title: Altered clot microstructure detected in obstructive sleep apnoea hypopnoea syndrome.
abstract: Abnormal clot microstructure plays a pivotal role in the pathophysiology of thromboembolic diseases. Assessing the viscoelastic properties of clot microstructure using novel parameters, Time to Gel Point (T GP ), Fractal Dimension (d f ) and clot elasticity (G׳ GP ) could explain the increased cardiovascular and thromboembolic events in patients with Obstructive Sleep Apnoea Hypopnea Syndrome (OSAHS). We wanted to compare T GP , d f , and G׳ GP and their diurnal variation in OSAHS and symptomatic comparators. thirty six patients attending a sleep disturbed breathing clinic with symptoms of OSAHS were recruited. T GP , d f and G׳ GP were measured alongside standard coagulation screening, thrombin generation assays, and platelet aggregometry at 16:00 h and immediately after an in-patient sleep study at 07:30 h. OSAHS group had significantly lower afternoon d f than comparators (1.705±0.033 vs. 1.731±0.031, p<0.05). d f showed diurnal variation and only in the OSAHS group, being significantly lower in the afternoon than morning (p<0.05). Diurnal changes in d f correlated with 4% DR, even after controlling for BMI (r=0.37, p=0.02). The lower d f in the afternoon in OSAHS suggests a partial compensatory change that may make up for other pro-clotting abnormalities/hypertension during the night. The change to the thrombotic tendency in the afternoon is biggest in severe OSAHS. d f Shows promise as a new microstructural indicator for abnormal haemostasis in OSAHS.
authors.affiliation: College of Medicine, Institute of Life Science, Swansea University, Swansea, United Kingdom; NISCHR Haemostasis Biomedical Research Unit, Morriston Hospital, Swansea, Abertawe Bro Morgannwg University Health Board, Swansea SA6 6NL, United Kingdom.
authors.forename: Lindsay
authors.initials: L
authors.lastname: D'Silva
authors.affiliation: Respiratory Department, Prince Philip Hospital, Llanelli, Hywel Dda University Health Board, United Kingdom.
authors.forename: Maria
authors.initials: M
authors.lastname: Wilczynska
authors.affiliation: College of Medicine, Institute of Life Science, Swansea University, Swansea, United Kingdom; Respiratory Department, Prince Philip Hospital, Llanelli, Hywel Dda University Health Board, United Kingdom.
authors.forename: Keir
authors.initials: K
authors.lastname: Lewis
authors.affiliation: NISCHR Haemostasis Biomedical Research Unit, Morriston Hospital, Swansea, Abertawe Bro Morgannwg University Health Board, Swansea SA6 6NL, United Kingdom.
authors.forename: Matthew
authors.initials: M
authors.lastname: Lawrence
authors.affiliation: College of Medicine, Institute of Life Science, Swansea University, Swansea, United Kingdom; NISCHR Haemostasis Biomedical Research Unit, Morriston Hospital, Swansea, Abertawe Bro Morgannwg University Health Board, Swansea SA6 6NL, United Kingdom.
authors.forename: Karl
authors.initials: K
authors.lastname: Hawkins
authors.affiliation: College of Engineering, Swansea University, Swansea, United Kingdom.
authors.forename: Rhodri
authors.initials: R
authors.lastname: Williams
authors.affiliation: NISCHR Haemostasis Biomedical Research Unit, Morriston Hospital, Swansea, Abertawe Bro Morgannwg University Health Board, Swansea SA6 6NL, United Kingdom.
authors.forename: Sophia
authors.initials: S
authors.lastname: Stanford
authors.affiliation: Department of Haematology, Royal Brompton Hospital, London, United Kingdom.
authors.forename: Simon
authors.initials: S
authors.lastname: Davidson
authors.affiliation: School of Applied Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom.
authors.forename: Keith
authors.initials: K
authors.lastname: Morris
authors.affiliation: College of Medicine, Institute of Life Science, Swansea University, Swansea, United Kingdom; NISCHR Haemostasis Biomedical Research Unit, Morriston Hospital, Swansea, Abertawe Bro Morgannwg University Health Board, Swansea SA6 6NL, United Kingdom.
authors.forename: Adrian
authors.initials: A
authors.lastname: Evans
keywords: Clot elasticity – G׳; Clot microstructure; Coagulation; Fractal dimension; Gel time; Sleep apnoea