Opportunities and challenges of a novel cardiac output response to stress (CORS) test to enhance diagnosis of heart failure in primary care: qualitative study

Objective To explore the role of the novel cardiac output response to stress (CORS), test in the current diagnostic pathway for heart failure and the opportunities and challenges to potential implementation in primary care. Design Qualitative study using semistructured in-depth interviews which were audio recorded and transcribed verbatim. Data from the interviews were analysed thematically using an inductive approach. Setting Newcastle upon Tyne, UK. Participants Fourteen healthcare professionals (six males, eight females) from primary (general practitioners (GPs), nurses, healthcare assistant, practice managers) and secondary care (consultant cardiologists). Results Four themes relating to opportunities and challenges surrounding the implementation of the new diagnostic technology were identified. These reflected that the adoption of CORS test would be an advantage to primary care but the test had barriers to implementation which include: establishment of clinical utility, suitability for immobile patients and cost implication to GP practices. Conclusion The development of a simple non-invasive clinical test to accelerate the diagnosis of heart failure in primary care maybe helpful to reduce unnecessary referrals to secondary care. The CORS test has the potential to serve this purpose; however, factors such as cost effectiveness, diagnostic accuracy and seamless implementation in primary care have to be fully explored.


GENERAL COMMENTS
In this qualitative study the authors aimed to determine primary and secondary care healthcare professional's perceptions of the current clinical care diagnostic pathway for heart failure and the potential implementation a novel Cardiac Output Response to Stress (CORS) test developed to improve diagnosis of heart failure. Fourteen healthcare professionals were interviewed with semi-structured in-depth interviews. The text were analysed thematically using an inductive approach, resulting in six broad themes. Comments: -This study include a twofold aim, and the rational for the first part is not clear to me.
-Some information about the participants is missing (e.g. working experience, gender, age). It is also not clear if the participants have worked with the new diagnostic test.
-A more detailed description about how the thematic analysis was performed is needed. The steps in the analysis process are not described.
-The results correspond mainly to the second part of the aim (how health care professionals perceive a new diagnostic test). In figure  2

GENERAL COMMENTS
Thank you for the opportunity to review this manuscript. The authors explore the opportunities and challenges of implementing a novel test of diagnosing HF in GB. In general, this is an interesting study, but I have major concerns regarding the objective, results and discussion, that need to be edited before a decision of acceptance can be done.
First, the objective is not consistent throughout the manuscript whether it is "opportunities and challenges of the CORS test" or "perceptions of the potential implementation of CORS" or "evaluation of the current clinical pathway of HF".
This reflects also my second concern, as the study mixes up two objectives as Theme 1 is the rationale for developing a novel test for diagnosing HF and Themes 2-6 reflect the opportunities and challenges of the implementation. It seems that the "clinical need in the current pathway" was rather a presupposition because one topic of the interviews was the implementation of a novel test. Can you give the rationale for describing the current clinical pathway in the results (and not e.g. in the introduction) as the relation to the objective and other results is missing and its only outlined in one sentence and one figure? This becomes also clear as the discussion starts with the key point of the rationale for implementing a novel diagnostic tool on Page 14, line 17-21 and is not associated with the research aim.
Third, the results and mayor themes should be more specific: The six broad themes are really broad and the reader can hardly understand the results when reading the abstract as they do not outline the opportunities and challenges clearly. Can you describe them more detailed in the abstract and first section of the results with regard to the aim of the study?
The Term of Theme 3 is misleading as it rather reflects "patient exclusion and suitability" than "usability and acceptability". The explanation of Theme 4 is confusing and the context to the term "costs and resources" is not worked out quite plausible. In addition, Theme 4, 5 and 6 seem to reflect the same issue. The content should be differentiated more clearly.
Fourth, the study remains very specific in the context of the CORS test, but would be more appropriate for international readers and implementation research when discussed in the overall context of opportunities and challenged of implementing novel diagnostic tool in primary care. In the discussion the clinical need and implementation of the CORS test is addressed but not the results of opportunities and challenges. Are there other studies, which have found similar opportunities and challenged of implementing novel diagnostic tool in primary care?
Lastly, I have some minor concerns: 1. Generally, introduce abbreviations when they are used the first time and use only the abbreviation in the following (e.g. page 5, line 37; Page 6, line 14).
Abstract: 2. The conclusion rather repeats two of the results themes. 8. Page 6, line 40-53: data analysis is described weakly. Can you explain why transcripts were grouped and subdivided?
Results: 9. Do the sentences on page 13, line 57-60 belong to the theme 6 or are they an overall statement. Then they should be moved to the beginning of the results section, as the context is misleading when they are placed here.

VERSION 1 -AUTHOR RESPONSE
REVIEWER #1: Comment 1: This is a well written qualitative piece assessing the potential utility and uptake of a novel cardiac output device to help stratify patients presenting to primary care with signs, symptoms of heart failure.
Response 1: The Authors appreciate this comment.
Comment 2: The methodology is sound, and the results are valid with the appreciated limitation of the small sample size of discussants.
Response 2: The authors appreciate this comment.
Comment 3: The manuscript raises the important points around access to secondary care for the large number of patients with features suggestive of heart failure and how services could be adapted to cope with this.
Response 3: Thank you for the comment.
Comment 4: It's well written and readable. It's relevant to current practice and provides a first impression of one potential solution.
Response 4: Thanks for the comment. This comment underlies the primary aim of the present manuscript.
REVIEWER #2: Comment 1: This study include a twofold aim, and the rational for the first part is not clear to me.
Response 1: Thank you for the comment. The aims/objective of the study has been revised to ensure consistency. This could be found in abstract 'Objective' and also in page 6, lines 10-12. The first part of the interviews which focused on the clinical care pathway for heart failure patients was done in order to find out what part of the pathway the CORS test could potentially fit into.
Comment 2: Some information about the participants is missing (e.g. working experience, gender, age). It is also not clear if the participants have worked with the new diagnostic test.
Response 2: The Participant information have now been updated in table 1(page 21) to include working experience and gender. The study team did not ask for age of interviewees as we thought working experience in the field of heart failure was a better descriptor with respect to the present study's goals. The participants have not previously worked with the new test. They were only given a demonstration of how the test works and this reflected under Methods section 'The CORS test' and in figure 2.
Comment 3: A more detailed description about how the thematic analysis was performed is needed. The steps in the analysis process are not described.
Response 3: The detailed explanation on how thematic analysis was performed have now been added to the method section under 'data analysis' (page 7/8 lines 1-12). Response 4: Thank you for the comment. Figure 1 describes the clinical pathway, which GP practices follow in the treatment of Heart failure. This is in line with the NICE guideline and not a deviation. We have also revised all themes so they are coherent with the objectives of the study.
REVIEWER #3: Comment 1: The authors explore the opportunities and challenges of implementing a novel test of diagnosing HF in GB. In general, this is an interesting study, but I have major concerns regarding the objective, results and discussion, that need to be edited before a decision of acceptance can be done.
Response 1: Thank you for your comment. We appreciate there are inconsistencies and we have modified the objectives to ensure consistency and clarity throughout the manuscript.
Comment 2: First, the objective is not consistent throughout the manuscript whether it is "opportunities and challenges of the CORS test" or "perceptions of the potential implementation of CORS" or "evaluation of the current clinical pathway of HF".
Response 2: Modifications have been made to ensure clarity of the manuscript. First, we seek to establish potential role of the CORS test in the clinical pathway for heart failure management and then we further discuss the opportunities and challenges for implementation. This has been modified and reflects in the abstract objective and also introduction page 6 lines 10-12.
Comment 3: This reflects also my second concern, as the study mixes up two objectives as Theme 1 is the rationale for developing a novel test for diagnosing HF and Themes 2-6 reflect the opportunities and challenges of the implementation. It seems that the "clinical need in the current pathway" was rather a presupposition because one topic of the interviews was the implementation of a novel test. Can you give the rationale for describing the current clinical pathway in the results (and not e.g. in the introduction) as the relation to the objective and other results is missing and its only outlined in one sentence and one figure? This becomes also clear as the discussion starts with the key point of the rationale for implementing a novel diagnostic tool on Page 14, line 17-21 and is not associated with the research aim.
Response 3: This comment is well thought out and we appreciate and acknowledge the inconsistency. The introduction have now been revised and a brief note added on the clinical care pathway for heart failure (page 5, lines 8-16) and the potential role for an add-on test to improve diagnosis.
Comment 4: Third, the results and mayor themes should be more specific: The six broad themes are really broad and the reader can hardly understand the results when reading the abstract as they do not outline the opportunities and challenges clearly. Can you describe them more detailed in the abstract and first section of the results with regard to the aim of the study? The Term of Theme 3 is misleading as it rather reflects "patient exclusion and suitability" than "usability and acceptability". The explanation of Theme 4 is confusing and the context to the term "costs and resources" is not worked out quite plausible. In addition, Theme 4, 5 and 6 seem to reflect the same issue. The content should be differentiated more clearly.
Response 4: As per your suggestion, all themes have been revised and rephrased (Themes 1-4 pages 8, 10,11and 12) to make for better meaning and to reflect the description given. The abstract results section have also been revised. Themes 4-6 have been compressed into one theme (theme 4 page 12 line 8) for clarity and better understanding.
Comment 5: Fourth, the study remains very specific in the context of the CORS test, but would be more appropriate for international readers and implementation research when discussed in the overall context of opportunities and challenged of implementing novel diagnostic tool in primary care. In the discussion the clinical need and implementation of the CORS test is addressed but not the results of opportunities and challenges. Are there other studies, which have found similar opportunities and challenged of implementing novel diagnostic tool in primary care?
Response 5: The 'discussion' section (page 14) has been drafted to reflect the broader discussion of opportunities and challenges of implementing novel diagnostic tool in primary care. However, the present study presents a unique challenge, as this is the first study of its kind in cardiac care and other studies have only been reported to give a sense of the barriers (page 15, lines 2-8) encountered in the implementation of other forms of diagnostic tests.