Platelets and Blood Cells Prognostic significance of mean platelet volume on admission in an unselected cohort of patients with non ST-segment elevation acute coronary syndrome Nevio Taglieri; Francesco Saia; Claudio Rapezzi; Cinzia Marrozzini; Maria Letizia Bacchi Reggiani; Tullio Palmerini; Paolo Ortolani; Giovanni Melandri; Stefania Rosmini; Laura Cinti; Laura Alessi; Fabio Vagnarelli; Caterina Villani; Angelo Branzi; Antonio Marzocchi Institute of Cardiology, St. Orsola/Malpighi Hospital, Bologna University, Bologna, Italy Summary Mean platelet volume (MPV) has been proposed as a marker of platelet reactivity and cardiovascular risk. Its prognostic significance has not been thoroughly investigated in patients with non-ST elevation acute coronary syndrome (NSTE-ACS). We included 1,041 consecutive pa- tients with NSTE-ACS. Patients were divided in quartiles according to the MPV value on admission (fl) i.e. Q1<7.5; Q2=7.5–8.0; Q3=8.1–8.8; Q4≥8.9. The primary study endpoint was the composite of cardiovascu- lar death and re-myocardial infarction (MI) at one year. Secondary study endpoints were individual cardiovascular death and re-MI. Patients in Q4 were older, had a higher prevalence of previous MI, peripheral artery disease and advanced Killip class compared to patients in Q1-Q3. Elev- ated MPV levels (Q4) was independently associated with gender, smok- ing status, platelet count and creatinine level. Overall, 210 patients (20.2%) reached the primary endpoint, 124 (12.1%) died from cardio- vascular causes and 125 (12.0%) suffered from re-MI. On multivariable Correspondence to: Nevio Taglieri, MD Institute of Cardiology, Bologna University St. Orsola/Malpighi Hospital Via Massarenti 9, 40138 Bologna, Italy Tel.: +39 051 6364475, Fax: +39 051 6364477 E-mail: neviotaglieri@hotmail.it analysis patients in Q4 were at higher risk of primary endpoint (HR=1.41; 95%CI 1.06–1.89; p=0.02) whilst the association with car- diovascular death and re-MI was attenuated. MPV as continuous vari- able was independently associated with both primary endpoint (HR=1.19; 95%CI 1.06–1.33; p=0.003) and cardiovascular death (HR=1.23; 95%CI 1.06–1.42, p=0.006). The incorporation of MPV into a comprehensive model of risk significantly increased the likelihood ratio chi-square for prediction of both the composite endpoint (p=0.004) and cardiovascular death (p=0.009). Therefore, MPV may be useful to improve risk stratification in NSTE-ACS patients and should be included in future prospective studies evaluating the role of platelet function in promoting cardiovascular events. Keywords Acute myocardial infarction, platelet physiology, risk factors Received: December 28, 2010 Accepted after major revision: April 8, 2011 Prepublished online: May 26, 2011 doi:10.1160/TH10-12-0821 Thromb Haemost 2011; 106: 132–140 Introduction Platelets play a crucial role in the atherothrombotic mechanisms leading to acute coronary syndrome (ACS) (1) and patients show- ing a high platelet activation and/or aggregation are at increased risk for cardiovascular events in several clinical scenarios (2–5). Al- though a variety of methods have been developed to measure pla- telet activation, they have not been implemented in clinical prac- tice owing to the lack of consensus on the best method and on the optimal cut-off to identify patients at higher risk. Furthermore these methods are time consuming, expensive and require particu- lar equipments. For these reasons, a promptly available ‘first line’ marker to identify patients with increased platelet activation and cardiovascular risk would be advisable to refer patients to addi- tional platelet function testing and to optimise clinical manage- ment and resources. Mean platelet volume (MPV) could be one of such marker (6). Indeed, MPV has been proposed as a marker of platelet activation since larger platelets are metabolically and enzimatically more ac- tive than smaller platelets and have an increased production of va- soactive and prothrombotic factors (7–10). Yet, MPV has been showed to influence platelet function assays (11). To date, few studies have evaluated the prognostic significance of MPV in patients suffering from myocardial infarction (MI)(12–15) with two of them carried out more than 10 years ago (12, 13) and the more recent ones focusing on ST-segment elev- ation MI (14, 15). No study has specifically addressed this issue in patients with non ST-segment elevation ACS (NSTE-ACS). How- ever, this topic appears relevant since NSTE-ACS is the main cause for hospitalisation in the Western world. Moreover, patients with NSTE-ACS belong to a more heterogeneous group in terms of risk stratification and prognosis as compared to patients with STE- Thrombosis and Haemostasis 106.1/2011 132 © Schattauer 2011 For personal or educational use only. No other uses without permission. All rights reserved. Downloaded from www.thrombosis-online.com on 2014-03-03 | ID: 1001043364 | IP: 137.204.230.5