title: Fractal dimension: a novel clot microstructure biomarker use in ST elevation myocardial infarction patients.
abstract: OBJECTIVE
  Changes in clot microstructure are increasingly implicated in the pathology of atherosclerosis although most data are from techniques in the remote laboratory using altered blood. We validate the novel biomarker Gel Point in STEMI patients and assess therapeutic interventions. Gel Point marks the transition of blood from a visco-elastic liquid to visco-elastic solid and is rapidly measured using unadulterated blood. The Gel Point provides measurements of three parameters to reflect clot microstructure (fractal dimension (df)), real-time clot formation time (TGP) and blood clot strength (elasticity at the Gel Point (G'GP)).
  
  
  METHODS
  We prospectively recruited 38 consecutive patients with STEMI undergoing primary percutaneous coronary intervention (pPCI). Venous blood samples were collected on admission, after pPCI and 24 h after admission for assessment of the new biomarkers, standard coagulation tests and scanning electron microscopy (SEM).
  
  
  RESULTS
  df after pPCI was lower than df on admission (mean 1.631 [SD 0.063] vs 1.751 [0.052], p < 0.000001) whereas df at 24 h was similar to that on admission. G'GP also showed similar trend to df (p < 0.001). TGP was prolonged at after-PCI measurement compared with admission (median 854 s [IQR 581-1801] vs 217 [179-305], p < 0.00001). Changes in the values of df and G'GP were consistent with changes in the SEM images of the mature clot.
  
  
  CONCLUSIONS
  We characterise Gel Point derived markers of clot microstructure in patients admitted with emergency arterial thrombosis. This point of care test can potentially be used to assess the efficacy of therapeutic interventions by measuring changes in clot microstructure.
authors.affiliation: NISCHR Haemostasis Biomedical Research Unit, Morriston Hospital, ABMU Health Board, Swansea SA6 6NL, UK; College of Medicine, Swansea University, Swansea SA2 8PP, UK.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Lawrence
authors.affiliation: NISCHR Haemostasis Biomedical Research Unit, Morriston Hospital, ABMU Health Board, Swansea SA6 6NL, UK; College of Medicine, Swansea University, Swansea SA2 8PP, UK.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Sabra
authors.affiliation: Cardiac Centre, Morriston Hospital, ABMU Health Board, Swansea SA6 6NL, UK.
authors.forename: Phillip
authors.initials: P
authors.lastname: Thomas
authors.affiliation: Cardiac Centre, Morriston Hospital, ABMU Health Board, Swansea SA6 6NL, UK.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Obaid
authors.affiliation: NISCHR Haemostasis Biomedical Research Unit, Morriston Hospital, ABMU Health Board, Swansea SA6 6NL, UK; College of Medicine, Swansea University, Swansea SA2 8PP, UK.
authors.forename: Lindsay A
authors.initials: LA
authors.lastname: D'Silva
authors.affiliation: School of Applied Science, Cardiff Metropolitan University, Cardiff CF5 2YB, UK.
authors.forename: Roger H K
authors.initials: RH
authors.lastname: Morris
authors.affiliation: NISCHR Haemostasis Biomedical Research Unit, Morriston Hospital, ABMU Health Board, Swansea SA6 6NL, UK; College of Medicine, Swansea University, Swansea SA2 8PP, UK.
authors.forename: Karl
authors.initials: K
authors.lastname: Hawkins
authors.affiliation: College of Engineering, Swansea University, Swansea SA2 8PP, UK.
authors.forename: Martin R
authors.initials: MR
authors.lastname: Brown
authors.affiliation: College of Engineering, Swansea University, Swansea SA2 8PP, UK.
authors.forename: Phylip R
authors.initials: PR
authors.lastname: Williams
authors.affiliation: Department of Haematology, Royal Brompton Hospital, Royal Brompton and Harefield NHS Foundation Trust, London SW3 6NP, UK.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Davidson
authors.affiliation: Cardiac Centre, Morriston Hospital, ABMU Health Board, Swansea SA6 6NL, UK.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Chase
authors.affiliation: Cardiac Centre, Morriston Hospital, ABMU Health Board, Swansea SA6 6NL, UK.
authors.forename: David
authors.initials: D
authors.lastname: Smith
authors.affiliation: NISCHR Haemostasis Biomedical Research Unit, Morriston Hospital, ABMU Health Board, Swansea SA6 6NL, UK; College of Medicine, Swansea University, Swansea SA2 8PP, UK. Electronic address: phillip.evans2@wales.nhs.uk.
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Evans
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use; D001777:Blood Coagulation / Q000187:drug effects; D001780:Blood Coagulation Tests / Q000379:methods*; D017023:Coronary Angiography; D003328:Coronary Thrombosis / Q000097:blood / Q000175:diagnosis* / Q000628:therapy; D004548:Elasticity; D005240:Feasibility Studies; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D017709:Fractals; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis* / Q000628:therapy; D062645:Percutaneous Coronary Intervention; D010974:Platelet Aggregation; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D000067716:Point-of-Care Testing; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D013997:Time Factors; D016896:Treatment Outcome; D014783:Viscosity
chemical_list: D000925:Anticoagulants; D005343:Fibrinolytic Agents; D010975:Platelet Aggregation Inhibitors
keywords: Acute myocardial infarction; Coagulation; Drug monitoring; Fractal dimension; Gel Point; Percutaneous coronary intervention