How Do Cardiovascular Biomarkers Behave in Patients with Severe Aortic Valve Stenosis with and without Echocardiographically Proven Pulmonary Hypertension?—A Retrospective Study of Biomarker Trends before and after Transcatheter Aortic Valve Replacement

Round 1

Reviewer 1 Report

Introduction section: since the study is focused on biomarkers for pulmonary hypertension in severe aortic valve stenosis, further elaboration on the association of pulmonary hypertension and aortic valve stenosis, as well as the clinical relevance of pulmonary hypertension are necessary in the introduction. 

Methods section: succinctly and effectively described the sampling method, echocardiography assessment technique for pulmonary hypertension, method for blood collection and analysis of serum biomarkers for pulmonary hypertension, and statistical analyses.

Results: the figures and tables facilitated comparison of the 2 study groups.

Discussion: provided useful background information on the various biomarkers included in this study and elaboration of study results in comparison to similar studies in the literature. It would also be useful to comment if presence of cardiopulmonary comorbidities such as coronary artery disease, atrial fibrillation, or COPD, for example, would impact the levels of serum biomarkers. Future studies could also be used to determine association between the serum biomarkers and mortality in patients with pulmonary hypertension who are post TAVI.

Overall, the study has high relevance in identifying biomarkers that allow healthcare providers to risk stratify patients with aortic stenosis and concomitant pulmonary hypertension. More studies with larger sample sizes will help to eventually pinpoint the serum biomarkers with the greatest application in direct clinical practice.

Author Response

Dear Reviewer 1,

thank you for taking the time to read and review our manuscript. The comments and remarks are very important for us to continuously improve.

In the following PDF version (please see the attachment), the comments have been answered and integrated into the running text.

Thank you in advance for reviewing again.

With kind regards

Elke Boxhammer

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper by Boxhammer et al. is a retrospective analysis on the differences between several cardiovascular biomarkers before and after a TAVR procedure in two groups (patients with sPAP>=40mmHg or <40mmHg). Although the paper appears well written and some of the results are of merit, statistical analysis has several limits. If same patients underwent different timepoints measurements, you cannot compare the overall results obtained at different timepoints two by two (e.g. 96 hours vs. 3 months). These are not unpaired data since the results come from the same patients at different timepoints. Furthermore, you need to adjust for multiple comparisons. I believe you should reanalyze all data with the help of a statistician. This will not only allow you to improve the accuracy of your current results, but will also give you insights on the predictive role of these new cardiovascular biomarkers. The real question is whether one of the biomarkers you analyzed is able to predict patients who will maintain high pulmonary pressure after TAVR. And you could obtain an answer with the right statistical analysis, which is not comparison between groups but other tests, including regression analysis (possibly adjusting for confounders such as C-reactive protein levels, since most of the biomarkers you analyzed are involved in systemic inflammation).  

Author Response

Dear Reviewer 2,

thank you for taking the time to read and review our manuscript. The comments and remarks are very important for us to continuously improve.

In the following PDF version (please see the attachment), the comments have been answered and integrated into the running text.

Thank you in advance for reviewing again.

With kind regards

Elke Boxhammer

Author Response File: Author Response.pdf

Reviewer 3 Report

Boxhammer et al. present a study on five potential biomarkers to prospectively predict outcome (?) of patients with severe aortic valve stenosis in dependence on additional pulmonary hypertension that was fixed according the endpoint sPAP determined via transthoracic echocardiography. Therefore biomarker levels were quantified by ELISA before and up to 12 months after TAVI procedure in 32 patients without PH and in 53 patients with PH (cutoff sPAP 40 mmHg).

Definition of biomarkers easy to analyse in the clinical practice is a reasonable aim and presented set may also be helpful to define outcome and relevance in the presented patient group that suffers from AS and in addition from PH.

Major points to adapt:

Please clearly define the aim of the study according to prediction of outcome, relevance of the markers for the definition of persistence of PH or any other definition according to clinical relevance. This only got partially obvious in outlook section of the manuscript.

Please discuss the values of the markers and the level of increase with literature data, if available. Is it possible or is it the aim to define a cut-off value for the marker concentrations?

Was the sPAP determined in the patients group e.g. at time point of 12 months and correlated with the persistence of higher marker concentrations? Echocardiographically evaluation was exclusively performed at baseline timepoint?

Statistical analysis: It is described that an unpaired student´s t-test was performed. To my knowledge a paired analysis via ANOVA should be applied to analyse different timepoints of marker concentrations in the same cohort. To compare the PH vs. non-PH group a two-way ANOVA should be performed to compare the results. Of course adapted according normal distribution. Why did the authors perform t-tests?

It seems as if in the sPAP≥40 mmHg group SDs are higher in most of the marker analyses, what is the reason?

Minor points

Include abbreviation for sPAP

Adapt graphs according to the statistical analysis performed and according to marker values (e.g. Figure 1 sST2 only up to 40.000) to allow better clarity and estimation of differences.

ELISA protocol: Is there also a capture AB necessary? Was there a need for dilution of the samples and storage at -80°C does not impact the analysis? Did you dilute the samples?

Author Response

Dear Reviewer 3,

thank you for taking the time to read and review our manuscript. The comments and remarks are very important for us to continuously improve.

In the following PDF version (please see the attachment), the comments have been answered and integrated into the running text.

Thank you in advance for reviewing again.

With kind regards

Elke Boxhammer

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Please include the actual figures in the PDF for Review.

Author Response

Dear Reviewer 3,

please find the figures attached in the current version!

Kind regards

Elke Boxhammer