question 20

Suture line to the Right

Answer 20

Line stays to right to ventricular septal crest and crosses RBB).
Causes small R-L shunt
Mouth of CS drains into the LA
Wide curve around AVN

Question 21

Suture line to the left

Answer 21

Mouth of CS to RA
Stays on left side of conduction tissue and requires shallow bites to not impinge on non-branching bundle, particularly inferior bridging leaflet.

Question 22

Partial AVSD Outcome for adult repair complications

Answer 22

• Atrial arrhythmias
• CHB
• Sub-aortic stenosis
• Recurrent left AV valve regurgitation through the cleft
• Left AV valve stenosis

Question 23

Indications for reoperation AVSD

Answer 23

1) Left AV valve stenosis, regurgitation or prosthesis dysfunction that causes symptoms, arrhythmias or increase in LV dimensions or dysfunction
2) LVOTO (MPG >50 mmHg; PPG > 70 mmHg; MPG<50 with significant left AVVR or AR)
3) Residual or recurrent ASD or VSD that meet criteria for closure

Question 24

Medical therapy for AVSD

Answer 24

ACE-i or diuretics for CHF associated with AV valve regurgitation
Anti-arrhythmics or BB for arrhythmias
If prior repair - arrhythmia should prompt investigation of haemodynamics

Question 25

Pregnancy in AVSD

Answer 25

Trisomy 21 is commonly seen in association with AVSD, and have 50% risk of transmitting Downs and other genetic defects to offspring Pre-conception counselling important to ensure no significant haemodynamic lesions present

Question 26

Most common unoperated adult presentation

Answer 26

Partial AVSD

Question 27

What causes abnormal activation sequence of the ventricles?

Answer 27

AVN is positioned inferoposterior to coronary sinus | BoH and LBB are displaced posteriorly

Question 28

What percentage of congenital cardiac defects do AVSDs account for?

Answer 28

3%

Question 29

What % of patients with AVSD have Down's?

Answer 29

35%

Question 30

What percentage of complete AVSDs occur in Down patients?

Answer 30

>75%

Question 31

What percentage of partial AVSDs occur in non-Down patients?

Answer 31

>90%

Question 32

By what age are unprepared partial AVSDs symptomatic?

Answer 32

Age 40

Question 33

When can endocardial pacing cause an increased risk of paradoxical emboli?

Answer 33

In cases of residual intertribal or inter ventricular communications. Epicardial pacing may be required

Question 34

How long should patients with AVSD (operated and unoperated) be followed-up?

Answer 34

Life-long

Question 35

How often should a surgically repaired AVSD without significant residual abnormalities be followed up?

Answer 35

At least every 2-3 years

Question 36

What patients should you avoid cardiac surgery in complete AVSD?

Answer 36

Eisenmenger physiology. If in doubt, PVR testing Indication for intervention = VSD

Question 37

When should Partial AVSD surgical closure be performed?

Answer 37

Significant RV volume overload (ASD guidelines)

Question 38

When should patients undergo valve surgery?

Answer 38

1) Symptomatic patients with moderate to severe AV valve regurgitation 2) Asymptomatic patients with moderate or severe left sided valve regurgitation and LVESD > 45 mm and/or impaired LV function (LVEF <60%) when other causes of LV impairment excluded

Question 39

When should patients have surgical repair considered?

Answer 39

Asymptomatic patients with moderate or severe left sided AV valve regurgitation who have signs of LV volume overload and a substrate of regurgitation that is amenable for surgical repair

Question 40

Exercise/sports advice for patients with AVSD

Answer 40

Uncomplicated, repaired AVSD - no physical activity restriction Patients with important residual problems require individual recommendations

Question 41

Pregnancy advice for patients with AVSD

Answer 41

Well tolerated in patients with complete repair and no significant residual lesions. Unoperated AVSD --> increased risk of paradoxical embolisation Closure of any significant ASD should be considered Severe PAH - pregnancy contraindicated Residual left AV valve regurgitation with no indication for surgery tolerate pregnancy relatively well, although arrhythmias and worsening of AV valve regurgitation may occur Recurrence risk of CHD is relatively high and up to 11%. Genetic counselling is necessary

Question 42

IE prophylaxis in patients with AVSD

Answer 42

Recommended only for high risk patients