[Comparative study of heparin and a very low molecular-weight heparin in hemodialysis in chronic renal insufficiency]. / Etude comparative de l'héparine et d'une héparine de très faible masse moléculaire en hémodialyse dans l'insuffisance rénale chronique.

In the course of dialysis sessions, we have compared the antithrombotic effect of two heparinization regimens: low molecular weight heparin (CY 222, mean molecular weight: 2,500, Institute Choay, France): 90 anti-Xa units/kg bodyweight as a bolus injection followed by a continuous infusion of 1,000 anti-Xa units/hour (regimen 1); or 300 anti-Xa units/kg as a bolus injection (regimen 3), with a standard heparinization regimen (100 IU/kg regimen 2). Eight patients received the 3 regimens successively. Factor IIa and factor Xa inactivation was measured by a method that uses chromogenic substrates. The frequency of adverse effects, ultrafiltration rates, creatinine and BUN clearances of the 3 regimens were similar, whereas dialyser blood loss was higher in the first regimen. At the dose of 300 anti-Xa units of CY 222 (regimen 3), inactivation of factor Xa was similar to Xa inhibition reached through the conventional treatment (regimen 2) but IIa inhibition was less pronounced.