http://informahealthcare.com/plt ISSN: 0953-7104 (print), 1369-1635 (electronic) Platelets, Early Online: 1–2 ! 2014 Informa UK Ltd. DOI: 10.3109/09537104.2013.868426
LETTER TO THE EDITOR
Mean platelet volume in hypertensive urgencies and emergencies: Opening the Pandora’s Box Eleni Gavriilaki1, Eugenia Gkaliagkousi1, Barbara Nikolaidou1, & Stella Douma2 Platelets Downloaded from informahealthcare.com by Universitaets- und Landesbibliothek Duesseldorf on 01/21/14 For personal use only.
1
2nd Propedeutic Department of Internal Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece and 23rd Department of Internal Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
To the editor We read with interest the study by Karabacak et al. [1] that investigates for the first time mean platelet volume (MPV) in patients with hypertensive emergencies and urgencies. Although this study confirms the hypothesis of increased MPV in these patients, we believe that these findings should be critically reviewed taking into consideration the following methodological issues. First, the definition of hypertensive emergencies in the current study differed from that of the previous [2] and current [3] guidelines of the European Society of Hypertension. Unlike the guidelines’ definitions, the authors included in this group patients with hypertensive crises and retinopathy or microangiopathy, which represent markers of subclinical target organ damage rather than impending or progressive organ damage characterising hypertensive emergencies. On the other hand, the authors did not include patients with elevated blood pressure (BP) and eclampsia. In addition, there is no information regarding the proportion of different organ damage associated with hypertensive emergencies and no sub-group analysis regarding MPV levels among patients with different organ damage. Second, MPV was measured only during the hypertensive crisis in these patients, for whom no previous or future assessment of hypertension grade was performed. It would have been necessary to assess other MPV values immediately after BP control and after a period of antihypertensive treatment in the same patients or at least assess MPV values in an age- and sexmatched group of patients with well-defined grade 3 or resistant hypertension, in order to reach a safe conclusion regarding the possibly increased MPV during hypertensive urgencies or emergencies. Third, another limitation of the present work is the lack of a well-defined normotensive control group. Office BP values were the only selection criterion for the normotensive control group, which could therefore have included patients with masked hypertension characterised by increased MPV as compared to true normotensive individuals [4]. Fourth, blood sampling conditions, which are known to affect platelet activation (for example use of 18G syringe instead of 21G, collection of blood in Sodium Citrate rather than EDTA) [5–7], are not clearly described by the authors, neither for the hypertensive individuals in the emergency room, nor for the normotensive control group in a probably quiter room. Correspondence: Eugenia Gkaliagkousi, MD PhD, Hippokration General Hospital, 49 Konstantinoupoleos Street, 54643 Thessaloniki, Greece. Tel: +30 2310 892 108. Fax: +302310 528 447. E-mail: [email protected]
Keywords Hypertensive crises, hypertensive emergencies, hypertensive urgencies, mean platelet volume, platelet activation History Received 5 November 2013 Revised 18 November 2013 Accepted 19 November 2013 Published online 16 January 2014
In conclusion, the present study has opened the Pandora’s Box regarding platelet activation during hypertension crises. A recent study has described elevated levels of soluble P-selectin in hypertensive emergencies [8]. Nevertheless, the most sensitive and reliable marker of platelet activation in several clinical settings including essential hypertension [6, 9] is nowadays considered the measurement of monocyte-platelet aggregates (MPA) [10]. Thus, well-designed studies using not only a widely accessible and rough marker of platelet activation, such as MPV but also more reliable markers such as MPA are warranted in order to confirm the hypothesis of increased platelet activation in hypertensive emergencies and urgencies.
Declaration of interest The authors report no conflicts of interest
References 1. Karabacak M, Dogan A, Turkdogan AK, Kapci M, Duman A, Akpinar O. Mean platelet volume is increased in patients with hypertensive crises. Platelets 2013. [Epub ahead of print]. 2. Mansia G, De Backer G, Dominiczak A, Cifkova R, Fagard R, Germano G, Grassi G, Heagerty AM, Kjeldsen SE, Laurent S, et al. 2007 Guidelines for the management of arterial hypertension: The Task Force for the Management of Arterial Hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). Eur Heart J 2007;28:1462–1536. 3. Mancia G, Fagard R, Narkiewicz K, Redon J, Zanchetti A, Bo¨hm M, Christiaens T, Cifkova R, De Backer G, Dominiczak A, et al. 2013 ESH/ESC Guidelines for the management of arterial hypertension: The Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). Eur Heart J 34:2159–219. 4. Guven A, Caliskan M, Ciftci O, Barutcu I. Increased platelet activation and inflammatory response in patients with masked hypertension. Blood Coagul Fibrinol: An international journal in haemostasis and thrombosis 2013;24:170–174.
2
E. Gavriilaki et al.
Platelets Downloaded from informahealthcare.com by Universitaets- und Landesbibliothek Duesseldorf on 01/21/14 For personal use only.
5. Shah B, Valdes V, Nardi MA, Hu L, Schrem E, Berger JS. Mean platelet volume reproducibility and association with platelet activity and anti-platelet therapy. Platelets 2013. [Epub ahead of print]. 6. Gkaliagkousi E, Corrigall V, Becker S, de Winter P, Shah A, Zamboulis C, Ritter J, Ferro A. Decreased platelet nitric oxide contributes to increased circulating monocyte-platelet aggregates in hypertension. Eur Heart J 2009;30:3048–3054. 7. Gasparyan AY, Ayvazyan L, Mikhailidis DP, Kitas GD. Mean platelet volume: a link between thrombosis and inflammation? Curr Pharmaceut Design 2011;17:47–58. 8. Derhaschnig U, Testori C, Riedmueller E, Aschauer S, Wolzt M, Jilma B. Hypertensive emergencies are associated with elevated
Platelets, Early Online: 1–2
markers of inflammation, coagulation, platelet activation and fibrinolysis. J Hum Hypertens 2013;27:368–373. 9. Gkaliagkousi E, Gavriilaki E, Yiannaki E, Markala D, Papadopoulos N, Triantafyllou A, Anyfanti P, Petidis K, Garypidou V, Doumas M. Platelet activation in essential hypertension during exercise: Pre- and post-treatment changes with an angiotensin II receptor blocker. Am J Hypertens 2013. [Epub ahead of print]. 10. Michelson AD, Barnard MR, Krueger LA, Valeri CR, Furman MI. Circulating monocyte-platelet aggregates are a more sensitive marker of in vivo platelet activation than platelet surface P-selectin: Studies in baboons, human coronary intervention, and human acute myocardial infarction. Circulation 2001;104:1533–1537.
LETTER TO THE EDITOR
Mean platelet volume in hypertensive urgencies and emergencies: Opening the Pandora’s Box Eleni Gavriilaki1, Eugenia Gkaliagkousi1, Barbara Nikolaidou1, & Stella Douma2 Platelets Downloaded from informahealthcare.com by Universitaets- und Landesbibliothek Duesseldorf on 01/21/14 For personal use only.
1
2nd Propedeutic Department of Internal Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece and 23rd Department of Internal Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
To the editor We read with interest the study by Karabacak et al. [1] that investigates for the first time mean platelet volume (MPV) in patients with hypertensive emergencies and urgencies. Although this study confirms the hypothesis of increased MPV in these patients, we believe that these findings should be critically reviewed taking into consideration the following methodological issues. First, the definition of hypertensive emergencies in the current study differed from that of the previous [2] and current [3] guidelines of the European Society of Hypertension. Unlike the guidelines’ definitions, the authors included in this group patients with hypertensive crises and retinopathy or microangiopathy, which represent markers of subclinical target organ damage rather than impending or progressive organ damage characterising hypertensive emergencies. On the other hand, the authors did not include patients with elevated blood pressure (BP) and eclampsia. In addition, there is no information regarding the proportion of different organ damage associated with hypertensive emergencies and no sub-group analysis regarding MPV levels among patients with different organ damage. Second, MPV was measured only during the hypertensive crisis in these patients, for whom no previous or future assessment of hypertension grade was performed. It would have been necessary to assess other MPV values immediately after BP control and after a period of antihypertensive treatment in the same patients or at least assess MPV values in an age- and sexmatched group of patients with well-defined grade 3 or resistant hypertension, in order to reach a safe conclusion regarding the possibly increased MPV during hypertensive urgencies or emergencies. Third, another limitation of the present work is the lack of a well-defined normotensive control group. Office BP values were the only selection criterion for the normotensive control group, which could therefore have included patients with masked hypertension characterised by increased MPV as compared to true normotensive individuals [4]. Fourth, blood sampling conditions, which are known to affect platelet activation (for example use of 18G syringe instead of 21G, collection of blood in Sodium Citrate rather than EDTA) [5–7], are not clearly described by the authors, neither for the hypertensive individuals in the emergency room, nor for the normotensive control group in a probably quiter room. Correspondence: Eugenia Gkaliagkousi, MD PhD, Hippokration General Hospital, 49 Konstantinoupoleos Street, 54643 Thessaloniki, Greece. Tel: +30 2310 892 108. Fax: +302310 528 447. E-mail: [email protected]
Keywords Hypertensive crises, hypertensive emergencies, hypertensive urgencies, mean platelet volume, platelet activation History Received 5 November 2013 Revised 18 November 2013 Accepted 19 November 2013 Published online 16 January 2014
In conclusion, the present study has opened the Pandora’s Box regarding platelet activation during hypertension crises. A recent study has described elevated levels of soluble P-selectin in hypertensive emergencies [8]. Nevertheless, the most sensitive and reliable marker of platelet activation in several clinical settings including essential hypertension [6, 9] is nowadays considered the measurement of monocyte-platelet aggregates (MPA) [10]. Thus, well-designed studies using not only a widely accessible and rough marker of platelet activation, such as MPV but also more reliable markers such as MPA are warranted in order to confirm the hypothesis of increased platelet activation in hypertensive emergencies and urgencies.
Declaration of interest The authors report no conflicts of interest
References 1. Karabacak M, Dogan A, Turkdogan AK, Kapci M, Duman A, Akpinar O. Mean platelet volume is increased in patients with hypertensive crises. Platelets 2013. [Epub ahead of print]. 2. Mansia G, De Backer G, Dominiczak A, Cifkova R, Fagard R, Germano G, Grassi G, Heagerty AM, Kjeldsen SE, Laurent S, et al. 2007 Guidelines for the management of arterial hypertension: The Task Force for the Management of Arterial Hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). Eur Heart J 2007;28:1462–1536. 3. Mancia G, Fagard R, Narkiewicz K, Redon J, Zanchetti A, Bo¨hm M, Christiaens T, Cifkova R, De Backer G, Dominiczak A, et al. 2013 ESH/ESC Guidelines for the management of arterial hypertension: The Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). Eur Heart J 34:2159–219. 4. Guven A, Caliskan M, Ciftci O, Barutcu I. Increased platelet activation and inflammatory response in patients with masked hypertension. Blood Coagul Fibrinol: An international journal in haemostasis and thrombosis 2013;24:170–174.
2
E. Gavriilaki et al.
Platelets Downloaded from informahealthcare.com by Universitaets- und Landesbibliothek Duesseldorf on 01/21/14 For personal use only.
5. Shah B, Valdes V, Nardi MA, Hu L, Schrem E, Berger JS. Mean platelet volume reproducibility and association with platelet activity and anti-platelet therapy. Platelets 2013. [Epub ahead of print]. 6. Gkaliagkousi E, Corrigall V, Becker S, de Winter P, Shah A, Zamboulis C, Ritter J, Ferro A. Decreased platelet nitric oxide contributes to increased circulating monocyte-platelet aggregates in hypertension. Eur Heart J 2009;30:3048–3054. 7. Gasparyan AY, Ayvazyan L, Mikhailidis DP, Kitas GD. Mean platelet volume: a link between thrombosis and inflammation? Curr Pharmaceut Design 2011;17:47–58. 8. Derhaschnig U, Testori C, Riedmueller E, Aschauer S, Wolzt M, Jilma B. Hypertensive emergencies are associated with elevated
Platelets, Early Online: 1–2
markers of inflammation, coagulation, platelet activation and fibrinolysis. J Hum Hypertens 2013;27:368–373. 9. Gkaliagkousi E, Gavriilaki E, Yiannaki E, Markala D, Papadopoulos N, Triantafyllou A, Anyfanti P, Petidis K, Garypidou V, Doumas M. Platelet activation in essential hypertension during exercise: Pre- and post-treatment changes with an angiotensin II receptor blocker. Am J Hypertens 2013. [Epub ahead of print]. 10. Michelson AD, Barnard MR, Krueger LA, Valeri CR, Furman MI. Circulating monocyte-platelet aggregates are a more sensitive marker of in vivo platelet activation than platelet surface P-selectin: Studies in baboons, human coronary intervention, and human acute myocardial infarction. Circulation 2001;104:1533–1537.
