Definitions
The hallmark of transposition of the great arteries is ventriculoarterial discordance, in which the aorta arises from the morphologic right ventricle and the pulmonary artery arises from the morphologic left ventricle.
Pathophysiology
Oxygenated pulmonary venous blood returns to the left atrium and left ventricle but is recirculated to the pulmonary vascular bed via the abnormal pulmonary arterial connection to the left ventricle.
Deoxygenated systemic venous blood returns to the right atrium and right ventricle where it is subsequently pumped to the systemic circulation, effectively bypassing the lungs.
This parallel circulatory arrangement results in a deficient oxygen supply to the tissues and an excessive right and left ventricular workload.
Aetiology
Gestational diabetes mellitus of an expectant mother is a risk factor that has been described for the fetus having TGV.
the children of diabeticmothers are more likely to have aortic coarctation
Epidemiology
commonest cause of cyanosis in the immediate newborn period
5% of all congenital cardiac defacts
Incidence: 4.8 in 10,000 live births
M:F=3:1
Presentation
Murmur if associated with other defects (eg VSD, pulmonic stenosis)
A single , loud S2 because the anteriorly positioned aortic valve closure obscures the sound of pulmonary valve closure
Cyanosis is the the dominant finding immediately after birth, unless as associated VSD is present
Investigation
Clinical
ECG- RVH and RAD
CXR
- normal heart size/mild cardiomegaly and normal to mild increase in pulmonary vascularity
- the classic cardiac silhouette- “egg on a string” (a narrowed mediastinum is visualized due to the anterior positioning of the aorta and posterior positioning of the pulmonary artery)
Echo+Doppler - diagnosis
Cardiac catheterization is rarely needed for diagnostic; balloon septostomy can be used to allow for better atrial mixing to mitigate cyanosis, providing short-term palliation.
Management
Prostaglandin E1- mantain patency of the ductus arteriosus and to decrease pulmonary vascular resistance, thereby increasing pulmonary blood flow (thus, venous return)- augments mixing through the foramen ovale.
balloon atrial septostomy- opens the foramen ovale to increase mixing in a restrictive patent foramen ovale and elevated pulmonary vascular resistant
The arterial switch procedure- during neonatal period or early infancy
Prognosis & Complications
success rate of early surgical repair is excellent
Low surgical mortality (2-5%) after the arterial switch operation in the presence of an associated VSD
The hallmark of transposition of the great arteries is ventriculoarterial discordance, in which the aorta arises from the morphologic right ventricle and the pulmonary artery arises from the morphologic left ventricle.
Pathophysiology
Oxygenated pulmonary venous blood returns to the left atrium and left ventricle but is recirculated to the pulmonary vascular bed via the abnormal pulmonary arterial connection to the left ventricle.
Deoxygenated systemic venous blood returns to the right atrium and right ventricle where it is subsequently pumped to the systemic circulation, effectively bypassing the lungs.
This parallel circulatory arrangement results in a deficient oxygen supply to the tissues and an excessive right and left ventricular workload.
Aetiology
Gestational diabetes mellitus of an expectant mother is a risk factor that has been described for the fetus having TGV.
the children of diabeticmothers are more likely to have aortic coarctation
Epidemiology
commonest cause of cyanosis in the immediate newborn period
5% of all congenital cardiac defacts
Incidence: 4.8 in 10,000 live births
M:F=3:1
Presentation
Murmur if associated with other defects (eg VSD, pulmonic stenosis)
A single , loud S2 because the anteriorly positioned aortic valve closure obscures the sound of pulmonary valve closure
Cyanosis is the the dominant finding immediately after birth, unless as associated VSD is present
Investigation
Clinical
ECG- RVH and RAD
CXR
- normal heart size/mild cardiomegaly and normal to mild increase in pulmonary vascularity
- the classic cardiac silhouette- “egg on a string” (a narrowed mediastinum is visualized due to the anterior positioning of the aorta and posterior positioning of the pulmonary artery)
Echo+Doppler - diagnosis
Cardiac catheterization is rarely needed for diagnostic; balloon septostomy can be used to allow for better atrial mixing to mitigate cyanosis, providing short-term palliation.
Management
Prostaglandin E1- mantain patency of the ductus arteriosus and to decrease pulmonary vascular resistance, thereby increasing pulmonary blood flow (thus, venous return)- augments mixing through the foramen ovale.
balloon atrial septostomy- opens the foramen ovale to increase mixing in a restrictive patent foramen ovale and elevated pulmonary vascular resistant
The arterial switch procedure- during neonatal period or early infancy
Prognosis & Complications
success rate of early surgical repair is excellent
Low surgical mortality (2-5%) after the arterial switch operation in the presence of an associated VSD
No comments:
Post a Comment