Initial clinical experience with the Quantra QStat System in adult trauma patients

Abstract

BackgroundWhole blood viscoelastic testing (VET) devices are routinely used in a variety of clinical settings to assess hemostasis. The Quantra QStat System is a cartridge-based point of care VET device that measures changes in clot stiffness during coagulation and fibrinolysis using ultrasound detection of resonance. The objective of this study was to assess the ability of the Quantra QStat System to detect coagulopathies in trauma patients.MethodsA multicenter observational study was conducted on adult subjects at two level 1 trauma centers. For each subject, whole blood samples were drawn upon arrival to the emergency department and again, in some cases, after administration of blood products and/or antifibrinolytics. Samples were analyzed on the Quantra in parallel to ROTEM delta. The QStat cartridge provides measures of Clot Time (CT), Clot Stiffness (CS), Fibrinogen and Platelet Contributions to clot stiffness (FCS and PCS), and Clot Stability to Lysis (CSL). Data analyses included linear regression of Quantra and ROTEM parameters and an assessment of the concordance of the two devices for the assessment of hyperfibrinolysis.ResultsA total of 56 patients were analyzed. 42% of samples had a low QStat CS value suggestive of an hypocoagulable state. The low stiffness values could be attributed to either low PCS, FCS or combination. Additionally, 13% of samples showed evidence of hyperfibrinolysis based on the QStat CSL parameter. Samples analyzed with ROTEM assays showed a lower prevalence of low CS and hyperfibrinolysis based on EXTEM and FIBTEM results. The correlation of CS, FCS and CT versus equivalent ROTEM parameters was strong with r-values of 0.83, 0.79 and 0.79, respectively.DiscussionThis first clinical experience with the Quantra in trauma patients showed that the QStat Cartridge was strongly correlated with ROTEM parameters and that it could detect coagulopathies associated with critical bleeding.Level of evidenceDiagnostic test, Level II.

Viscoelastometric Testing to Assess Hemostasis of COVID-19: A Systematic Review

“…Reagents consist of a consumable, ready-to-use cartridge with four parallel channels prefilled with specific lyophilized reagents [22]. There are currently two kinds of cartridges: the QPlus cartridge and the QStat one dedicated to exploring fibrinolysis [23]. Measurements of clot coagulation time with (CTH) or without (CT) heparinase and coagulation initiation with kaolin, clot stiffness (CS) after initiation with thromboplastin, and fibrinogen contribution to the overall clot stiffness (FCS) after platelet inhibition with abciximab are performed simultaneously in four parallel channels.…”

“…Two used the ClotPro device [24,68] and its ready-to-use tPA-test reagents, which are now CE-marked, whereas the two others [39,40] used an in-house ROTEM assay with two different tPA concentrations (named TEM-tPA), making a comparison between them problematic. No study has investigated a defective fibrinolysis using the Quantra device into the COVID-19 context, whereas a new dedicated reagent cartridge is now available [23]. The four articles share the same conclusion that increased clot maximum amplitude and decreased lysis index reflect an increase in clot strength and a decreased fibrinolytic capacity, results that need to be confirmed with a larger cohort.…”

Viscoelastic hemostatic assays: Update on technology and clinical applications

“…This study identifies potential cut‐off values for QPlus FCS and PCS proposed for use in place of or in conjunction with laboratory‐based assays fibrinogen and platelet thresholds to guide transfusion decisions in surgical patients. Several groups have assessed the utility of the devices when compared to other VHA and standard laboratory tests in adult patients undergoing cardiac surgery 28–30 and in traumatized patients 31 . All these studies found the Quantra QPlus useful in predicting the need for hemostatic products.…”

Questions about COVID-19 associated coagulopathy: possible answers from the viscoelastic tests

“…The Quantra system does not provide a TF activated clotting time (CT) and is limited to assess the intrinsic pathway (activation by kaolin). Furthermore, hyperfibrinolysis can only be detected in the Quantra system using a specific cartridge (QStat cartridge) [33]. No data are available whether the Quantra system can detect fibrinolysis shutdown which is an important issue in bacterial sepsis and COVID-19 [34][35][36][37].…”