Number 15-11: Cardiac magnetic resonance is the technique to evaluate anatomically corrected malposition of the great arteries

Case from: Lamia Ait-Ali*§,MD, PhD,  Bruno Murzi†, MD, MD, Pierluigi Festa§ ‡, MD

Clinical history:

A symptomatic 50 year old woman previously diagnosed as congenitally corrected transposition of great arteries (L-TGA) was referred to our department. She was overweight and  complained shortness of breath  and palpitations.

Basal echocardiogram showed a situs solitus, levocardia, a small restrictive ventricular septal defect (VSD), associated to a mild sub-pulmonary stenosis and a severe sub-aortic tunnel –like stenosis with the aorta lying anteriorly and to the left of the pulmonary artery and finally two hypertrophied ventricles; however because of a bad acoustic window, the AV valve and ventricles morphology were not well identified. She was scheduled for Cardiac Magnetic Resonance (CMR) evaluation.

CMR Finding:

At CMR the following features were found: -the left side sided AV valve was bileaflet , therefore consistent with a mitral valve (Fig. 1; movie 1,2) and a morphological tricuspid valve was identified on the right side (atrio-ventricular concordance)

Figure 1

Movie 1

Fig 1: Still image and cine SSFP short axis ventricle (movie 1), 4 chamber view (movie 2): typical mitral valve (white arrow) connected to a posterior left ventricle. LA: left atrium; LV: Left ventricle.

-a sub-pulmonary VSD  (Fig. 2) leading to a left-to-right shunt with QP/QS evaluated as 2; 

Fig 2: Black blood MR of right ventricle outflow tract showing a sub-pulmonary ventricular septal defect

VSD: ventricular septal defect; PA: pulmonary artery.

- both great arteries abnormally arising above the appropriate ventricles (ventriculo-arterial concordance)  with conal tissue beneath each great artery, resulting in aortic-mitral and pulmonary-tricuspid discontinuity; the aorta arises form the posterior hypertrophic left ventricle (LV) through a stenotic fibro-muscular tunnel, lying anterior and to the left of the pulmonary artery ; the last arises from the anterior RV with a mild sub-valvular stenosis (Fig 3, 4; movies 3,4,5). 

Fig 3, movie 3: Cine SSFP showing anterior aorta arising form the posterior LV through a stenotic fibromuscular tunnel (white arrow)

AO: aorta; LV: Left ventricle.

Fig 4, movie 4:  Sagittal Cine SSFP showing anterior aorta arising form the posterior LV and a posterior pulmonary artery arising from the anterior RV

AO: aorta; LA: left atrium; LV: left ventricle; PA: pulmonary artery.

Movie 5:  Axial stack showing the relations of the ventricles to the corresponding great vessels.

Conclusion :  CMR diagnosis was Anatomically corrected malposition of the great arteries (ACMGA) -  VSD- sub aortic and sub pulmonary stenosis.  A cardiac catheterization confirmed the severe sub-aortic stenosis with a LV-Ao gradient of 60 mmHg, moderate sub-pulmonary stenosis (RV-PA gradient 30 mmHg), and a restricted VSD with QP/QS = 2.  Surgical report confirmed the CMR diagnosis, therefore bilateral miectomy to relieve LVOT and sub-pulmonary obstruction was performed and the VSD was also closed by means of an autologous treated pericardial patch. Post–op CMR (Fig 5) illustrates the good surgical result. 

Fig 6: Post operative CMR

A) Cine SSFP left outflow tract

B)  Cine SSFP right outflow tract

AO: aorta; LV: Left ventricle; PA: pulmonary artery: RV: right ventricle. 

Perspective: CMR was critical to obtain the correct diagnosis of ACMGA, restrictive VSD, subaortic and subpulmonary stenosis.  ACMGA is a very rare form of congenital heart disease in which the great arteries arise above the anatomically correct ventricles but are abnormally related to the ventricles and to each other [1,2].  Subaortic stenosis occurs in about 15% of ACMGA [3].  ACMGA is frequently misdiagnosed  as congenitally corrected transposition (L-TGA)[4,5] however because of the technical problem of the ventricular septal defect closure to avoid the conduction pathway, they must be differentiated precisely [6].  CMR should be the preferred technique in this setting because it is radiation-free, has a high anatomic definition and overcomes some of the limitations of ultrasound mainly in adult patients.

References:

1. Van Praagh R, Durnin RE, Jockin H, Wagner HR, Korns M, Garabedian H, Ando M, Calder L (1975) Anatomically corrected malposition of the great arteries. Circulation 1975;51:20–31. 

2. Van Praagh R. The story of anatomically corrected malposition of the great arteries. Chest. 1976;69:2–4. 7.  3.

3. Bernasconi A, Cavalle-Garrido T, Perrin DG, Anderson RH: What s anatomically corrected malposition? Cardiol Young 2007;17:26-34.   

4. Oku H, Shirotani H, Yokoyama T, Kawai J, Nishioka T, Noritake S et al. "Anatomically corrected malposition of the great arteries--case reports and a review." Jpn Circ J. 1982;46:583-594. 

5. Rittenhouse EA, Tenckhoff L, Kawabori I, Mansfield PB, Hall DG, Brown JW. Surgical repair of anatomically corrected malposition of the great arteries. Ann Thorac Surg.1986;42:220–8.

6. Anderson RH, Becker AE, Losekoot TG, Gerlis LM. Anatomically corrected malposition of great arteries. Br Heart J. 1975 Oct;37(10):993-1013.