High and low molecular weight heparins do not modify red blood cell aggregability in vitro

The usefulness of heparins as anticoagulants has been demonstrated, but the ir effects on hemorheological parameters, such as erythrocyte aggregability , are under discussion. If the heparins had adverse effect on erythrocyte a ggregability, its use would be especially undesirable in patients with path ologies involving red blood cell hyperaggregability as is the case of cardi ac disease. In the present study we examine the in vitro effect of unfracti onated and fractionated heparins on red blood cell aggregability. The resul ts show that heparins do not increase this rheological parameter but show a slight tendency to lower it.