Summary
A randomised, prospective, placebo-controlled phase III multicentre clinical trial
(KyberSept) has been performed to test the efficacy of high-dose antithrombin therapy
in patients with severe sepsis. Concomitant low-dose heparin has been routinely given
in two thirds of patients for deep vein thrombosis prophylaxis.This study analyses
heparin – antithrombin interactions in terms of long-term mortality, adverse events,
and thromboembolic events. From a total of 2,314 patients with severe sepsis (placebo:
n=1,157; antithrombin: n=1,157) 1,616 patients (placebo: 811, antithrombin: 805) received
heparin concomitantly with study drug (antithrombin 30,000 IU) over four days, whereas
698 patients (346 and 352, respectively) did not. In patients with no concomitant
heparin, 28-day mortality was lower with antithrombin than with placebo (37.8% vs.
43.6%; absolute reduction: 5.8%; risk ratio: 0.860 [0.725–1.019]), which increased
until day-90 (44.9% vs. 52.5%; absolute reduction: 7.6%; risk ratio: 0.851 [0.735–0.987]).
In patients with concomitant heparin, no effect of antithrombin on mortality was seen
(28-day mortality: 39.4% vs. 36.6%; absolute increase: 2.8%; risk ratio: 1.08 [0.96–1.22]).
Frequency of use of concomitant heparin increased during conduct of the study. Increased
bleeding incidences were reported with antithrombin plus concomitant heparin as compared
to antithrombin alone. Rates of thromboembolic events were similar when antithrombin
was given with or without concomitant heparin. In the treatment of severe sepsis,
high-dose antithrombin may sufficiently protect against development of venous thromboembolism
when no concomitant heparin is given. Combined administration of the two increases
bleeding risk and probably abolishes efficacy of antithrombin.
Keywords
Heparin - antithrombin III - severe sepsis - bleeding - survival