Reviewer's report
Title:Bleeding from gastrointestinal angioectasias is not related to bleeding
disorders - a case control study
Version: 1Date:8 February 2010
Reviewer: Augusto Federici
Reviewer's report:
The authors have approached an interesting topic, namely the role of acquired
hemostatic defects in the bleeding tendency from gastrointestinal angioectasias
and they wanted to organize a case control study. However the design of the
study is not clear since the authors do not describe in detail the time of the
enrolment of patients and controls. Moreover the description af the VWF
methods and results should be better described especially in those patients who
showed abnormal values VWF activity and of VWF multimers
MAJOR POINTS:
<!--[if !supportLists]-->1) <!--[endif]-->Methods and Design of the study page 6 :
The design of the study is not described in detail. If this is really a case control
study, the enrolment of the each patient and his/her control should be organized
at the same time. Did the authors use this approach ? Since the outcome of this
case-control study is to evaluate the causes of the GI bleeding the withdrawal of
blood to test hemostasis abnormalities should be performed when bleeding
occurs. Did the authors use during this case-control study blood samples
obtained during the day of bleeding?
<!--[if !supportLists]-->2) <!--[endif]-->Methods for VWF activities and VWF
Multmers: The authors used commercial tests for VWF activities but they do not
report any data of CV of these test and no information about calibration against
Internanational Standard. For VWF activities. This should be added.
<!--[if !supportLists]-->3) <!--[endif]-->Methods for VWF Multmers: The authors
used one of the mot sensitive techniques to assess VWF multimers by
SDS-gel-electrophoresis followed by western bloot and tried to calculate the
amounts of large, intermediate, low VWF multimers by densitometric analyses.
Which agarose did they use and which concentration ?
<!--[if !supportLists]-->4) <!--[endif]-->Results page 9: The authors have
summarized the data of patients versus control in one single Table and have
provided values of statistical difference. However they also report two patients
with prolonged bleeding time and two with loss of the high molecular weight
multimers. I think it could be useful to prepare an additional Table showing all the
parameters found in these four cases.
<!--[if !supportLists]-->5) <!--[endif]-->Discussion It is well know that the
mechanism of the acquired von Willebrand syndrome of patients with
gastrointestinal bleeding is always associated with aortic stenosis or other
cardiovascular disorders. No data have been reported on the specific role of
VWF in GI angioectasias: therefore several statements and comments are
inappropriate and should be modified with comments based on published data.
MINOR POINTS
Please use capital letters for VWF abbreviations: VWF:Ag, VWF activity, VWF
multimers
Reviewer's report
Title:Bleeding from gastrointestinal angioectasias is not related to bleeding
disorders - a case control study
Version: 1Date:8 February 2010
Reviewer: Augusto Federici
Reviewer's report:
The authors have approached an interesting topic, namely the role of acquired
hemostatic defects in the bleeding tendency from gastrointestinal angioectasias
and they wanted to organize a case control study. However the design of the
study is not clear since the authors do not describe in detail the time of the
enrolment of patients and controls. Moreover the description af the VWF
methods and results should be better described especially in those patients who
showed abnormal values VWF activity and of VWF multimers
MAJOR POINTS:
<!--[if !supportLists]-->1) <!--[endif]-->Methods and Design of the study page 6 :
The design of the study is not described in detail. If this is really a case control
study, the enrolment of the each patient and his/her control should be organized
at the same time. Did the authors use this approach ? Since the outcome of this
case-control study is to evaluate the causes of the GI bleeding the withdrawal of
blood to test hemostasis abnormalities should be performed when bleeding
occurs. Did the authors use during this case-control study blood samples
obtained during the day of bleeding?
<!--[if !supportLists]-->2) <!--[endif]-->Methods for VWF activities and VWF
Multmers: The authors used commercial tests for VWF activities but they do not
report any data of CV of these test and no information about calibration against
Internanational Standard. For VWF activities. This should be added.
<!--[if !supportLists]-->3) <!--[endif]-->Methods for VWF Multmers: The authors
used one of the mot sensitive techniques to assess VWF multimers by
SDS-gel-electrophoresis followed by western bloot and tried to calculate the
amounts of large, intermediate, low VWF multimers by densitometric analyses.
Which agarose did they use and which concentration ?
<!--[if !supportLists]-->4) <!--[endif]-->Results page 9: The authors have
summarized the data of patients versus control in one single Table and have
provided values of statistical difference. However they also report two patients
with prolonged bleeding time and two with loss of the high molecular weight
multimers. I think it could be useful to prepare an additional Table showing all the
parameters found in these four cases.
<!--[if !supportLists]-->5) <!--[endif]-->Discussion It is well know that the
mechanism of the acquired von Willebrand syndrome of patients with
gastrointestinal bleeding is always associated with aortic stenosis or other
cardiovascular disorders. No data have been reported on the specific role of
VWF in GI angioectasias: therefore several statements and comments are
inappropriate and should be modified with comments based on published data.
MINOR POINTS
Please use capital letters for VWF abbreviations: VWF:Ag, VWF activity, VWF
multimers
Please review this paper.
user
Reviewer's report
Title:Bleeding from gastrointestinal angioectasias is not related to bleeding
disorders - a case control study
Version: 1Date:8 February 2010
Reviewer: Augusto Federici
Reviewer's report:
The authors have approached an interesting topic, namely the role of acquired
hemostatic defects in the bleeding tendency from gastrointestinal angioectasias
and they wanted to organize a case control study. However the design of the
study is not clear since the authors do not describe in detail the time of the
enrolment of patients and controls. Moreover the description af the VWF
methods and results should be better described especially in those patients who
showed abnormal values VWF activity and of VWF multimers
MAJOR POINTS:
<!--[if !supportLists]-->1) <!--[endif]-->Methods and Design of the study page 6 :
The design of the study is not described in detail. If this is really a case control
study, the enrolment of the each patient and his/her control should be organized
at the same time. Did the authors use this approach ? Since the outcome of this
case-control study is to evaluate the causes of the GI bleeding the withdrawal of
blood to test hemostasis abnormalities should be performed when bleeding
occurs. Did the authors use during this case-control study blood samples
obtained during the day of bleeding?
<!--[if !supportLists]-->2) <!--[endif]-->Methods for VWF activities and VWF
Multmers: The authors used commercial tests for VWF activities but they do not
report any data of CV of these test and no information about calibration against
Internanational Standard. For VWF activities. This should be added.
<!--[if !supportLists]-->3) <!--[endif]-->Methods for VWF Multmers: The authors
used one of the mot sensitive techniques to assess VWF multimers by
SDS-gel-electrophoresis followed by western bloot and tried to calculate the
amounts of large, intermediate, low VWF multimers by densitometric analyses.
Which agarose did they use and which concentration ?
<!--[if !supportLists]-->4) <!--[endif]-->Results page 9: The authors have
summarized the data of patients versus control in one single Table and have
provided values of statistical difference. However they also report two patients
with prolonged bleeding time and two with loss of the high molecular weight
multimers. I think it could be useful to prepare an additional Table showing all the
parameters found in these four cases.
<!--[if !supportLists]-->5) <!--[endif]-->Discussion It is well know that the
mechanism of the acquired von Willebrand syndrome of patients with
gastrointestinal bleeding is always associated with aortic stenosis or other
cardiovascular disorders. No data have been reported on the specific role of
VWF in GI angioectasias: therefore several statements and comments are
inappropriate and should be modified with comments based on published data.
MINOR POINTS
Please use capital letters for VWF abbreviations: VWF:Ag, VWF activity, VWF
multimers
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