Analyzing the Effects of Multi-Layered Porous Intraluminal Thrombus on Oxygen Flow in Abdominal Aortic Aneurysms
Round 1
Reviewer 1 Report
Dear Authors,
The frame of this paper is confusing and needing major revisions.
Introduction: it is too long, some part could be placed in the discussion. In this section you did not report and comment your outcomes, you must introduce generic aim of the study.
Methods: Avoid to report refernces. Detail your methods without outcomes. Report the outcomes only in its section and comment it in the discussion.
Discussion: good section, in the first part you can add some paragraphs of the introduction.
Author Response
Please see the attached PDF.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Review report of the manuscript oxygen-1952410
by A. Throop et al.
GENERAL COMMENTS
The authors around A. Throop attempt to study the porous thrombus-mediated limitations to mass transport in aortic abdominal aneurysms. In particular, they investigate the structural features of the intraluminal thrombus that can provide structural stability. The ILT is modeled as a multilayered material and the relationship between its porous structure and the oxygen flow to the aneurysmal wall is analyzed.
The work is well written and organized. Its main contribution to the field is related to the investigation of the relationship between the ILT modeled as a multilayered structure and the oxygen concentration and diffusion. However, several aspects of the manuscript need to be addressed.
The main flaw of the model is the geometry used for the computations: it is too simple for making strong conclusions; it neglects any bifurcations and it looks not really physiological. Furthermore, the sections 'Materials and Methods' and 'Discussion' needs to be extensively improved.
DETAILED COMMENTS
Following comments should be addressed before the manuscript can be accepted for publication:
1. All the presented cases are based on a specific geometry i.e. the symmetric AAA.
First of all, it is worth mentioning why did the authors chose this specific aneurysmal sac. It is not exactly a ballon, and its shape is actually not properly physiological.
Then, it would be actually interesting, when not necessary, to prove the obtained results with a non symmetric sac.
Also the first aortic bifurcation is neglected but it could have a great influence on the oxygen metric. If it is neglect able or not should be proved.
2. The work present several cases and reading the manuscript is sometimes difficult to follow what the authors want to say. I suggest to clarify with a Table or with a comprehensive explanation which case are performed and which details correspond to each. This should be performed in the section 'Materials and Methods'.
3. The Discussion of this work completely focused on the presented results. However, I personally believe that the Discussion should be a section in which the obtained results, presented in the appropriate section 'Results' have to be discussed with the literature data. The authors have not discussed anything. they have mainly rediscussed the implication of their results, which is correct but not sufficient. A comparison with evidences of previous literature studies is recommended.
4. Figure 6: The obtained flow structure is difficult to be understood. The recirculation visible in the ventral region of the AAA should actually not be present in the dorsal wall? Even at small velocity rates, the flow should tend to be attached to the ventral walls and promote a dorsal recirculation.
Please explain in details the reason of this finding.
5. The legend of all the Figures is written in scientific format. I suggest to use the fixed format that looks much more elegant (Example: in the Figure 6, instead of 5.120e-03 as maximum use the notation 0.00512).
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The paper is quite interesting and covers important topic. Just few issues requires more explanation:
Abstract: The abstract is lacking the material and methods description as well as most important conclusion. Introduction: In the introduction part Authors should add some overall information in paragraph/paragraphs dedicated on numerical and experimental methods applied in medical diagnosis/treatment. The authors should consider justifying the motivation of this study with recent study and e.g. cite the paper listed below: Artificial Circulatory Model for Analysis of Human and Artificial Vessels, https://doi.org/10.3390/app8071017 Material and Methods: 1. It is not clear if Authors prepared geometries basing on the medical data or not? If not how does it corelate t the real shape of aorta? 2. Authors mentioned “Blood flow is also considered to be laminar”. There is no information about the Reynolds number. It should be added to justify this assumption. 3. There is no information about the mesh creation. What about the mesh independent test. What mesh structure was assumed and why? Results: 1. What physical meaning has filtration velocity and why its range is between 10^-8 - 10^-1? 2. Figure 6 presents the real AAA. With red color thrombus was marked. How its spatial configuration and physical properties were reconstructed with the use of numerical tools? There is no information about the inlet boundary for this assumption. 3. Authors mentioned “Blood flow is also considered to be laminar”. It is confused. A living organism is characterized by the pulsatile nature of blood flow.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
My only concern remains the introduction, it is too long. Please reduce some commas.
Author Response
We thank the reviewer for carefully reading the manuscript a second time.
In the first round of revision, we attempted to tighten up the introduction in response to this concern and reduced this section by more than half a page. Our goal in the Introduction section is to help readers who are not familiar with the computational techniques to appreciate the importance and relevance of it for cardiovascular simulation and to keep the information comprehensible to the scientists outside the field of arterial biomechanics. Therefore, we need to provide enough information about the background and significance of the problem as well as related computational studies. We believe the current form serves this need, and by further reducing the length of the Introduction we will not be able to place the study in a broad context and review key publications.
Reviewer 2 Report
The authors have improved the manuscript responding to all the concerns highlighted during the review.
For this reason, I am pleased to recommend the study for publication.
Author Response
We thank the reviewer for encouraging evaluation of our revision and positive assessment of the paper.
Reviewer 3 Report
Thank you for provided answers - I am satisfied, the paper is suitable for publication.
Author Response
We thank the reviewer for the positive assessment and suitability for publication of the revised version
