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Background: Circulating miRNAs are emerging as a prominent class

Aims: Our aim is to extract mechanical property of venous thrombus

of biomarkers in many diseases. Previous studies reported differen-to predict the breakdown of venous thrombus preemptively, using

tial expression patterns of certain miRNAs in venous thromboembo-

multiscale mechanics simulation model and mathematical model oflism (VTE). In these reports, differentially expressed miRNAs could

biological structure.

be a consequence of the disease rather than a cause. No study hasMethods: Human venous blood was obtained from healthy volun-prospectively evaluated the association between the expression ofteers. We separated red blood cells (RBCs), washed platelets andplasma miRNAs and risk of future VTE.

platelet free plasma by centrifugation. We mixed them with variousAims: To investigate whether plasma levels of miRNAs are differ-ratios of platelets or RBCs. Plasma was fluorescently-stained withentially expressed in subjects with and without incident VTE during

FITC-conjugated dextran to visualize RBCs. Platelets were fluores-

follow-up.

cently-stained with quinacrine. Alexa fluor 546-conjugated fibrinogen

Methods: We conducted a pilot nested case-control study including

was added to visualize fibrin formation.

19 subjects who developed VTE within 3 years after blood sampling

The blood sample was introduced to a home build microfluidic

and 19 age- and sex-matched healthy controls recruited from thechannels that ware fully siliconized and partly coated with col-general population (Tromsø VI survey). Total RNA was extracted fromlagen. The thrombus imaged was observed by a fluorescenceplasma using the miRNeasy Mini kit (Qiagen, USA) with modifications.

microscope.

Screening of 179 miRNAs was performed on a Serum/Plasma Focus

Results: The structures of thrombus with various ratios of blood com-microRNA PCR panel (Exiqon, Denmark). miRNAs expression levels

ponents were much different from each other.

were normalized by the expression of miR-425-5p as suggested by

1. Thrombus formed by platelet poor blood traps more RBCs com-BestRef. Statistical analyses were performed in R software (v3.2.3). We

pared with control.

used logistic regression with backward selection to build a predictive

2. Fibrin fibers of thrombus formed using very low hematocrit bloodmodel of incident VTE. The study was approved by the regional ethi-

appeared to anisotropic in orientation and also fibers are thinner andcal committee and all participants gave their informed written consent.

unclear than control.

Results: High quality signals from 61 miRNAs were identified in all 38

3. The size of platelet clusters adhered on collagen surface formed

plasma samples. Plasma levels of nine miRNAs, namely, miR-328-3p,

by very low hematocrit blood is much bigger compared with that of

miR-208a-3p, miR-629-5p, miR-15a-5p, miR-451a, miR-199a-3p,

normal hematocrit blood.

miR-363-3p, miR-20b-5p, miR-223-5p were found to be associatedConclusions: RBCs and platelets play pivotal roles to determinewith future risk of incident VTE.

thrombus structure. Our findings are very informative to construct

Conclusions: In this pilot nested case-control study, we found ninemathematical model of venous thrombus to elucidate mechanicalplasma miRNAs that could be important markers of future risk of in-property of thrombus in various conditions.

cident VTE in the general population. Currently, these miRNAs areincluded in a larger-scale validation study.

PB 1415 | The Blood Components Strongly
Affect Thrombus Structure Formed in a Novel
Microfluidic Device
N. Sugita1, H. Hirakata2, K. Inoue2, K. Tatsumi3, S. Ii4,H. Niioka4, S. Wada4, K. Koike2
1
Kyoto University Hospital, Psychiatry, Kyoto City, Japan, 2Kyoto University
Hospital, Emergency Medicine, Kyoto City, Japan, 3Kyoto University, Engineering,
Kyoto City, Japan, 4Osaka University, Mechanical Science and Bioengineering,Toyonaka, Japan

Background: Venous thromboembolism (VTE) is a major cause of
sudden death. Prevention is still hard for lacking understanding of
mechanical property of thrombus, that should be important because
fatal VTE is caused by breakdown of thrombus. We reported thatshear rate strongly affects thrombus structures in the ISTH SSC 2016
Meeting (BR06). In this study, we tried to clarified the effect of somekinds of blood cell on thrombus structure.

PB 1416 | D-dimer in Acute Medically Ill Adults:
A Multicenter Observational Study Evaluating
the Prevalence of Elevated D-dimer in Acute
Medically Ill, Hospitalized Adults: The DAMIACT
Study, Initial Results
C.L. Clark1, A.H. Shams1, W.F. Peacock2, G.J. Fermann3,B. Kea4, A.M. Chang5, S.E. Mace6, B.C. Hiestand7, J.A. Welker8,R.A. Swor1, K.N. Sawyer1,9, A. Bastani10, on behalf of theDAMIACT Study Investigators
1

Beaumont Health System-Royal Oak, Emergency Medicine, Royal Oak, UnitedStates, 2Baylor College of Medicine/Texas Childrens Hospital, Emergency Medicine,Houston, United States, 3University of Cincinatti, Emergency Medicine, Cincinatti,United States, 4Oregon Health and Science University School of Medicine,
Emergency Medicine, Portland, United States, 5Thomas Jefferson University,EmergencyMedicine, Philadelphia, United States, 6Cleveland Clinic, EmergencyMedicine, Cleveland, United States, 7Wake Forest School of Medicine, EmergencyMedicine, Winston-Salem, United States, 8Anne Arundel Health System, InternalMedicine, Baltimore, United States, 9University of Pittsburgh, Emergency Medicine,Pittsburgh, United States, 10Beaumnt Health System-Troy, Emergency Medicine,Troy, United States