Aprotinin does not prolong the Sonoclot aprotinin-insensitive activated clotting time

Abstract

Study Objective To determine whether a new Sonoclot-based, aprotinin-insensitive activated clotting time (aiACT) assay yields stable results over a broad range of aprotinin concentrations. Design Prospective trial conducted on in vitro blood samples. Setting Tertiary-care teaching medical center. Participants 19 healthy adult volunteers. Interventions Whole blood samples were collected from volunteers. Heparin (2 U/mL) and escalating concentrations of aprotinin of 160 to 500 kallikrein inhibitory units (KIU)/mL were added in vitro. Measurements and Main Results Celite ACT, kaolin ACT, and aiACT assays were completed. The aiACT showed stable activated clotting time (ACT) results on heparinized, noncitrated blood with added aprotinin ( P = nonsignificant). In contrast, celite ACT and kaolin ACT were greatly prolonged when aprotinin was added to heparinized, noncitrated, and citrated blood ( P < 0.05). The aiACT had consistent results at all aprotinin concentrations ( P = nonsignificant). Conclusions Aprotinin (160, 320, and 500 KIU/mL) significantly prolongs the ACT value with celite and kaolin activators but not with the aprotinin-insensitive activator.