title: Platelet reactivity and mean platelet volume as risk markers of thrombogenesis in atrial fibrillation.
abstract: Atrial fibrillation (AF) is associated with increased risk of thromboembolic complications. One of the markers of the increased risk of hypercoagulable state is platelet hyperreactivity. The aim of the study was to assess impact of arrhythmia on platelet reactivity.
  
  
  METHODS
  The study included 36 (mean age 48,3; range 21-60) male patients with lone atrial fibrillation, with exclusion of concomitant diseases known to trigger hypercoagulable state. The AF patients underwent cardioversion to restore sinus rhythm and were subsequently under observation for 1month. Echocardiography, ECG and blood collection was performed before cardioversion (T0) and 4weeks after successful cardioversion (T1). During the study period patients have been contacted and examined every week and 24h ECG monitoring was performed. Platelet reactivity was assessed based on changes of CD62 and CD42b expression on platelet surface after stimulation with thrombin. Also changes in MPV were assessed.
  
  
  RESULTS
  In all patients sinus rhythm was maintained at the end of the study period, however in 14 patients recurrences of AF were observed, confirmed by 24h ECG monitoring (atrial fibrillation recurrence group - AFR) and 22 patients maintained sinus rhythm throughout the whole study period (SR group). Mean fluorescence intensity (MFI) of CD62 on thrombin stimulated platelets decreased significantly 4weeks after electrical cardioversion as compared to T0 (48.04±22.42 vs 41.47±16.03; p<0.01). Also MFI of CD42b on thrombin stimulated platelets decreased significantly 4weeks after electrical cardioversion as compared to T0 (22.16±10.82 vs 12.06±5.99; p<0.0001). Platelets reactivity estimated by CD 62 expression in SR group decreased significantly after 4weeks observation (58.01±15.26 vs 46.57±13.44; p<0.001) opposite to AFR group 35.66±21.87 vs 34.54±16.4; p-ns). Moreover there were significant differences between basal reactivity during AF between SR and AFR groups (58.01±15.26 vs 35.66±21.87; p-0.01). MFI of CD42b on thrombin stimulated platelets decreased significantly both in AFR and SR groups (22.05±11.36 vs 13.8±6.03; p<0.001 and 21.87±14.18 vs 10.04±5.09; p<0005). MPV decreased significantly 4weeks after electrical cardioversion as compared to T0 (8.81±0.19 vs 8.42±0.14; p<0.0001).
  
  
  CONCLUSIONS
  The changes of platelet reactivity to thrombin observed after restoration of sinus rhythm in patients prove that arrhythmia intrinsically leads to increased reactivity of platelets.
authors.affiliation: Department of Interventional Cardiology and Cardiac Arrhythmias, Medical University of Lodz, Poland. Electronic address: drmarmak@gmail.com.
authors.forename: Marcin
authors.initials: M
authors.lastname: Makowski
authors.affiliation: Department of Pathophysiology and Immunology, Medical University of Lodz, Poland.
authors.forename: Ireneusz
authors.initials: I
authors.lastname: Smorag
authors.affiliation: Department of Rheumatology, Medical University of Lodz, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Makowska
authors.affiliation: Department of Interventional Cardiology and Cardiac Arrhythmias, Medical University of Lodz, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Bissinger
authors.affiliation: Department of Interventional Cardiology and Cardiac Arrhythmias, Medical University of Lodz, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Grycewicz
authors.affiliation: Department of Paediatrics, Preventive Cardiology and Immunology of Developmental Age, Medical University of Lodz, Poland.
authors.forename: Jarek
authors.initials: J
authors.lastname: Paśnik
authors.affiliation: Intensive Cardiac Therapy Clinic, Medical University of Lodz, Poland.
authors.forename: Michal
authors.initials: M
authors.lastname: Kidawa
authors.affiliation: Department of Interventional Cardiology and Cardiac Arrhythmias, Medical University of Lodz, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Lubiński
authors.affiliation: Intensive Cardiac Therapy Clinic, Medical University of Lodz, Poland.
authors.forename: Marzenna
authors.initials: M
authors.lastname: Zielińska
authors.affiliation: Department of Pathophysiology and Immunology, Medical University of Lodz, Poland.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Baj
mesh_terms: D001281:Atrial Fibrillation / Q000097:blood / Q000150:complications / Q000503:physiopathology / Q000628:therapy; D015415:Biomarkers / Q000032:analysis; D001777:Blood Coagulation / Q000502:physiology; D004452:Echocardiography / Q000379:methods; D004554:Electric Countershock / Q000379:methods*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D063847:Mean Platelet Volume / Q000379:methods*; D008875:Middle Aged; D015539:Platelet Activation / Q000502:physiology*; D010980:Platelet Membrane Glycoproteins / Q000032:analysis / Q000502:physiology; D011044:Poland; D012307:Risk Factors; D013223:Statistics as Topic; D013917:Thrombin / Q000502:physiology*; D013923:Thromboembolism / Q000097:blood / Q000209:etiology; D019851:Thrombophilia / Q000175:diagnosis; D013927:Thrombosis / Q000097:blood / Q000209:etiology
chemical_list: D015415:Biomarkers; D010980:Platelet Membrane Glycoproteins; D013917:Thrombin
keywords: Atrial fibrillation; Mean platelet volume; Platelet reactivity