Control of Heparin Treatment with three Different Methods. Behaviour of Antithrombin III

Abstract

In 63 plasma samples from patients under heparin we determined the heparin concentration using the chromogenic substrats S-2222 (COATEST Heparin). Thrombin time (TT), activated partial thromboplastin time (APTT), antithrombin III activity (ATIIIact) and concentration (ATIIIimm) were also measured. A good correlation was found between heparin concentration and TT (r= .850, p< .001), heparin concentration and APTT (r =669, p < .001) while the correlation coefficient r between TT and APLT was .896 (p< .001).We found a statilttically significant reduction of ATIIIact with increasing APTT (p < .05. The ATIIIact and ATIIIimm values were also lower (p < .001) in the overanticoaculated group (n=ll) than in the group with insufficient heparinisation (0.18). The mean (±SO) heparin concentration in 12 plasmas with both TT and APTT in the therapeutic range was .54 (±.15) USP-U/al, very similar to that of 13 plasma (.68 ± .46 U/al) insufficiently heparinised accordirig to the APTT. However, the TT recognised then as correctly anticoagulated. Regarding these findings and our good experience without complication by monitoring heparin therapy with TT we assume that TT is more accurate than APTT for this aim.