(S-193) Hipp, R.F., Monday 9:15

TITLE: COMPARATIVE NEUTRALIZATION OF LMWH USING PROTAMINE AND HEPARINASE IN WHOLE BLOOD

AUTHORS: Andreas Calatzis1, Omar Iqbal2, Jaweed Fareed2, Elmar Entholzner3, Stefan R. Hargasser3, Rudolf F. Hipp, Prof3
AFFILIATION: 1Ludwigs Maximilians Universität München, München, Germany; 2Loyola University Medical Center, Maywood, IL; 3Technische Universität München, München, Germany.

Low molecular weight heparins are routinely used for prevention and management of thromboembolic disorders. Because of new high-dose indications, their longer halftime in comparison to unfractionated heparin and their limited neutralization by protamine improved methods of antagonization are of high interest. In this study we compared in vitro in whole blood the possibilities to antagonize high dosages of LMWH using protamine and heparinase.
METHODS: Citrated blood was drawn from 4 healthy volun- teers. Whole blood coagulation was analyzed on three roTEG analyzer systems (a thrombelastographic system with 4 channels and automatic analysis, Nobis, Endingen, Germany). Various doses of certoparine (Novartis), protamine (Roche), Heparinase (IBEX) were added to citrated blood (0.3 ml/test). Coagulation was started by addition of CaCl2 (StartTEG, Nobis) and ellagic acid (Actin, Dade-Behring). Simultaneously the following tests were performed (all concentrations: [/ml]):

a) control

h) + 5 aXa U

b) + 1.25 aXa U

+ 5 U Protamine

c) + 2.5 aXa U

i) + 5 aXa U

d) + 5 aXa U

+ 2.5 U Protamine

e) + 5 aXa U

j) + 5 aXa U

+ 0.05 U Heparinase

+ 1.25 U Protamine

f) + 5 aXa U

k) + 0.05 U Heparinase

+ 0.025 U Heparinase

l) + 5 U Protamine

g) + 5 aXa U

  

+ 0.0125 U Heparinase

  

RESULTS: Coagulation times (average)

a) 215 ± 28 sec

g) 246% of control

b) 384% of control

h) 1496% of control

c) 833% of control

i) 708 % of control

d) no clotting

j) no clotting

e) 153% of control

k) 97% of control

f) 169% of control

l) 608% of control

INTERPRETATION: As expected, certoparine prolonged coagulation in a concentration dependent manner. All tested dosages of heparinase were able to antagonize 5 aXa U of certoparine, while protamine failed. Heparinase alone has little or no impact on coagulation while protamine if given in excess can inhibit coagulation by itself.
CONCLUSION: Antagonization of LMWH using heparinase may be a promising approach for clinical practice and for future indications where high doses of LMWH will be used.