The New Modified Mustard Operation With an Introduction By Cardiothoracic Pioneer Professor Magdi Yacoub

This video is part of CTSNet’s 2024 Innovation Video Competition. Watch all entries into the competition, including the winning videos.    

Although the arterial switch operation (ASO) is the procedure of choice worldwide, it requires early diagnosis and referral to a specialized center. The facilities and expertise required to achieve this target are lacking in many developing countries, a significant number of patients with TGA are referred late and are therefore not suitable for a one-stage switch due to an unprepared left ventricle (LV) (1). These patients could be treated by the atrial switch operation (1).  However, there are ongoing concerns regarding the long-term outcomes of atrial switch operations (2). 

Cardiothoracic surgery pioneer Professor Magdi Yacoub introduces this video, in which the authors used the modified Mustard technique to improve the pattern of filling in the left ventricle, which could enhance the long-term results of the Mustard operation (3). 
 
The Patient 
 
The patient was a three-year-old female from Egypt with cyanosis. Echocardiography showed transposition of the great arteries (D-TGA) with a secundum ASD. The function of the left ventricle (LV) was good on the echocardiography; however, it showed low pressure on the hemodynamic catheter and was not suitable for an arterial switch operation. Therefore, the decision was made to proceed with an atrial switch procedure (the modified Mustard procedure). 
 
The Surgery 
 
Modifications in this procedure included: 

1. A small right atrial incision made in the lower part of the atrium close to the crista terminalis to preserve most of the contractile function of the lateral wall of the atrium, as well as the sinoatrial node (SAN). 
 
2. The atrial septum was excised and re-endothelialized. The atrial cavity was enlarged by slitting the orifice of the coronary sinus (CS) to incorporate it into the inferior channel connecting the inferior chamber receiving the inferior vena cava (IVC) to the supra-mitral chamber. This allowed blood flow to join from the superior vena cava (SVC) forming parallel streamlines across the mitral valve, analogous to those in normal hearts. This could help form the vortices in the LV with important functional implications. 

3. The entire right atrial appendage was incorporated into the superior channel to enhance its volume (reservoir and contractile functions). 

4. The superior channel was enlarged by placing the inferior suture line on the posterior atrial wall away from the roof of the left atrium. This allowed unimpeded flow from the superior chamber to the supra-mitral chamber. 

5. The Eustachian valve was excised, and the areas surrounding the entry of the IVC and SVC were incorporated into the inferior channel and superior channels, respectively. This had the effect of enhancing both the reservoir and contractile functions of the combined superior and inferior channels, as well as the supra-mitral chamber. 
 
Operative Steps 

The patient underwent a median sternotomy, and cardiopulmonary bypass was initiated. A large rectangular pericardial patch was harvested and cleaned, ensuring it was positioned 1 cm from both phrenic nerves to preserve them. An aortic cross-clamp was applied, and a small right atrial (RA) incision, as described, was made. The heart was arrested using antegrade cold crystalloid cardioplegia. 

The intracardiac anatomy was then examined. The interatrial septum was completely excised, followed by re-endothelialization, and a slit opening of the coronary sinus (CS).

Stay stitches were placed, as shown in the diagram in the video. The lower border of the inferior channel was approached in front of the left pulmonary veins, separating them from the left atrial appendage and mitral valve. This line continued until it reached the IVC. The upper border was then stitched, separating both the mitral and tricuspid valves until it fully incorporated the IVC and the surrounding area. 

The lower border of the superior limb started in front of the left pulmonary veins on the posterior wall of the left atrium. The upper border was then started from the crux toward the SVC, incorporating the entire right atrial appendage, thus maintaining both the reservoir and contractile function of the superior chamber. 

The systemic venous baffle was checked, and pulmonary venous obstruction was excluded. The patient was successfully weaned from bypass in normal sinus rhythm. The chest was closed, and the patient had an uneventful hospital course, with discharge on postoperative day five. 

References

1. Yacoub MH, Radley-Smith R, Maclaurin R. Two-stage operation for anatomical correction of transposition of the great arteries with intact interventricular septum. Lancet. 1977;1:1275-8.
2. Kiener A, Kelleman M, McCracken C, Kochilas L, St Louis JD, Oster ME. Longterm survival after arterial versus atrial switch in d-transposition of the great arteries. Ann Thorac Surg. 2018;106:1827-33.
3. Hosny H, Sedky Y, Romeih S, Simry W, Afifi A, Elsawy A, Khalek MA, Doss R, Elguindy A, Aguib H, Yacoub M. Revival and modification of the Mustard operation. J Thorac Cardiovasc Surg. 2020 Jan;159(1):241-249. doi: 10.1016/j.jtcvs.2019.03.027.

Disclaimer

The information and views presented on CTSNet.org represent the views of the authors and contributors of the material and not of CTSNet. Please review our full disclaimer page here.