Download 2/09 Transpostion of the Great Arteries

Transposition of the Great Arteries
Francesca N. Delling, MD
January 11, 2009
Cardiac Tube
Complete Transposition of the Great Arteries
 Ventriculoarterial discordance
 Also known as d-TGA
(d = dextroposition of the
bulboventricular loop)
 Aorta on the right and anterior
Complete Transposition of the Great Arteries
 Systemic and pulmonary circulation
run in parallel  need for a
communication between the two ASD, VSD (most common), or
PDA to support life
 One of the most common cyanotic
defects in the newborns
 If circulatory mixing via
PDA, its physiological closure
 abrupt cyanosis and
deterioration  need for Rashkind
atrial balloon septostomy until
definite surgery
Atrial switch procedures
 Senning (1958):
atrial baffle from autologous
tissue to direct the venous
return to the contralateral AV
valve and ventricle
Atrial switch procedures
 Mustard: atrial septum is excised, baffle is created with
synthetic material
Late complications of atrial switch procedures:
Arrhythmias
 Late development of both brady and tachyarrhythmias
 Sinus node dysfunction common in adults
 Series of 534 children by Gelatt et al (J Am Coll Cardiol.1997;29:194-201)
- NSR in 77% at 5 years, 40% at 20 years
- 11% needed PPM
- 14% had atrial flutter
- 16% had a late death (due to arrhythmias and myocardial
failure)
 Ventricular arrhythmias uncommon in the absence of severe
ventricular dysfunction
Late complications of atrial switch procedures:
Systemic Ventricular dysfunction and TR
 RV is the systemic ventricle
 TR secondary to annular dilatation (TVR not indicated) or
damage at the time of VSD repair or endocarditis (TVR
warranted)
 Treatment of systemic ventricular dysfunction is challenging:
- No convincing data of utility of ACE-inhibitors
- Caution with the use of beta-blockers (AVB, bradycardia)
- Two-stage repair surgery (pulmonary artery banding
to “retrain” the LV, followed by baffle take-down and
arterial switch) is extensive and LV failure occurs after
pulmonary banding
Late complications of atrial switch procedures:
Atrial baffle obstruction and leaks
 Obstruction of SVC (with “SVC syndrome”) more common
than IVC (hepatic congestion or cirrhosis).
If significant stenosis, may need percutaneous balloon
and stenting or even surgery
 Pulmonary vein stenosis much less common but may
cause PHTN
Late complications of atrial switch procedures:
Pulmonary hypertension
 Occurs in 7% of those who survive to adulthood
 Cause unclear (in some cases: PV baffle obstruction)
 Risk factors: age > 2, shunts at ventricular or great artery
level before repair (Newfeld EA et al. Am J Cardiol.1974;34:539-543)
Comparison between atrial switch procedures
 Senning better than Mustard
340 pts (124 Mustard vs. 215 Senning) Heart, 2004; 90:307-313
• Mortality
– 82 deaths (24%)
» Senning showed trend to better mortality but not statistically
significant
• Baffle Obstruction
– 15% - Mustard
– 1% - Senning
• Senning patients had better functional status
Atrial switch procedures and pregnancy
 Pregnancy poses a significant volume load that may increase
RV dimensions and is sometimes irreversible
 Poses a definite risk of deterioration of functional class, even
if pt is asymptomatic
 Risk of congenital heart disease in the offspring, in the absence
of a family history, is probably < 5% (Clarkson PM et al. J Am
Coll Cardiol.1994;24:190-193)
Arterial switch procedure
Jatene 1976
Complications: coronary stenoses with sudden death or MI, RV
outflow tract distortion, dilatation of neo-aortic root with AI
Rastelli procedure
 Used when d-TGA +
large subaortic VSD and
pulmonary stenosis
 A patch directs blood
from the LV through the
VSD to the aorta (1)
 PV is oversewn and a
valved conduit is inserted
from the RV to the PA to
bypass the pulmonary
stenosis (2)
Rastelli procedure (continued)
 Advantages: LV functions as systemic ventricle
 Disadvantages:
- Conduit degeneration and stenosis, necessitating reoperation
- Atrial and ventricular arrhythmias with sudden death
- Possible RV and LV failure
Echo: parasternal long-axis
Posterior pulmonary artery and anterior aorta aligned rather than in
the usual crossing arrangement
Parasternal short-axis
Aorta is anterior and on the right
Parasternal short-axis base
4-chamber view
CMR: 4-chamber
LVOT
RV 2-chamber
Short axis
Congenitally corrected Transposition
RA enters the morphological LV  PA, and left atrium communicates
with morphological RV  aorta
Congenitally corrected Transposition (continued)
 Left-handed looping of the heart tube 
morphologic RV in levo-position  AV
discordance
 Aortopulmonary septum fails to rotate 180
 ventriculoarterial discordance (although
blood flows in the normal directions, it
passes through the “wrong” chamber)
 Aorta anterior and to the left, great arteries
may be side to side
Congenitally corrected Transposition (continued)
Because the TV always enters a morphological RV
it too is on the left side in the systemic circulation and is termed
systemic AV valve
AV concordance
AV discordance
Congenitally corrected Transposition:
Associated anomalies
 VSD (70%): if large (LR flow), pts present in infancy
or childhood with congestive heart failure. Reversal of flow
R L leads to desaturation
 Pulmonary stenosis (40%), commonly subvalvular. Associated
valvular PS also occurs
 Abnormalities of the systemic (tricuspid) AV valve (90%)
 Ebstein’s anomaly:
- apical displacement of valve BUT no “saillike” anterior
leaflet
Congenitally corrected Transposition:
Conduction anomalies
 AV node and His have unusual position
 Many have dual AV nodes
 Conduction system is vulnerable to fibrosis  2% per
year incidence of CHB
Congenitally corrected Transposition:
CXR
Levocardia
Dextrocardia
Congenitally corrected Transposition:
EKG
Ventriculuar excitation begins at the septal endocardium of the right sided LV
Congenitally corrected Transposition:
Echocardiography
1. Hypertrophied
RV on the left
2. Moderator Band
3. Apical
attachment of
the TV
Congenitally corrected Transposition:
Echocardiography
Overriding great
vessels
a. Aorta arises
anteriorly and
comes off the
RV
b. PA arises
posteriorly from
the LV
Congenitally corrected Transposition:
Echocardiography
anterior and leftward aorta
Congenitally corrected Transposition:
Cardiac cath:
- hemodynamic assessment of associated anomalies
- evaluation of systemic AV valve regurgitation and ventricular
function
MRI: Defines ventricular function and volumes
Systemic ventricular failure and AV valve
regurgitation
? Cause
 Inherent vulnerability to failure
- concordant coronary anatomy: morphological RV perfused
by single right coronary artery with limitations of perfusion
-Acar et al. Heart 1999: 20 pts with L-TGA and ETT MIBI 
all 20 had perfusion defects at rest, 17 worsened with exercise
 Controversy exists as to which comes first: AV valve
regurgitation or ventricular failure
Systemic ventricular failure and AV valve
regurgitation
PM implantation may precipitate deterioration in systemic
ventricular function and worsening of AV valve regurgitation
Congenitally corrected Transposition:
Surgical repair
 Two schools of thought:
– Classic approach – fix only the defects associated with the
condition (VSD, systemic AV valve regurgitation)
– Newer approach is to restore the LV as the systemic ventricle
(anatomical repair)
• Major advantage is drastically reduces risk of TR which is
associated with RV failure and late sudden death
Congenitally corrected Transposition:
Classical repair
 118 pt classical repair J Thorac Cardiovasc Surg 117 (1999), pp. 1190–1203
– 15 % operative mortality
– 56% underwent reoperation within 20 yrs
– 48% survival rate at 20 years – CHF > 70%
Congenitally corrected Transposition:
Double switch operation
 Venous Switch via
Mustard or Senning
 Great vessel Switch
 Closure of VSD
Congenitally corrected Transposition
And VSD
A patch can be inserted to
tunnel the LV flow into the
aorta, and the morphological
RV is connected to the
pulmonary artery via
conduit “Rastelli technique”
Before anatomic repair (either double switch or
Rastelli) LV needs to be prepared to function as a
systemic ventricle  pulmonary banding
Congenitally corrected Transposition:
Anatomic repair
 54 pt restoration of LV – J Thorac CV Surg. 2003;125:1229-41
– Early mortality 5.6 % (3 pts)
– Long term mortality:
• 1 year – 94% survival
• 4 year – 90% survival
• 9 year – 90% Survival vs. Classic 60 – 83% (10 years)
Congenitally corrected Transposition:
Anatomic repair
 Early mortality of 5% encouraging, but:
- 7 pts with Rastelli needed repeat conduit, aortic valve replacement
or transplantation.
- Balloon angioplasty of baffle obstruction or pulmonary stenosis
also needed
 Need for re-intervention post anatomic repair confirmed by
more recent paper by Sharma et al (J Thorac Cardiovasc Surg. 2009 Feb;137)
- 68 patients (31 Rastelli/atrial switch; 37 arterial switch/atrial rerouting)
- early deaths, late re-operations, late deaths (LV dysfunction, tachyarrhytmias
observed in both groups
Pregnancy and C-TGA
 Women with systemic EF <40% or significant systemic AV
valve regurgitation should be counseled against pregnancy
 Series of Connolly et al ( J Am Coll Cardiol.1999;33:1962)
60 pregnancies 22 ♀ resulting in 50 live births (83%)
•
none of the offspring had congenital heart disease
•
no pregnancy related deaths
•
1 woman with significant AV valve regurgitation
•
1 had CHF
 45 pregnancies 19 ♀ (Am J. Card. 1999;84:820-24)
• 27 live births; 12 miscarriages; 6 elective term
• 1 child with a congenital heart defect
• Mothers with 6 CV events
–3 episodes of CHF
–2 Episodes of increasing cyanosis, one CVA
Antibiotic prophylaxis
 Prophylaxis is reasonable in patients with CHD with the
highest risk for adverse outcome from infective endocarditis
- patients with prosthetic valves
- previous endocarditis
- unrepaired and palliated CHD
- repaired CHD within 6 months after the procedure
- repaired CHD with residual defects at or adjacent to the site
of a prosthetic patch or prosthetic device that inhibits
endothelization
ACC/AHA guidelines for the management of adults with congenital heart disease. J Am
Coll Cardiol. 2008 Dec 2;52(23):e1-121
References
Carole A. Warnes. Transposition of the great arteries. Circulation
2006;114:2699-2709.
Yale University School of Medicine. Congenital Heart Disease
Echo Atlas. http://www.med.yale.edu/intmed/cardio/chd/
http://pediatriccardiology.uchicago.edu/MP/embryology/embryolo
gy.htm
Thank you