Xylum CSA®: Automated System for Assessing Hemostasis in Simulated Vascular Flow

Abstract

Nearly 20 years ago it became clear that analysis of hemostasis function in blood was affected by sample shear rate and anticoagulation (1). Yet, present technologies still perform hemostasis analysis on anticoagulated samples under static conditions. In 1984, Gorog and Ahmed developed a test system that analyzed hemostasis function of untreated whole blood under physiological flow (2), a technology potentially useful for assessing patients with bleeding disorders (2)(3). This approach has been automated in a user-friendly benchtop instrument, the Clot Signature Analyzer (CSA®; Xylum Corp.). From a single venipuncture, the CSA provides information on platelet adhesion induced by high shear, platelet aggregation, and coagulation attributable to humoral factors (4). Measurements are performed on untreated nonanticoagulated whole blood under the physiological conditions of nonrecirculating flow at 37 °C. The single-use, disposable CSA cassette consists of two perfusion channels, the “punch” and “collagen” channels. In each channel, blood is perfused in tubing under conditions simulating vascular flow. Blood is drawn into two 3-mL syringes, which are attached to luer fittings on the cassette. When the cassette is loaded onto the instrument, low-density oil is delivered into the syringes from a reservoir on the instrument. The imiscible oil rises in the syringes and displaces the blood, which then flows into perfusion lines maintained at 37 °C. The luminal pressure exerted by the flowing blood is measured continuously in both channels by sensors on the instrument. In the punch channel, vascular injury is simulated by piercing the …