The Clinical Respiratory Journal LETTER TO THE EDITOR
The relationship between red cell distribution width and chronic thromboembolic pulmonary hypertension
We read the article entitled ‘Red cell distribution width is increased in chronic thromboembolic pulmonary hypertension’ in Clin Respir J by Wang et al. with interest (1). Authors found a correlation between red cell distribution width (RDW) levels and hemoglobin, cardiac index and pulmonary vascular resistance in chronic thromboembolic pulmonary hypertension (CTEPH) patients. They reported that RDW values were significantly higher in CTEPH patients compared with healthy controls. Additionally, RDW was an independent parameter in the diagnosis of CTEPH. Thanks to the authors for their contributions. However, we think that some points should be discussed. RDW is a parameter measured as a component of complete blood count. It represents the variability in the red blood cell volume distribution (2). Authors have excluded patients who have anemia, known hematological diseases such as leukemia or myelodysplastic syndrome, left ventricular dysfunction, renal dysfunction, malignancy, acute infectious conditions, or recent transfusion within the past 2 weeks. Additionally, the RDW levels are among easy laboratory tests for evaluating the development and progression of cardiovascular diseases (2–4). Lately, various studies have reported that elevated RDW levels are related with a poor prognosis in patients, some disorders including acute coronary syndrome, essential hypertension, coronary bypass surgery and venous thromboembolism (2–5). Additionally, RDW values can be affected by thrombotic thrombocytopenic purpura, neurohumoral activation, thyroid disease, renal and/or hepatic dysfunction, nutritional deficiencies of iron, vitamin B12 and folic acid, bone marrow dysfunction, inflammatory diseases, systemic inflammation, and using some medications (2, 5).
Conflicts of interest The authors have stated explicitly that there are no conflicts of interest in connection with this article.
The 264Clinical Respiratory Journal (2014) • ISSN 1752-6981 © 2014 John Wiley & Sons Ltd
In conclusion, the authors wanted to assess the change and the diagnostic value of RDW in CTEPH (1). However, authors only measured hemoglobin, mean corpuscular volume and RDW values. They did not evaluate additional factors, including iron, vitamin B12, folic acid, platelet count, liver function tests, thyroid function tests and inflammatory markers, and used medications. Increased RDW value may not be an independent diagnostic parameter for CTEPH. Therefore, we believe that this parameter should be evaluated with the other blood parameters. We need further studies to best understand the relationship between RDW values and CTEPH. Mehmet Agilli1, Fevzi Nuri Aydin2, Tuncer Cayci3 and Yasemin Gulcan Kurt3 1 Department of Biochemistry, Agri Military Hospital, Agri, Turkey 2 Department of Biochemistry, Sirnak Military Hospital, Sirnak, Turkey 3 Department of Medical Biochemistry, Gulhane Military Medical Academy, Ankara, Turkey
References 1. Wang W, Liu J, Yang YH, Zhai ZG, Wang C, Wang J. Red cell distribution width is increased in chronic thromboembolic pulmonary hypertension. Clin Respir J. 2014; doi: 10.1111/crj.12181. 2. Yaman H, Celik T, Akgul EO, Cayci T, Kurt Y. Red cell distribution width and acute coronary syndromes. Int J Cardiol. 2010;145: 353. 3. Balta S, Demirkol S, Aydogan M, Unlu M. Red cell distribution width is a predictor of mortality in patients undergoing coronary artery bypass surgery. Eur J Cardiothorac Surg. 2013;44: 396–7. 4. Fici F, Celik T, Balta S, et al. Comparative effects of nebivolol and metoprolol on red cell distribution width and neutrophil/lymphocyte ratio in patients with newly diagnosed essential hypertension. J Cardiovasc Pharmacol. 2013;62: 388–93. 5. Aydin I, Aydin F, Agilli M. The association between red cell distribution width and venous thromboembolism: a biochemical evaluation. Thromb Res. 2014;133: 1164.
1 The Clinical Respiratory Journal (2016) • ISSN 1752-6981 C 2014 John Wiley & Sons Ltd V
The relationship between red cell distribution width and chronic thromboembolic pulmonary hypertension
We read the article entitled ‘Red cell distribution width is increased in chronic thromboembolic pulmonary hypertension’ in Clin Respir J by Wang et al. with interest (1). Authors found a correlation between red cell distribution width (RDW) levels and hemoglobin, cardiac index and pulmonary vascular resistance in chronic thromboembolic pulmonary hypertension (CTEPH) patients. They reported that RDW values were significantly higher in CTEPH patients compared with healthy controls. Additionally, RDW was an independent parameter in the diagnosis of CTEPH. Thanks to the authors for their contributions. However, we think that some points should be discussed. RDW is a parameter measured as a component of complete blood count. It represents the variability in the red blood cell volume distribution (2). Authors have excluded patients who have anemia, known hematological diseases such as leukemia or myelodysplastic syndrome, left ventricular dysfunction, renal dysfunction, malignancy, acute infectious conditions, or recent transfusion within the past 2 weeks. Additionally, the RDW levels are among easy laboratory tests for evaluating the development and progression of cardiovascular diseases (2–4). Lately, various studies have reported that elevated RDW levels are related with a poor prognosis in patients, some disorders including acute coronary syndrome, essential hypertension, coronary bypass surgery and venous thromboembolism (2–5). Additionally, RDW values can be affected by thrombotic thrombocytopenic purpura, neurohumoral activation, thyroid disease, renal and/or hepatic dysfunction, nutritional deficiencies of iron, vitamin B12 and folic acid, bone marrow dysfunction, inflammatory diseases, systemic inflammation, and using some medications (2, 5).
Conflicts of interest The authors have stated explicitly that there are no conflicts of interest in connection with this article.
The 264Clinical Respiratory Journal (2014) • ISSN 1752-6981 © 2014 John Wiley & Sons Ltd
In conclusion, the authors wanted to assess the change and the diagnostic value of RDW in CTEPH (1). However, authors only measured hemoglobin, mean corpuscular volume and RDW values. They did not evaluate additional factors, including iron, vitamin B12, folic acid, platelet count, liver function tests, thyroid function tests and inflammatory markers, and used medications. Increased RDW value may not be an independent diagnostic parameter for CTEPH. Therefore, we believe that this parameter should be evaluated with the other blood parameters. We need further studies to best understand the relationship between RDW values and CTEPH. Mehmet Agilli1, Fevzi Nuri Aydin2, Tuncer Cayci3 and Yasemin Gulcan Kurt3 1 Department of Biochemistry, Agri Military Hospital, Agri, Turkey 2 Department of Biochemistry, Sirnak Military Hospital, Sirnak, Turkey 3 Department of Medical Biochemistry, Gulhane Military Medical Academy, Ankara, Turkey
References 1. Wang W, Liu J, Yang YH, Zhai ZG, Wang C, Wang J. Red cell distribution width is increased in chronic thromboembolic pulmonary hypertension. Clin Respir J. 2014; doi: 10.1111/crj.12181. 2. Yaman H, Celik T, Akgul EO, Cayci T, Kurt Y. Red cell distribution width and acute coronary syndromes. Int J Cardiol. 2010;145: 353. 3. Balta S, Demirkol S, Aydogan M, Unlu M. Red cell distribution width is a predictor of mortality in patients undergoing coronary artery bypass surgery. Eur J Cardiothorac Surg. 2013;44: 396–7. 4. Fici F, Celik T, Balta S, et al. Comparative effects of nebivolol and metoprolol on red cell distribution width and neutrophil/lymphocyte ratio in patients with newly diagnosed essential hypertension. J Cardiovasc Pharmacol. 2013;62: 388–93. 5. Aydin I, Aydin F, Agilli M. The association between red cell distribution width and venous thromboembolism: a biochemical evaluation. Thromb Res. 2014;133: 1164.
1 The Clinical Respiratory Journal (2016) • ISSN 1752-6981 C 2014 John Wiley & Sons Ltd V
