S J X Murphy1,2, S T Lim1,2, J A Kinsella3, D Murphy4, H M Enright4, Dominick J H McCabe5,6,7,8,9,10. 1. Department of Neurology, The Adelaide and Meath Hospital, Dublin, incorporating the National Children's Hospital (AMNCH), Dublin, Ireland. 2. Stroke Service, The Adelaide and Meath Hospital, Dublin, incorporating the National Children's Hospital (AMNCH), Dublin, Ireland. 3. Department of Neurology, St Vincent's University Hospital, University College Dublin, Dublin, Ireland. 4. Department of Haematology, The Adelaide and Meath Hospital, Dublin, incorporating the National Children's Hospital (AMNCH), Dublin, Ireland. 5. Department of Neurology, The Adelaide and Meath Hospital, Dublin, incorporating the National Children's Hospital (AMNCH), Dublin, Ireland. dominick.mccabe@amnch.ie. 6. Vascular Neurology Research Foundation, The Adelaide and Meath Hospital, Dublin, incorporating the National Children's Hospital (AMNCH), Tallaght, Dublin, Ireland. dominick.mccabe@amnch.ie. 7. Stroke Service, The Adelaide and Meath Hospital, Dublin, incorporating the National Children's Hospital (AMNCH), Dublin, Ireland. dominick.mccabe@amnch.ie. 8. Department of Clinical Neurosciences, Royal Free Campus, UCL Institute of Neurology, London, UK. dominick.mccabe@amnch.ie. 9. Irish Centre for Vascular Biology, Dublin, Ireland. dominick.mccabe@amnch.ie. 10. Academic Unit of Neurology, School of Medicine, Trinity College Dublin, Dublin, Ireland. dominick.mccabe@amnch.ie.
Abstract
BACKGROUND: The pathophysiological mechanisms responsible for the disparity in stroke risk between asymptomatic and symptomatic carotid stenosis patients are not fully understood. The functionally important reticulated platelet fraction and reticulocytes could play a role. OBJECTIVES: We performed a prospective, multi-centre, observational analytical study comparing full blood count parameters and platelet production/turnover/activation markers in patients with asymptomatic versus recently symptomatic moderate (≥ 50-69%) or severe (≥ 70-99%) carotid stenosis. PATIENTS/ METHODS: Data from 34 asymptomatic patients were compared with 43 symptomatic patients in the 'early phase' (≤ 4 weeks) and 37 of these patients in the 'late phase' (≥ 3 months) after TIA/ischaemic stroke. Reticulated platelets were quantified by whole blood flow cytometry and reticulated platelets and red cell reticulocytes by 'automated assays' (Sysmex XE-2100™). Bilateral simultaneous transcranial Doppler ultrasound monitoring classified patients as micro-embolic signal (MES)+ve or MES-ve. RESULTS: Mean platelet count was higher in early (216 × 109/L; P = 0.04) and late symptomatic (219 × 109/L; P = 0.044) than asymptomatic patients (194 × 109/L). Mean platelet volume was higher in early symptomatic than asymptomatic patients (10.8 vs. 10.45 fl; P = 0.045). Automated assays revealed higher % reticulated platelet fractions in early (5.78%; P < 0.001) and late symptomatic (5.11%; P = 0.01) than asymptomatic patients (3.48%). Red cell reticulocyte counts were lower in early (0.92%; P = 0.035) and late symptomatic (0.93%; P = 0.036) than asymptomatic patients (1.07%). The automated % reticulated platelet fraction was also higher in early symptomatic than asymptomatic MES-ve patients (5.7 vs. 3.55%; P = 0.001). DISCUSSION: The combination of increased platelet counts and a shift towards production of an increased population of larger, young, reticulated platelets could contribute to a higher risk of first or recurrent cerebrovascular events in recently symptomatic versus asymptomatic carotid stenosis, including those who are MES-ve.
BACKGROUND: The pathophysiological mechanisms responsible for the disparity in stroke risk between asymptomatic and symptomatic carotid stenosispatients are not fully understood. The functionally important reticulated platelet fraction and reticulocytes could play a role. OBJECTIVES: We performed a prospective, multi-centre, observational analytical study comparing full blood count parameters and platelet production/turnover/activation markers in patients with asymptomatic versus recently symptomatic moderate (≥ 50-69%) or severe (≥ 70-99%) carotid stenosis. PATIENTS/ METHODS: Data from 34 asymptomatic patients were compared with 43 symptomatic patients in the 'early phase' (≤ 4 weeks) and 37 of these patients in the 'late phase' (≥ 3 months) after TIA/ischaemic stroke. Reticulated platelets were quantified by whole blood flow cytometry and reticulated platelets and red cell reticulocytes by 'automated assays' (Sysmex XE-2100™). Bilateral simultaneous transcranial Doppler ultrasound monitoring classified patients as micro-embolic signal (MES)+ve or MES-ve. RESULTS: Mean platelet count was higher in early (216 × 109/L; P = 0.04) and late symptomatic (219 × 109/L; P = 0.044) than asymptomatic patients (194 × 109/L). Mean platelet volume was higher in early symptomatic than asymptomatic patients (10.8 vs. 10.45 fl; P = 0.045). Automated assays revealed higher % reticulated platelet fractions in early (5.78%; P < 0.001) and late symptomatic (5.11%; P = 0.01) than asymptomatic patients (3.48%). Red cell reticulocyte counts were lower in early (0.92%; P = 0.035) and late symptomatic (0.93%; P = 0.036) than asymptomatic patients (1.07%). The automated % reticulated platelet fraction was also higher in early symptomatic than asymptomatic MES-ve patients (5.7 vs. 3.55%; P = 0.001). DISCUSSION: The combination of increased platelet counts and a shift towards production of an increased population of larger, young, reticulated platelets could contribute to a higher risk of first or recurrent cerebrovascular events in recently symptomatic versus asymptomatic carotid stenosis, including those who are MES-ve.
Authors: Bianca Rocca; Paola Secchiero; Giovanni Ciabattoni; Franco O Ranelletti; Lucia Catani; Lia Guidotti; Elisabetta Melloni; Nicola Maggiano; Giorgio Zauli; Carlo Patrono Journal: Proc Natl Acad Sci U S A Date: 2002-05-28 Impact factor: 11.205
Authors: Dominick J H McCabe; Paul Harrison; Ian J Mackie; Paul S Sidhu; Gordon Purdy; Andrew S Lawrie; Hilary Watt; Martin M Brown; Samuel J Machin Journal: Br J Haematol Date: 2004-06 Impact factor: 6.998
Authors: Stephen J Murphy; Soon T Lim; Justin A Kinsella; Sean Tierney; Bridget Egan; Tim M Feeley; Clare Dooley; James Kelly; Sinead M Murphy; Richard A Walsh; Ronan Collins; Tara Coughlan; Desmond O'Neill; Joseph A Harbison; Prakash Madhavan; Sean M O'Neill; Mary P Colgan; Jim F Meaney; George Hamilton; Dominick Jh McCabe Journal: J Cereb Blood Flow Metab Date: 2019-11-11 Impact factor: 6.200
Authors: S J X Murphy; S T Lim; J A Kinsella; S Tierney; B Egan; T M Feeley; S M Murphy; R A Walsh; D R Collins; T Coughlan; D O'Neill; J A Harbison; P Madhavan; S M O'Neill; M P Colgan; D Cox; N Moran; G Hamilton; J F Meaney; D J H McCabe Journal: J Neurol Date: 2019-10-12 Impact factor: 4.849
Authors: Stephen J X Murphy; Soon Tjin Lim; Fionnuala Hickey; Justin A Kinsella; Deirdre R Smith; Sean Tierney; Bridget Egan; T Martin Feeley; Sinéad M Murphy; D Rónán Collins; Tara Coughlan; Desmond O'Neill; Joseph A Harbison; Prakash Madhavan; Sean M O'Neill; Mary-Paula Colgan; James S O'Donnell; Jamie M O'Sullivan; George Hamilton; Dominick J H McCabe Journal: Thromb Haemost Date: 2020-09-15 Impact factor: 5.249