Multicenter evaluation of the Quantra with the QStat Cartridge in adult patients undergoing liver transplantation

Abstract

Blood loss and transfusion of blood products are key concerns during liver transplantation. Whole-blood viscoelastic testing devices have been used to monitor hemostatic function and guide the transfusion of blood products in this patient population. The Quantra System with the QStat Cartridge is a new point-of-care, closed-system viscoelastic testing device that measures changes in clot stiffness during coagulation and fibrinolysis using ultrasound detection of resonance. The aim of this multicenter prospective observational study was to evaluate the Quantra System against the ROTEM delta device in monitoring coagulation and fibrinolysis in patients undergoing liver transplantation. One hundred twenty-five (125) adult subjects (above 18 y old) were enrolled across 5 medical centers in the US. Blood samples were collected at a minimum of 3-time points: preincision (baseline), during the anhepatic phase, and after the start of reperfusion. Performance was assessed as the correlation of equivalent measurements from the QStat Cartridge and ROTEM delta INTEM, EXTEM, and FIBTEM assays. In addition, a clinical concordance analysis was performed to assess the agreement between the 2 devices related to the detection of fibrinolysis. The correlation between the 2 viscoelastic testing devices was strong, with r -values ranging between 0.88 and 0.95, and the overall agreement with respect to detecting fibrinolysis was 90.3% (CI, 86.9%-93.2%). The results indicate that the Quantra with the QStat Cartridge provides comparable information as the ROTEM delta in the assessment of hemostatic function during a liver transplant. Quantra's simplicity of use and availability of rapid results may provide clinicians with a faster, more convenient means to assess coagulation and fibrinolysis status in the operating room and critical care setting.

FIGURE 1

Scatter plots of QStat parameters versus corresponding ROTEM delta parameters. The value of EXTEM A20 and FIBTEM A20 were converted from clot amplitude in units of millimeter to elasticity in units of Pascals (Pa) using validated conversion formulas.^, PLATEM A20 is not a parameter output by the ROTEM delta, but instead it was calculated offline by subtracting EXTEM A20 and FIBTEM A20 after conversions to Pascals. Abbreviations: CS, clot stiffness; CT, clot time; PCS, platelet contribution to clot stiffness; FCS, fibrinogen contribution to clot stiffness.

FIGURE 2

QStat Cartridge results (left column: Dial View, right column: corresponding Curve Screens) across 4-time points for one of the subjects enrolled in the study. The bottom panel shows the perioperative Trend View for the individual measurements of the clot stiffness-based parameters CS, FCS, and PCS. Abbreviations: CS, clot stiffness; CSL, clot stability to lysis; PCS, platelet contribution to clot stiffness; FCS, fibrinogen contribution to clot stiffness.