Tinzaparin vs. Nadroparin Safety and Efficacy in Neurosurgery

Round 1

Reviewer 1 Report

Wilhelmy et al. present a comparison of tinzaparin and nadroparin as prophylactic anticoagulation in neurosurgical patients after cranial tumor surgery and SAH, based on a retrospective single center  study.  Although of retrospective character, as the authors themselves already stated, I rate the study  as very relevant concerning practical purposes and therefore recommend to accept the paper after minor corrections .

Remarks:

1) Title and text:

Fraxiparin is the trade name of the drug. Nadroparin as the active component would be more appropiate, in correlation to tinzaparin.

2) Methods , page2 line 60:

The authors mention patients treated between 2012 and 2015 , while on p.2  line 49 they describe the patient cohorts as being derived from 2012 to 2018 .  The first mentioned may be mistyping?

3) Methods , page 3 line 82 and Results section , esp. Table 2:

The authors list under primary endpoints "intracranial rebleeding" and "ischemia  (cerebral and systemic)"

In the results section, the term ischemia does not appear any more, but is replaced (?) by "thromboembolic events" in Table 2 (which seems to me more appropiate than "ischemic").

Please clarify and harmonize. The main message "no difference in thromboembolic events" should be stated in the text, as it is done concerning bleeding complications.  

4) Results p.3 line 97

814 patients (?)

5) Results  p.3 line 107

"There was no difference between tinzaparin and fraxiparin groups...."

Which groups? Only the SAH groups ? Those with preexisting anticoagulation?  Please clarify.

Author Response

Thank you a lot for your comments, which helped to improve the paper. We made the corrections according to your suggestion as follows:

1) We changed the name to Nadroparin, but provided the trade name aswell, as nadroparin is not commonly used as a name for the drug.

2) Indeed, the correct date here is 2018. We corrected accordingly.

3) Correct. We harmonized and clarified that we meant thromboembolic events as primary endpoint, regardless of actual ischemia (as DVT does not necessearily mean ischemia). We changed the following phrase in the abstract:

Accordingly, the rates of overall thromboembolic events were not significantly different (5.5% vs 4.3%). 

And in the results:

No differences were observed regarding bleeding complications nor thromboembolic events.

4) the word patients has been added.

5) We clarified as follows: In all SAH patients combined, there was no difference between tinzaparin and nadroparin groups (p = 0.7101).

Reviewer 2 Report

The authors retrospectively compared fraxiparin and tinzaparin used for perioperative venous thromboembolism prophylaxis, regarding adverse events (bleeding versus thromboembolic events) in neurosurgical patients.

The methods and results were clear. And the results can be usefle in clinical practice. 

Threfore, I think this paper deserves publication for this journal.

Author Response

Thank you for your assessment.