The treatment of deep vein thrombosis in a person with pancytopenia is the same as the treatment in someone with normal blood parameters. Anemia and leucopenia don’t cause any problem in anticoagulation. Thrombocytopenia, if severe, increases the risk of bleeding complications; but it’s a risk you have to take. Not treating an acute DVT with anticoagulant can cause far bigger problems than possible bleeding after anticoagulation in a patient with thrombocytopenia. Having said that, in order to minimize the risk of bleeding, it’s prudent to keep the INR or PTT close to the lower level of the therapeutic range. Even if bleeding complications force you to stop anticoagulant therapy after a few days or weeks, the risk of recurrent thrombosis or extension of thrombosis is still less than if you had never anticoagulated. This is because the initial heparin therapy would have neutralized the activated clotting factors that often drive the extension of the thrombus.