Publication Date

2-2024

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Abstract

Background: Transposition of the great arteries (TGA) is a common cyanotic critical congenital heart disease, with a feasible prenatal diagnosis. Arterial switch operation (ASO) with/without VSD closure is the preferred surgical approach with added challenge when an intramural coronary artery (IMC) is present. ASO is technically quite demanding with IMC, and incidence of post-operative complications and mortality are potentially higher. We present our recent TGA-IMC experience focusing on salient features identified on echocardiography, CT and invasive angiograms, as well as variations in ASO surgical techniques for repair. Methods: Our echo imaging acquisition required high frequency transducers and shallow image depth in the para-sternal short axis plane, with focus on the aortic root; color Flow Doppler optimization with narrow color box, CF Color Setting and low Nyquist limit was also used. CT angiograms were performed with retrospective gating and breath-hold, after contrast bolus of an Omnipaque-240 contrast/saline mixture (70%-30%). Images were obtained at normal neonatal heart rate of 140s/min with appropriate dose reduction technique. Invasive angiograms were performed in the cardiac Cath lab, with balloon occlusion aortograms using a 5Fr Berman catheter and a combination of camera angulations. Results/Discussion: Two consecutive patients with TGA/intact ventricular septum and intramural left main coronary artery were identified. Both coronary artery systems originated from the right facing sinus in TGA (2 R, AD, Cx Leiden classification). The left main coronary artery had an intramural course, coursing through the pulmonary/septal/posterior commissure and then normally bifurcated to left anterior descending and circumflex arteries. Echocardiographic hallmark for the intramural course was the side-by-side origins of the two coronary arteries from the same sinus and the LCA course between the commissure and the aortic wall. On CT angiogram, key findings were an acute angle origin and subtle caliber change at the extramural coronary exit. Two different surgical approaches were undertaken. In one, the coronary button to be taken en bloc for transfer to the neo-aorta. Ischemia due to inadvertent left coronary artery injury, necessitated patch augmentation of the left main coronary artery. In the other, unroofing of the LCA intramural segment into sinus 1 enabled the transfer of two separate coronary buttons. Both patients had an uneventful subsequent post-operative course. Conclusion: Transposition of the great arteries with intramural left or right coronary artery presents a surgical challenge during ASO repair. By focused trans-thoracic echocardiography, anomalous/intramural coronary artery in TGA can be suspected. The intramural course can be confirmed by ECG gated CT angiograms, with measurement of intramural length, which can assist in operative planning. A recent report from a single center series suggest coronary unroofing with separate 2-button coronary transfer may be associated with lower risk of coronary and ischemic complications. Our limited experience suggests advance imaging with CT angiograms can help determine length of intramural segment, and feasibility of coronary artery unroofing, and 2-button transfer technique. Our institutional experience presents an opportunity for further exploration of the best surgical technique for TGA-IMC with a multi-center approach and longer term follow-up.

Disciplines

Cardiology | Pediatrics

Notes

Presented at the 27th Annual Update on Pediatric and Congenital Cardiovascular Disease (Cardiology 2024); Scottsdale, AZ; Feb 14-18, 2024.

Transposition of the great arteries with intramural left main coronary artery: Salient imaging findings and description of two operative techniques

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