Dear Editor,
We read the recent article "Influence of obstructive sleep apnea on serum butyrylcholinesterase
activity and ischemia-modified albumin levels" by Liu-Xue Yang et al. with great interest (11. Liu-Xue Yang, Shao-Gang Ma, Hong Liu, Wei Xu. Influence of obstructive sleep
apnea on serum butyrylcholinesterase activity and ischemia-modified albumin levels. Clinics.
2013;68(7):968-73, http://dx.doi.org/10.6061/clinics/2013(07)13.
http://dx.doi.org/10.6061/clinics/2013(0...
). It is interesting that the ischemia-modified albumin (IMA)
level was significantly associated with obstructive sleep apnea and that the IMA level was a more
sensitive indicator of obstructive sleep apnea than butyrylcholinesterase activity. We appreciate
the authors' well-designed study and encouraging results, which will act as a guide for
additional basic and clinical research on OSA. To our knowledge, it is the first study to examine
IMA in relation to OSA. However, we still have some concerns about this study.
IMA, which is produced by ischemia stresses (e.g., hypoxia, acidosis, and free radical injury),
increases within minutes after the onset of ischemia, remains elevated for 6-12 h, and returns to
normal within 24 h (22. Lippi G, Montagnana M, Salvagno GL, Guidi GC. Potential value for new diagnostic
markers in the early recognition of acute coronary syndromes. CJEM.
2006;8(1):27-31.). The attenuation of IMA often
indicates an acute ischemic event, such as acute coronary syndrome, a pulmonary embolism, or acute
ischemic stroke (33. Pantazopoulos I, Papadimitriou L, Dontas I, Demestiha T, Iakovidou N, Xanthos T.
Ischaemia modified albumin in the diagnosis of acute coronary syndromes. Resuscitation.
2009;80(3):306-10, http://dx.doi.org/10.1016/j.resuscitation.2008.10.035.
http://dx.doi.org/10.1016/j.resuscitatio...
4. Turedi S, Gunduz A, Mentese A, Topbas M, Karahan SC, Yeniocak S, et al. The value
of ischemia-modified albumin compared with d-dimer in the diagnosis of pulmonary embolism. Respir
Res. 2008;9:49, http://dx.doi.org/10.1186/1465-9921-9-49.
http://dx.doi.org/10.1186/1465-9921-9-49...
-55. Abboud H, Labreuche J, Meseguer E, Lavallee PC, Simon O, Olivot JM, et al.
Ischemia-modified albumin in acute stroke. Cerebrovasc Dis. 2007;23(2-3):216-20,
http://dx.doi.org/10.1159/000097644.
http://dx.doi.org/10.1159/000097644...
).
In this study, blood samples were drawn from OSA patients after an overnight fast so that the peak IMA concentration would be properly timed to yield positive results. However, if extra IMA values were collected using dynamic observation with overnight polysomnography in the sleep unit, especially when the patients appeared to experience sleep apnea or a decrease in SaO2, the ischemia and oxidative stress mechanisms of OSA could be further clarified. We hypothesize that there is dynamic ischemic damage in OSA patients: mild ischemia and anoxia appear during the daytime, and while the patients sleep, apnea occurs and leads to even more serious ischemia and anoxia.
In addition, a minor problem may exist in this study. It is well known that OSA often leads to
ischemic diseases, increases the incidence of coronary artery disease (CAD), and raises the risk of
cardiovascular diseases (CVEs) (66. Pataka A, Riha RL. Continuous positive airway pressure and cardiovascular events
in patients with obstructive sleep apnea. Curr Cardiol Rep. 2013;15(8):385,
http://dx.doi.org/10.1007/s11886-013-0385-z.
http://dx.doi.org/10.1007/s11886-013-038...
,77. Carpio C, Alvarez-Sala R, García-Río F. Epidemiological and pathogenic
relationship between sleep apnea and ischemic heart disease. Pulm Med.
2013;2013:405827.). In this study, ischemic diseases, even stable CAD (which is associated with an
elevated IMA level according to our research) (88. Yigang Zhong, Ningfu Wang, Haiying Xu, Xuwei Hou, Peng Xu, Zhanlin Zhou.
Ischemia-modified albumin in stable coronary atherosclerotic heart disease: clinical diagnosis and
risk stratification. Coron Artery Dis. 2012;23(8):538-41,
http://dx.doi.org/10.1097/MCA.0b013e328358a5e9.
http://dx.doi.org/10.1097/MCA.0b013e3283...
), were not
considered among the baseline characteristics of the two groups. This minor carelessness may have
played a role in the positive results of the study.
REFERENCES
-
1Liu-Xue Yang, Shao-Gang Ma, Hong Liu, Wei Xu. Influence of obstructive sleep apnea on serum butyrylcholinesterase activity and ischemia-modified albumin levels. Clinics. 2013;68(7):968-73, http://dx.doi.org/10.6061/clinics/2013(07)13.
» http://dx.doi.org/10.6061/clinics/2013(07)13 -
2Lippi G, Montagnana M, Salvagno GL, Guidi GC. Potential value for new diagnostic markers in the early recognition of acute coronary syndromes. CJEM. 2006;8(1):27-31.
-
3Pantazopoulos I, Papadimitriou L, Dontas I, Demestiha T, Iakovidou N, Xanthos T. Ischaemia modified albumin in the diagnosis of acute coronary syndromes. Resuscitation. 2009;80(3):306-10, http://dx.doi.org/10.1016/j.resuscitation.2008.10.035.
» http://dx.doi.org/10.1016/j.resuscitation.2008.10.035 -
4Turedi S, Gunduz A, Mentese A, Topbas M, Karahan SC, Yeniocak S, et al. The value of ischemia-modified albumin compared with d-dimer in the diagnosis of pulmonary embolism. Respir Res. 2008;9:49, http://dx.doi.org/10.1186/1465-9921-9-49.
» http://dx.doi.org/10.1186/1465-9921-9-49 -
5Abboud H, Labreuche J, Meseguer E, Lavallee PC, Simon O, Olivot JM, et al. Ischemia-modified albumin in acute stroke. Cerebrovasc Dis. 2007;23(2-3):216-20, http://dx.doi.org/10.1159/000097644.
» http://dx.doi.org/10.1159/000097644 -
6Pataka A, Riha RL. Continuous positive airway pressure and cardiovascular events in patients with obstructive sleep apnea. Curr Cardiol Rep. 2013;15(8):385, http://dx.doi.org/10.1007/s11886-013-0385-z.
» http://dx.doi.org/10.1007/s11886-013-0385-z -
7Carpio C, Alvarez-Sala R, García-Río F. Epidemiological and pathogenic relationship between sleep apnea and ischemic heart disease. Pulm Med. 2013;2013:405827.
-
8Yigang Zhong, Ningfu Wang, Haiying Xu, Xuwei Hou, Peng Xu, Zhanlin Zhou. Ischemia-modified albumin in stable coronary atherosclerotic heart disease: clinical diagnosis and risk stratification. Coron Artery Dis. 2012;23(8):538-41, http://dx.doi.org/10.1097/MCA.0b013e328358a5e9.
» http://dx.doi.org/10.1097/MCA.0b013e328358a5e9
-
No potential conflict of interest was reported.
Publication Dates
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Publication in this collection
Nov 2013