In 2014, in the Annals of Thoracic Surgery, Lugones and García reported a new surgical approach to scimitar syndrome (Ann Thorac Surg 2014;97:353-5).

Excellent results have been achieved with this technique in terms of mortality, morbidity and postoperative pathway patency. Connections between the pulmonary venous return and the left atrium are wide, and even in small children, anastomosis of 2.5 cm x 1 cm can be performed.

This technique can be applied in any patient, regardless of age, weight or the presence of scimitar vein stenosis, which accounts for up to 21% of the cases and increases the risk of postoperative pathway obstruction.

Nevertheless, there is a specific anatomic scenario in which it can be difficult to apply. The trickiest part of this operation is performing the left atriotomy. When dextrorotation of the heart is marked, the right ventricle is actually located to the right, and the right atrium lies posterior to the right ventricle. Thus, the left atrium leaves its normal posterior location and moves left. The degree of frontal plane displacement varies, but is usually more marked in young patients with severe hypoplasia of the right lung. Then, the left atrium becomes inaccessible from the right pulmonary venous pericardial recess and the left atriotomy can´t be performed.

To deal with this, we recently described a new concept called “atrial septum repositioning”. The posterior insertion of the atrial septum is detached from the atrial wall and sutured to the anterior border of the right atriotomy, after having resected a portion of right atrial free wall. In this way, a wide opening is created in the left atrium to receive pulmonary blood flow through the in situ pericardial tunnelization.

This modification is especially useful in small children, and results have been excellent too. Very large connections can be achieved, even 2.5 cm long in patients less than 1 year of age.

Advantages and potential disadvantages of these techniques:

  • Advantages:
    • Straightforward and reproducible procedures
    • Low risk of obstruction
      • No kinking or traction of the scimitar vein
      • Wide anastomosis
      • Wide tunnelization
      • Autologous tissue
    • Mild/moderate hypothermia, short CPB and aortic crossclamping times, usual inferior vena cava cannulation
    • No need to open the interatrial septum or the diaphragm
    • No risk of AV block or inferior vena cava obstruction
  • Potential disadvantages:
    • Right phrenic nerve injury
    • Difficult control of posterior suture lines bleeding
    • Sinus node injury

The strategies to mitigate these complications are: 1) always look at the phrenic nerve and take superficial bites in the inner surface of the pericardium; 2) be careful with the suture lines in order to prevent bleeding; and 3) stay low, away from the sinus node, when suturing the pericardium to the external surface of the right atrium