Tricuspid Valve Atresia Flashcards
1
Q
What is tricuspid valve atresia (TVA)?
A
- Cyanotic heart lesion
- Characterised by congenital agenesis or absence of TV
2
Q
Lesions associated with TVA?
A
- TVA
- Hypoplastic RV
- VSD
- Hypoplastic PA
- ASD (R-L)
- As a result, no communication between the RA and RV
- Therefore, must be R-L shunting of systemic venous return at atrial level across PFO or ASD for survival
3
Q
TVA Classification
A
- 3 main classifications of TVA based on anatomic relationship of the great vessels
- Main classification sub classified depending on the:
1. Presence or absence of a VSD
2. Pulmonary stenosis or pulmonary atresia
4
Q
What is type I TVA?
A
- Type I = normally related great arteries
- Type 1a = intact IVS with pulmonary atresia
- Type Ib = small VSD with PS or hypoplasia (most common type of TVA)
- Type Ic = large VSD without PS or atresia
5
Q
What is type II TVA?
A
- Type II = d-TGA
- Type IIa = VSD with pulmonary atresia
- Type IIb = VSD with PS or hypoplasia
- Type IIc = VSD without PS or atresia
6
Q
What is type III TVA?
A
Type III = l-transposition of great arteries (mal-position of great arteries/cc-TGA)
7
Q
TVA: Associated CHDs?
A
- ASD (present in all cases)
- RV hypoplasia
- Aortic or subaortic stenosis
- CoAo or interrupted aortic arch
- Coronary artery anomalies
8
Q
TVA: Circulatory Pathway in Type Ib?
A
- Deoxygenated blood from IVC/SVC –> RA –> blood shunted to LA across ASD where it mixes with oxygenated blood returning to LA via pulmonary veins
- From LA, desaturated blood travels to LV where majority of blood ejected into aorta and systemic circulation = marked cyanosis
- Small portion of blood shunted though restrictive VSD to small RV where it is ejected through hypoplastic PV to the lungs
9
Q
TVA diagnosis on echo?
A
- Based on absence of TV as well as presence of ASD and RV hypoplasia
- Best identified in apical 4 chamber
- No TV; the only way RA can communicate with rest of circulation will be via ASD (R-L shunt)
10
Q
Surgical repair for TVA?
A
Fontan connection / Fontan circuit
11
Q
Aim of original Fontan connection surgery?
A
- Principle of procedure physiological rather than anatomical restoration of pulmonary blood flow with elimination of R and L-sided blood mixing
- Over time, found procedure resulted in RA dilatation which reduced propelling force of atrial contraction; and was associated with atrial arrhythmias and thrombus so further modifications made
12
Q
Elements of Original Fontan Connection?
A
- RPA to SVC (Glenn shunt)
- Closure of ASD
- Pulmonary homograft into IVC
- Ligation of MPA
- RAA ro LPA (Atriopulmonary connection)
13
Q
Total Cavopulmonary Connection (TCPC) in TVA repair?
A
- Nowadays TCPC op most common
- Includes bidirectional Glenn shunt or hemi-Fontan
- Plus redirection of systemic venous return to the PA via 1) an intra-atrial tunnel or 2) extracardiac conduit
- Operation increases pulmonary blood flow by diversion of systemic venous return directly to the PA i.e. blood flow bypasses the RV
14
Q
What is the staged procedure approach for TVA?
A
- 3 different stages of Fontan operation in TVA as FOntan circulation is contraindicated in neo-natal period because of relatively high PVR
- Staged approach allows adaptations heart and lungs and reduced overall perioperative morbidity and mortality
15
Q
Staged Fontan Operation: Stage One?
A
- First stage usually new-iron
- Artificial shunt placed between right subclavian artery and RPA
- Modified Blalock-Taussig shunt
