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.