Article Text

Download PDFPDF

BS42 How warfarin and antiplatelets affect clot structure in atrial fibrillation
  1. Ahsan Khan1,
  2. Eduard Shantsila2,
  3. Y.C. Lau2,
  4. Lewis Hardy3,
  5. Helen Philippou3,
  6. Gregory Lip1
  1. 1Liverpool Heart & Chest Hospital NHS Foundation Trust
  2. 2University of Birmingham
  3. 3University of Leeds


Introduction Atrial fibrillation (AF) and coronary artery disease (CAD) are two common cardiovascular conditions associated with increased morbidity and mortality. Both conditions bring a risk of thrombosis and thus antithrombotic therapy is indicated. Despite recognised treatment, stroke and myocardial infarctions still occur. Accordingly, the identification of patients whose haemostasis remains unimpaired by treatment is valuable.

Purpose To investigate differences in plasma clot properties in patients with AF and CAD and compare the effect of warfarin and antiplatelets on clot structure in AF population.

Methods We studied 270 patients and divided them into 3 groups: AF on warfarin (n=184), AF on antiplatelets (n=46) and CAD (n=40). Plasma samples were obtained from participants and centrifuged to prepare platelet poor plasma. Assays were performed in 96-well polystyrene microtiter plates. Reagents were diluted in standard buffer (10 mM N-2-hydroxyethylpiperazine-N’-2-ethanesulphonic acid [HEPES], pH 7.4, 150 mM NaCl). Patient plasma samples (25 %) were incubated with tissue plasminogen activator (500 ng.mL-1) for 10 minutes at 37°C before the addition of CaCl2 (7.5 mM). Either PPP reagent (2.5 %), aPPT reagent (2.5 %), or thrombin (0.5 U.mL-1) were then added to initiate coagulation. Polymerisation of fibrin in plasma was monitored (ΔOD340 nm) using a Synergy H1 hybrid multi-mode plate reader, readings were taken in 12 second intervals for up to 60 minutes.

Results Comparisons between the 3 groups was performed using Kruskal-Wallis test, with Dunn’s post-hoc analysis and Holm-Sidak adjustment. There were no significant differences in clot structure between 3 subgroups. The maximum rate of clot formation was significantly delayed in the warfarin subgroup with all reagents used (p<0.001) (table 1). Plasma clot susceptibility to fibrinolysis increased with warfarin compared to antiplatelets but was significant only with APPT and thrombin reagents (p<0.001 and 0.04 respectively).

Abstract BS42 Table 1 Demographic, clinical and heamostatic characteristic of patients with atrial fibrillation and coronary artery disease (control group)

Conclusion Warfarin was effective in delaying clot formation compared to antiplatelets and also resulted in increased susceptibility of plasma clot to fibrinolysis.

Conflict of interest None

  • clot structure
  • antithrombotics
  • atrial fibrillation

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.