d-Transposition of Great Arteries

More of fetal d-Transposition of Great Arteries here

Link to CVICU website of Boston Children's Hospital on d-TGA

d-TGA - Case and Echocardiography images

In d-Transposition of Great Arteries, there is an inversion of the ventriculo-arterial segments. As such, the aorta is coming out of the right ventricle and the pulmonary artery is coming out of the left ventricle. The coronary arteries are connected to the aorta, and their configuration may be diverse. The left ventricle will face pulmonary vascular resistances (PVR). In the context of an open ductus arteriosus and high PVR, one may observe a reverse differential of saturation with the right arm saturating < the lower limbs, since saturated blood enters the post-ductal aorta. In the parasternal short axis view, when PVR have dropped, the inter-ventricular septum will be flat or bowing towards the LV cavity. Surgical correction is usually with the arterial switch "Jatene procedure", with the LeCompte manoeuvre (when configuration of great arteries allows for it). The aorta is disconnected and attached to the left ventricle. The native pulmonary valve becomes the neo-aortic valve. The coronary arteries are disconnected and re-attached to the aorta. Waiting too long for surgery may lead to de-conditioning of the left ventricle (since it faces the PVR). However, in the context of a large PDA, the LV may be facing relative iso-systemic pressure. A large PDA may lead, after prolonged period of time, to over-circulation and these patients may present with significant pulmonary edema and respiratory symptoms. As such, the surgery is usually done at 7-14 days. The LeCompte manoeuvre consists on arranging the great vessels in a way where the pulmonary artery becomes anterior to the ascending aorta. 

From: "Describing Congenital Heart Disease by Using Three-Part Segmental Notation" 

By: Erica K. Schallert, MD • Gary H. Danton, MD, PhD • Richard Kardon, DO Daniel A. Young, MD

If the aorta is anterior to and rightward of the MPA, the anomaly is described as dextrotransposition, or d-transposition, of the great vessels, which is denoted as “{_, _, d-TGV}”; if the aorta is anterior to and leftward of the MPA, the anomaly is described as levotransposition (l-transposition) or congenitally corrected transposition, which is denoted as “{_, _, l-TGV}.” If the aorta is neither anterior nor posterior to the MPA, the great vessels are usually described as malpositioned: If the aorta is rightward of the MPA, the anomaly is described as d-malposition, which is denoted as “{_, _, d-MGV}”; if the aorta is leftward of the MPA, the anomaly is described as l-malposition, which is denoted as “{ _, _, lMGV}.” 

Great vessels are seen parallel to each other, with a mostly left to right PDA.

Atrial septostomy (Rashkind balloon procedure)

Some patients may require atrial septostomy, which allows for increased mixing. In our centre, the procedure is done at the bedside in the neonatal intensive care unit. A catheter is introduced in the right atrium by an umbilical approach (or femoral approach if the umbilical one is unsuccessful). The balloon goes through the foramen ovale and is inflated and then pulled in order to open the inter-atrial septum. One may need to pay attention to the mitral valve, and avoid avulsion of the valve when pulling the balloon. 

D-TGA presentation by Satit Manopunya and Thien-An Lam (Montreal Children's Hospital)