Studies on Increased Heparin Resistance Measured by the Plasma Heparin Thrombin Time

Abstract

SummaryIncreased heparin resistance was found to remain unchanged in BaSO4-adsorbed plasma, but disappeared following adsorption with large quantities of Al(OH)3. The factor V content in the plasma could be considerably reduced without any alteration in the heparin resistance. Antihaemophilic globulin exerted no influence upon the heparin thrombin time. Tissue thromboplastin in quantities sufficient to accelerate the clotting of recalcified plasma considerably, did not affect the heparin thrombin time. Plasma thromboplastin had no antiheparin effect. Increased heparin resistance was — although usually less marked — still demonstrable in most cases in plasma defibrinated with thrombin from patients with a greatly shortened heparin thrombin time, but not in cases of less pronounced shortening. Fibrinogen prepared by the freeze-thaw technique from normal plasma and patient plasma showed no difference in reactivity to heparin and thrombin. In experiments on plasma mixtures, a shortening of the heparin thrombin time was still demonstrable at the ratio 9 parts of normal plasma to 1 part of plasma from patients with greatly increased heparin resistance. The antithrombin content of plasma was not reduced in increased heparin resistance.

The Antiheparin Effect of α₁-Acid Glycoprotein and Platelet Material, Evaluated by the Heparin Thrombin Clotting Time

“…Increased heparin tolerance is regularly seen during the acute stage of inflammatory and degenerative diseases, i.e., conditions associated with increased frequency of thrombo embolic complications [7,10,11].…”

Reduction of Heparin Activity by Plasma Globulins in Patients with Increased Heparin Resistance

“…These findings correspond to previous studies by the present author which have shown that a heparin resistance increased in relation to nor mal, determined by the heparin thrombin time, remained quanti tatively unchanged following adsorption. Thus, the values for the heparin thrombin time on BaS04-adsorbed oxalated plasma cor responded in all essentials to the values found on untreated citrated plasma (8).…”

“…

Previous papers have dealt with the increased heparin resis tance (in the form of a plasma heparin thrombin time shortened in relation to normal) observed in certain conditions,especially acute coronary occlusion and postoperatively (7,9). In the present study precipitation with ammonium sulphate was used to obtain plasma proteins from patients with increased heparin re sistance in order to investigate whether these proteins, when added to normal plasma, influenced the heparin thrombin time and the heparin clotting time.

Methods and Materials

A detailed description of the methods and materials has been rendered elsewhere (6,7,8).

The heparin thrombin time was determined as described previously (6).

…”

Heparin Resistance (Measured by the Heparin Thrombin Time) and Plasma Fibrinogen in Various Diseases

“…The heparin thrombin time was determined as described elsewhere (6,8). Principle: 0.2 ml platelet-poor citratcd plasma is incubated for 3 min.…”