Tricuspid Atresia and Fontan Circulation: Anatomy, Physiology, and Perioperative Considerations
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis is a very extensive review of cardiology. The authors are to be congratulated on a tremendous amount of work.
Is this manuscript aimed more towards a review of pediatric cardiology, the Fontan, or Tricuspid atresia? For example, most of the Fontan discussion would pertain to any patient that has the Fontan, and not just tricuspid atresia.
To what audience is this manuscript aimed? On one aspect the manuscript is very simplistic. For example, for pre-surgical/anesthetic care, is the statement for “the necessity of adequate intra-venous access”. This is really quite mundane. On the other-hand is the description of Fontan physiology, which is very complex.
Much of the manuscript is redundant.
In the first paragraph on classification, the authors note classification by Van Praagh and another based on xray. Other than purely historical perspective, does this add valuable information?
The author spend a great deal of time discussing classifications, and use the abbreviations associated with the classifications. This becomes confusing in that there are several classifications. Further-more, it necessitates memorization. In the section on classification, paragraph 3, the authors use the abbreviations that relates to the physiology. This becomes difficult, unless the abbreviations are memorized. In the current era of 2 D echo, 3 D echo, MRI and CT the anatomy can be exquisitely detailed. Most major centers don’t even use abbreviations or classification, but rather just describe the anatomy. Would the authors agree?
It would be very important if the authors described in more detail the issues related to a restrictive VSD. Often- tImes the VSD becomes more restrictive over time. In normal related great arteries causing cyanosis, and in TGA causing “Sub AS”.
How does the extracardiac Fontan itself reduce atrial pressure?
Not all centers feel the extracardiac Fontan, is the Fontan of choice.
On page 7 paragraph 2 the authors describe the normal circulation. This seems far too sImplistic and even out of place, ie after describing the TrIcuspid Atresia circulation.
No center would do a Potts or Waterson shunt in this current era. Do the authors need to include this?
Why include vectorcardiography? Does any center do this test?
Why include m-mode echo?
Why did the authors not include information about 3DE, CT or MRI
The authors point out that a long-term deleterious effect of the Fontan is that the systemic ventricle must now eject into three different areas of resistance in a series circuit. However, is the impact additive, or is related to just the highest resistance circuit, etc.?
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThis is a well-written review manuscript that will be interesting to readers. However, there are several limitations that should be eliminated prior to publishing.
The title
The manuscript is entitled "Tricuspid Atresia and Fontan Circulation: Pathophysiology and
Anesthetic Considerations", however, "anesthetic considerations" cannot be considered as one of the most important topics of this article. It is clear even from looking at the amount of text devoted to "anesthetic considerations" (281 lines in total if compared to 489 lines devoted to other topics). Thus, changing the title is strongly recommended.
Section 8. Preoperative Assessment
Physical examination, auscultation, which is the part of physical examination, and ECG are not very important for the diagnosis of tricuspid atresia and choosing the surgical strategy. Thus, these subsections can be omitted or at least significantly shortened. On the contrary, cardiac catheterization and angiocardiography that is fundamental for above mentioned purposed should be included.
Section 9. Preoperative optimization
Antibiotic prophylaxis described in detail, is not specific for tricuspid atresia. This subsection can be omitted or at least significantly shortened. Most importantly, information about thromboprophylaxis is misleading because it is related not to preoperative but to postoperative management.
Section 10. Intraoperative management
in subsection 10.2, the authors provide valid information about postoperative values of central venous pressure and their influence on the course of postoperative period. However, it is not clear how it is related to "management". It is more logical to describe that in the next subsection devoted to postoperative hemodynamics.
General comment
The value of the review would be higher if the manuscript included information about the outcomes of Fontan operation in patients with tricuspid atresia.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe manuscript provides a comprehensive review of tricuspid atresia. This is a critical topic and highly relevant for pediatric cardiologists and surgeons. Overall, the review is well-written and provide a nice summary of the topic
There are several areas that require improvement:
Regarding IE prophylaxis:
The review state that clindamycin in no longer recommended. This is contradictory to the current AHA guidelines where clindamycin is still listed as a potential prophylactic agent.
The preference and use of clindamycin is decreasing but it is still recommended. Please amend the language to clearly indicate this distinction.
Revise the recommendation of aggressive ventilatory target for PVR reduction in order not to induce severe hypocapnia and cerebral VC I Fontan patients.
Fluid management: The recommendation of fixed preop fluid bolus should be changed to goal directed fluid management based on CVP, Co to avoid volume overload.
Conclusions should provide a concise take-home message
The references (191) are too many.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsThank you to the Editor for the opportunity to review this manuscript.
The paper addresses a significant congenital cardiac malformation and its subsequent surgical palliation.
The topic is highly relevant, and the manuscript is well written and up to date.
I recommend unifying the terminology used for the ventricular morphology, specifically the terms “systemic ventricle,” “single ventricle,” and “Fontan ventricle,” into a consistent nomenclature throughout the text.
I have no further comments, and following this minor revision, I recommend the manuscript for publication.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThis manuscript will serve as a good basic review article of the Fontan operation.
Reviewer 2 Report
Comments and Suggestions for AuthorsNo additional comments.
