AVSD Flashcards
Other names for AVSD
- Common AV canal defect
- AVSD
- AV canal defect
- AV communis
- Endocardial cushion defect
Associations of AVSD
- 75% of complete AVSD occurs with trisomy 21
- Associated with heterotaxy syndrome
- Can occur with ToF
What role do the superior and inferior endocardial cushions have?
Superior and inferior endocardial cushions help from outlet portion of atrium as well as inlet portion of ventricular septum
AVSD embryology
Failure of fusion of superior and inferior endocardial cushions
Types of AVSD
Complete
Partial
Transitional
What is a Partial AVSD?
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
What is a transitional AVSD?
2 distinct AV annuli with defects in the atrial and ventricular septum. Restrictive VSD.
What is a complete AVSD?
ASD and unrestrictive VSD leaving a complete, common AV annulus with an inferior and superior bridging leaflet
What is a common AV annulus
Guarded by 5 leaflets: Right antero-superior leaflet, Right mural leaflet, superior and inferior bridging leaflet and the left mural leaflet.
Mural = lateral
What classification system is used for complete AVSD?
Rastelli Classification
Types A, B and C
Based on morphology of anterior bridging leaflet and degree of bridging and its chordal attachment
Mechanisms of LVOTO in complete AVSD
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
Partial AVSD presentation
RV volume overload from L-R shunt at atrial level
Left AV valve regurgitation
AF
Transitional AVSD presentation
Features similar to Partial AVSD
May have left AV valve regurgitation
Minimal ventricular level shunting due to restrictive VSD
Complete AVSD presentation
Unrestricted PBF dominates picture in childhood
HF and failure to thrive
Pulmonary vasculature disease by age 1
Physical Examination Findings of AVSD
Unprepared partial/transitional aVSD: Wide and fixed splitting o S2; PESM; Tricuspid MDM; RV+; PSM; Complete, unprepared AVSD has Eisenmenger’s (Loud P2)
ECG findings of AVSD
LAD
1st degree HB/ A Flutter/AF
LAE; LVH
RVH if PHTN or RVOTO
Goals of Echo Exam
- Define primum ASD borders
- VSD and direction of shunting
- Morphology and function of the AV valve, looking for AV valve regurgitation or stenosis
- LVOTO
Surgical Options of AVSD
1) Classic Single Patch technique
2) Two Patch technique
Possible placements of suture line
To the right or to the left
Suture line to the Right
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
Suture line to the left
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.
Partial AVSD Outcome for adult repair complications
- Atrial arrhythmias
- CHB
- Sub-aortic stenosis
- Recurrent left AV valve regurgitation through the cleft
- Left AV valve stenosis
Indications for reoperation AVSD
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
Medical therapy for AVSD
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
Pregnancy in AVSD
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
Most common unoperated adult presentation
Partial AVSD
What causes abnormal activation sequence of the ventricles?
AVN is positioned inferoposterior to coronary sinus
BoH and LBB are displaced posteriorly
What percentage of congenital cardiac defects do AVSDs account for?
3%
What % of patients with AVSD have Down’s?
35%
What percentage of complete AVSDs occur in Down patients?
> 75%
What percentage of partial AVSDs occur in non-Down patients?
> 90%
By what age are unprepared partial AVSDs symptomatic?
Age 40
When can endocardial pacing cause an increased risk of paradoxical emboli?
In cases of residual intertribal or inter ventricular communications.
Epicardial pacing may be required
How long should patients with AVSD (operated and unoperated) be followed-up?
Life-long
How often should a surgically repaired AVSD without significant residual abnormalities be followed up?
At least every 2-3 years
What patients should you avoid cardiac surgery in complete AVSD?
Eisenmenger physiology.
If in doubt, PVR testing
Indication for intervention = VSD
When should Partial AVSD surgical closure be performed?
Significant RV volume overload (ASD guidelines)
When should patients undergo valve surgery?
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
When should patients have surgical repair considered?
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
Exercise/sports advice for patients with AVSD
Uncomplicated, repaired AVSD - no physical activity restriction
Patients with important residual problems require individual recommendations
Pregnancy advice for patients with AVSD
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
IE prophylaxis in patients with AVSD
Recommended only for high risk patients
