Heparin treatment of microangiopathic haemolytic anaemia associated with an experimental tumour.

In rats bearing the solid Walker 256 carcinosarcoma microangiopathic haemolytic anaemia (MHA) developed during the course of tumour growth. A phase of hypercoagulability was followed by a significant decrease in plasma fibrinogen, platelet count and antithrombin III. A diminished haematocrit and a rise in plasma haemoglobin and schistocyte count were accompanied by fibrin deposits in the tumour vessels. When the rats were treated with heparin during the growth of the Walker tumour, both DIC and MHA were prevented except of the last period of the experiment. The tumour sizes, however, did not differ in the controls and the heparinized animals. There is a fair amount of evidence to suggest that the MHA was induced by a tumour-dependent DIC which was blocked by heparin over a certain time period. In contrast, the tumour growth was not modified by effective suppression of DIC and MHA.