Transposition of the Great Arteries

What is transposition?

• presence of incorrect connections between the atria and ventricles and or the great arteries (PA or Aorta)

• Variants:

  • D-TGA 

  • CC-TGA/L-TGA

D TGA (Dectro Position)

Is a cyanotic heart defect

Characteristics of D-TGA

• conotruncal septum grows straight down vs spiral

• AO is anterior and right sided

• PA is posterior and left sided

• Atrioventricular concordance

• Ventriculoarterial discordance

• Systemic and pulmonary circulation runs in parallel

• Cyanotic heart defect, required an ASD/PFO and/or PDA for survival

What is this diagram showing?

D-TGA:

• AO is ANTERIOR and to the RIGHT of PA

• PA is POSTERIOR and to the LEFT of AO

What is this diagram showing?

L TGA

• AO is ANTERIOR and to the LEFT of PA

• PA is POSTERIOR and to the RIGHT of AO

What is this diagram showing?

Normal orientation:

• AO is POSTERIOR and to the RIGHT

• PA is ANTERIOR and to the LEFT
  

What is this an image of?

D-TGA

Clinical presentation of D-TGA

• cyanosis

• SOB

• Weak pulse

• Lack of Appetite

• Poor weight gain (failure to thrive)

• Diagnosed and treated shortly after birth

• Associated with other defects:

  • VSD

  • Ao Arch Abnormalities

  • LVOTO

  • MV/TV abnormalities

  • PS

  • Coronary artery abnormalities 

What is the APGAR score?

A = Appearance

P = Pulse

G = Grimace (reflexes)

A = Activity (muscle tone)

R = Respiration

Pre-op Echo Findings of D-TGA

• PLAX visualization of side-by-side/parallel course of AO & PA

• AO will be anterior to PA

• PSAX visualization of both semilunar valves in short axis with AO anterior

• Establish patency of PDA, ASD/PFO or  presence of VSD

• Verify coronary anatomy (important for one of the repair options

What are these images of?

D-TGA

Atrial Switch

• surgical intervention for D-TGA

• first successful repair option (Pre 1980)

• replacement of a baffle (conduit) into the atria

• Systemic venous return (deoxygenated) is baffled to the LV so it can exit to the lungs

• Pulmonary return (oxygenated) is baffled to the RV so it can exit to systemic circulation

• Variants:

  • Mustard: uses patient’s OWN tissue to create a baffle

  • Senning: uses a SYNTHETIC baffle

Common complications of Atrial Switch D-TGA

• Baffle leaks

• Obstructions

• RV failure

• Significant TR

Arterial Switch

• currently the method of choice for D-TGA correction

• Called the Jatene procedure

• Dissection of AO & PA above their roots and detachment of coronaries

• Great arteries are switched:

  • AO connects to the original PA root with implantation of the coronaries

  • PA connects to the original AO root   - LeCompte Manuever: PA and branches may be moved to anterior position

  • More “normal” configuration is achieved

Complications of Arterial Switch D-TGA

• Narrowing of the anastomosis sites

• Narrowing PA branches (LeCompte)

• Supravalvular PS

Rastelli Procedure D-TGA

• Performed when there is D-TGA, a large VSD & significant PS

• Patches the VSD to baffle blood flow from the LV across to the AO

• Inserts a RV à PA valved conduit

• Procedure also performed on other CHD:

  • Truncus Arteriosus

  • Pulmonary Atresia & VSD

  • Double Outlet RV with PS

Common complications of Rastelli D-TGA

• conduit degeneration

• stenosis/regurgitation of conduit valve

• LVOTO

What does CC-TGA stand for?

Congenitally Corrected TGA

What is CC-TGA AKA?

L-TGA Levocardia TGA

Characteristics of CC-TGA (levo TGA)

• outer curve of the bulboventricular loop points to the LEFT side which causes ventricular inversion

• Atrioventricular discordance, ventriculoarterial discordance

• Systemic and pulmonary circulation runs in parallel vs crossed over

• Anatomy is incorrect but circulation is technically “correct” and so named congenitally corrected

• In isolation, it is not a cyanotic syndrome: Quite rare and often has “friends” in 90% of cases

Clinical Presentation of CC-TGA

• possible to be mostly asymptomatic until adolescence/adulthood

• Fatigue

• Chest pain

• SOV

• Diagnosed in childhood in patients with additional CHD

• Associated with other defects like VSD (more common perimembranous), PS, TV abnormalities (Ebstein-like), arrythmias, dextrocardia or mesocardiac, coarctation of the aorta 

What are these images of?

CC-TGA

Pre op findings of CC-TGA

• Septal insertion of left sided AV valve is more apically displaced than right sided valve in AP4

• Notation of coarse trabeculation and moderator band in left sided ventricle (RV)

• On axis PLAX not possible due to transposed and parallel great arteries

• Usually has “friends” so look out for VSD, Pulmonary outflow tract obstruction, Ebstein’s anomaly, and conduction defects

• RV dilation and systolic failure

• Potential for large amount of TR

What are these images of?

CC-TGA

• LV and RV swapped

• TV and MV swapped

What is this an image of?

CC-TGA:

• AO is ANTERIOR and to the LEFT of PA

What is this an image of?

CC TGA Fetal ECHO

Double Switch

• Surgical intervention for CC TGA

• Atrial switch AND Arterial switch

• Systemic venous blood > RV/PA

• Pulmonary venous blood > LV/AO

• Coronaries reimplanted into “neo” AO

• More “normal” configuration is achieved

• In cases of CC-TGA + VSD + significant PS, Rastelli & Atrial Switch procedure may be performed

• Common complications:

  • Baffle leaks

  • Obstructions

  • RV failure

  • Significant TR

  • Narrowing of anastomosis sites

  • Narrowing of PA branches (LeCompte)

  • Supravalvular PS