OC 06.1 - Trauma Induces Mechanistic and Morphological Changes in Microfluidic Hemostasis

Saturday, June 24, 2023

13:00 – 13:15 ET

Room: 510

Session Available As: On-Demand

Co-Author(s)

RR

Rassam M.G. Rassam

Senior Research Laboratory Specialist
Trauma and Transfusion Medicine Research Center, Department of Surgery, University of Pittsburgh
Pittsburgh, Pennsylvania, United States

Presenting Author(s)

Devin M. Dishong

Research Fellow
Trauma and Transfusion Medicine Research Center, Department of Surgery, University of Pittsburgh
Pittsburgh, Pennsylvania, United States

Co-Author(s)

Katelin C. Rahn

Research Technician
Trauma and Transfusion Medicine Research Center, Department of Surgery, University of Pittsburgh
Pittsburgh, Pennsylvania, United States
RK

Ronit Kar

Medical Student
University of Pittsburgh - School of Medicine
Pittsburgh, Pennsylvania, United States
RF

Ricardo Fonseca

Postdoctoral Research Associate
Department of Surgery, Washington University in St. Louis
St. Louis, Missouri, United States
MC

Melissa Canas

Postdoctoral Research Associate
Department of Surgery, Washington University in St. Louis
St. Louis, Missouri, United States
JA

Jose Aldana

Postdoctoral Research Associate
Department of Surgery, Washington University in St. Louis
St. Louis, Missouri, United States
HA

Hussain Afzal

Postdoctoral Research Associate
Department of Surgery, Washington University in St. Louis,
St. Louis, Missouri, United States
KB

Kelly Bochicchio

Senior Research Administrator
Department of Surgery, Washington University in St. Louis
St. Louis, Missouri, United States
KT

Kimberly A. Thomas

Assistant Investigator
Vitalant Research Institute
Denver, Colorado, United States
Matthew D. Neal, MD FACS (he/him/his)

Associate Professor
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
GB

Grant Bochicchio

Edison Professor of Surgery
Department of Surgery, Washington University in St. Louis
St. Louis, Missouri, United States
Philip C. Spinella, MD

Professor, Surgery and Critical Care Medicine
University of Pittsburgh School of Medicine
SEWICKLEY, Pennsylvania, United States
Susan M. Shea, MSME, PhD (she/her/hers)

Assistant Professor
Trauma and Transfusion Medicine Research Center, Department of Surgery and Department of Bioengineering, University of Pittsburgh
Pittsburgh, Pennsylvania, United States

Background: Traumatic injury is the leading cause of death in young people, and 25% of trauma patients present with trauma-induced-coagulopathy (TIC), which is incompletely understood. Mechanisms may be more accurately informed with the use of microfluidics.

Aims: To characterize TIC using a microfluidic model of hemostasis and standard clinical coagulation assays.

Methods: Samples were collected from level I trauma patients within 60min of arrival and perfused at venous (N=19; shear 150/s) and arterial (N=16;3500/s) flow through a microfluidic chamber, comprising an injury site (IS) coated with collagen/tissue factor. Time to seal the IS was recorded (bleeding time, BT). Healthy volunteers were used as controls. Brightfield images were analyzed to isolate clot surface area (SA) and determine end mean intensity. Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen concentration (FGN), VWF antigen levels (VWF:Ag), and D-dimer were measured. Results are reported as mean±SEM, compared by t-tests.

Results: Trauma patients were 78% male, 61% blunt injury, age 42±2y, and ISS=18±4. Trauma patients had longer BTs than controls for both venous [776±93s vs 317±48s; p=0.010] and arterial [890±92s vs 327±47s; p< 0.001]. Trauma patients had slower deposition rates (Fig.1) but similar end clot for venous [2,197±130.7µm2 vs 2,495±1.628µm2] and arterial samples [1,821±249.2µm2 vs 2,346±97.77µm2], yet morphology differed from controls (Fig.2). Despite having a similar PT [13.6±0.3s vs 13.3±0.2s], trauma patients had lower FGN [290.2±27.5mg/dl vs 404.7±21.5mg/dl; p=0.012), and aPTT [27.9±0.8s vs 37.6±1.8s; p< 0.001]; with higher VWF:Ag [317.3(28.2%) vs 111.7(17.6%); p< 0.001] and D-dimer [0.258±0.015µg/mL vs. 6.566±1.761 µg/mL; p=0.029] when compared to controls.

Conclusion(s): The microfluidic model yielded additional mechanistic data not provided by standard tests.While still depositing substantial clot under flow, trauma samples had reduced hemostatic capacity, indicating dysfunction perhaps in crosslinking and retraction. Trauma clots appear to have differential morphology in brightfield imaging, perhaps a result of compensatory mechanisms for slower deposition and platelet dysfunction.

Learning Objectives:

Understand the benefits from assessing platelet activity and function under flow compared to standard clinical assays, which do not evaluate platelets in arterial and venous flow settings.
Describe the morphological clot differences and flow-based hemostatic functional differences between healthy control samples and trauma patient samples.
Understand the phenotype of traumatic injury is highly heterogenous, does not present ubiquitously, and severity of injury parameters may not correlate with platelet (dys)function.