- under 18 years old - pregnant women - known allergy to heparin - participant in another clinical trial that is not approved for joint enrollment. - aptt> 120 seconds, not due to anticoagulant therapy. - platelet count <20 x 109 per l - lung bleeding. - uncontrolled bleeding - advanced neurological impairment - advanced oncological disease

- under 18 years old - pregnant women - known allergy to heparin - participant in another clinical trial that is not approved for joint enrollment. - aptt> 120 seconds, not due to anticoagulant therapy. - platelet count <20 x 109 per l - lung bleeding. - uncontrolled bleeding - advanced neurological impairment - advanced oncological disease