Cardiac Implantable Electronic Device Infections; Long-Term Outcome after Extraction and Antibiotic Treatment

Round 1

Reviewer 1 Report

Hornstein and colleagues examined cardiac implantable electronic device infections with long-term outcome after extraction and antibiotic treatment.  

Comments:

1.  The manuscript seems to suggest that all CIED extractions also had lead extractions.  Is that correct?  If it is, then please make it explicit in the text.  If not, then please specify proportion with lead extraction.  

 

2. There were 168 extractions but only 68 patient had echocardiography of any type.  Could the authors explain why more patients did not have echos?

 

3. Were the echos done mainly in the systemic infection group?

 

4. The microbial findings on table 4, were these based on blood cultures, or cultures from the extracted vegetations?  This is of some interest because not all vegetations on leads are necessary infections (as shown in historical autopsy data and recent echo data). 

 

 

Author Response

Dear Professor  Petrosillo,

I here send the revised manuscript  of the invited article “Cardiac implantable electronic device infections; long term outcome after extraction and antibiotic treatment” by Hörnsten for consideration as an article for publication in your journal.

Thanks for the valuable comments by the reviewers.

The answers to the reviewers are found  below.

All the authors have approved the revised manuscript.

Stockholm June 30, 2021

Yours sincerely

Katarina Westling

Associate professor, Senior consultant in Infectious Diseases

Karolinska University Hospital and Karolinska Institutet

Stockholm  Sweden

 

Dear Reviewers,

Thanks for your valuable comments.

I send my answers to you questions below.

Best regards

Katarina Westling

Hornstein and colleagues examined cardiac implantable electronic device infections with long-term outcome after extraction and antibiotic treatment.  

 R 1 Comments:

The manuscript seems to suggest that all CIED extractions also had lead extractions.  Is that correct?  If it is, then please make it explicit in the text.  If not, then please specify proportion with lead extraction.  

All patient included underwent Transvenous Lead Extraction, TLE. This is changed in the text, result part P 3.

 

2. There were 168 extractions but only 68 patient had echocardiography of any type.  Could the authors explain why more patients did not have echos?

There were 165 extractions, of which 68 patients had echo. The patients who had echo were mainly in the systemic infection group. Patients with a low suspicion of endocarditis were not investigated with echo.

3. Were the echos done mainly in the systemic infection group?

Yes, echos were most performed in the patients with systemic infection,

4. The microbial findings on table 4, were these based on blood cultures, or cultures from the extracted vegetations?  This is of some interest because not all vegetations on leads are necessary infections (as shown in historical autopsy data and recent echo data). 

The microbiologic findings were both from blood cultures and from leads. This is highlighted in the result part, in the text. All patients in the study had a TLE performed due to an infection. Vegetations could be non-infectious, and difficult to distinguish from infectious vegetations on echo, something that was recently presented by George et al, CID 2021). The aim of our study was not to compare vegetations on CIED with or without an infection.

 

 

R 2 since it seems 1 complication occurred, maybe just say that and what the complication was instead of giving a rate?

This is changed in the abstract and results page 4.

reimplantation was made (a median of?) 9.5 days...

Reimplantation was made after mean 9.5 days. That is changed in the abstract.

is it really possible that the mean LOS for the sixty one patients w systemic infection was 38.6 days? these seems highly improbable!!

Patients with systemic infection were hospitalized for a long time. This  include hospitalizations at departments of cardiology, infectious diseases and geriatric clinics where they received intravenous antibiotic treatment. OPAT treatment was not given at that time, that is described in the discussion.

One result of the study is that at home treatment program for patients with endocarditis is started at the hospital.

Introduction:

when you say "... followed by a 57% increase in infections" what are you referring to? not clear to me

The text is changed, there was a 57% increase in CIED infections, that was reported in the paper by Voigt et al.

pocket incisional drainage and or device exposure should also be listed as symptoms of pocket infection

Thanks for your comments, this is added in the text in Materials and Methods.

Methods:

why were patients from outside Stockhold county excluded?

The patients outside Stockholm County were excluded because they were difficult to follow-up, due to different patient record systems. There is not yet a national patient record system in healthcare in Sweden

maybe need to give more detail about procedural generalizability to help readers extrapolate to their local populations (how common are use of laser sheats for example?)

TLE is a highly specialized procedure and is recommended to be performed only if back up thoracic surgery is immediately available in the facilities/in your hospital. Specific extraction tools are usually needed and may vary depending on local routines and preferences. In Sweden only one TLE center use laser extraction sheats, Sahlgrenska Hospital in Gothenburg,

Results:

regarding the data on days to reimplantation and days on antibiotics, can you say what guidelines are typically followed in Sweden/if there were changes in local/European guidelines during the time period of the study?e

In Sweden, the European and US guidelines were followed. We also have Swedish guidelines for endocarditis. There were some minor changes in the guidelines during the study period, but this did not affect the outcome of the study.

how did 16S results compare to traditional culture in terms of yield and congruence with each other?

In 47% of the patients results from 16 S and culture  were congruent. In 51% the results differed between 16 S and culture, but the vast majority had a negative culture and positive 16 S, or positive culture and negative 16 S. In only two patients (5%) we found different species comparing results from 16 S and cultures.

can you clarify FIgure 2? you state in your text that mortality was higher with S aureus infections, but the red and blue line cross, and it seems at 140 months there were actually FEWER deaths in the S aureus group!

Figure 2 is changed, there was a mistake in the figure. Thanks for your comment.

I had problems to cut the revised figure 2 into the text, so I send it in a separate file.

Reviewer 2 Report

Abstract:

since it seems 1 complication occurred, maybe just say that and what the complication was instead of giving a rate?

reimplantation was made (a median of?) 9.5 days...

is it really possible that the mean LOS for the sixty one patients w systemic infection was 38.6 days? these seems highly improbable!!

Introduction:

when you say "... followed by a 57% increase in infections" what are you referring to? not clear to me

pocket incisional drainage and or device exposure should also be listed as symptoms of pocket infection

Methods:

why were patients from outside Stockhold county excluded?

maybe need to give more detail about procedural generalizability to help readers extrapolate to their local populations (how common are use of laser sheats for example?)

Results:

regarding the data on days to reimplantation and days on antibiotics, can you say what guidelines are typically followed in Sweden/if there were changes in local/European guidelines during the time period of the study?

how did 16S results compare to traditional culture in terms of yield and congruence with each other?

can you clarify FIgure 2? you state in your text that mortality was higher with S aureus infections, but the red and blue line cross, and it seems at 140 months there were actually FEWER deaths in the S aureus group!

 

Author Response

Dear Reviewer

Thanks for your valuable comments. My answers to the question follows below.

Yours sincerely

Katarina Westling

R 2 since it seems 1 complication occurred, maybe just say that and what the complication was instead of giving a rate?

This is changed in the abstract and results page 4.

reimplantation was made (a median of?) 9.5 days...

Reimplantation was made after mean 9.5 days. That is changed in the abstract.

is it really possible that the mean LOS for the sixty one patients w systemic infection was 38.6 days? these seems highly improbable!!

Patients with systemic infection were hospitalized for a long time. This  include hospitalizations at departments of cardiology, infectious diseases and geriatric clinics where they received intravenous antibiotic treatment. OPAT treatment was not given at that time, that is described in the discussion.

One result of the study is that at home treatment program for patients with endocarditis is started at the hospital.

Introduction:

when you say "... followed by a 57% increase in infections" what are you referring to? not clear to me

The text is changed, there was a 57% increase in CIED infections, that was reported in the paper by Voigt et al.

pocket incisional drainage and or device exposure should also be listed as symptoms of pocket infection

Thanks for your comments, this is added in the text in Materials and Methods.

Methods:

why were patients from outside Stockhold county excluded?

The patients outside Stockholm County were excluded because they were difficult to follow-up, due to different patient record systems. There is not yet a national patient record system in healthcare in Sweden

maybe need to give more detail about procedural generalizability to help readers extrapolate to their local populations (how common are use of laser sheats for example?)

TLE is a highly specialized procedure and is recommended to be performed only if back up thoracic surgery is immediately available in the facilities/in your hospital. Specific extraction tools are usually needed and may vary depending on local routines and preferences. In Sweden only one TLE center use laser extraction sheats, Sahlgrenska Hospital in Gothenburg,

Results:

regarding the data on days to reimplantation and days on antibiotics, can you say what guidelines are typically followed in Sweden/if there were changes in local/European guidelines during the time period of the study?e

In Sweden, the European and US guidelines were followed. We also have Swedish guidelines for endocarditis. There were some minor changes in the guidelines during the study period, but this did not affect the outcome of the study.

how did 16S results compare to traditional culture in terms of yield and congruence with each other?

In 47% of the patients results from 16 S and culture  were congruent. In 51% the results differed between 16 S and culture, but the vast majority had a negative culture and positive 16 S, or positive culture and negative 16 S. In only two patients (5%) we found different species comparing results from 16 S and cultures.

can you clarify FIgure 2? you state in your text that mortality was higher with S aureus infections, but the red and blue line cross, and it seems at 140 months there were actually FEWER deaths in the S aureus group!

Figure 2 is changed, there was a mistake in the figure. Thanks for your comment.

I had problems to cut the revised figure 2 into the text, so I send it in a separate file.