* renal insufficiency with a gfr\<15 ml/min/1.73m² * acute kidney injury kdigo3 * prophylactic dose of low molecular weight heparin for more than 3 days * curative dose of low molecular weight heparin for more than 1 day * recurrent catheter/hemodialysis access thromboses * ecmo required in the next 24h * contraindication to low molecular weight heparin * high bleeding risk (e.g. uncontrolled severe systemic hypertension, recent major bleeding, disseminated intravascular coagulopathy, thrombocytopenia \< 75g/l) * history of heparin-induced thrombocytopenia * contraindication to blood-derived products * impossibility to perform a doppler ultrasound of the lower limbs (e.g. above the knee amputation, severe burn injuries) * expected death in the next 48h * vulnerable subjects according to articles l. 1121-5, l. 1121-7 et l1121-8 of french public health code

* renal insufficiency with a gfr\<15 ml/min/1.73m² * acute kidney injury kdigo3 * prophylactic dose of low molecular weight heparin for more than 3 days * curative dose of low molecular weight heparin for more than 1 day * recurrent catheter/hemodialysis access thromboses * ecmo required in the next 24h * contraindication to low molecular weight heparin * high bleeding risk (e.g. uncontrolled severe systemic hypertension, recent major bleeding, disseminated intravascular coagulopathy, thrombocytopenia \< 75g/l) * history of heparin-induced thrombocytopenia * contraindication to blood-derived products * impossibility to perform a doppler ultrasound of the lower limbs (e.g. above the knee amputation, severe burn injuries) * expected death in the next 48h * vulnerable subjects according to articles l. 1121-5, l. 1121-7 et l1121-8 of french public health code

- renal insufficiency with a gfr<15 ml/min/1.73m² - acute kidney injury kdigo3 - prophylactic dose of low molecular weight heparin for more than 3 days - curative dose of low molecular weight heparin for more than 1 day - recurrent catheter/hemodialysis access thromboses - ecmo required in the next 24h - contraindication to low molecular weight heparin - high bleeding risk (e.g. uncontrolled severe systemic hypertension, recent major bleeding, disseminated intravascular coagulopathy, thrombocytopenia < 75g/l) - history of heparin-induced thrombocytopenia - contraindication to blood-derived products - impossibility to perform a doppler ultrasound of the lower limbs (e.g. above the knee amputation, severe burn injuries) - expected death in the next 48h - vulnerable subjects according to articles l. 1121-5, l. 1121-7 et l1121-8 of french public health code

- renal insufficiency with a gfr<15 ml/min/1.73m² - acute kidney injury kdigo3 - prophylactic dose of low molecular weight heparin for more than 3 days - curative dose of low molecular weight heparin for more than 1 day - recurrent catheter/hemodialysis access thromboses - ecmo required in the next 24h - contraindication to low molecular weight heparin - high bleeding risk (e.g. uncontrolled severe systemic hypertension, recent major bleeding, disseminated intravascular coagulopathy, thrombocytopenia < 75g/l) - history of heparin-induced thrombocytopenia - contraindication to blood-derived products - impossibility to perform a doppler ultrasound of the lower limbs (e.g. above the knee amputation, severe burn injuries) - expected death in the next 48h - vulnerable subjects according to articles l. 1121-5, l. 1121-7 et l1121-8 of french public health code