Monitoring of heparin therapy during cardiopulmonary bypass by using three different devices that measure the activated clotting time

Abstract number: P1601

Paniccia R., Pretelli P., Stefano P. L., Costanzo M., Bandinelli B., Conti A. A., Attanasio M., Pieralli M., Abbate R., Gensini G. F., Prisco D., Paniccia R., Pretelli P., Stefano P. L., Costanzo M., Bandinelli B., Conti A. A., Attanasio M., Pieralli M., Abbate R., Gensini G. F., Prisco D.

University of Florence, Italy; Unviersity of Florence, Italy

The activated clotting time (ACT), performed by point-of-care instruments, is the method traditionally used to monitor heparin treatment during cardiopulmonary by pass (CPB). A new device, Hemochron Junior II (HJII – International Technidyne Corp., USA), which measures ACT by the use of cartridges containing a mixture of silica, kaolin and phospholipids, has recently become available. A 20-µL blood drop is loaded and flowed into capillaries and when blood flow stops the device records clotting formation. ACTII (Medtronic, USA) is a second system commercially available for ACT determinations, which uses cuvettes preloaded with kaolin and records clotting formation with a mechanical detector. A third point-of-care instrument, Sonoclot analyzer (SIENCO Inc, USA), measures blood viscoelastic properties, but among other specific parameters, it provides also a celite-ACT (SonACT). Aim of this study was to compare the performances of these 3 devices in the determination of ACT. One hundred 11 samples from 16 CPB patients were obtained throughout the surgical procedure. All samples were assayed in duplicate with two different HJII instruments and one fold with Sonoclot; 60 samples were also performed in duplicate by one ACTII device. A significant correlation was observed between ACT values obtained with the two HJII (r = 0.99; P < 0.001) and the duplicates obtained with ACTII (r = 0.84; P < 0.001). Bland and Altman analysis revealed a good performance for both systems (P < 0.001), although ACT values obtained by ACTII were more scattered. Significant correlations were found between ACT values obtained with different devices: HJII vs. Sonoclot, r = 0.92, P < 0.001; HJII vs. ACTII r = 0.91; P < 0.001; ACT II vs. Sonoclot (r = 0.91; P < 0.001). In conclusion a significant relationship exists among ACT values obtained with the three systems employed in this study.