Platelet Reactivity in Patients and Recurrent Events Post-Stenting
Results of the PREPARE POST-STENTING Study
Paul A. Gurbel, MD*,*,
Kevin P. Bliden, BS*,
Kirk Guyer, BS ,
Peter W. Cho, MD ,
Kazi A. Zaman, MD*,
Rolf P. Kreutz, MD*,
Ashwani K. Bassi, MD* and
Udaya S. Tantry, PhD*
* Sinai Center for Thrombosis Research, Baltimore, Maryland
Indiana University, Department of Chemistry, South Bend, Indiana
Department of Surgery, Sinai Hospital, Baltimore, Maryland
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Figure 1 Schematic of thrombelastograph system: a torsion wire suspending a pin that is immersed in blood. As the clot forms while the cup is rotated 45°, the pin will rotate depending on the strength of the fibrin-platelet bonds. Signal is discharged continuously that reflects the onset of clotting (reaction time [R]) and the clot strength (MA).
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Figure 2 Graph demonstrating the time of occurrence of the first ischemic event.
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Figure 3 Adenosine-diphosphate-induced posttreatment platelet aggregation (20 µM) measured by light transmittance aggregometry (LTA) in patients without ischemic events and with ischemic events.
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Figure 4 The observed frequency of patients with ischemic events in each quartile of light transmittance aggregometry (LTA) values is shown in the figure. The p values given in the figure indicate that the proportions of ischemic events in the first and the fourth quartiles are significantly different, whereas the proportions of ischemic events in the fourth quartile are not significantly different from the second or the third quartiles.
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Figure 5 Post-treatment clot strength (MA) measured by thrombelastograph (TEG) in patients without ischemic events and with ischemic events.
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Figure 6 Post-treatment reaction time measured by thrombelastograph in patients without ischemic events and with ischemic events.
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Figure 7 The observed frequency of patients with ischemic events in each quartile of clot strength (MA) values is shown in the figure. The p values given indicate that the proportion of ischemic events in each of the first three quartiles is significantly different from the proportion of ischemic events in the fourth quartile (p < 0.001). TEG = thrombelastograph.
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Figure 8 The observed frequency of patients with ischemic events in each quartile of reaction time (R) values is shown in the figure. The p values indicate that the proportions of ischemic events in first and the second quartiles are not significantly different (p = 0.41) whereas the proportions of ischemic events in the first quartile is significantly different from the third (p = 0.006) and the fourth quartiles (p = 0.004). TEG = thrombelastograph.
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Figure 9 Combined receiver operator curve for clot strength (Thrombelastograph [TEG] MA), reaction time (TEG R), and 20 µM adenosine-diphosphate-induced posttreatment platelet aggregation (light transmittance aggregometry [LTA]). High TEG MA has 74% sensitivity and 89% specificity; low TEG R has 42% sensitivity and 79% specificity; high LTA has 37% sensitivity and 79% specificity.
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