Multicenter Evaluation of the Quantra QPlus System in Adult Patients Undergoing Major Surgical Procedures

Abstract

BACKGROUND: The management of perioperative bleeding and the optimization of the available therapies are subjects of significant clinical interest. Clinical guidelines recommend the use of whole blood viscoelastic testing devices to target the utilization of blood products during major surgical procedures. The Quantra QPlus System is a new cartridge-based viscoelastic testing device based on an innovative ultrasound technology. The aim of this study was to evaluate this new system in a surgical population. METHODS: Two hundred seventy-seven adult subjects were enrolled in a multicenter, prospective observational study consisting primarily of patients undergoing cardiac and major orthopedic surgeries. Samples were obtained at multiple time points for testing on the Quantra QPlus System, the rotational thromboelastometry (ROTEM) delta, and standard coagulation tests. Quantra measurements included Clot Time (CT), Heparinase Clot Time (CTH), Clot Time Ratio (CTR), Clot Stiffness (CS), Fibrinogen (FCS), and Platelet (PCS) Contributions to CS. Data analyses included assessment of the concordance of Quantra parameters with a series of clinical composite indexes formed on the basis of standard coagulation tests in 3 domains representing increased, decreased, and normal/subclinical coagulation function. Linear regression and receiver operator characteristic (ROC) analyses of Quantra parameters with corresponding parameters from ROTEM assays were also performed. RESULTS: The accuracy (overall percent agreement or ratio of true positives and true negatives over the entire population) between the Quantra and the composite indexes was between 72% and 98% depending on the specific parameter. Linear regression analysis indicated that the correlation between ROTEM delta and Quantra was very strong with r values ranging between 0.84 and 0.89. Results from ROC analysis demonstrated sensitivities and specificities in the 80%–90% range when QPlus parameters were used to discriminate ROTEM threshold values currently used in goal-directed treatment algorithms. CONCLUSIONS: This study demonstrated that the Quantra QPlus System is strongly correlated with a well-established viscoelastic testing device and its parameters effectively represent the results from multiple standard laboratory assays. The Quantra has been designed to operate at the point of care with the potential to provide rapid and comprehensive results to aid in the management of coagulopathic patients.

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

“…The comparative data obtained with the QStat parameters CT, CS and FCS versus ROTEM are in agreement with the results previously presented in studies in cardiac and major orthopedic surgeries using the QPlus Cartridge. 22–26 Notwithstanding the strong correlation between the two systems, the Quantra-based stiffness results demonstrated a higher number of samples with values below the respective reference ranges as compared with the ROTEM delta . Interestingly, the main contributor to a low Quantra CS value was a low PCS value, highlighting the potential importance of an indicator of platelet contribution to clot stiffness (note that the correlation of PCS with platelet count was moderate with r value of 0.54, data not shown).…”

“…As previously discussed with respect to the QPlus parameters, the bias does not introduce concerns regarding the comparison of these devices since measured results are interpreted in relation to the respective reference intervals. 22 …”

“…As previously demonstrated, the relationship between shear modulus and clot amplitude is non-linear, with larger values of shear modulus being compressed more in millimeters. 22 30 This means that small relative changes in mm from a high clot stiffness represent large changes in shear modulus, which should be readily measured by CSL.…”

“…The parameters CT, CS, FCS and PCS and their respective reference range intervals are the same as those previously described for the QPlus Cartridge. 22 The CSL parameter is calculated as the normalized difference between the clot stiffness change after maximum clot stiffness in the absence of tranexamic acid and the corresponding clot stiffness change in the presence of tranexamic acid. The CSL reportable range extends from 100% (no fibrinolysis) to 10% (significant fibrinolysis).…”

“… 20 The system uses an ultrasound-based technology that does not require moving parts or direct contact with the sample being measured while enabling a comprehensive set of internal quality control measures. 21 The performance of the Quantra with the QPlus Cartridge has been previously reported in a number of single-center and multicenter studies involving patients undergoing elective surgical procedures 22–26 and, most recently, in patients affected by SARS-CoV-2. 27 A new cartridge has been developed for the Quantra, the QStat Cartridge, which provides CT and CS measurements and a test to assess fibrinolytic function.…”