Transposition of the Great Arteries with Intramural Left Main Coronary Artery—Salient Imaging Findings and Choice of Operative Technique

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 

The case report discusses two neonates diagnosed with Transposition of the Great Arteries (TGA) and intramural left coronary artery anomalies, highlighting diagnostic imaging techniques and variations in surgical approaches. Both patients underwent arterial switch operations (ASO) but with distinct coronary transfer techniques, leading to differential short-term postoperative courses.

•  The report effectively integrates fetal echocardiography, postnatal transthoracic echocardiography, computed tomography angiography (CTA), and invasive angiography to diagnose and plan surgical interventions.
•  By presenting two distinct surgical approaches (en bloc transfer and two-button transfer), the authors offer valuable insights into the decision-making process and outcomes in managing rare coronary anomalies.
• The inclusion of clear imaging figures and step-by-step explanations enriches the understanding of the anomalies and techniques employed.
•  The authors provide a thorough review of prior research, contextualizing their findings within existing knowledge on coronary anomalies in TGA.

• Although short-term outcomes are promising, long-term complications,  remain unexplored.
• While surgical techniques are detailed, the authors do not adequately discuss the risk-benefit trade-offs of each method, which could be critical for guiding surgeons unfamiliar with these approaches.

 

1.  The report emphasizes the utility of advanced imaging (e.g., ECG-gated CTA) for surgical planning. However, it lacks a critical comparison of these modalities with alternatives like magnetic resonance imaging (MRI).
2. Both approaches led to favorable discharge outcomes, yet the complications in Patient B (e.g., ECMO support and arrhythmias) warrant further exploration to determine whether these issues were technique-specific or incidental.
3.  The report acknowledges the need for larger studies or meta-analyses but does not propose specific research methodologies or collaborative frameworks to address these gaps.

 Detailed discussion of potential intraoperative complications and strategies to mitigate them would enhance the report's clinical applicability.

• Tracking patients’ outcomes over an extended period could provide valuable insights into the durability of surgical techniques.

The report is a commendable contribution to the understanding of TGA with coronary anomalies. It underscores the importance of precise imaging in operative planning and highlights the complexity of surgical decision-making in these cases. However, its limited scope and short-term focus restrict its applicability. 

Author Response

Comment 1: The report emphasizes the utility of advanced imaging (e.g., ECG-gated CTA) for surgical planning. However, it lacks a critical comparison of these modalities with alternatives like magnetic resonance imaging (MRI).

Response: Thanks for the comment, we added the following portion to address this request:

On CT angiogram, key findings were an acute angle origin and subtle caliber change at the extramural coronary exit. ECG gated CT scan is preferred over cardiac MRI for neonatal coronary imaging in a non-invasive way; CT scan has superior spatial resolution than cardiac MRI. CT is quicker to obtain as data is acquired over seconds rather than minutes to an hour. Moreover, CT scan technology and expertise is much more widely available than MRI. Lastly if there are post-operative ECMO support, CT scan can be performed with ECMO while an MRI cannot be performed in that situation. CT technology advancements like dual source scanners and photon counting scanners can enable diagnostic coronary imaging without breath-hold and anesthesia even in neonates.

Comment 2: Both approaches led to favorable discharge outcomes, yet the complications in Patient B (e.g., ECMO support and arrhythmias) warrant further exploration to determine whether these issues were technique-specific or incidental.

Response: This is a great point, and something we debated on including. After much discussion with surgeons and imagers, alike, we agreed that the outcomes we saw in the immediate post-operation phase for Patient B were not found to be in relation to the different techniques implemented, rather, they were incidental complications. I added this into the discussion portion of the manuscript.

Comment 3: The report acknowledges the need for larger studies or meta-analyses but does not propose specific research methodologies or collaborative frameworks to address these gaps.

Response: We were happy to include some more thoughts on potential launching points: More reports of patients with TGA-IMC may also reveal certain anatomic variants in which better outcomes can be achieved with the use of one technique over the other. A large-scale prospective analysis tracking long term patient outcomes including mortality, development of coronary lesions, and subsequent interventions is needed to adequately identify the better surgical option. However, the best surgical choice may very well be the one with which the surgeon is most familiar.

Reviewer 2 Report

Comments and Suggestions for Authors

The present case report illustrates two cases of newborns with transposition of great arteries (TGA) diagnoses in the pre-natal period, with anomalous coronary artery course. TGA is a rare but very serious congenital heart disease which requires prompt surgical treatment. These cases underline the importance of proper and careful pre-natal assessment in order to plan the optimal surgical strategy. The reports are adequately presented, the discussion is clear and concise. The figures are well representative of the different pre and post-natal imaging modalities which allow the diagnosis. I would suggest revising the abbreviations, as some are not spelled-out in the manuscript (i.e. CHD, CT), in another case the abbreviation appears before the spelled-out form (LCA), and in another case the abbreviation is not needed as it appears only once in the text (CF). In page 6 line 66 there is a repetition which should be corrected (“Two neonates were delivered were then delivered”). Finally, I would removed that the CT images where acquire during “breath-holding” as it is difficult to obtain in newbors.

Author Response

Comment 1:  I would suggest revising the abbreviations, as some are not spelled-out in the manuscript (i.e. CHD, CT), in another case the abbreviation appears before the spelled-out form (LCA), and in another case the abbreviation is not needed as it appears only once in the text (CF). In page 6 line 66 there is a repetition which should be corrected (“Two neonates were delivered were then delivered”). Finally, I would remove that the CT images were acquires during “breath-holding” as it is difficult to obtain in newborns.

 

Response: Thank you very much for these thoughtful remarks, we did go back through and alter our abbreviations to be more consistent throughout the manuscript and fixed the edit mentioned above. We also removed the portion about the "breath-holding." Thanks for your responses.