Arterial Switch Operation and Mee Procedure

The patient was a 4.0 kg boy born at 40+2 weeks via uncomplicated spontaneous vaginal delivery. It is unknown whether an APGAR test and pulse ox screen test were administered at birth. The hospital course was uncomplicated, and the patient was subsequently discharged home. The patient was seen twice at the pediatrician for poor weight gain, although he was asymptomatic and was tolerating 30-minute feeds every two hours at the time. At four weeks of life, the patient presented at an outside hospital emergency department with new onset of feeding intolerance with increased work of breathing. Upon exam, the patient appeared cyanotic and was found to be profoundly hypoxic. The patient was subsequently intubated and nitric oxide inhalation was initiated. The patient demonstrated cardiomegaly and pulmonary edema on chest x-ray, prompting a transthoracic echocardiogram. Echo revealed that the patient had d-transposition of the great arteries (dTGA) with intact ventricular septum (IVS), a small patent foramen ovale (PFO), and a small patent ductus arteriosus (PDA). Further interrogation of the coronary arteries demonstrated an anomalous aortic origin of a coronary artery (AAOCA). The left coronary artery arose from the posterior aspect of the right sinus of Valsalva with an intramural and interarterial course. Prostaglandin infusion was started at 0.02 mcg/kg/min. The patient was transferred to Cincinnati Children’s Hospital for further management. Upon arrival, the patient’s marginal perfusion status, despite multiple fluid boluses en route, prompted an emergent balloon atrial septostomy in the cath lab. The patient recovered well and post-procedure echo demonstrated an unrestrictive atrial level shunt.

At five weeks of life, the patient underwent Jatene’s arterial switch operation (ASO), Mee procedure, atrial septal defect closure, and PDA ligation and division. The Mee procedure is the surgical technique to translocate the intramural coronary artery in a patient undergoing an ASO. The procedure is described originally as detachment of the posterior commissure from the aortic wall, unroofing of the intramural segment of the left coronary artery, wedge resection of the internal aortic wall (to ensure adequate orifice size), and excision of the right and left coronary artery buttons in a single button, which was subsequently divided into two separate cuffs and re-implanted into the neoaortic root.

This video illustrates this technique, with the minor difference of the coronary artery buttons being excised separately. Jatene’s ASO was carried out in standard fashion. The left coronary artery button was implanted in the neoaortic root using the medially-based trapdoor incision. The right coronary artery was implanted in the neoaortic root using an oblique incision. A LeCompte maneuver was performed. The neoaortic root was anastomosed directly to the ascending aorta. The previously detached posterior commissure was re-suspended to a pantaloon-style patch (pulmonary homograft) during the reconstruction of the neopulmonary root. The reconstructed neopulmonary root was anastomosed to the branch pulmonary arteries. The atrial level shunt was closed primarily. The patient weaned from bypass in normal sinus rhythm and was decannulated successfully. The chest was closed. The patient had a relatively uneventful hospital course and was discharged on postoperative day 15.

References

1. Tweddell JS, Litwin B. Transposition of the Great Arteries. Op Tech Thorac Cardiovasc Surg. 2002;7(1):49-63.
2. Asou T, Karl TR, Pawade A, Mee RB. Arterial switch: translocation of the intramural coronary artery. Ann Thorac Surg. 1994;57(2):461-465.