Platelet contraction provides a minimally invasive source for physiologic information. In this article, we describe a device that directly measures the kinetics of platelet contraction. Whole blood is injected between acrylic plates and an adherent clot forms. The bottom plate is fixed, and the top plate is attached to a wire cantilever. Platelet contraction drives deflection of the wire cantilever which is captured by a camera. Force generated by the clot with time is derived using beam equations. Force derivations were verified using a microelectromechanical (MEMS) force sensor. Kinetics of clot contraction were defined, including maximum contraction force (FMAX), lift-off time (TLIFTOFF), and contraction rate (CR). Metrics were compared with optical aggregometry and thromboelastography. FMAX correlates with optical aggregometry maximal amplitude with a Spearman’s rho of 0.7904 and p = 0.0195 and thromboelastography maximal amplitude with a Spearman’s rho of 0.8857 and p = 0.0188. Lift-off time correlates with optical aggregometry lag time with a Spearman’s rho of 0.9048 and p = 0.002. This preliminary study demonstrates the repeatability of a useful platelet contraction device and its correlation with thromboelastography and optical aggregometry, the gold standard platelet function test.
From the University of Texas Health Science Center, Houston, Texas.
Submitted for consideration June 2017 ; accepted for publication in revised form August 2017.
Disclosure: Mitchell George is funded by an NIH T32 grant (No. 4T32GM008792-14). Kevin R. Aroom, Charles S. Cox and Brijesh S. Gill report equity ownership in Coagulex, Inc., which develops blood coagulation assays. The remaining authors have no conflicts of interest to report.
This study was funded in part by Coagulex, Inc.
Correspondence: Mitchell J George, MD, University of Texas Health Science Center, 6431 Fannin Street, MSB 5.004, Houston, TX 77030. Email: Mitchell.firstname.lastname@example.org.