Dear Editor,
We read with deep interest the paper “Evaluation of the mean platelet volume in
patients with cardiac syndrome X” by Demirkol et al. (11. Demirkol S, Balta S, Unlu M, Yuksel UC, Celik T, Arslan Z, et al.
Evaluation of the mean platelet volume in patients with cardiac syndrome X.
Clinics. 2012;67(9):1019-22,
http://dx.doi.org/10.6061/clinics/2012(09)06.
http://dx.doi.org/10.6061/clinics/2012(0...
). The authors (11. Demirkol S, Balta S, Unlu M, Yuksel UC, Celik T, Arslan Z, et al.
Evaluation of the mean platelet volume in patients with cardiac syndrome X.
Clinics. 2012;67(9):1019-22,
http://dx.doi.org/10.6061/clinics/2012(09)06.
http://dx.doi.org/10.6061/clinics/2012(0...
) aimed to
evaluate the mean platelet volume (MPV) in patients with cardiac syndrome X (CSX) and
compare patients with coronary artery disease (CAD) with a control group. We have a
minor criticism concerning their methodology.
Although statistical significance was defined as p<0.05 and the
p-values of MPV were given, the p-values of all
variables should have been provided in the paper (11. Demirkol S, Balta S, Unlu M, Yuksel UC, Celik T, Arslan Z, et al.
Evaluation of the mean platelet volume in patients with cardiac syndrome X.
Clinics. 2012;67(9):1019-22,
http://dx.doi.org/10.6061/clinics/2012(09)06.
http://dx.doi.org/10.6061/clinics/2012(0...
). It seems that some of the variables are not compatible with a normal
distribution. However, the continuous variables were only reported as mean±standard
deviation (SD). In addition, the authors (11. Demirkol S, Balta S, Unlu M, Yuksel UC, Celik T, Arslan Z, et al.
Evaluation of the mean platelet volume in patients with cardiac syndrome X.
Clinics. 2012;67(9):1019-22,
http://dx.doi.org/10.6061/clinics/2012(09)06.
http://dx.doi.org/10.6061/clinics/2012(0...
) used
a one-way analysis of variance (ANOVA) or Kruskal-Wallis test to compare the variables.
ANOVA is used to analyze the means of two or more samples. The Kruskal-Wallis test is
the nonparametric equivalent of the ANOVA test. The statistical test used for each
variable in the study is thus unclear (11. Demirkol S, Balta S, Unlu M, Yuksel UC, Celik T, Arslan Z, et al.
Evaluation of the mean platelet volume in patients with cardiac syndrome X.
Clinics. 2012;67(9):1019-22,
http://dx.doi.org/10.6061/clinics/2012(09)06.
http://dx.doi.org/10.6061/clinics/2012(0...
).
CSX is an angina with signs associated with decreased blood flow to the heart tissue but
with normal coronary arteries. A number of systemic microvascular abnormalities,
including endothelial cell dysfunction, diffuse atherosclerosis, and systemic
inflammation, result in reduced blood flow (22. Arthur HM, Campbell P, Harvey PJ, McGillion M, Oh P, Woodburn E,
et al. Women, cardiac syndrome X, and microvascular heart disease.
Can J Cardiol. 2012;28(2 Suppl):S42-9.,33. Jones E, Eteiba W, Merz NB. Cardiac syndrome X and microvascular
coronary dysfunction. Trends Cardiovasc Med. 2012;22(6):161-8,
http://dx.doi.org/10.1016/j.tcm.2012.07.014.
http://dx.doi.org/10.1016/j.tcm.2012.07....
). Platelets play a key role in
atherothrombosis and inflammation. MPV, an index of platelet function, is a potential
marker of platelet reactivity. Therefore, recent studies have focused on platelet
function and inflammatory markers to determine their importance in cardiovascular
diseases, including CSX (44. Chu SG, Becker RC, Berger PB, Bhatt DL, Eikelboom JW, Konkle B,
et al. Mean platelet volume as a predictor of cardiovascular risk: a systematic
review and meta-analysis. J Thromb Haemost. 2010;8(1):148-56,
http://dx.doi.org/10.1111/j.1538-7836.2009.03584.x.
http://dx.doi.org/10.1111/j.1538-7836.20...
,55. Gasparyan AY, Ayvazyan L, Mikhailidis DP, Kitas GD. Mean platelet
volume: a link between thrombosis and inflammation? Curr Pharm Des.
2011;17(1):47-58, http://dx.doi.org/10.2174/138161211795049804.
http://dx.doi.org/10.2174/13816121179504...
). Most conditions, including traditional risk factors (e.g.,
hypertension, atherogenic lipoproteins, obesity, and hyperglycemia) and many
inflammatory conditions (e.g., infection and inflammatory diseases), can influence MPV
(44. Chu SG, Becker RC, Berger PB, Bhatt DL, Eikelboom JW, Konkle B,
et al. Mean platelet volume as a predictor of cardiovascular risk: a systematic
review and meta-analysis. J Thromb Haemost. 2010;8(1):148-56,
http://dx.doi.org/10.1111/j.1538-7836.2009.03584.x.
http://dx.doi.org/10.1111/j.1538-7836.20...
,55. Gasparyan AY, Ayvazyan L, Mikhailidis DP, Kitas GD. Mean platelet
volume: a link between thrombosis and inflammation? Curr Pharm Des.
2011;17(1):47-58, http://dx.doi.org/10.2174/138161211795049804.
http://dx.doi.org/10.2174/13816121179504...
).
However, the authors (11. Demirkol S, Balta S, Unlu M, Yuksel UC, Celik T, Arslan Z, et al.
Evaluation of the mean platelet volume in patients with cardiac syndrome X.
Clinics. 2012;67(9):1019-22,
http://dx.doi.org/10.6061/clinics/2012(09)06.
http://dx.doi.org/10.6061/clinics/2012(0...
) did not exclude local or
systemic infections or any previous history of infection (particularly <3
months).
In addition, the authors (11. Demirkol S, Balta S, Unlu M, Yuksel UC, Celik T, Arslan Z, et al.
Evaluation of the mean platelet volume in patients with cardiac syndrome X.
Clinics. 2012;67(9):1019-22,
http://dx.doi.org/10.6061/clinics/2012(09)06.
http://dx.doi.org/10.6061/clinics/2012(0...
) did not analyze
inflammation markers, such as C-reactive protein (CRP), even though their role in
inflammation has been previously reported in CAD. It is still unclear whether MPV
measurement is the best method to determine the inflammation in patients with CSX. If
other proven inflammatory markers (in addition to MPV) had been screened and were found
to correlate with the MPV of these patients, the conclusions would have been more
definitive. Therefore, the MPV should be evaluated together with the other serum
inflammatory markers. Although the authors (11. Demirkol S, Balta S, Unlu M, Yuksel UC, Celik T, Arslan Z, et al.
Evaluation of the mean platelet volume in patients with cardiac syndrome X.
Clinics. 2012;67(9):1019-22,
http://dx.doi.org/10.6061/clinics/2012(09)06.
http://dx.doi.org/10.6061/clinics/2012(0...
)
did not include other markers relevant to CSX in their paper, we agree with their
follow-up letter that suggests that MPV itself (without other inflammatory markers) may
not provide comprehensive information about ongoing inflammation (66. Balta S, Demirkol S, Unlu M, Celik T. Other inflammatory markers
should be kept in mind when assessing the mean platelet volume. Platelets. 2013.
[Epub ahead of print].). Furthermore, in addition to the p values, the
exact MPV values for each group should have been provided in order to analyze the entire
study group to determine the clinical impact of the MPV.
We would like to congratulate the authors (11. Demirkol S, Balta S, Unlu M, Yuksel UC, Celik T, Arslan Z, et al.
Evaluation of the mean platelet volume in patients with cardiac syndrome X.
Clinics. 2012;67(9):1019-22,
http://dx.doi.org/10.6061/clinics/2012(09)06.
http://dx.doi.org/10.6061/clinics/2012(0...
) for
highlighting the efficacy of MPV in patients with CSX. MPV appears to be a novel marker
and an important indicator and predictor of atherothrombosis together with traditional
risk factors and other proven inflammatory markers. Large-scale prospective clinical
studies with these recommendations are now needed.
REFERENCES
-
1Demirkol S, Balta S, Unlu M, Yuksel UC, Celik T, Arslan Z, et al. Evaluation of the mean platelet volume in patients with cardiac syndrome X. Clinics. 2012;67(9):1019-22, http://dx.doi.org/10.6061/clinics/2012(09)06.
» http://dx.doi.org/10.6061/clinics/2012(09)06 -
2Arthur HM, Campbell P, Harvey PJ, McGillion M, Oh P, Woodburn E, et al. Women, cardiac syndrome X, and microvascular heart disease. Can J Cardiol. 2012;28(2 Suppl):S42-9.
-
3Jones E, Eteiba W, Merz NB. Cardiac syndrome X and microvascular coronary dysfunction. Trends Cardiovasc Med. 2012;22(6):161-8, http://dx.doi.org/10.1016/j.tcm.2012.07.014.
» http://dx.doi.org/10.1016/j.tcm.2012.07.014 -
4Chu SG, Becker RC, Berger PB, Bhatt DL, Eikelboom JW, Konkle B, et al. Mean platelet volume as a predictor of cardiovascular risk: a systematic review and meta-analysis. J Thromb Haemost. 2010;8(1):148-56, http://dx.doi.org/10.1111/j.1538-7836.2009.03584.x.
» http://dx.doi.org/10.1111/j.1538-7836.2009.03584.x -
5Gasparyan AY, Ayvazyan L, Mikhailidis DP, Kitas GD. Mean platelet volume: a link between thrombosis and inflammation? Curr Pharm Des. 2011;17(1):47-58, http://dx.doi.org/10.2174/138161211795049804.
» http://dx.doi.org/10.2174/138161211795049804 -
6Balta S, Demirkol S, Unlu M, Celik T. Other inflammatory markers should be kept in mind when assessing the mean platelet volume. Platelets. 2013. [Epub ahead of print].
Publication Dates
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Publication in this collection
July 2013