PB1160 - Detection of drug-induced platelet inhibition with sonic estimation of elasticity via resonance using the QuantraTM: an observational in-vitro study with healthy volunteers

Background: Viscoelastic tests (VETs) based on rotational thromboelastometry give insight into coagulation. However, current VETs cannot reliably detect drug-induced platelet inhibition (DIPI). A new test, “QuantraTM” is a VET based on sonic resonance. QuantraTM measures clot elasticity more directly than other VETs, therefore, it is suggested it can detect DIPI. If so, it could be useful for guiding perioperative management.

Aims: To investigate whether sonic estimation of elasticity with the QuantraTM assay can detect DIPI in vitro in healthy volunteers.

Methods: Whole blood samples of 16 healthy volunteers were collected. The QuantraTM was used to determine Clot Stiffness (CS), Platelet Contribution to Clot Stiffness (PCS), and Fibrinogen Contribution to Clot Stiffness (FCS) expressed in hectopascal (hPa). Samples were measured before and after spiking with aspirin or ticagrelor. The difference, before and after spiking, was determined for each sample and paired samples t-tests were used to test for statistical significance (primary endpoint). In addition, samples were also tested using multiple electrode aggregometry (MEA) to check if spiking did indeed inhibit platelet aggregation.

Results: Samples of 4 volunteers were excluded because of missing parameters, test errors, or no inhibition detected with MEA. Samples of 5 volunteers were spiked with aspirin and 7 with ticagrelor. MEA detected aspirin or ticagrelor-induced platelet inhibition in all but one sample. Aspirin spiking did not show any significant differences in CS, PCS and FCS. Ticagrelor spiking did show a significant increase in CS (from 18.3 hPa to 20.7 hPa; p=0.020) and PCS (from 16.7 hPa to 19.0 hPa; p=0.020).

Conclusion(s): The QuantraTM could not detect DIPI after spiking whole blood with aspirin. Moreover, while a decrease was expected after ticagrelor spiking, significant increases were seen for the parameters CS and PCS. Inhibitory effects were detected with MEA. It is, therefore, unlikely that the QuantraTM can detect and quantify DIPI.