A 6.6 ml aliquot of whole physiological native blood was taken directly from the patient and

Transcription

1 Supplemental 1 Gel Point Measurement A 6.6 ml aliquot of whole physiological native blood was taken directly from the patient and loaded into a double-gap concentric cylinder of a TA Instruments AR-G2 controlled-stress rheometer at 37 ºC (± 0.1ºC) (see Figure S1). Immediately after sample loading, small amplitude oscillatory shear measurements were performed at test frequencies 0.20Hz, 0.43Hz, 0.93Hz and 2.00Hz with a peak stress amplitude of 0.03Pa. Sample loading from taking the blood to starting the experiment was timed and always took less than 60 seconds. The small amplitude oscillatory shear measurements provide measures of the shear elastic modulus, G (a measure of elastic/solid component of the sample) and the loss modulus, G (a measure of viscous/liquid properties), and phase angle, (a measure of the visco-elastic properties of the blood where: tan G /G ) with respect to time. 1-4 has a range of 0 to 90 where 90 identifies a perfect liquid response and 0 identifies a perfect solid material. As blood coagulates it changes from a viscoelastic liquid material to a viscoelastic solid. To detect the Gel Point, the changes in with respect to time were measured at the 4 different frequencies. The Gel Point marks the first time that the fluid transitions to a solid. In coagulating blood this transition corresponds to the formation of the incipient clot, whose sample-spanning fibrin network provides the mechanical basis for attaining a haemostatic function. 5,6 The Winter Chambon Gel Criteria states that the Gel Point is located at the point where is independent of frequency (see Figure S2). 1-4 In addition to providing information on the visco-elastic properties of the clot, the Gel Point also provides information on the structure of the fibrin network of the incipient clot. Fractal dimension is a tool commonly used in biology to describe complex structures. Previous work

2 has shown that the d f is related to the stress relaxation exponent by the equation: d f = (D + 2)(2 D)/2( D) where D is the space dimension (D = 3 herein), and that, is directly related to at the Gel Point by =. 7-9 Furthermore, recent studies involving analysis of GP and imaging data have established that the incipient clot in very important in further clot development and acts as a template for ensuing clot growth. 10,11 As a result the Gel Point test provides 3 important markers of coagulation: (i) the time taken to reach the Gel Point (the incipient clot formation time), T GP, which is a measure of the biochemical reaction of the clotting enzymes; (ii) the shear elastic modulus at the Gel Point G GP, which is a measure of the strength of the incipient clot; and (iii) the value of δ at the Gel Point which is used to calculate, d f, which is a measure of the clots biophysical properties/ quantification of the clot structure. All Gel Point data was corroborated by an experienced, blinded-assessor, independent of the study.

3 Figure S1 Diagram of a Double Gap Concentric Cylinder Measurement Geometry. The Double Gap Geometry consists of a stationary cup or stator into which a 6.6ml sample of blood is added. After which a bob which is free to rotate, called a rotor is then lowered into the sample. The movement of the rotor is controlled by an AR-G2 Controlled Stress Rheometer and will oscillate back and fore at 4 different frequencies (0.20Hz, 0.43Hz, 0.93Hz and 2.00Hz) sequentially over time.

4 Figure S2 GP Trace: Is a typical representation of a GP curve showing the change in phase angle for the different testing frequencies with respect to time. The initial response is characteristic of a viscoelastic liquid, where Figure S2 shows the measurement of the phase angle, δ, with respect to time ( being a measure of the viscoelastic response to imposed stress). The frequency dependence of δ decreases as clotting proceeds and δ becomes frequency independent as the incipient clot is established at the Gel Point. Thereafter the frequency dependence is characteristic of a viscoelastic solid. The structural property of the incipient clot (in terms of its fractal dimension, d f ) is derived from the frequency independent value of δ.

5 References 1. Lawrence MJ, Kumar S, Hawkins K, Boden S, Rutt H, Mills G, Sabra A, Morris RH, Davidson SJ, Badiei N, Brown MR, Williams PR, Evans PA. A new structural biomarker that quantifies and predicts changes in clot strength and quality in a model of progressive haemodilution. Thromb Res 2014;134: Lawrence MJ, Sabra A, Mills G, Pillai SG, Abdullah W, Hawkins K, Morris RH, Davidson SJ, D'Silva LA, Curtis DJ, Brown MR, Weisel JW, Williams PR, Evans PA. A new biomarker quantifies differences in clot microstructure in patients with venous thromboembolism. Br J Haematol 2014;168: Evans PA, Hawkins K, Morris RHK, Thirumalai N, Munro R, Wakeman L, Lawrence MJ, Williams PR. Gel Point and fractal microstructure of incipient blood clots are significant new markers of haemostasis for healthy and anticoagulated blood. Blood 2010;116: Winter HH, Chambon F. Analysis of linear viscoelasticity of a cross-linking polymer at the Gel-Point. J Rheol 1986; 30: Weisel JW, Litvinov RI. Mechanisms of fibrin polymerization and clinical implications. Blood 2013;121: Weisel JW. The mechanical properties of fibrin for basic scientists and clinicians. Biophys Chem 2004; 112: Muthukumar M, Winter HH. Fractal dimension of a crosslinking polymer at the gel point. Macromolecules 1986;19: Scanlan JC, Winter HH. Composition dependence of the viscoelasticity of end-linked poly(dimethylsiloxane) at the gel point. Macromolecules 1991;24: Brown MR, Curtis DJ, Rees P, Summers HD, Hawkins K, Evans PA, Williams PR. Fractal discrimination of random fractal aggregates and its application in biomarker analysis for blood coagulation. Chaos Soliton Fract 2012;45:

6 10. Curtis DJ, Brown MR, Hawkins K, Evans PA, Lawrence MJ, Rees M, Williams PR. Rheometrical and molecular dynamics simulation studies of incipient clot formation in fibrin-thrombin gels: An activation limited aggregation approach. J Nonnewton Fluid Mech 2011;166: Curtis DJ, Williams PR, Badiei N, Campbell AI, Hawkins K, Evans PA, Brown MR. A study of microstructural templating in fibrin thrombin gel networks by spectral and viscoelastic analysis. Soft Matter 2013;9:4883-9